Post by: Alberto-Girardi on 05/13/2021 07:01 pm
https://twitter.com/nextspaceflight/status/1392915876643438592
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Post by: Herb Schaltegger on 05/13/2021 07:14 pm
Post by: VaBlue on 05/13/2021 07:16 pm
I like the plan, but do wish they could find a way to try to save some Raptors. But, in the big scheme, these Raptors have already been written off in the name of forward testing...
Post by: vaporcobra on 05/13/2021 07:19 pm
Quote
The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate approximately 170 seconds into flight. The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying between the Florida Straits. It will achieve orbit until performing a powered, targeted landing approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing.
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021
Post by: uhuznaa on 05/13/2021 07:29 pm
https://twitter.com/nextspaceflight/status/1392915876643438592
Finally we know something!!!
Why they aren't going to attempt a landing on the pad?
Expecially for the raptors.
Is possible that some agency denied a ground landing attempt for SH? IMO it is possible, because the flight profile will prove a complete RTLS?
Could, if they splash down softly, the SH and the SS be recovered and inspected? (obviusly salt water will prevent any reuse).
BTW, this is my 307th post. Thanks to everyone of this beautiful community!
Main reason for the booster not returning will be that it has no legs to land on and the catching tower isn't ready. They also will want to test/demonstrate to have good enough control to nail a precise pad/tower landing. With the ship a landing on the pad would require it coming in over Mexico and Texas after one orbit which would be a bit much to risk on the first orbital flight...
They will to have either recover or scuttle both stages if they survive the splashdown, I guess. Recovery won't be easy though. There's also a very real chance of the ship not making it through all phases of reentry. In fact I would be surprised if it would.
"Objectives
SpaceX intends to collect as much data as possible during flight to quantify entry dynamics
and better understand what the vehicle experiences in a flight regime that is extremely
difficult to accurately predict or replicate computationally. This data will anchor any changes in vehicle design or CONOPs after the first flight and build better models for us to use in our internal simulations."
Post by: Lars-J on 05/13/2021 07:30 pm
Post by: Alberto-Girardi on 05/13/2021 07:46 pm
Post by: Coastal Ron on 05/13/2021 07:48 pm
As I’ve been telling anyone who will listen. They are going to willfully expend shiny new hardware until they’re confident they won’t expend their shiny new GSE.
Can you expand this a little?
I'm assuming they are willing to expend the first SS/SH because they don't have an easy way to land them yet.
How are you thinking GSE fits into this? Concern about landing back at the pad at doing a RUD?
Post by: schuttle89 on 05/13/2021 07:51 pm
Is there any chanche to see SS flip, if it makes through reentry, via a non SpaceX camera?
Almost certainly not so hopefully they'll broadcast it and it'll be a clear day.
Post by: equiserre on 05/13/2021 07:53 pm
https://twitter.com/nextspaceflight/status/1392915876643438592
Finally we know something!!!
Why they aren't going to attempt a landing on the pad?
Expecially for the raptors.
Is possible that some agency denied a ground landing attempt for SH? IMO it is possible, because the flight profile will prove a complete RTLS?
Could, if they splash down softly, the SH and the SS be recovered and inspected? (obviusly salt water will prevent any reuse).
BTW, this is my 307th post. Thanks to everyone of this beautiful community!
this is great!!
It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
As for Starship, they have a lot of things to validate, so let´s be patient. They already did the powered landing thing!
Post by: AndyH on 05/13/2021 07:54 pm
It's the same pattern Spacex used with Falcon 9, and even then there was drone ship damage in the early years.As I’ve been telling anyone who will listen. They are going to willfully expend shiny new hardware until they’re confident they won’t expend their shiny new GSE.
Can you expand this a little?
I'm assuming they are willing to expend the first SS/SH because they don't have an easy way to land them yet.
How are you thinking GSE fits into this? Concern about landing back at the pad at doing a RUD?
ETA:
https://youtu.be/CQnR5fhCXkQ
https://www.youtube.com/watch?v=bvim4rsNHkQ
Post by: DavP on 05/13/2021 07:56 pm
Anyway, great news to see some information about this test. Let's if it occurs in July but I don't think so
Post by: snotis on 05/13/2021 07:59 pm
NSF Threads for Starship Orbital - First Flight : Discussion (https://forum.nasaspaceflight.com/index.php?topic=53846)
NET July 2021 using Starship SN20 and Superheavy BN3 from OLP at Starbase, TX.
FCC documents:
Starship Orbital - First Flight FCC Exhibit (https://apps.fcc.gov/els/GetAtt.html?id=273481&x&fbclid=IwAR2XT71AP8jewZ1HnrIrPUAyt7upANm0C771rQWhs3xoHCz3he3l1bIiucU)
Quote
Flight Profile
The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate
approximately 170 seconds into flight. The Booster will then perform a partial return and land in the
Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying
between the Florida Straits. It will achieve orbit until performing a powered, targeted landing
approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing.
Quote
Event Timelines
Event T+ time (seconds) Liftoff 0 MECO 169 Stage Separation 171 SES 176 Booster Touchdown 495 SECO 521 Ship Splashdown 5420
Quote
Objectives
SpaceX intends to collect as much data as possible during flight to quantify entry dynamics
and better understand what the vehicle experiences in a flight regime that is extremely difficult
to accurately predict or replicate computationally. This data will anchor any changes in vehicle
design or CONOPs after the first flight and build better models for us to use in our internal
simulations
Post by: capoman on 05/13/2021 08:03 pm
Very cool. What I find interesting is that the staging is later than anticipated, MECO seems to be about 20-30 seconds later than F9. Although it is possible that once the booster does a full boost-backs to the launch pad they will end up staging earlier.
Agreed, I think the late MECO will be due to having a minimal amount of Raptors on SH, and is a good thing since they intend expend. They obviously don't have or don't plan to use legs on it, or they might consider having it attempt to land on drone ship. If they are going to try to catch without testing on legs on early versions, that's pretty bold. Makes you wonder how many they will be willing to throw away... They should get good data on precision landing though, even over water. Might also act as a demo for FAA approval to land as well.
Post by: meekGee on 05/13/2021 08:06 pm
So... SpaceX has filed for an FCC STA for the first "Starship Orbital test flight", NET June 20th, 2021.QuoteThe Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate approximately 170 seconds into flight. The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying between the Florida Straits. It will achieve orbit until performing a powered, targeted landing approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing.
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021
... leaving very little time for #16 and #17... and if #15 flies again, even more so. So clearly some adjustments are forthcoming...
Post by: ugordan on 05/13/2021 08:09 pm
It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
Post by: wannamoonbase on 05/13/2021 08:09 pm
That orbital launch mount and heat shield facility in FL are going to be so important now.
It’s full speed ahead now, but if it happens anytime before the end of the year it’s an incredible accomplishment.
Post by: kevinof on 05/13/2021 08:12 pm
Inclined to agree. This is aggressive which is not unusual for SpaceX. I’ll be happy it reaches and completes staging. Everything else is gravy.It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
Post by: timmccloud on 05/13/2021 08:19 pm
Quote
Who has make this plan? What is the FCC?
The FCC is the Federal Communications Commission, and SpaceX has to get permission to use their telemetry channels every time a prototype rocket is launched. Eventually they get license to use the channels when the rocket moves from the experimental stage and becomes fully functional rocket.
Post by: meekGee on 05/13/2021 08:19 pm
It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
I don't see why if there's a chance it will explode on ascent then they shouldn't worry about the case where it doesn't...
F9 and FH first flights didn't fail on ascent, right? How about older EELVs? Saturn? STS?
Post by: scr00chy on 05/13/2021 08:24 pm
Post by: capoman on 05/13/2021 08:24 pm
Inclined to agree. This is aggressive which is not unusual for SpaceX. I’ll be happy it reaches and completes staging.It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
Agreed as well, although staging will be something they are familiar with and likely has a reasonable chance of success. It's just a matter of scale. Reentry however is a totally different story. I suspect it has a high probability of failure.
Looking at the document it doesn't exactly say but it looks like Starlink is going to involved in the telemetry streams. No surprise though since they first did that with SN15.
Post by: Toast on 05/13/2021 08:26 pm
Post by: jimvela on 05/13/2021 08:27 pm
Post by: Curriston on 05/13/2021 08:28 pm
Post by: nacnud on 05/13/2021 08:30 pm
Any chance the mysterious missing drone ship is in Hawaii somewhere?
A shortfall of gravitas is in Louisiana
Post by: Negan on 05/13/2021 08:38 pm
Post by: FutureSpaceTourist on 05/13/2021 08:38 pm
Leaving in missions for now; easy to move later if it’s decided this thread sits better in the SS section with the other test flight threads.
Post by: neoforce on 05/13/2021 08:40 pm
This document says they will land the booster in the Gulf, it specifically mentions a water landing for Starship, but Heavy it just says land in the Gulf? They could tow one of the barges over from the cape and have it on hand to recover the booster if they want to try? But then maybe this first booster will not have as many Raptors, but the Gulf is pretty shallow, I would expect some other country might just want to try and come recover those engines if left in the Gulf? No matter what they do, they have a lot of building to do on the launch pad in the next 60 days, going to be exciting!!!
I was wondering this as well... The wording in the doc is:
Quote
The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship ... off the northwest coast of Kauai in a soft ocean landing.
"land" vs "soft ocean landing"
For this filing do they need to be specific? Could they be considering ASOG, Phobos or Deimos to land the booster?
Post by: niwax on 05/13/2021 08:45 pm
Reading those FCC exhibits, it says "Booster Touchdown" vs "Ship Splashdown" in the event timelines. Correct me if I'm wrong, but I'm reading that as saying they're going to expend the Starship prototype (or at best fish it out of the ocean), but they're going to attempt to land the booster. Is it looking like the Phobos/Deimos platforms will be ready by June?
I guess they wouldn't need much of the pad infrastructure on a platform to support landings. Any chance they might only outfit one of them for launches and the other one for landings?
Post by: neoforce on 05/13/2021 08:52 pm
So I assume there will be other filings for things like requesting NOTAMs etc?
Would any of the filings require SpaceX to be specific that they are attempting a landing on a platform in the gulf vs just a controlled landing into the ocean and expending the SuperHeavy?
Post by: mark_m on 05/13/2021 08:53 pm
Reading those FCC exhibits, it says "Booster Touchdown" vs "Ship Splashdown" in the event timelines. Correct me if I'm wrong, but I'm reading that as saying they're going to expend the Starship prototype (or at best fish it out of the ocean), but they're going to attempt to land the booster. Is it looking like the Phobos/Deimos platforms will be ready by June?Also, the FCC document specifically says, "a soft ocean landing", which seems pretty unambiguous. It seems the plan is to pretend the ocean is a hard surface, practice landing, then softly sink/fall over, just like the initial Falcon 9 landing tests.
Edit: For Starship, I mean. It does sound like the booster will attempt a landing on Phobos/Deimos. Exciting times!
Post by: nacnud on 05/13/2021 08:54 pm
Reading those FCC exhibits, it says "Booster Touchdown" vs "Ship Splashdown" in the event timelines. Correct me if I'm wrong, but I'm reading that as saying they're going to expend the Starship prototype (or at best fish it out of the ocean), but they're going to attempt to land the booster. Is it looking like the Phobos/Deimos platforms will be ready by June?
I guess they wouldn't need much of the pad infrastructure on a platform to support landings. Any chance they might only outfit one of them for launches and the other one for landings?
I can think of lots of possible combinations of launching and landing sites. The question that needs to be answered before these can be narrowed down is will the booster ever have legs?
Post by: DavP on 05/13/2021 08:55 pm
Post by: Rocket Surgeon on 05/13/2021 08:58 pm
Sorry, I'm a bit newbie at this. Who has make this plan? What is the FCC?
Anyway, great news to see some information about this test. Let's if it occurs in July but I don't think so
Well this isn't so much who they have to make the plan with but they need to inform the FCC, Federal Communications Commission, of any broadcasting during any flight.
Hence why they've filed this plan with the FCC.
We tend to get most of our information from either them, or enviromental assessment really :D
Post by: lrk on 05/13/2021 09:00 pm
Post by: Vikranth on 05/13/2021 09:04 pm
Also will they be testing the R-Vacs for the first time in Orbit?
Post by: 2megs on 05/13/2021 09:07 pm
Can this actually complete a full orbit? Looking at the times (SECO @ 521, Ship Splashdown @ 5420) I'm having a hard time seeing how they launch from Boca Chica, orbit all the way around past Boca Chica, and then make it another 300 degrees around to Kauai.
Assuming the answer is "No, it doesn't go all the way around"... Will this achieve orbital velocity and then do a de-orbit burn? Or will it just be a very long ballistic trajectory? (The lack of a second burn of the second stage would suggest it's the later.)
Post by: ugordan on 05/13/2021 09:08 pm
Post by: Coopman0 on 05/13/2021 09:10 pm
Post by: ugordan on 05/13/2021 09:14 pm
Will this Starship have a heatshield on it?
It better if they're really planning on a "soft ocean landing".
Post by: snotis on 05/13/2021 09:15 pm
Will this Starship have a heatshield on it?
Post by: DaveS on 05/13/2021 09:18 pm
Admittedly, I only have a KSP-level knowledge of orbital mechanics, so please gently educate me if I'm wrong here.Remember, they're last east-ward, so you're going to pass over Kauai first before making landfall over CONUS and heading back over TX.
Can this actually complete a full orbit? Looking at the times (SECO @ 521, Ship Splashdown @ 5420) I'm having a hard time seeing how they launch from Boca Chica, orbit all the way around past Boca Chica, and then make it another 300 degrees around to Kauai.
Assuming the answer is "No, it doesn't go all the way around"... Will this achieve orbital velocity and then do a de-orbit burn? Or will it just be a very long ballistic trajectory? (The lack of a second burn of the second stage would suggest it's the later.)
Post by: nacnud on 05/13/2021 09:18 pm
So , since it's getting real , What could be the final orbit of Starship after insertion. Will they keep it low to minimise TPS heating for the time being , also since the landing (or splashdown) is 90 minutes after liftoff , from Boca TX to Hawaii in eastward direction could mean the it will complete a single orbit before re-entering.
Also will they be testing the R-Vacs for the first time in Orbit?
I think the flight will be suborbital, but only just, like a shuttle eternal tank. Then you can target the landing zone even if the raptors fail to complete the deorbit burn.
Edit: Also starship landing occurs at T+90 minuets, so exactly like an ET
Post by: mmonce on 05/13/2021 09:35 pm
Post by: AC in NC on 05/13/2021 09:35 pm
Doesn't sound like there's going to be any booster hops. ;D
You got lucky on that one. The argument was still wrong 2 or more years ago when SS was carbon composite. :P
Post by: Jeff Lerner on 05/13/2021 09:40 pm
Post by: Lars-J on 05/13/2021 09:40 pm
I think it will be fully orbital. And it is going further than the ET… that impacted in the Indian Ocean.So , since it's getting real , What could be the final orbit of Starship after insertion. Will they keep it low to minimise TPS heating for the time being , also since the landing (or splashdown) is 90 minutes after liftoff , from Boca TX to Hawaii in eastward direction could mean the it will complete a single orbit before re-entering.
Also will they be testing the R-Vacs for the first time in Orbit?
I think the flight will be suborbital, but only just, like a shuttle eternal tank. Then you can target the landing zone even if the raptors fail to complete the deorbit burn.
Edit: Also starship landing occurs at T+90 minuets, so exactly like an ET
Post by: jimvela on 05/13/2021 09:44 pm
If they splash Starship, how will they be able to see how well the complete set of tiles performed ??..presumably they will be damaged on impact with the water ...
If it survives entry to the point where it hits the water more or less intact, then the biggest test of whether the heatshield will work at all is answered.
I'd imagine they would have observing assets in place to try and assess the reentry as well.
Post by: scr00chy on 05/13/2021 09:45 pm
If they splash Starship, how will they be able to see how well the complete set of tiles performed ??..presumably they will be damaged on impact with the water ...
If they actually get to the landing part, that will mean the tiles worked. That's probably good enough for the first ever reentry attempt.
Post by: nacnud on 05/13/2021 09:46 pm
I think it will be fully orbital. And it is going further than the ET… that impacted in the Indian Ocean.
True, I wonder how much it would fly a lofted re-entry to reduce max heating temperature or a depressed entry to reduce heating time.
I'm guessing a lofted reentry, which would lengthen the flight distance, but its just a guess.
Post by: 2megs on 05/13/2021 09:49 pm
Admittedly, I only have a KSP-level knowledge of orbital mechanics, so please gently educate me if I'm wrong here.Remember, they're last east-ward, so you're going to pass over Kauai first before making landfall over CONUS and heading back over TX.
Can this actually complete a full orbit? Looking at the times (SECO @ 521, Ship Splashdown @ 5420) I'm having a hard time seeing how they launch from Boca Chica, orbit all the way around past Boca Chica, and then make it another 300 degrees around to Kauai.
Assuming the answer is "No, it doesn't go all the way around"... Will this achieve orbital velocity and then do a de-orbit burn? Or will it just be a very long ballistic trajectory? (The lack of a second burn of the second stage would suggest it's the later.)
I thought that was what I was saying?
Headed east from Boca Chica, Kauai is about 294 degrees around the earth, plus another 22.5 degrees for the rotation of the earth during those 5420 seconds. A just-barely-sub-orbital ballistic trajectory can get them there very naturally in that timeline.
But there's no trajectory that can complete a full orbit (i.e. 360 degrees east from Boca to go past Boca again), and then go another 294 + 22.5 degrees east to Kauai, and still fit that timeline.... right?
So I'm assuming this can't complete a full orbit. IMO that's for the best on the first flight, no risk of stranding a Starship in a low unstable orbit, re-entering at an unpredictable place.
(If I'm wrong here, help me understand what the orbit could be.)
Post by: oldAtlas_Eguy on 05/13/2021 09:51 pm
Post by: nacnud on 05/13/2021 09:54 pm
The FCC doc specifically states orbit not suborbital. As well as a reentry burn executed by the SS.
Thanks, didn't realise there was a PDF as well, only saw the tweet!
Post by: Lars-J on 05/13/2021 09:55 pm
Admittedly, I only have a KSP-level knowledge of orbital mechanics, so please gently educate me if I'm wrong here.Remember, they're last east-ward, so you're going to pass over Kauai first before making landfall over CONUS and heading back over TX.
Can this actually complete a full orbit? Looking at the times (SECO @ 521, Ship Splashdown @ 5420) I'm having a hard time seeing how they launch from Boca Chica, orbit all the way around past Boca Chica, and then make it another 300 degrees around to Kauai.
Assuming the answer is "No, it doesn't go all the way around"... Will this achieve orbital velocity and then do a de-orbit burn? Or will it just be a very long ballistic trajectory? (The lack of a second burn of the second stage would suggest it's the later.)
I thought that was what I was saying?
Headed east from Boca Chica, Kauai is about 294 degrees around the earth, plus another 22.5 degrees for the rotation of the earth during those 5420 seconds. A just-barely-sub-orbital ballistic trajectory can get them there very naturally in that timeline.
But there's no trajectory that can complete a full orbit (i.e. 360 degrees east from Boca to go past Boca again), and then go another 294 + 22.5 degrees east to Kauai, and still fit that timeline.... right?
So I'm assuming this can't complete a full orbit. IMO that's for the best on the first flight, no risk of stranding a Starship in a low unstable orbit, re-entering at an unpredictable place.
(If I'm wrong here, help me understand what the orbit could be.)
My assumption is that Starship will reach orbital velocity, but will not complete a full orbit. (if that makes sense - similar to Gagarin's flight)
And with the total flight time being ~90 minutes, it makes sense. The first 9-10 minutes is just acceleration to orbital speed. Which leaves 80 mins afterwards, and then subtract the re-entry slowdown time. It seems to add up.
Post by: neoforce on 05/13/2021 09:55 pm
The FCC doc specifically states orbit not suborbital. As well as a reentry burn executed by the SS.
Thanks, didn't realise there was a PDF as well, only saw the tweet!
PDF doesn't explicitly say re-entry burn:
Quote
It will achieve orbit until performing a powered, targeted landing
Post by: joek on 05/13/2021 09:56 pm
If they splash Starship, how will they be able to see how well the complete set of tiles performed ??..presumably they will be damaged on impact with the water ...If it survives entry to the point where it hits the water more or less intact, then the biggest test of whether the heatshield will work at all is answered.
I'd imagine they would have observing assets in place to try and assess the reentry as well.
Agree. Expect both SH booster and SS will end up in the water. These are pathfinders. SpaceX does not need to recover them intact (as much as that might be desirable) to get much of the data they need to proceed to the next step... for which intact recovery will be the next step.
Patience everyone. Simply getting SH/SS launched and SS into an orbital reentry profile is a giant step forward.
Post by: Lars-J on 05/13/2021 09:58 pm
If they splash Starship, how will they be able to see how well the complete set of tiles performed ??..presumably they will be damaged on impact with the water ...If it survives entry to the point where it hits the water more or less intact, then the biggest test of whether the heatshield will work at all is answered.
I'd imagine they would have observing assets in place to try and assess the reentry as well.
Agree. Expect both SH booster and SS will end up in the water. These are pathfinders. SpaceX does not need to recover them intact (as much as that might be desirable) to get much of the data they need to proceed to the next step... for which intact recovery will be the next step.
Yes. But I fully expect there to be boats in both places ready to safe/recover/scuttle landed hardware that is bobbing around in the ocean.
Post by: Barry Brisco on 05/13/2021 09:58 pm
Is there any chanche to see SS flip, if it makes through reentry, via a non SpaceX camera?There won’t be any non-SpaceX cameras out in the ocean 100kM northwest of Kauai. My guess is that a Starlink antenna will be installed on the SS and the flight will be live streamed.
The SN15 test flight appears to be the first time the vehicle had a Starlink antenna in place. The stream certainly did not work very well, but the problems should be correctable.
Post by: joek on 05/13/2021 10:00 pm
...
But there's no trajectory that can complete a full orbit (i.e. 360 degrees east from Boca to go past Boca again), and then go another 294 + 22.5 degrees east to Kauai, and still fit that timeline.... right?
So I'm assuming this can't complete a full orbit. IMO that's for the best on the first flight, no risk of stranding a Starship in a low unstable orbit, re-entering at an unpredictable place.
...
Correct. However, they do not necessarily need to complete a full orbit to get the data they need (at least at this point).
Post by: Lars-J on 05/13/2021 10:01 pm
Is there any chanche to see SS flip, if it makes through reentry, via a non SpaceX camera?There won’t be any non-SpaceX cameras out in the ocean 100kM northwest of Kauai. My guess is that a Starlink antenna will be installed on the SS and the flight will be live streamed.
The SN15 test flight appears to be the first time the vehicle had a Starlink antenna in place. The stream certainly did not work very well, but the problems should be correctable.
There will likely by assets in the air (from NASA or contracted) to image the re-entry, even if it is not streamed live. Dragon 1 re-entry footage was captured from the Hawaii area.
Post by: oldAtlas_Eguy on 05/13/2021 10:01 pm
Post by: AC in NC on 05/13/2021 10:13 pm
OK Orbit but one that is just barely such that it will rapidly decay to the point it will reenter around Kauji. If on the way up it is off target (this is just a few 10s of m/s) then it will either splash before or after Kuaji into the Pacific somewhere.
I can't reconcile "achieve orbit" with rapidly decaying around T+90mins. That just doesn't compute for me. Achieving Orbit necessarily means a full once-around.
"until performing a powered, targeted landing" suggests to me that they would achieve a meaningful orbit insertion and then perform a deorbit burn, or perhaps even a deorbit-acceleration burn to test EDL at a higher than orbital velocity.
Post by: 2megs on 05/13/2021 10:16 pm
...
But there's no trajectory that can complete a full orbit (i.e. 360 degrees east from Boca to go past Boca again), and then go another 294 + 22.5 degrees east to Kauai, and still fit that timeline.... right?
So I'm assuming this can't complete a full orbit. IMO that's for the best on the first flight, no risk of stranding a Starship in a low unstable orbit, re-entering at an unpredictable place.
...
Correct. However, they do not necessarily need to complete a full orbit to get the data they need (at least at this point).
Certainly. It's worth pointing out that even if they don't complete an orbit, they can exceed orbital speed (a scalar quantity) for atmospheric re-entry purposes, but not achieve an orbital velocity (a vector with a direction as well as a magnitude) that would take them around the earth.
Post by: nacnud on 05/13/2021 10:18 pm
edit: velocity != speed, doh
Post by: Jcc on 05/13/2021 10:34 pm
Is there any chanche to see SS flip, if it makes through reentry, via a non SpaceX camera?
I bet NASA would like to track it from the air, like they did the first Starship 10Km flight
Post by: joek on 05/13/2021 10:35 pm
Will this Starship have a heatshield on it?It better if they're really planning on a "soft ocean landing".
Agree. And if anyone remembers, the specific verbiage in the FAA launch license way-back for F9 (LLS 17-096 (https://www.faa.gov/about/office_org/headquarters_offices/ast/licenses_permits/media/Final_LLS%2017-096%20-%20Vandenberg%20-%20License%20Mod%20(Iridium-7)_11_27_2018.pdf)) was (emphasis added):
Quote
... Flight includes landing of the Falcon 9 first stage either on a droneship in the ocean or in the ocean. ...
Post by: OneSpeed on 05/13/2021 10:46 pm
OK Orbit but one that is just barely such that it will rapidly decay to the point it will reenter around Kauji. If on the way up it is off target (this is just a few 10s of m/s) then it will either splash before or after Kuaji into the Pacific somewhere.
I can't reconcile "achieve orbit" with rapidly decaying around T+90mins. That just doesn't compute for me. Achieving Orbit necessarily means a full once-around.
"until performing a powered, targeted landing" suggests to me that they would achieve a meaningful orbit insertion and then perform a deorbit burn, or perhaps even a deorbit-acceleration burn to test EDL at a higher than orbital velocity.
This is not a very hi-res image, but the orbit *looks* circular.
Edit: Changed my mind. Entry appears to be at around 70km altitude if it is 100km from Kauai. It could be ballistic.
Post by: daavery on 05/13/2021 10:48 pm
QuoteWho has make this plan? What is the FCC?
The FCC is the Federal Communications Commission, and SpaceX has to get permission to use their telemetry channels every time a prototype rocket is launched. Eventually they get license to use the channels when the rocket moves from the experimental stage and becomes fully functional rocket.
actually for now commercial space needs an STC for every flight becuase commercial rocket comms are not a class of operation that is in the regs yet
Post by: Orbiter on 05/13/2021 10:50 pm
Post by: Lars-J on 05/13/2021 10:58 pm
This is going to be such a wild launch. Do we know how many Raptors BN3 will have? We're talking about a liftoff thrust that at minimum will rival the Saturn V.
Oh it should exceed it by some margin, unless they launch both Starship and SuperHeavy partially filled (allowing them to use fewer raptors).
This could be the first flight test of Raptor-Vacuum. Unless they do a high sub-orbital attempt with SN2X - which is possible since Vacuum Raptor can be fired at sea level. But this aggressive time schedule suggests they may opt to go directly orbital. But they could also do both...
Post by: beentheredengthat on 05/13/2021 11:04 pm
Booster first flight, MAX Q, MECO, separation, (vac raps?), Full suite of heat tiles, Reentry heating
I'm going to need a party thread to discuss this one.
Post by: DistantTemple on 05/13/2021 11:11 pm
The choice of "100kM northwest of Kauai" is likely deliberate to make such observation flights easier! If SX has a flexible launch window, crews and planes can be on standby, and have a comfortable 90 mins to (finish their tea,) get airborne, travel 100km or so and climb to observation station..... adjusting for trajectory etc.... And SX personnel can also be on hand.Is there any chanche to see SS flip, if it makes through reentry, via a non SpaceX camera?There won’t be any non-SpaceX cameras out in the ocean 100kM northwest of Kauai. My guess is that a Starlink antenna will be installed on the SS and the flight will be live streamed.
The SN15 test flight appears to be the first time the vehicle had a Starlink antenna in place. The stream certainly did not work very well, but the problems should be correctable.
There will likely by assets in the air (from NASA or contracted) to image the re-entry, even if it is not streamed live. Dragon 1 re-entry footage was captured from the Hawaii area.
Also apart from Cuba South Africa (Namibia and Botswana) and Papa New Guinea (interesting?), there is no land at all on the great circle, until you overshoot and hit Mexico. So there is the lowest possible chance of dropping on anyone if below the expected trajectory.
Post by: Framryk on 05/13/2021 11:18 pm
Post by: raivo45 on 05/13/2021 11:21 pm
Post by: wannamoonbase on 05/13/2021 11:21 pm
What a huge leap!
Booster first flight, MAX Q, MECO, separation, (vac raps?), Full suite of heat tiles, Reentry heating
I'm going to need a party thread to discuss this one.
Yeah the full heat shield, that's going to be the interesting pucker item on teh flight.
Maybe it's wrong to assume that I expect the booster to execute it's full flight and test objectives on the first flight out. Why not, it's only more capable than a Saturn V!
Post by: rpapo on 05/13/2021 11:32 pm
Very cool. What I find interesting is that the staging is later than anticipated, MECO seems to be about 20-30 seconds later than F9. Although it is possible that once the booster does a full boost-backs to the launch pad they will end up staging earlier.Idea: SH is stainless steel. F9 is Al. SH should be able to tolerate reentry heating better than F9. Unless the engine compartment cannot handle it.
Post by: DistantTemple on 05/13/2021 11:36 pm
Reading Eric Berger's excellent book (https://forum.nasaspaceflight.com/index.php?topic=52010.0), I note the early history of SpaceX used Kwajalein Atoll (and specifically, Omelek Island) during the Falcon 1 days. Does this and the associated ballistic missile tracking capability on the islands aid in following the first Starship orbit? Is this on the track from a Boca Chica launch to NW Kauai splashdown? (I'd love to simulate the flight path but don't have the skill or software!)Yes that makes logical sense. Kwajalein Atoll seems to be about 100km from the track of the apparent SS "orbit". Perfect
Post by: chopsticks on 05/13/2021 11:38 pm
"until performing a powered, targeted landing" suggests to me that they would achieve a meaningful orbit insertion and then perform a deorbit burn, or perhaps even a deorbit-acceleration burn to test EDL at a higher than orbital velocity.
While this would be cool and a proper definition of being in orbit, I'm quite doubtful that perigee will extend beyond the atmosphere for this flight. Starship would have to reorient itself retrograde and perform a deorbit burn (not a small thing to ask on its maiden flight in space) then reorient itself again prograde for re-entry. This would have to be done in a timely manner with not much room for error. I don't know, it just seems like a large risk item for the first flight, and given the global reaction of the Long March 5B re-entry, I have a hard time believing that a low orbit like this would have to be reliant on a deorbit burn for the first flight.
Post by: DecoLV on 05/13/2021 11:49 pm
given the global reaction of the Long March 5B re-entry, I have a hard time believing that a low orbit like this would have to be reliant on a deorbit burn for the first flight.
Not only that, but as you inferred, the plan basically rules out entry concerns by overflight countries...including the US! The agency with the most concerns is the FAA not the FCC. And if there is no overflight and no land landing at all by either booster or Starship,those safety and environmental concerns become pretty moot for this flight, don't they!? ;)
Post by: Nascent Ascent on 05/14/2021 12:03 am
Post by: Rocket Surgeon on 05/14/2021 12:32 am
Though I'll admit, I'm a little surprised they don't even seem interested in recovery... not even going to try and land the SH on a drone ship? Maybe even if they did land it, it would be too much effort at this point to properly secure it and return it to port and they can learn enough from a 'disposable' flight. (I am hesitant to say 'expendable' as they are choosing to get rid of these stages)
Post by: Negan on 05/14/2021 12:38 am
Doesn't sound like there's going to be any booster hops. ;D
You got lucky on that one. The argument was still wrong 2 or more years ago when SS was carbon composite. :P
Musk announced they were going to stainless in January 2019. There is no argument anymore. I was right.
Super Heavy will hop because there's every reason for it to do so and no reasons not. How much it hops is a separate question. Arguing otherwise is silly. Arguing otherwise without an argument is Trolling. Be silly. Don't be a Troll.
Post by: AndrewRG10 on 05/14/2021 12:49 am
How about launching a Crew Dragon just a bit later in order to shadow and photograph the partial orbit and re-entry
Sounds very expensive. Cheaper to launch a Falcon 9 with literally nothing but a camera on the second stage. If they want a picture of Starship on orbit, I don't see why they couldn't have a camera which is ejected from starship and sends the images back as it floats away.
Post by: StefsEngineering on 05/14/2021 01:17 am
Post by: wannamoonbase on 05/14/2021 01:26 am
So this is interesting and seems to imply they're just gonna get rid of the SS and SH at the end of the flight.
Though I'll admit, I'm a little surprised they don't even seem interested in recovery... not even going to try and land the SH on a drone ship? Maybe even if they did land it, it would be too much effort at this point to properly secure it and return it to port and they can learn enough from a 'disposable' flight. (I am hesitant to say 'expendable' as they are choosing to get rid of these stages)
You’re assuming the vehicles survive.
There is very little experience with boosters this size (none) and
Starship entry decent and landing is not probable.
They can gather almost all the data in disposable mode. Once it survives then maybe the authorities will allow the 100 ton super sonic projectile to fly over land.
Also, looks like they are going to land 20 miles out. Maybe ASOG will get an early assignment 🤪
Post by: lrk on 05/14/2021 01:35 am
Post by: AC in NC on 05/14/2021 01:47 am
Doesn't sound like there's going to be any booster hops. ;D
You got lucky on that one. The argument was still wrong 2 or more years ago when SS was carbon composite. :P
Musk announced they were going to stainless in January 2019. There is no argument anymore. I was right.Super Heavy will hop because there's every reason for it to do so and no reasons not. How much it hops is a separate question. Arguing otherwise is silly. Arguing otherwise without an argument is Trolling. Be silly. Don't be a Troll.
Damn. I misremembered the timing of that argument.
I can only say that I guess I (and others) couldn't conceptualize at the time how cheap stainless could be.
Post by: oldAtlas_Eguy on 05/14/2021 01:51 am
Don't feel to bad. Even as little as 5 months ago. The consensus was BN1 would do a hotfire test. BN2 would do a hop. And BN3 would go to orbit.Doesn't sound like there's going to be any booster hops. ;D
You got lucky on that one. The argument was still wrong 2 or more years ago when SS was carbon composite. :P
Musk announced they were going to stainless in January 2019. There is no argument anymore. I was right.Super Heavy will hop because there's every reason for it to do so and no reasons not. How much it hops is a separate question. Arguing otherwise is silly. Arguing otherwise without an argument is Trolling. Be silly. Don't be a Troll.
Damn. I misremembered the timing of that argument.
I can only say that I guess I (and others) couldn't conceptualize at the time how cheap stainless could be.
SpaceX decided to skip to 3. Go to ORBIT.
Post by: Lars-J on 05/14/2021 01:57 am
Unless plans have changed yet again, SH boosters are designed to be caught and won't have legs. Adding legs for a one-off downrange landing test seems like a waste of engineering effort.
The only caveat that I would make is that the booster pieces at Boca Chica continue to be labeled with images that show booster legs.
So I would not rule it out. In fact I still believe there will be booster hops with legs until catching is deemed possible by the booster showing the detailed aiming capacity.
Whether those hops end at the landing pad next to the launch pad or an ocean platform is another matter. And such hops could happen both before and after this planned orbital flight.
Post by: AC in NC on 05/14/2021 02:02 am
Don't feel to bad. Even as little as 5 months ago. The consensus was BN1 would do a hotfire test. BN2 would do a hop. And BN3 would go to orbit.
SpaceX decided to skip to 3. Go to ORBIT.
I don't. My recollection is the only argument he put forth was "but F9" which is an entirely different argument than "cheap".
F9 had customers paying the freight for landing tests. SS was never going to have that out of the gate. He still got lucky in that SS was so cheap that they could throw them (and Raptors) away on their own dime. Negan (as I recall) didn't believe that (or at least ever put it out as an argument).
Post by: chopsticks on 05/14/2021 02:33 am
Another thing I thought I would point out is to explore why SH is supposed to land where it is. There could be a few reasons for this. GSE: catching tower not ready or risk is too high, or: environmental concerns. If SH reenters offshore, the sonic boom should not be too noticeable from land, correct? The boom will be substantial, and I don't believe the environmental assessment allows yet for sonic booms at Boca Chica. Correct me if I'm wrong. Also, given that the landing location is not too far from land, the boostback burn can be attempted without actually landing back at the launch site. This is genius. By landing close(ish) to shore, it also put SH (or its remains) close to the SpX Texas team. I like this idea.
Post by: Zed_Noir on 05/14/2021 03:00 am
Reading Eric Berger's excellent book (https://forum.nasaspaceflight.com/index.php?topic=52010.0 (https://forum.nasaspaceflight.com/index.php?topic=52010.0)), I note the early history of SpaceX used Kwajalein Atoll (and specifically, Omelek Island) during the Falcon 1 days. Does this and the associated ballistic missile tracking capability on the islands aid in following the first Starship orbit? Is this on the track from a Boca Chica launch to NW Kauai splashdown? (I'd love to simulate the flight path but don't have the skill or software!)Yes that makes logical sense. Kwajalein Atoll seems to be about 100km from the track of the apparent SS "orbit". Perfect
How about the uninhabited Johnston Atoll that have a runway and a post super-fund area. Is it close to the flight path?
Johnston Atoll is where they disposed the remaining stock of U.S. chemical agents/weapons by incineration in the late 1990s.
Post by: Negan on 05/14/2021 03:00 am
Don't feel to bad. Even as little as 5 months ago. The consensus was BN1 would do a hotfire test. BN2 would do a hop. And BN3 would go to orbit.
SpaceX decided to skip to 3. Go to ORBIT.
I don't. My recollection is the only argument he put forth was "but F9" which is an entirely different argument than "cheap".
F9 had customers paying the freight for landing tests. SS was never going to have that out of the gate. He still got lucky in that SS was so cheap that they could throw them (and Raptors) away on their own dime. Negan (as I recall) didn't believe that (or at least ever put it out as an argument).
I argued that getting to orbit ASAP was more important than doing hops with SH. Considering the HLS situation I could very well be correct.
Can't really comment on cost because I have no idea how the cost of expending a orbital booster compares to the cost of a successful SH hop (which I feel would be highly probable). I would imagine a SH hop would be considerably less.
Just for the record, I never doubted Musk's statements about stainless or Raptor cost.
Edit: Plus as other people pointed out we really don't know if the SH is going to be expendable yet.
Also: Also I have no way to gauge what SpaceX is willing to throw away to try to even come up with such an argument after all the time an effort they went through to recover fairings.
Post by: Robotbeat on 05/14/2021 03:22 am
So this is interesting and seems to imply they're just gonna get rid of the SS and SH at the end of the flight.Wait, where did you get THAT idea for Super Heavy? The FCC document says it will land, and do a "touchdown"! (Unlike the "soft ocean landing" for Starship.)
Though I'll admit, I'm a little surprised they don't even seem interested in recovery... not even going to try and land the SH on a drone ship? Maybe even if they did land it, it would be too much effort at this point to properly secure it and return it to port and they can learn enough from a 'disposable' flight. (I am hesitant to say 'expendable' as they are choosing to get rid of these stages)
Sounds like they'll try to recover the Super Heavy, probably on a droneship (Phobos?), for all those Raptors if nothing else. Starship might possibly be recovered (ala Electron for study) but not for reuse.
Post by: RotoSequence on 05/14/2021 03:27 am
Don't feel to bad. Even as little as 5 months ago. The consensus was BN1 would do a hotfire test. BN2 would do a hop. And BN3 would go to orbit.
SpaceX decided to skip to 3. Go to ORBIT.
I don't. My recollection is the only argument he put forth was "but F9" which is an entirely different argument than "cheap".
F9 had customers paying the freight for landing tests. SS was never going to have that out of the gate. He still got lucky in that SS was so cheap that they could throw them (and Raptors) away on their own dime. Negan (as I recall) didn't believe that (or at least ever put it out as an argument).
I argued that getting to orbit ASAP was more important than doing hops with SH. Considering the HLS situation I could very well be correct.
Can't really comment on cost because I have no idea how the cost of expending a orbital booster compares to the cost of a successful SH hop (which I feel would be highly probable). I would imagine a SH hop would be considerably less.
Just for the record, I never doubted Musk's statements about stainless or Raptor cost.
Edit: Plus as other people pointed out we really don't know if the SH is going to be expendable yet.
Also: Also I have know way to gauge what SpaceX is willing to throw away to try to even come up with such an argument after all the time an effort they went through to recover fairings.
SpaceX has not flown any Starship hardware more than once, notwithstanding Starhopper. I think they figure the trend is likely to continue as their highly immature designs are built, obsoleted before they fly, and dramatically improved with what they learn with each flight. Even if they did land the first Superheavy, it would never fly again. This is probably true of the next several Superheavies, as well.
Post by: Negan on 05/14/2021 03:51 am
I think they figure the trend is likely to continue as their highly immature designs are built, obsoleted before they fly, and dramatically improved with what they learn with each flight. Even if they did land the first Superheavy, it would never fly again. This is probably true of the next several Superheavies, as well.
So kind of mirroring F9 development.
Post by: Robotbeat on 05/14/2021 05:13 am
The difference with Super Heavy is there are a LOT of Raptors on there. Fine if they don't fly the booster again, but they'd probably like all those Raptors back!Don't feel to bad. Even as little as 5 months ago. The consensus was BN1 would do a hotfire test. BN2 would do a hop. And BN3 would go to orbit.
SpaceX decided to skip to 3. Go to ORBIT.
I don't. My recollection is the only argument he put forth was "but F9" which is an entirely different argument than "cheap".
F9 had customers paying the freight for landing tests. SS was never going to have that out of the gate. He still got lucky in that SS was so cheap that they could throw them (and Raptors) away on their own dime. Negan (as I recall) didn't believe that (or at least ever put it out as an argument).
I argued that getting to orbit ASAP was more important than doing hops with SH. Considering the HLS situation I could very well be correct.
Can't really comment on cost because I have no idea how the cost of expending a orbital booster compares to the cost of a successful SH hop (which I feel would be highly probable). I would imagine a SH hop would be considerably less.
Just for the record, I never doubted Musk's statements about stainless or Raptor cost.
Edit: Plus as other people pointed out we really don't know if the SH is going to be expendable yet.
Also: Also I have know way to gauge what SpaceX is willing to throw away to try to even come up with such an argument after all the time an effort they went through to recover fairings.
SpaceX has not flown any Starship hardware more than once, notwithstanding Starhopper. I think they figure the trend is likely to continue as their highly immature designs are built, obsoleted before they fly, and dramatically improved with what they learn with each flight. Even if they did land the first Superheavy, it would never fly again. This is probably true of the next several Superheavies, as well.
Post by: Surfdaddy on 05/14/2021 05:31 am
So this is interesting and seems to imply they're just gonna get rid of the SS and SH at the end of the flight.
Though I'll admit, I'm a little surprised they don't even seem interested in recovery... not even going to try and land the SH on a drone ship? Maybe even if they did land it, it would be too much effort at this point to properly secure it and return it to port and they can learn enough from a 'disposable' flight. (I am hesitant to say 'expendable' as they are choosing to get rid of these stages)
We saw F9 first stages crash onto the drone ship and cause some damage. Seems that the much higher mass SH booster would be a substantial risk to a drone ship. Not all that surprising that they would want at least one dress rehearsal landing on water before risking a ship.
Post by: joek on 05/14/2021 05:32 am
The difference with Super Heavy is there are a LOT of Raptors on there. Fine if they don't fly the booster again, but they'd probably like all those Raptors back!But do they need all of them for this test? (Certainly a high fidelity test with everything all-up would be desirable.)
Post by: FutureSpaceTourist on 05/14/2021 05:35 am
Quote
Starship to do an orbital flight from Texas to Hawaii. 🤯🤯🤯 @elonmusk
https://twitter.com/elonmusk/status/1393064162335485952
Quote
3/4 of the way around the Earth
Post by: joek on 05/14/2021 05:46 am
We saw F9 first stages crash onto the drone ship and cause some damage. Seems that the much higher mass SH booster would be a substantial risk to a drone ship. Not all that surprising that they would want at least one dress rehearsal landing on water before risking a ship.
Likely depends on how much confidence they have dealing with off-nominal landing situations. We have seen F9 boosters divert-abort (from drone ship) when it puts the drone ship at risk. If they think they have that covered, expect they might go for it.
Post by: Robotbeat on 05/14/2021 05:48 am
Again, nothing in the FCC thing suggest they will be dumping the SH booster into the drink. It suggest the opposite.So this is interesting and seems to imply they're just gonna get rid of the SS and SH at the end of the flight.
Though I'll admit, I'm a little surprised they don't even seem interested in recovery... not even going to try and land the SH on a drone ship? Maybe even if they did land it, it would be too much effort at this point to properly secure it and return it to port and they can learn enough from a 'disposable' flight. (I am hesitant to say 'expendable' as they are choosing to get rid of these stages)
We saw F9 first stages crash onto the drone ship and cause some damage. Seems that the much higher mass SH booster would be a substantial risk to a drone ship. Not all that surprising that they would want at least one dress rehearsal landing on water before risking a ship.
Post by: FutureSpaceTourist on 05/14/2021 06:02 am
Quote
And of course the landing is targetted and controlled, but there will be no landing barge, I'm, not sure if that means they'll tow it back or sink it. Given that it's [Starship] gone through reentry there's lots of value in looking at it. (assuming it doesn't break up)
https://twitter.com/elonmusk/status/1393083299526889473
Quote
We need to make sure ship won’t break up on reentry, hence deorbit over Pacific
Post by: tater on 05/14/2021 06:03 am
Again, nothing in the FCC thing suggest they will be dumping the SH booster into the drink. It suggest the opposite.
Exactly.
Starship says "splashdown" and the booster says "touchdown." That can't be accidental.
Post by: su27k on 05/14/2021 06:22 am
Again, nothing in the FCC thing suggest they will be dumping the SH booster into the drink. It suggest the opposite.
They'll probably expend the first few SuperHeavy boosters, this is in the latest NSF Starship article (https://www.nasaspaceflight.com/2021/05/sn15s-success-spacex-next-steps-orbital-goals/):
Quote
The Launch Tower will also sport a crane for mating Starship atop Super Heavy and eventually large mechanical arms that will “catch” the booster when it returns to the launch site.
The latter is not expected to occur during the first few flights, likely resulting in SpaceX undertaking the path it used during the first Falcon 9 booster landings, with a soft touchdown on water.
Same info from reddit sources, they'll probably only fly 16 to 18 Raptors per booster, so not a big loss, they pancaked 12 Raptors just to figure out belly flop.
Post by: steveleach on 05/14/2021 07:44 am
I wonder if SpaceX make things deliberately ambiguous and then sit around laughing at all the arguments that result on forums like this ;DAgain, nothing in the FCC thing suggest they will be dumping the SH booster into the drink. It suggest the opposite.
Exactly.
Starship says "splashdown" and the booster says "touchdown." That can't be accidental.
Post by: Slarty1080 on 05/14/2021 08:40 am
New vehicle and all that must introduce a degree of risk, but I'm not sure its that great a risk. They should be able to model the landing fairly well by now and in general it should be a lot easier to land Superheavy than Falcon 9 as they have the ability to hover SH unlike F9.So this is interesting and seems to imply they're just gonna get rid of the SS and SH at the end of the flight.
Though I'll admit, I'm a little surprised they don't even seem interested in recovery... not even going to try and land the SH on a drone ship? Maybe even if they did land it, it would be too much effort at this point to properly secure it and return it to port and they can learn enough from a 'disposable' flight. (I am hesitant to say 'expendable' as they are choosing to get rid of these stages)
We saw F9 first stages crash onto the drone ship and cause some damage. Seems that the much higher mass SH booster would be a substantial risk to a drone ship. Not all that surprising that they would want at least one dress rehearsal landing on water before risking a ship.
Post by: Star One on 05/14/2021 08:45 am
Or they will just task a commercial reconnaissance satellite to do the job.How about launching a Crew Dragon just a bit later in order to shadow and photograph the partial orbit and re-entry
Sounds very expensive. Cheaper to launch a Falcon 9 with literally nothing but a camera on the second stage. If they want a picture of Starship on orbit, I don't see why they couldn't have a camera which is ejected from starship and sends the images back as it floats away.
Post by: Humuku on 05/14/2021 08:56 am
Post by: libra on 05/14/2021 08:58 am
It imaged Columbia back in 2003 (sigh :( how far in time does that sounds) - it could certainly image an even larger Starship.
Post by: DreamyPickle on 05/14/2021 08:59 am
Post by: uhuznaa on 05/14/2021 09:04 am
Again, nothing in the FCC thing suggest they will be dumping the SH booster into the drink. It suggest the opposite.
Exactly.
Starship says "splashdown" and the booster says "touchdown." That can't be accidental.
This is just an FCC document, don't read too much into these words. Heck, in the image in this document the ship even has windows...
Post by: Jarnis on 05/14/2021 09:56 am
I can't believe they are going to attempt this. All the hardware for BN2 and SN20 is at most a few stacked barrels, how are they going to weld them into a full stack in a few months?
Just like they welded BN1 and SN15 in just a few months.
I'm far more worried about the obital launch pad infrastructure and July is obviously an optimistic target, but launch this year seems pretty likely.
Post by: CMac on 05/14/2021 10:19 am
Post by: nacnud on 05/14/2021 10:29 am
They might reduce suborbital testing and focus on getting the orbital facility up and running. All hands on new facility?
Building stainless starship skins is one set of skills,
Building steel framed buildings is another set of skills,
Building ground support equipment and plumbing is another set of skills,
as is building rocket engines, and software, etc
So all these things can happen in parallel.
Post by: capoman on 05/14/2021 12:06 pm
Not sure a hop of SH would tell them much. It’s really just a larger version of SN5 or 6, and the early hops were really about testing Raptor, plumbing and avionics. SH is just stretched version of SN5 and SN6.
Primary goals for this mission are likely:
SS and SH stacking and integration
SH launch and staging
SS reentry and heatshield testing
Secondary goals are likely:
Boost back and targeted return using grid fins for SH, likely on water
Targeted soft landing on water
Not sure what they might do about potential recovery. Safing the vehicles for recovery, partial recovery or sampling heatshield e.g. may be problematic. Might end up as target practice.
Post by: spacenut on 05/14/2021 12:14 pm
Post by: kevinof on 05/14/2021 12:22 pm
Would they have one of the platforms ready to put out in the Gulf for the SH landing?
Post by: CorvusCorax on 05/14/2021 12:27 pm
Doubt it. Nowhere near finished and also needs propulsion, control and positioning. Think they are at least 8/12 months from having anything near that.Would they have one of the platforms ready to put out in the Gulf for the SH landing?
The platforms in question already have propulsion, control and positioning, that comes standard with free floating oil platforms. All they need to do is remove all the stuff so there's a clear, level deck.
Like this:
https://twitter.com/Herbo/status/1392556639434256390
Post by: kevinof on 05/14/2021 12:30 pm
Last I heard their "oil rigs" were still getting taken apart and a long way from being ready for sea.
Doubt it. Nowhere near finished and also needs propulsion, control and positioning. Think they are at least 8/12 months from having anything near that.Would they have one of the platforms ready to put out in the Gulf for the SH landing?
The platforms in question already have propulsion, control and positioning, that comes standard with free floating oil platforms. All they need to do is remove all the stuff so there's a clear, level deck.
Like this:
https://twitter.com/Herbo/status/1392556639434256390
Post by: RocketLover0119 on 05/14/2021 12:38 pm
There is still a lot of things to be done enforce this happens. Table needs to be brought over to the launch site, some more GSE tanks need to be rolled out (not completely sure if ALL the GSE tanks are needed for the first flight), tower needs to be ready, stacking (which can go pretty quickly once it starts) needs to happen. Obviously, not a small list, however, this is SpaceX, and I’m confident July is a month they can meet.
As far as recovery ops are concerned, everything makes sense. Don’t want to risk the pad or anything nearby, so offshore landings are smart.
I think once this flight happens, the cadence will sky rocket.
Also, seeing this thread in the “missions” section makes it seem a lot more real! ;D
Post by: kevinstout on 05/14/2021 12:40 pm
Post by: Tommyboy on 05/14/2021 12:51 pm
Post by: Alvian@IDN on 05/14/2021 01:11 pm
It surprises me that nobody has mentioned that an other launch is also scheduled for NET July 20th. I wonder which one will get more media attention should they both occur on that day.Where can I find it in the filings?
Post by: steveleach on 05/14/2021 01:22 pm
Doubt it. Nowhere near finished and also needs propulsion, control and positioning. Think they are at least 8/12 months from having anything near that.If it's ready (by any definition of "ready"), they'll probably land on it; if it's not, they'll soft land on the water. No need to stick rigidly to a pre-defined plan.Would they have one of the platforms ready to put out in the Gulf for the SH landing?
All IMHO, of course.
Post by: su27k on 05/14/2021 01:26 pm
It surprises me that nobody has mentioned that an other launch is also scheduled for NET July 20th. I wonder which one will get more media attention should they both occur on that day.
July who? :D
I think it's safe to say there's very little chance Starship will actually launch in July, so Blue Origin is pretty safe from being overshadowed.
Post by: cdebuhr on 05/14/2021 01:30 pm
It surprises me that nobody has mentioned that an other launch is also scheduled for NET July 20th. I wonder which one will get more media attention should they both occur on that day.A humble suggestion .... instead of "that other launch", please just specify which launch you're talking about (ideally with a reference). The latter would make you seem helpful and informative, the former conjures an image of "Nah nah nah nah! I know something you don't know!!" from the lips of a bratty child.
Please note that I am unequivocally not saying that is how you intended this to come across, it's just the first thing that came to mind as I wondered what mission you were talking about. Id really appreciate it if you could enlighten me!
Post by: Robotbeat on 05/14/2021 02:11 pm
Even odds that Blue also is delayed. Blue has been promising “crewed launch next year” for a long time.It surprises me that nobody has mentioned that an other launch is also scheduled for NET July 20th. I wonder which one will get more media attention should they both occur on that day.
July who? :D
I think it's safe to say there's very little chance Starship will actually launch in July, so Blue Origin is pretty safe from being overshadowed.
I would say it’s an even race at this point.
Post by: chief on 05/14/2021 02:11 pm
But do they? Were they fixed platforms or station keeping and if the latter, do they still have all the gear to sit active in one spot?
They are semi-subs not fixed platforms, and they were photographed (see Jack Beyer's twitter feed in January) with their thrusters stowed on board to allow them to be towed into port. Perhaps they will still be far from ready for any function in July.
Deimos & Phobos thread: https://forum.nasaspaceflight.com/index.php?topic=52841
Post by: chopsticks on 05/14/2021 02:16 pm
It surprises me that nobody has mentioned that an other launch is also scheduled for NET July 20th. I wonder which one will get more media attention should they both occur on that day.A humble suggestion .... instead of "that other launch", please just specify which launch you're talking about (ideally with a reference). The latter would make you seem helpful and informative, the former conjures an image of "Nah nah nah nah! I know something you don't know!!" from the lips of a bratty child.
Please note that I am unequivocally not saying that is how you intended this to come across, it's just the first thing that came to mind as I wondered what mission you were talking about. Id really appreciate it if you could enlighten me!
I agree. Please don't be vague.
I believe this is the launch that is being referred to.
https://nextspaceflight.com/launches/details/6779
1st crewed flight of Blue Origin's New Shepard.
Post by: Robotbeat on 05/14/2021 02:20 pm
Similar height as a Falcon 9 booster, so for the same stability, the landing footprint would be about the same. The weight of the booster shouldn’t be too much for the barge. Although it might be a bit of a hazard to have such a huge booster with crew on board trying to secure it. But 20 miles off the coast of Texas should have much calmer waters than the middle of the Atlantic, so that would help keep it safer.
It seems more Starshippy to try to sprint to get Phobos finished in time, but I’m not sure it’s really that feasible.
My real opinion is they haven’t actually decided yet to splash SH or land it on some droneship (ASDS or Phobos), and so they wrote the FCC document to keep open all those possibilities (to spur their crew to work more quickly if nothing else).
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
Post by: FutureSpaceTourist on 05/14/2021 02:25 pm
Quote
SpaceX's FCC flight plan yesterday is one piece of the regulatory puzzle before Starship's orbital flight.
The FAA today notes "SpaceX must meet all licensing requirements before Starship/Super Heavy can launch," with an environmental review ongoing.
https://www.faa.gov/space/stakeholder_engagement/spacex_starship/
Post by: kaiser on 05/14/2021 02:58 pm
At Kauai, they have PMRF and its big dishes on the ridge. Those are good, but are still horizon limited. You have KTF, ran by the DOE with it's dishes also. Between the two you have more than enough antennas to bring down the TM while you're above the horizon to Kauai.
If you need to grab stuff form over-the-horizon, you have the MATSS barge, which can provide some TM and optics from over the horizon. It can get fairly far off shore, but not too far. I'm not sure that would be far enough for all the coverage, but could gap-fill some. It also gets a lot of use, and scheduling can be tricky.
Then there's the Pacific Collector / Pacific Tracker that MDA has to put ships out in the ocean for collecting TM/radar. Those should be able to be dotted along the trajectory if needed. But they're MDA assets, and I assume scheduling them might be hard. Similarly with the KMRSS, Cobra King/Ball, the support ship Trident uses, etc. They'll all be hard to schedule for this, and make sure they're available for what's probably a moving-window test.
There's attempting to use Elon's plane again...but they never really got any decent sized antenna on it.
Commercially, there's not really many people. These guys do both maritime and airborne TM as a service:
https://www.ravendefense.com/maritime-telemetry
https://www.ravendefense.com/airborne-telemetry
Looks like the airborne system is on a BT-67, which has the mounts for an optical turret. So they could provide TM and optics from over the horizon, and even contract some boats to go out and get the coverage they want. Edit: The BT-67 also already has a FTS system onboard. Might be useful, optics/TM/FTS/whatever else they want - https://www.dcmilitary.com/tester/news/local/ww-ii-aircraft-flies-again-for-nawcad/article_6476ae2e-de1d-547b-a93a-8c4b490962db.html
Would be interesting to see where SpaceX ends up here, whether they coordinate with the ranges, MDA, and all the stakeholders to try and get everything out there. Whether they just pay a small commercial entity to go collect, or whether they just roll their own. Last (and least likely in my opinion) is that they wait for it to be within the horizon for Kauai, and accept blackouts. It seems for just a little scratch via a commercial entity they could get more comprehensive coverage, and even provide some angular diversity to the look-angles to mitigate any issues. They could attempt to only user Starlink, but that seems to just add risk onto risk there.
Post by: sebk on 05/14/2021 03:13 pm
Admittedly, I only have a KSP-level knowledge of orbital mechanics, so please gently educate me if I'm wrong here.
Can this actually complete a full orbit? Looking at the times (SECO @ 521, Ship Splashdown @ 5420) I'm having a hard time seeing how they launch from Boca Chica, orbit all the way around past Boca Chica, and then make it another 300 degrees around to Kauai.
Assuming the answer is "No, it doesn't go all the way around"... Will this achieve orbital velocity and then do a de-orbit burn? Or will it just be a very long ballistic trajectory? (The lack of a second burn of the second stage would suggest it's the later.)
So , since it's getting real , What could be the final orbit of Starship after insertion. Will they keep it low to minimise TPS heating for the time being , also since the landing (or splashdown) is 90 minutes after liftoff , from Boca TX to Hawaii in eastward direction could mean the it will complete a single orbit before re-entering.
Also will they be testing the R-Vacs for the first time in Orbit?
I think the flight will be suborbital, but only just, like a shuttle eternal tank. Then you can target the landing zone even if the raptors fail to complete the deorbit burn.
Edit: Also starship landing occurs at T+90 minuets, so exactly like an ET
OK Orbit but one that is just barely such that it will rapidly decay to the point it will reenter around Kauji. If on the way up it is off target (this is just a few 10s of m/s) then it will either splash before or after Kuaji into the Pacific somewhere.
I can't reconcile "achieve orbit" with rapidly decaying around T+90mins. That just doesn't compute for me. Achieving Orbit necessarily means a full once-around.
"until performing a powered, targeted landing" suggests to me that they would achieve a meaningful orbit insertion and then perform a deorbit burn, or perhaps even a deorbit-acceleration burn to test EDL at a higher than orbital velocity.
Once you go beyond 180° around you're essentially orbital: In the sense that your semi-major axis is longer than the planet radius. This also means you have orbital velocity.
Ballistic trajectories end at 180° of the way around.
For example for such a flight an orbit like 270x30km would work well (with perigee around West coast of Mexico). But note that such an orbit has the same energy as 150x150km (I'm assuming spherical Earth for simplicity, real orbit would be a bit different).
And of course they can chose higher orbit and active deorbit.
Post by: CMac on 05/14/2021 04:15 pm
Post by: CMac on 05/14/2021 04:20 pm
Post by: kaiser on 05/14/2021 04:23 pm
how would it work to have a few high altitude blimps in position along track to monitor. Tow them out East from Hawaii and release. Have some station keeping ability. Fairly equatorial so maybe upper level winds not very strong?
Good idea. WorldView did stuff like that, but is struggling/laying off? It seems that the high altitude balloon market enjoyed a renaissance, then is kinda fading away again. Seems like logistics would be weird; how long can it loiter on station (able to take slip days), how many days before hand do you have to deploy it to get in position and verify it's working? Might actually be cheaper to just pay for some flight hours.
These guys seem to be doing "Sky Range" via Reaper and Global Hawk drones, but not positive if it's operational or not, the press release is pretty recent so guessing not yet: https://i3-corps.com/technology-solutions/skyrange/
Post by: Alberto-Girardi on 05/14/2021 05:26 pm
They could actually try landing on one of their regular droneships. They’re building a third one, and so they’ll have a bit of a spare (soonish).
Similar height as a Falcon 9 booster, so for the same stability, the landing footprint would be about the same. The weight of the booster shouldn’t be too much for the barge. Although it might be a bit of a hazard to have such a huge booster with crew on board trying to secure it. But 20 miles off the coast of Texas should have much calmer waters than the middle of the Atlantic, so that would help keep it safer.
It seems more Starshippy to try to sprint to get Phobos finished in time, but I’m not sure it’s really that feasible.
My real opinion is they haven’t actually decided yet to splash SH or land it on some droneship (ASDS or Phobos), and so they wrote the FCC document to keep open all those possibilities (to spur their crew to work more quickly if nothing else).
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
Great point.
IIUC how they land SH and SS doesn't change too much things for FCC. At the end, they bother about communications? Water landing or droneship should not make that much of a difference in this aspect.
WHy did they file a report to the FCC before one to the FAA? Is allowenc from the FCC more important than from FAA or they just take longer to say yes or no? (THis could be a dumb question, but I'm not an expert of USA federal agencies).
Post by: Robotbeat on 05/14/2021 05:35 pm
Post by: Alberto-Girardi on 05/14/2021 05:36 pm
twitter.com/teslaownerssv/status/1392989623169667073QuoteStarship to do an orbital flight from Texas to Hawaii. 🤯🤯🤯 @elonmusk
https://twitter.com/elonmusk/status/1393064162335485952Quote3/4 of the way around the Earth
Why only 3/4 of the orbit? Why to not do 1 orbit + 3/4? Is keeping propellant tmperature the problem because they aren't going to do this?
Post by: JohnM on 05/14/2021 05:39 pm
twitter.com/teslaownerssv/status/1392989623169667073QuoteStarship to do an orbital flight from Texas to Hawaii. 🤯🤯🤯 @elonmusk
https://twitter.com/elonmusk/status/1393064162335485952Quote3/4 of the way around the Earth
Why only 3/4 of the orbit? Why to not do 1 orbit + 3/4? Is keeping propellant tmperature the problem because they aren't going to do this?
They want to test entry, decent and landing. They need to be going at orbital speed for a good reentry test of the tiles. Staying any longer doesn't give them the data they're looking for right now.
Post by: philw1776 on 05/14/2021 05:42 pm
Instead, SpaceX went all Saturn V on us and is going for an all up full stack orbital attempt, albeit with likely fewer SH raptors, maybe ~16 or so.
My recollection is that it is still very shallow 20Km offshore from Boca and having looked at oil platform maps again years ago in the facilities thread, there are no platforms 10s of Km from Boca on ESE track.
Hope for a quick, definitive, positive outcome on the Boca spaceport environmental review, essential for a summer or whenever SH launch from there.
Post by: racevedo88 on 05/14/2021 05:42 pm
More than likely because doing a 1 + 3/4 orbit of the earth changes landing location, incurs in having to support additional tracking ansd support facilities, and bercause it is not necessary for what they want to do
Why only 3/4 of the orbit? Why to not do 1 orbit + 3/4? Is keeping propellant tmperature the problem because they aren't going to do this?
Edit/Lar: Preview exists for a reason. Fix your quotes. My patience is not inexhaustible.
Post by: Alberto-Girardi on 05/14/2021 05:44 pm
Reading Eric Berger's excellent book (https://forum.nasaspaceflight.com/index.php?topic=52010.0 (https://forum.nasaspaceflight.com/index.php?topic=52010.0)), I note the early history of SpaceX used Kwajalein Atoll (and specifically, Omelek Island) during the Falcon 1 days. Does this and the associated ballistic missile tracking capability on the islands aid in following the first Starship orbit? Is this on the track from a Boca Chica launch to NW Kauai splashdown? (I'd love to simulate the flight path but don't have the skill or software!)Yes that makes logical sense. Kwajalein Atoll seems to be about 100km from the track of the apparent SS "orbit". Perfect
How about the uninhabited Johnston Atoll that have a runway and a post super-fund area. Is it close to the flight path?
Johnston Atoll is where they disposed the remaining stock of U.S. chemical agents/weapons by incineration in the late 1990s.
It is far from Kuai, but IMO not impossible to reach for SS. The point is if to get to it they need to overfly some territory on ascent. Moreover the atoll is in the middel of a wildlife reserve.
Post by: RonM on 05/14/2021 05:51 pm
Why only 3/4 of the orbit? Why to not do 1 orbit + 3/4? Is keeping propellant tmperature the problem because they aren't going to do this?More than likely because doing a 1 + 3/4 orbit of the earth changes landing location, incurs in having to support additional tracking ansd support facilities, and bercause it is not necessary for what they want to do
Also avoids problems if SpaceX looses control of SS. Don't need a repeat of the recent Chinese booster random reentry.
Post by: Framryk on 05/14/2021 06:42 pm
Get Phobos with a flat deck only, tow it into the Gulf, get it ready for a SH landing ("touchdown") instead of RTLS. Ticks all the boxes, with a basic flat deck there is minimal risk.
Prepare for SS re-entry over Kauai, track it with Kwajalein missile tracking and Maui radar, maybe get a WB-57 loitering in the area near the splashdown point. Get a few marine expendable drones with 4K cameras at the expected entry point.
I have my doubts that SN20 will survive re-entry, but my gosh wouldn't it be a sight. People are exclaiming about Raptor losses but they forget, this might be a few million sunk (literally) to validate the whole launch-stage sep-re-entry-soft landing (splashdown) in one fell swoop.
Total respect, this is hubris only SpaceX can go for!
Post by: Lars-J on 05/14/2021 06:43 pm
I was in the camp that SH would hop and then quickly try for orbit.
Instead, SpaceX went all Saturn V on us and is going for an all up full stack orbital attempt, albeit with likely fewer SH raptors, maybe ~16 or so.
I guess I fail to see the difference. Or were you one of the "Starship can do SSTO" crowd? They pretty much need a full(ish) stack to get it to orbit with margin to spare.
Post by: cscott on 05/14/2021 07:16 pm
I have my doubts that SN20 will survive re-entry, but my gosh wouldn't it be a sight.
It will probably be even more photogenic if it *doesn't* survive re-entry.
Post by: neoforce on 05/14/2021 07:35 pm
I have my doubts that SN20 will survive re-entry, but my gosh wouldn't it be a sight.
It will probably be even more photogenic if it *doesn't* survive re-entry.
Didn't Elon tweet that he expects it will take multiple attempts before they get through entry? I couldn't find the tweet, but I think they will be thrilled to orbit and start getting data on re-entry.
Post by: eriblo on 05/14/2021 07:35 pm
Post by: RedLineTrain on 05/14/2021 07:45 pm
They could actually try landing on one of their regular droneships. They’re building a third one, and so they’ll have a bit of a spare (soonish).
Similar height as a Falcon 9 booster, so for the same stability, the landing footprint would be about the same. The weight of the booster shouldn’t be too much for the barge. Although it might be a bit of a hazard to have such a huge booster with crew on board trying to secure it. But 20 miles off the coast of Texas should have much calmer waters than the middle of the Atlantic, so that would help keep it safer.
It seems more Starshippy to try to sprint to get Phobos finished in time, but I’m not sure it’s really that feasible.
My real opinion is they haven’t actually decided yet to splash SH or land it on some droneship (ASDS or Phobos), and so they wrote the FCC document to keep open all those possibilities (to spur their crew to work more quickly if nothing else).
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
My inexpert searches didn't show any abandoned platforms. According to the Bureau of Safety and Environmental Enforcement (https://bobson.maps.arcgis.com/apps/webappviewer/index.html?id=9c82bd4a9ef541f0bf32dfa107173c21), it looks like most/all have been removed.
That said, Perdido (https://www.shell.com/about-us/major-projects/perdido/perdido-an-overview.html) is some 140 miles downrange and could see quite a show.
Post by: Jim on 05/14/2021 07:53 pm
It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
I don't see why if there's a chance it will explode on ascent then they shouldn't worry about the case where it doesn't...
F9 and FH first flights didn't fail on ascent, right? How about older EELVs? Saturn? STS?
All did static firings before their first flights.
Post by: Jim on 05/14/2021 08:05 pm
how would it work to have a few high altitude blimps in position along track to monitor. Tow them out East from Hawaii and release. Have some station keeping ability. Fairly equatorial so maybe upper level winds not very strong?
Good idea. WorldView did stuff like that, but is struggling/laying off? It seems that the high altitude balloon market enjoyed a renaissance, then is kinda fading away again. Seems like logistics would be weird; how long can it loiter on station (able to take slip days), how many days before hand do you have to deploy it to get in position and verify it's working? Might actually be cheaper to just pay for some flight hours.
These guys seem to be doing "Sky Range" via Reaper and Global Hawk drones, but not positive if it's operational or not, the press release is pretty recent so guessing not yet: https://i3-corps.com/technology-solutions/skyrange/
Just put it on boats. No need for the high altitude.
Post by: meekGee on 05/14/2021 08:27 pm
Agreed - there's certainly risk on ascent..It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
I don't see why if there's a chance it will explode on ascent then they shouldn't worry about the case where it doesn't...
F9 and FH first flights didn't fail on ascent, right? How about older EELVs? Saturn? STS?
All did static firings before their first flights.
But the OP was "why bother thinking about landing if there's a chance it'll fail on ascent.
I get that if the odds were 99% and it was a hail mary.. but it isn't.
The most likely scenario is failure on reentry...
The odds that they make it to the water are not zero.. it really depend on how much they have ready on SS20. It could be that the thermal protection is known to be insufficient from the beginning - we don't have that insight... But if it's launched fully formed, I'd say 50% that they get through reentry, and 20% that they manage to relight and touch the water in one piece.
Post by: ugordan on 05/14/2021 08:53 pm
Agreed - there's certainly risk on ascent..It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
I don't see why if there's a chance it will explode on ascent then they shouldn't worry about the case where it doesn't...
F9 and FH first flights didn't fail on ascent, right? How about older EELVs? Saturn? STS?
All did static firings before their first flights.
But the OP was "why bother thinking about landing if there's a chance it'll fail on ascent.
No, it wasn't. My post was about managing expectations of Super Heavy recovery as some people on this forum already seem to think it's a given, as if there's nothing that can possibly go wrong. I said nothing whatsoever about SS and its recovery odds. Maybe, just maybe, SpaceX are aware of the likely odds of successful SH recovery and that weighed into their decision on what to do with the booster after reentry, *if* it gets that far.
This is like complaining that SpaceX should have had considered success and had landing legs and barges ready just in case for all flights starting with CASSIOPE onward. That's not how they operate. They're more of the "dog-catching-the-vehicle" operation. Come to think of it, I can see some parallels with CASSIOPE here, the SH legs are not there and there's no safe place to land without at least risking the public's ear drums.
Finally, If I may inject some proverbial cold water into this forum optimism that a SH safe splashdown is a given, how many more tries would you have guessed it would take SpaceX to actually safely land a Starship, immediately after the, seemingly better-than-anyone-hoped-for, SN8 flight? I bet hardly anyone would have bet 4 more flights. That's my point. Don't even take SH ascent for granted and worry over "spilled" Raptors just yet. These are still very early days.
Post by: meekGee on 05/14/2021 09:05 pm
Agreed - there's certainly risk on ascent..It is a pity to loose all those Raptors, but let´s remember that they still need to validate booster reentry without the reentry burn. They have good data on the rest of the booster flight profile, but this.
I mean, it's not like the whole stack successfully getting to staging is a slam dunk IMHO.
Expecting the first launch to sail through all the way to booster reentry is a tall order. This isn't a campaign like the F9 development one was. There are no extended static tests of an integrated booster propulsion unit (with however many Raptors they're planning to fit on it) planned or even possible. There's a real chance the whole flight goes the way of an N1 so already worrying about dunking perfectly good Raptors into the drink is maybe a tad premature?
I don't see why if there's a chance it will explode on ascent then they shouldn't worry about the case where it doesn't...
F9 and FH first flights didn't fail on ascent, right? How about older EELVs? Saturn? STS?
All did static firings before their first flights.
But the OP was "why bother thinking about landing if there's a chance it'll fail on ascent.
No, it wasn't. My post was about managing expectations of Super Heavy recovery as some people on this forum already seem to think it's a given, as if there's nothing that can possibly go wrong. I said nothing whatsoever about SS and its recovery odds. Maybe, just maybe, SpaceX are aware of the likely odds of successful SH recovery and that weighed into their decision on what to do with the booster after reentry, *if* it gets that far.
This is like complaining that SpaceX should have had considered success and had landing legs and barges ready just in case for all flights starting with CASSIOPE onward. That's not how they operate. They're more of the "dog-catching-the-vehicle" operation. Come to think of it, I can see some parallels with CASSIOPE here, the SH legs are not there and there's no safe place to land without at least risking the public's ear drums.
Finally, If I may inject some proverbial cold water into this forum optimism that a SH safe splashdown is a given, how many more tries would you have guessed it would take SpaceX to actually safely land a Starship, immediately after the, seemingly better-than-anyone-hoped-for, SN8 flight? I bet hardly anyone would have bet 4 more flights. That's my point. Don't even take SH ascent for granted and worry over "spilled" Raptors just yet. These are still very early days.
Those people are strawmen... There's always people with unrealistic expectations.
The parallel to CASSIOPE is good. Try for the improbable, and damn it may just work.
And manage expectations is exactly right.
The expectation is that the ship won't be landable or even make it out of EDL.
Since getting it to land requires hardware (legs) and facilities (pad) and a regulatory effort, and since ships are (as shown before) largely expendable, then yeah, likely best course is to try and land at sea, and get all the lost data on the next flight - which is why it's more likely they'll try to recover BN3.
But a parallel universe in which they manage to get a permit to land in some missile range was not that crazy: legs are cheap and so is a pad.
Right now it's decided, so we're doing the NSF thing - arguing about what-ifs. We need another development to happen...
Post by: oldAtlas_Eguy on 05/14/2021 09:15 pm
SH
Engines -> From $30M to $40M depending on number of engines used (18 vs 23)
Tank -> from $10M to $15M
Ancillary hardware etc. -> from $10M to $15M
Totals
Min = ~$50M
Max = ~$70M
SS
Engines -> from $8M to $10M
Tank and Fairing -> from $10M to $15M due to complexity of the nose cone shape and extra internal piping and header tanks + tiles attachments
Ancillary Hardware -> from $15M to $20M The fins complications and the tiles
Totals
Min = ~$33M
Max = ~$45M
Cost of flight hardware for orbital flight
Min =~$83M
Max = ~$115M
Or about 6 launches or more in a year without any recoveries for a total cost including all non flight hardware costs such as support GSE, tooling and other ground equipment fees and cryo costs. From a total spending of ~$1B.
Post by: philw1776 on 05/14/2021 10:04 pm
I was in the camp that SH would hop and then quickly try for orbit.
Instead, SpaceX went all Saturn V on us and is going for an all up full stack orbital attempt, albeit with likely fewer SH raptors, maybe ~16 or so.
I guess I fail to see the difference. Or were you one of the "Starship can do SSTO" crowd? They pretty much need a full(ish) stack to get it to orbit with margin to spare.
I have no idea what you're talking about. Said nothing about SS SSTO.
The SH can orbit a SS with far fewer than 28 engines. I've run the #s and so have many others here.
Post by: Lars-J on 05/14/2021 10:46 pm
I was in the camp that SH would hop and then quickly try for orbit.
Instead, SpaceX went all Saturn V on us and is going for an all up full stack orbital attempt, albeit with likely fewer SH raptors, maybe ~16 or so.
I guess I fail to see the difference. Or were you one of the "Starship can do SSTO" crowd? They pretty much need a full(ish) stack to get it to orbit with margin to spare.
I have no idea what you're talking about. Said nothing about SS SSTO.
The SH can orbit a SS with far fewer than 28 engines. I've run the #s and so have many others here.
It was not an accusation. But there is a whole thread of people who think that Starship can do SSTO if you add enough engines to it. My confusion comes from reading your original message (see bolded)... It seems like there is only two ways for Starship to get to orbit. SSTO or full stack. So if you are not in the SSTO camp, why is a full stack surprising?
(And I know a full 28 engines is not needed, hence the "full(ish) stack")
Post by: Joffan on 05/14/2021 10:48 pm
It is worth noting that to place the horizon at 20 nautical miles offshore you need an altitude of ~110 m. So if it is clear enough the returning booster should disappear beneath the horizon for ground level observers (although they might just be able to see splashes/fireballs) but good optics placed on top of say an at least partially stacked launch integration tower or a 400 ft condominium should be able to track it all the way down...Normal building rules for Kauai are essentially "no taller than a palm tree" (taken as 50ft). No doubt with some (e.g. military) exemptions, but it ain't Maui.
Post by: eriblo on 05/15/2021 12:14 am
I was talking about the SH booster which will be hard to see from Kauai no matter how high you are ;)It is worth noting that to place the horizon at 20 nautical miles offshore you need an altitude of ~110 m. So if it is clear enough the returning booster should disappear beneath the horizon for ground level observers (although they might just be able to see splashes/fireballs) but good optics placed on top of say an at least partially stacked launch integration tower or a 400 ft condominium should be able to track it all the way down...Normal building rules for Kauai are essentially "no taller than a palm tree" (taken as 50ft). No doubt with some (e.g. military) exemptions, but it ain't Maui.
With regard to Starship splashdown: Ground level has a different meaning in Kauai compared to South Padre Island - From a quick look at the map it looks like Kalalau Lookout should provide excellent views to the north and at ~4000 ft be plenty high enough. Actually seeing something through 100 km of dense atmosphere is a different matter...
Post by: tater on 05/15/2021 12:31 am
I was talking about the SH booster which will be hard to see from Kauai no matter how high you are ;)It is worth noting that to place the horizon at 20 nautical miles offshore you need an altitude of ~110 m. So if it is clear enough the returning booster should disappear beneath the horizon for ground level observers (although they might just be able to see splashes/fireballs) but good optics placed on top of say an at least partially stacked launch integration tower or a 400 ft condominium should be able to track it all the way down...Normal building rules for Kauai are essentially "no taller than a palm tree" (taken as 50ft). No doubt with some (e.g. military) exemptions, but it ain't Maui.
With regard to Starship splashdown: Ground level has a different meaning in Kauai compared to South Padre Island - From a quick look at the map it looks like Kalalau Lookout should provide excellent views to the north and at ~4000 ft be plenty high enough. Actually seeing something through 100 km of dense atmosphere is a different matter...
Waialeale is also about the wettest place on Earth. Being there without clouds would be amazing luck. We drove up, and for maybe 15 seconds we could see down a canyon to the surf before it closed up again in thick clouds.
Post by: cuddihy on 05/15/2021 12:56 am
Post by: oldAtlas_Eguy on 05/15/2021 01:33 am
Should only be ~ 260 km from the NASA /USSF Maui optical sites on top of Haleakala. Well within range for the parts of the entry & descent where it will be in ionization signal cutout. (60-20 km altitude)Ionization signal cutout occurs for communicating to transceivers on the ground to the sides or below the entering vehicle. A Starlink terminal can still link to a near overhead Starlink sat during this period. NASA actual linked to TDRSS during some reentry testing they did to gather data while in the ionization blackout period which was also in the Kauai area on the inflatable heat shield experiments.
The use of a Starlink terminal would be a seperate FCC application for this flight than the normal FCC application for TLM and CC comms during a launch attempt.
Post by: JAFO on 05/15/2021 02:19 am
TIA
Post by: su27k on 05/15/2021 03:46 am
Quote
Space Exploration Technologies Corp. (SpaceX) of Hawthorne, California
SpaceX will partner with Langley to capture imagery and thermal measurements of its Starship vehicle during orbital re-entry over the Pacific Ocean. With the data, the company plans to advance a reusable thermal protection system, which protects the vehicle from aerodynamic heating, for missions returning from low-Earth orbit, the Moon, and Mars.
Post by: M.E.T. on 05/15/2021 04:03 am
Post by: Vanspace on 05/15/2021 04:44 am
Is the Pacific splashdown spot in US territorial waters? Thinking this might be a consideration in preventing covert Raptor recovery attempts by “interested parties”.
Pacific Missile Range
This is where the US tests all its most advanced weapons. While details are obviously not available,it is presumably wired with every tracking, imaging and monitoring system that unlimited top secret funds can dream up. I suspect that if a seal farts in the area they will know.
Post by: philw1776 on 05/15/2021 02:48 pm
I was in the camp that SH would hop and then quickly try for orbit.
Instead, SpaceX went all Saturn V on us and is going for an all up full stack orbital attempt, albeit with likely fewer SH raptors, maybe ~16 or so.
I guess I fail to see the difference. Or were you one of the "Starship can do SSTO" crowd? They pretty much need a full(ish) stack to get it to orbit with margin to spare.
I have no idea what you're talking about. Said nothing about SS SSTO.
The SH can orbit a SS with far fewer than 28 engines. I've run the #s and so have many others here.
It was not an accusation. But there is a whole thread of people who think that Starship can do SSTO if you add enough engines to it. My confusion comes from reading your original message (see bolded)... It seems like there is only two ways for Starship to get to orbit. SSTO or full stack. So if you are not in the SSTO camp, why is a full stack surprising?
(And I know a full 28 engines is not needed, hence the "full(ish) stack")
Expected SH hop first.
Instead surprised that SpaceX going directly to full stack Saturn V style with possibly just over half the engines (speculation)
Post by: kevinof on 05/15/2021 04:42 pm
Is the Pacific splashdown spot in US territorial waters? Thinking this might be a consideration in preventing covert Raptor recovery attempts by “interested parties”.Not unless it’s within 12 miles of U.S. landmass, which it won’t. Assuming it sinks, it will be in very deep water. My chart says 4km deep around there.
Post by: envy887 on 05/15/2021 10:53 pm
Admittedly, I only have a KSP-level knowledge of orbital mechanics, so please gently educate me if I'm wrong here.
Can this actually complete a full orbit? Looking at the times (SECO @ 521, Ship Splashdown @ 5420) I'm having a hard time seeing how they launch from Boca Chica, orbit all the way around past Boca Chica, and then make it another 300 degrees around to Kauai.
Assuming the answer is "No, it doesn't go all the way around"... Will this achieve orbital velocity and then do a de-orbit burn? Or will it just be a very long ballistic trajectory? (The lack of a second burn of the second stage would suggest it's the later.)So , since it's getting real , What could be the final orbit of Starship after insertion. Will they keep it low to minimise TPS heating for the time being , also since the landing (or splashdown) is 90 minutes after liftoff , from Boca TX to Hawaii in eastward direction could mean the it will complete a single orbit before re-entering.
Also will they be testing the R-Vacs for the first time in Orbit?
I think the flight will be suborbital, but only just, like a shuttle eternal tank. Then you can target the landing zone even if the raptors fail to complete the deorbit burn.
Edit: Also starship landing occurs at T+90 minuets, so exactly like an ETOK Orbit but one that is just barely such that it will rapidly decay to the point it will reenter around Kauji. If on the way up it is off target (this is just a few 10s of m/s) then it will either splash before or after Kuaji into the Pacific somewhere.
I can't reconcile "achieve orbit" with rapidly decaying around T+90mins. That just doesn't compute for me. Achieving Orbit necessarily means a full once-around.
"until performing a powered, targeted landing" suggests to me that they would achieve a meaningful orbit insertion and then perform a deorbit burn, or perhaps even a deorbit-acceleration burn to test EDL at a higher than orbital velocity.
Once you go beyond 180° around you're essentially orbital: In the sense that your semi-major axis is longer than the planet radius. This also means you have orbital velocity.
Ballistic trajectories end at 180° of the way around.
For example for such a flight an orbit like 270x30km would work well (with perigee around West coast of Mexico). But note that such an orbit has the same energy as 150x150km (I'm assuming spherical Earth for simplicity, real orbit would be a bit different).
And of course they can chose higher orbit and active deorbit.
The Verge is reporting that the maximum altitude will be 72 miles, or 120 km. I don't know if that's enough to get 20,000 miles downrange before reentering.
Post by: OneSpeed on 05/15/2021 11:32 pm
The Verge is reporting that the maximum altitude will be 72 miles, or 120 km. I don't know if that's enough to get 20,000 miles downrange before reentering.
My sims so far suggest that 120km could be the apogee for the Super Heavy booster. Orbital insertion usually happens around 167km or higher. I agree with sebk, 273 x 55 is my current estimate for Starship's (single) orbit.
Post by: envy887 on 05/16/2021 12:12 am
The Verge is reporting that the maximum altitude will be 72 miles, or 120 km. I don't know if that's enough to get 20,000 miles downrange before reentering.
My sims so far suggest that 120km could be the apogee for the Super Heavy booster. Orbital insertion usually happens around 167km or higher. I agree with sebk, 273 x 55 is my current estimate for Starship's (single) orbit.
That would make more sense. I don't think 3/4 of an orbit would even be possible below 120 km, since drag is still quite significant at that altitude.
Post by: Gridfire on 05/16/2021 12:54 am
Firstly landing / touchdown observation. For SS and BN if entering the water, SX could simply obtain 3 floating objects. Scrap pleasure craft hulls, foam filled water tanks etc. Fit each with 3 mooring winches for anchors (3 for position keeping), tow them out and and anchor them in a triangular array for coverage lets say 500m from the anticipated touch down location then load each with gyro stabilised camera mounts. Gyro selfie sticks are dirt cheap now then hope they don't get splattered or burnt up. Video transmitters on each could help.
Secondly if they are intact, they may not sink. I would expect the last command on touchdown would be to shut all valves. You then have a couple of large almost empty tanks full of gas. Great buoyancy. Then they only need safeing and towing to an appropriate location for lifting out of the water.
If they do sink, before flight you fit a buoyancy block to the outside with a lifting line attached long enough for the water depth and with a hydrostatic release. The item sinks, the buoyancy floats up both marking the location and allowing easier retrieval. I can see a problem with the strength of the line required and proofing for re-entry but this could be worked around.
Finally I have many years of experience on oil rigs. Most semi-submersible rigs like Phobos and Deimos can moor and use Dynamic positioning in fact DP mooring only is relatively new -the older generation are only moored using 8-12 winches shared around the corners. I have been on a DP rig that was moored and using DP. Perhaps the power generation and mooring winches have been left intact. All that is needed is a flat deck (not easy in the time but who knows). They are then towed to the landing location and moored on anchors using widely available vessels and techniques used in the oil industry for many years. Both these rigs had 4 powerful mooring winches. In a previous life they may have been moored with this on the drilling location and used their DP for fine positioning. Finally it may be necessary to have GPS telemetry from the rig for last second landing point correction but only within a few meters.
Post by: DistantTemple on 05/16/2021 01:16 am
I have come late to this thread but would like to pitch a few ideas for consideration.Where the SS is planned to land is too deep for anchoring, so your cheap hulls need to be autonomous... or maybe a sea anchor if some drift can just be factored in (my bold):
Firstly landing / touchdown observation. For SS and BN if entering the water, SX could simply obtain 3 floating objects. Scrap pleasure craft hulls, foam filled water tanks etc. Fit each with 3 mooring winches for anchors (3 for position keeping), tow them out and and anchor them in a triangular array for coverage lets say 500m from the anticipated touch down location then load each with gyro stabilised camera mounts. Gyro selfie sticks are dirt cheap now then hope they don't get splattered or burnt up. Video transmitters on each could help.
Secondly if they are intact, they may not sink. I would expect the last command on touchdown would be to shut all valves. You then have a couple of large almost empty tanks full of gas. Great buoyancy. Then they only need safeing and towing to an appropriate location for lifting out of the water.
If they do sink, before flight you fit a buoyancy block to the outside with a lifting line attached long enough for the water depth and with a hydrostatic release. The item sinks, the buoyancy floats up both marking the location and allowing easier retrieval. I can see a problem with the strength of the line required and proofing for re-entry but this could be worked around.
Finally I have many years of experience on oil rigs. Most semi-submersible rigs like Phobos and Deimos can moor and use Dynamic positioning in fact DP mooring only is relatively new -the older generation are only moored using 8-12 winches shared around the corners. I have been on a DP rig that was moored and using DP. Perhaps the power generation and mooring winches have been left intact. All that is needed is a flat deck (not easy in the time but who knows). They are then towed to the landing location and moored on anchors using widely available vessels and techniques used in the oil industry for many years. Both these rigs had 4 powerful mooring winches. In a previous life they may have been moored with this on the drilling location and used their DP for fine positioning. Finally it may be necessary to have GPS telemetry from the rig for last second landing point correction but only within a few meters.
Some hints the SH will land on something and not splash.Is the Pacific splashdown spot in US territorial waters? Thinking this might be a consideration in preventing covert Raptor recovery attempts by “interested parties”.Not unless it’s within 12 miles of U.S. landmass, which it won’t. Assuming it sinks, it will be in very deep water. My chart says 4km deep around there.
Post by: Gridfire on 05/16/2021 01:38 am
Where the SS is planned to land is too deep for anchoring, so your cheap hulls need to be autonomous... or maybe a sea anchor if some drift can just be factored in (my bold):
Following this comment I see this is correct. Rigs can only be moored to roughly 5000ft depth which is way less than the landing location so yes, full DP would be required. This may be hard on the rigs they are converting with the bridge removed. My experience is mainly North Sea where its shallow enough to only moor with some deeper work in the GoM.
Post by: VaBlue on 05/16/2021 02:42 am
Is the Pacific splashdown spot in US territorial waters? Thinking this might be a consideration in preventing covert Raptor recovery attempts by “interested parties”.
Pacific Missile Range
This is where the US tests all its most advanced weapons. While details are obviously not available,it is presumably wired with every tracking, imaging and monitoring system that unlimited top secret funds can dream up. I suspect that if a seal farts in the area they will know.
A nice thought, but it doesn't really work that way. I'm sure there are some additional sensors dropped down on the bottom, but that's ~20,000' deep - so it's nice if you're sniffing submarines. Being a missile range, it'll be saturated with missile sensors (radar, telemetry, IR), but no cameras. It's in the middle of the Pacific Ocean - there's no place to mount a camera! Satellite? Nope... Not good for open ocean or missiles (unless its IR, but that's a special case).
But it is protected ocean - meaning that its a safe place to land, free of shipping and fishing lanes. There can be ships in the area, but they're operating in a restricted zone so they are liable for any damage - not SpaceX (or whoever is using the range). Water depth, should SS sink (probably), will preclude any recovery attempts because the mothership would have to loiter in one sot for too long. Long enough for someone to intervene...
Post by: Robotbeat on 05/16/2021 03:02 am
Territorial waters only extend 12 nautical miles. But the Exclusive Economic Zone (EEZ) extends 200 nautical miles, so Starship's 100km-off-the-coast-of-Kauai flight is within the EEZ of the US. So that's additional protection.Is the Pacific splashdown spot in US territorial waters? Thinking this might be a consideration in preventing covert Raptor recovery attempts by “interested parties”.
Pacific Missile Range
This is where the US tests all its most advanced weapons. While details are obviously not available,it is presumably wired with every tracking, imaging and monitoring system that unlimited top secret funds can dream up. I suspect that if a seal farts in the area they will know.
A nice thought, but it doesn't really work that way. I'm sure there are some additional sensors dropped down on the bottom, but that's ~20,000' deep - so it's nice if you're sniffing submarines. Being a missile range, it'll be saturated with missile sensors (radar, telemetry, IR), but no cameras. It's in the middle of the Pacific Ocean - there's no place to mount a camera! Satellite? Nope... Not good for open ocean or missiles (unless its IR, but that's a special case).
But it is protected ocean - meaning that its a safe place to land, free of shipping and fishing lanes. There can be ships in the area, but they're operating in a restricted zone so they are liable for any damage - not SpaceX (or whoever is using the range). Water depth, should SS sink (probably), will preclude any recovery attempts because the mothership would have to loiter in one sot for too long. Long enough for someone to intervene...
Post by: Tomness on 05/16/2021 03:50 am
SpaceX Hired Company to Destroy Floating GovSat Booster, Not USAF
http://www.americaspace.com/2018/02/09/spacex-hired-company-to-destroy-floating-govsat-booster-not-usaf/QuoteAmericaSpace has since learned that the Air Force was, instead, initially considered to take care of the job, but a commercial company of demolition specialists was eventually hired to safely destroy the hazardous booster.
Again, not the USAF; no strike by the U.S. military was carried out on the Falcon 9.
Post by: Robotbeat on 05/16/2021 04:44 am
...Found one, and it appears to be about 20 miles off-shore, in the spot indicated on the FCC document:
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
https://skytruth-org.carto.com/viz/6b36c068-1dd0-11e6-b5c7-0e8c56e2ffdb/public_map
https://apps.fcc.gov/els/GetAtt.html?id=273481
Post by: Scintillant on 05/16/2021 06:50 am
That map says it's current as of 2016, so I'm not sure if that platform is there anymore. From what I can tell, the parent of the operating company hasn't mentioned platforms in their financial statements since 2017, and the Bureau of Ocean Energy Management dashboard (https://www.boem.gov/gom-interactive-lease-statistics-dashboard) doesn't show an active lease there currently....Found one, and it appears to be about 20 miles off-shore, in the spot indicated on the FCC document:
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
https://skytruth-org.carto.com/viz/6b36c068-1dd0-11e6-b5c7-0e8c56e2ffdb/public_map
https://apps.fcc.gov/els/GetAtt.html?id=273481
Maybe someone could ask RGV to fly over and check :P
Post by: Jcc on 05/16/2021 03:00 pm
Post by: RonM on 05/16/2021 03:35 pm
I really doubt that there will be any attempt to have the booster land on anything but water. They did that several times with F9, even with production legs deploying at the right moment. They used several water landings to refine the models and flight software. There is close to zero chance a first landing attempt with the booster would be successful, trying it would not accelerate progress, but would probably slow it.
The lessons of landing F9 have been learned. Super Heavy requires engineering work because it is a different vehicle, but it is basically an overgrown F9. There's a pretty good chance a prototype with legs will successfully land the first time they try it. Whether SpaceX tries this time is more of a schedule and resource issue.
Post by: electricdawn on 05/16/2021 03:46 pm
But what do I know? ;)
Post by: RedLineTrain on 05/16/2021 03:56 pm
...Found one, and it appears to be about 20 miles off-shore, in the spot indicated on the FCC document:
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
https://skytruth-org.carto.com/viz/6b36c068-1dd0-11e6-b5c7-0e8c56e2ffdb/public_map
https://apps.fcc.gov/els/GetAtt.html?id=273481
As referenced above in my post, the BSEE says (https://bobson.maps.arcgis.com/apps/webappviewer/index.html?id=9c82bd4a9ef541f0bf32dfa107173c21) both of the platforms in lease block 1133 (A & B) were removed in 2012.
I guess you would have to do a flyover to determine whether anything suitable for use remains. Seems unlikely, but you never know.
Edit: More information from BSEE. Platforms A & B were fixed structures at 127 feet depth and had heliports. Latitude 26.15071399 and longitude -96.88102027 (17.9 miles from shore). Platform A was considered a major structure while Platform B was not.
https://www.google.com/maps/place/76R55429%2B7H/@26.1506923,-96.8832512,17z
Post by: Robotbeat on 05/16/2021 04:13 pm
can we get someone to do some Planet Labs images of that spot?...Found one, and it appears to be about 20 miles off-shore, in the spot indicated on the FCC document:
BTW, just as a complete shot in the dark, but has anyone checked if there’s an existing platform on the spot on the map where SH is shown to be landing? What’s the water depth there?
https://skytruth-org.carto.com/viz/6b36c068-1dd0-11e6-b5c7-0e8c56e2ffdb/public_map
https://apps.fcc.gov/els/GetAtt.html?id=273481
As referenced above in my post, the BSEE says (https://bobson.maps.arcgis.com/apps/webappviewer/index.html?id=9c82bd4a9ef541f0bf32dfa107173c21) both of the platforms in lease block 1133 (A & B) were removed in 2012.
I guess you would have to do a flyover to determine whether anything suitable for use remains. Seems unlikely, but you never know.
Edit: More information from BSEE. Platforms A & B were fixed structures at 127 feet depth and had heliports. Latitude 26.15071399 and longitude -96.88102027. Platform A was considered a major structure while Platform B was not.
Post by: Robotbeat on 05/16/2021 04:32 pm
Post by: RedLineTrain on 05/16/2021 04:38 pm
In addition to the one that was “removed” in 2016, there’s also this other platform very near by. But it doesn’t have an installation date.
That structure appears to have been permitted, but never installed.
You can download an Excel file and peruse.
https://www.data.bsee.gov/Platform/PlatformStructures/Default.aspx
Post by: StarshipTrooper on 05/16/2021 04:47 pm
How many raptor engines?
Will it have meth/lox thrusters?
Will it include non-throttle-able raptors?
Will starship have vacuum raptors?
Post by: RedLineTrain on 05/16/2021 04:48 pm
Post by: FutureSpaceTourist on 05/16/2021 05:07 pm
Post by: andyr on 05/16/2021 06:02 pm
As SS won't have a payload, you'd imagine they could have far fewer Raptors on BN3.
You could also ask if SN20 will *only* have vacuum raptors if its not going to try and land.
Post by: Alberto-Girardi on 05/16/2021 06:06 pm
There are just weeks to go until the earliest possible launch date for the first orbital test flight of Starship & Superheavy. What do you think the configuration of engines/thrusters be? Why do you think so?
How many raptor engines?
Will it have meth/lox thrusters?
Will it include non-throttle-able raptors?
Will starship have vacuum raptors?
AFAIU there isn't a certain answer to any of your questions.
1) almost surely less than the number of a full operational flight.
2) there is progres being made at McGregor with testing, so it is possible that sn20 will be equipped with them
3) This IIUC is the least sure answer of all the questions. I think no, because most probably there will be less raptors, and no heavy payload that necessitetes the high thrust version to lift off.
4) There was (I'm not sure, but probably it is still there)a pathfinder theust dome with vavuum raptors mounting hardware. On the raptor engine thread (not the corruent one, the thread 3 IIRC) there was a discussion about flying SS with three seal level engines. The resoult was that there were challenges (the vacuum version is longer than the sea level one). So it is probable that they will use vac raptors.
Post by: electricdawn on 05/16/2021 06:06 pm
Post by: philw1776 on 05/16/2021 06:08 pm
There are just weeks to go until the earliest possible launch date for the first orbital test flight of Starship & Superheavy. What do you think the configuration of engines/thrusters be? Why do you think so?
How many raptor engines? my guess minimum 16 on SH, 8+ outer, 8 inner and 6 on SS
Will it have meth/lox thrusters? Not yet
Will it include non-throttle-able raptors? Yes, 8+ outer rim SH engines will be non-throttle-able and non-moveable
Will starship have vacuum raptors? Yes 3 of the 6 SS engines will be Rvac
Plus...
SH will land on something, not just settle into the ocean like the Starship off Kauai
Above are opinion, not definitive facts
Post by: andyr on 05/16/2021 06:12 pm
Will it have grid fins.
As SS won't have a payload, you'd imagine they could have far fewer Raptors on BN3.
You could also ask if SN20 will *only* have vacuum raptors if its not going to try and land.
there isn't enough space for three vacum raptor in the center of the skirt.
I didn't say they should be in the centre. I'm saying in their proper position, but without the 3 centre gimbaling raptors.
Post by: CruddyCuber on 05/16/2021 06:14 pm
Image credit: Gary Blair
Image credit: Rgvaerialphotography
Image credit: Bocachicagal
Post by: Lars-J on 05/16/2021 06:22 pm
No. It needs 6 raptors to reach orbit.Will it have grid fins.
As SS won't have a payload, you'd imagine they could have far fewer Raptors on BN3.
You could also ask if SN20 will *only* have vacuum raptors if its not going to try and land.
there isn't enough space for three vacum raptor in the center of the skirt.
I didn't say they should be in the centre. I'm saying in their proper position, but without the 3 centre gimbaling raptors.
And you cannot mount 3 sea level raptors where the vac Raptor mounts are since they are so much smaller and will melt the skirt and sea level raptors. You would need a janky 6ft mount extension to make sure that the nozzle end is at the same level as the center engine.
See this image, which is also interestingly roughly how close the vacuum engines will be mounted to the center raptors.
In certainly think the first orbital (expendable) Starship will have the final engine configuration, given that vacuum Raptor testing at McGregor has been going on for a while now.
Post by: andyr on 05/16/2021 06:23 pm
Post by: Lars-J on 05/16/2021 06:27 pm
Are you sure it needs 6 raptors when it will have zero payload ?
Not 100% sure, but these prototypes so far are heavier than they want to make the final Starships.
And there is no realistic option to mount 4 or 5 engines. It needs to be 3 or 6. And I don’t think 3 would be sufficient even if tanks are half full.
Post by: cdebuhr on 05/16/2021 06:36 pm
[... sigh ...]Will it have grid fins.
As SS won't have a payload, you'd imagine they could have far fewer Raptors on BN3.
You could also ask if SN20 will *only* have vacuum raptors if its not going to try and land.
there isn't enough space for three vacum raptor in the center of the skirt.
I didn't say they should be in the centre. I'm saying in their proper position, but without the 3 centre gimbaling raptors.
This is what happens when a few not-as-well-informed-as-they-think-they-are local "experts" who don't know what they don't know spout an I'll founded idea as though it were a "fact". There is a persistent myth that just won;t die here that the SL Raptors are there only for use as landing engines. This is a good example of why its so important to separate fact from opinion/speculation, and also why one need to recognize the limits of ones own understanding.
As others have already pointed out, all six engines will be fired to reach orbit. Even with little or no payload, I suspect that the TWR just isn't there to get from staging to orbit with only vacuum engines. Plus SL engines are needed for control authority, as the VacRaptors aren't planned to gimbal. I guess maybe you could only fly with two SL Raptors if you were flying no payload and minimum required fuel?? You'd need to stage above enough atmosphere that the canted flight resulting from off-axis thrust didn't result in aerodynamic unpleasantness.
Edit to add: andyr, please don't take my first paragraph as directed specifically at you, as that is not what I intended. For all I know, you picked this idea up here and ran with it - I've probably done similar myself without realizing it. I do try to make sure what I learn here is sound before I repeat it. Learning who the real experts are here (and there are a lot of them!) goes a long way.
Post by: Kazioo on 05/16/2021 06:51 pm
Post by: tbellman on 05/16/2021 06:57 pm
Will it have grid fins.
SuperHeavy, absolutely yes; without them, it can't steer on the way down. Starship, absolutely not; it has no need for grid fins.
Quote from: andyr
You could also ask if SN20 will *only* have vacuum raptors if its not going to try and land.
The flight profile they filed with FCC explicitly states it will do "a powered, targeted landing approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing". So it will need sea-level Raptor engines. And as others have already said, you need the thrust vectoring on the way up as well.
Post by: soyuzu on 05/16/2021 07:10 pm
These starships also lacks equipments compare with final ones, and IIUC current 4mm 304 stainless body is sufficient to achieve the 120t target dry mass.Are you sure it needs 6 raptors when it will have zero payload ?
Not 100% sure, but these prototypes so far are heavier than they want to make the final Starships.
And there is no realistic option to mount 4 or 5 engines. It needs to be 3 or 6. And I don’t think 3 would be sufficient even if tanks are half full.
User Onespeed has did a simulation and confirmed 19 engine Superheavy + 3 engine Starship is enough with booster RTLS.
https://youtu.be/pHkr89hGd_8
Post by: AU1.52 on 05/16/2021 08:44 pm
Post by: cdebuhr on 05/16/2021 08:53 pm
LabPabre shows a launch date of NET June 20th. Where did he get this from?
Edit 2: Oh there it is ... 3rd reply on this thread:
So... SpaceX has filed for an FCC STA for the first "Starship Orbital test flight", NET June 20th, 2021.The info in the FCC link gives an operational date range of 2021 06 20 to 2021 12 20. I strongly suspect using this as a NET date for the launch is on the extremely early end of the spectrum, but as far as I know its the only official specific date seen yet.QuoteThe Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate approximately 170 seconds into flight. The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying between the Florida Straits. It will achieve orbit until performing a powered, targeted landing approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing.
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021
Post by: philw1776 on 05/17/2021 12:00 am
According to Val's source either 16 or 18 Raptors for BN3.
Who is Val?
Val's source???
Not that I disagree. See earlier post.
Post by: sferrin on 05/17/2021 12:10 am
This has the feel of just trying to get a grip on SH handing characteristics without endangering their shiny new launch platform and tower, located just next door to the landing pad. Bringing it back within 20 miles and picking a spot to hit on the water will prove out models and characteristics quite well. As for Starship, they're probably concerned about the TPS - if it allows partial damage, controlling the fall back to Earth could well be problematic. Dump her in the ocean for piece of mind, you know she can land if everything else is good after a re-entry.Hopefully they fish it (and the Hawaii-bound Starship) out of the water if only to prevent somebody else from doing that. (And they would.)
I like the plan, but do wish they could find a way to try to save some Raptors. But, in the big scheme, these Raptors have already been written off in the name of forward testing...
Post by: chopsticks on 05/17/2021 04:16 am
Post by: XenIneX on 05/17/2021 08:40 am
Maybe for SH, but I'd pass on recovering SS. They'd have to contract a heck of a salvage fleet to land that fish. The real value here is proof-of-concept so that the FAA is will give the nod for re-entry over the continental US.This has the feel of just trying to get a grip on SH handing characteristics without endangering their shiny new launch platform and tower, located just next door to the landing pad. Bringing it back within 20 miles and picking a spot to hit on the water will prove out models and characteristics quite well. As for Starship, they're probably concerned about the TPS - if it allows partial damage, controlling the fall back to Earth could well be problematic. Dump her in the ocean for piece of mind, you know she can land if everything else is good after a re-entry.Hopefully they fish it (and the Hawaii-bound Starship) out of the water if only to prevent somebody else from doing that. (And they would.)
I like the plan, but do wish they could find a way to try to save some Raptors. But, in the big scheme, these Raptors have already been written off in the name of forward testing...
So long as they get the data they need, far easier to pop the FTS charges and scuttle the lot.
Post by: Pete on 05/17/2021 09:03 am
The lessons of landing F9 have been learned. Super Heavy requires engineering work because it is a different vehicle, but it is basically an overgrown F9. There's a pretty good chance a prototype with legs will successfully land the first time they try it. Whether SpaceX tries this time is more of a schedule and resource issue.
The Starship's mass and engines is also such that a hover is possible. Not desired, of course, but it does greatly expand the landing performance envelope, and reduces the need for absolute-precision-first-time suicide burn landing that F9 needs to use (due to having TWR >> 1 at all times, even under deepest throttle)
Landing Starship *should*, in theory, be a good bit easier than landing F9 boosters.
Same is true for the SH booster, just even more so.
Post by: Kazioo on 05/17/2021 09:53 am
Post by: Yggdrasill on 05/17/2021 10:07 am
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
Post by: Alvian@IDN on 05/17/2021 10:46 am
Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.Not according to NSF article
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
Post by: JaimeZX on 05/17/2021 12:00 pm
Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.Others have suggested the RVacs are necessary for getting to orbit, even without cargo. I'm not sure what you mean about adding them "when they try to land the Starship." RVacs are not for landing... on Earth anyway.
Post by: chevvie on 05/17/2021 12:02 pm
Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
They are trying to land starship. It'll just be in the ocean, but the landing profile will be the same as it would have been for a landingpad. So they will need those raptors.
Post by: BZHSpace on 05/17/2021 01:02 pm
(https://pbs.twimg.com/media/EyZQs8AWgAcX2b1.jpg)
Post by: edzieba on 05/17/2021 01:25 pm
According to this picture taken by Mary maybe BN3 will have more than 18 Raptor SL ?9 fully visible pairs of non-gimbal-non-throttle Raptor ports (one for fuel & one for oxidiser each) means a ring of at least 18, possibly 19 or 20 depending on lens focal length.
(https://pbs.twimg.com/media/EyZQs8AWgAcX2b1.jpg)
8 angled ports on the thrust puck matches the expected 8 gimbalable-and-throttleable Raptors in the centre cluster.
So somewhere between 26 and 28 raptors still seems to be the target as of that particular dome being completed. No guarantees that dome hasn't since been quietly scrapped for a newer design, though.
Post by: BZHSpace on 05/17/2021 01:32 pm
According to this picture taken by Mary maybe BN3 will have more than 18 Raptor SL ?9 fully visible pairs of non-gimbal-non-throttle Raptor ports (one for fuel & one for oxidiser each) means a ring of at least 18, possibly 19 or 20 depending on lens focal length.
(https://pbs.twimg.com/media/EyZQs8AWgAcX2b1.jpg)
8 angled ports on the thrust puck matches the expected 8 gimbalable-and-throttleable Raptors in the centre cluster.
So somewhere between 26 and 28 raptors still seems to be the target as of that particular dome being completed. No guarantees that dome hasn't since been quietly scrapped for a newer design, though.
I like the configuration :
-SN20
3 RVAC 3 RSL
-BN03
20 non-thottleable RSL - 8 thottleable RSL
Post by: Yggdrasill on 05/17/2021 01:40 pm
9 fully visible pairs of non-gimbal-non-throttle Raptor ports (one for fuel & one for oxidiser each) means a ring of at least 18, possibly 19 or 20 depending on lens focal length.It's also possible they make a "final" design for the Super Heavy, and then just close off the ports they don't need for the specific vehicle. That way they get experience making as close to production-intent parts as soon as possible.
8 angled ports on the thrust puck matches the expected 8 gimbalable-and-throttleable Raptors in the centre cluster.
So somewhere between 26 and 28 raptors still seems to be the target as of that particular dome being completed. No guarantees that dome hasn't since been quietly scrapped for a newer design, though.
And if they suddenly decide to change the number of Raptors for some reason, they can just modify the thrust puck accordingly.
Like if BN3 is supposed to have 18 Raptors, and BN4 is supposed to have 22 Raptors for a more ambitious test, and BN3 is a total failure, they might be able to easily close off the four extra ports on the thrust puck for BN4 and repeat the BN3 test. Or if BN3 performs above all expectation, they could go for the full 28 on BN4 for an even more ambitious test.
All the number of ports really says is that the vehicle will have *no more than* that number of Raptors.
Post by: philw1776 on 05/17/2021 02:01 pm
Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
They are trying to land starship. It'll just be in the ocean, but the landing profile will be the same as it would have been for a landingpad. So they will need those raptors.
No they do not need "those raptors" meaning Rvacs to land. 3 sea level engines are more than enough and include engine out redundancy.
They DO need the Rvacs to reach orbit as the Starship needs to carry enough propellant to achieve 9.x Km/sec orbital velocity allowing for gravity losses. Carrying the needed propellant mass means more Newtons force needed to move the Starship 2nd stage up to orbital velocity.
Post by: Space_Puzzle on 05/17/2021 02:52 pm
Did SN5/6 have 3 raptor ports eventhough they only used 1?According to this picture taken by Mary maybe BN3 will have more than 18 Raptor SL ?9 fully visible pairs of non-gimbal-non-throttle Raptor ports (one for fuel & one for oxidiser each) means a ring of at least 18, possibly 19 or 20 depending on lens focal length.
(https://pbs.twimg.com/media/EyZQs8AWgAcX2b1.jpg)
8 angled ports on the thrust puck matches the expected 8 gimbalable-and-throttleable Raptors in the centre cluster.
So somewhere between 26 and 28 raptors still seems to be the target as of that particular dome being completed. No guarantees that dome hasn't since been quietly scrapped for a newer design, though.
If that's the case, BN3 could also fly with less engines than it has ports.
Post by: hkultala on 05/17/2021 03:00 pm
Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
Vacuum raptors have nothing to do with landing. It's the SL engines which are used for landing.
The vacuum engines are needed to get
1) Enough thrust
2) Good specific impulse.
Without any payload, Starship might be able to reach orbit with just 3 sea level engines, and might even have enough fuel left for the landing burn.
However, the flight profile would be quite different than on operational flights. Either it would have quite bad T/W ratio, and the Superheavy would lift it to more lofted trajectory to make it stay in the air for long enough to accelerate to orbital speed, or it would be only partially fueled and then the staging would happen later than normally. Or more probably, a little bit of both.
Reaching orbit with SL engines in place of the vacuum engines (so just total 6 SL engines) would be easy, just some payload capacity would be lost. My quess is in this option - as they do not really need the vacuum version yet, they can concentrate on improving the SL version and then making the "high thrust dumb version" and make the vacuum versions later when they start flying to higher orbits/trajectories where isp matters more.
And it probably makes more sense to make the vacuum engines based on the "high thrust dumb version" anyway as that version will also have slightly improved isp, and the higher pressure will also mean less flow separation issues if the vacuum engines need to be operated in the atmosphere in an emergency situation to perform an abort in case of Superheavy failure.
Post by: Yggdrasill on 05/17/2021 03:17 pm
They DO need the Rvacs to reach orbit as the Starship needs to carry enough propellant to achieve 9.x Km/sec orbital velocity allowing for gravity losses. Carrying the needed propellant mass means more Newtons force needed to move the Starship 2nd stage up to orbital velocity.They don't really *need* the vacuum Raptors to reach orbit, though they would of course be nice to have.
For instance, a centaur upper stage with one RL10 has 0.44G* of acceleration, Starship with 3x 200 ton Raptors and 1350 ton mass has 0.44G. So they aren't that different in that regard. Though the first stage of the Atlas V does burn for a longer time, which helps the upper stage get past more of the gravity losses before firing up, so you probably would want to compensate by reducing the propellant load to some extent.
I don't really know what they will prioritize, though.
1. Not expending three additional Raptors.
2. Getting additional data on vacuum Raptor performance in space.
I guess if they have the vacuum Raptors to spare, they will use them.
* Edit: Sorry, that's actually without payload. A single engine Centaur may actually carry as much as 18.8 tons of payload. In that case the acceleration is 0.23G. Starship with 3x SL Raptors and no payload has almost twice the T/W.
Post by: Yggdrasill on 05/17/2021 03:23 pm
Vacuum raptors have nothing to do with landing. It's the SL engines which are used for landing.I wasn't saying the vacuum Raptors had anything to do with the landing. Just that if they hold off on installing the vacuum Raptors until they try landing (and recovering) the Starship, they won't have to intentionally expend any vacuum Raptors.
The vacuum engines are needed to get
1) Enough thrust
2) Good specific impulse.
Without any payload, Starship might be able to reach orbit with just 3 sea level engines, and might even have enough fuel left for the landing burn.
If we say they cost $1 million each, that's a $3 million saving by dropping them from this test flight. That's not huge of course, but these flights aren't making SpaceX any money. And having to replace them for a new flight might actually delay the test program, if availability is a challenge.
Post by: StarshipTrooper on 05/17/2021 03:37 pm
Vacuum raptors have nothing to do with landing. It's the SL engines which are used for landing.I wasn't saying the vacuum Raptors had anything to do with the landing. Just that if they hold off on installing the vacuum Raptors until they try landing (and recovering) the Starship, they won't have to intentionally expend any vacuum Raptors.
The vacuum engines are needed to get
1) Enough thrust
2) Good specific impulse.
Without any payload, Starship might be able to reach orbit with just 3 sea level engines, and might even have enough fuel left for the landing burn.
If we say they cost $1 million each, that's a $3 million saving by dropping them from this test flight. That's not huge of course, but these flights aren't making SpaceX any money. And having to replace them for a new flight might actually delay the test program, if availability is a challenge.
An interesting side note, using vacuum raptors on starship may fulfill some portion of a $67 million dollar contract with the DOD to create a second stage raptor engine.
https://spacenews.com/air-force-adds-more-than-40-million-to-spacex-engine-contract/ (https://spacenews.com/air-force-adds-more-than-40-million-to-spacex-engine-contract/)
Post by: Robotbeat on 05/17/2021 04:00 pm
I trust our reporters, but I'd really like confirmation that this (that Super Heavy WILL be expended, not just most likely expended) is actually well-sourced information. Several other folks have said the FCC document mentions Super Heavy being expended and splashed, when in fact it refers specifically to landing and "touchdown", which is very different language than the "splashdown" used for Starship in the same section.Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.Not according to NSF article
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
And in case someone misreads this: I would bet money that Super Heavy will be expended this flight (i.e. that there won't be anything solid to land it on). But we do not have sourced information that *says* they will expend it. From what I can telling, this is something we are *inferring*, and we cannot yet 100% rule out that they may still hold out hope for landing the booster on something.
Post by: su27k on 05/17/2021 04:49 pm
Post by: Robotbeat on 05/17/2021 04:57 pm
Given SpaceX changes the plan on a weekly basis, there's not much point to be "100% sure" about anything, since it may very well change next week. I think it is enough for us to know that they're gearing up for the ability to expend multiple SuperHeavy's (ramp up Raptor production, pair new SuperHeavy with Starship), whether they actually expend them can be left as a surprise...I am simply insisting that unsourced inferences (regardless of how likely) not be accidentally upgraded to sourced “fact” without some kind of confirmation.
Post by: Alberto-Girardi on 05/17/2021 05:39 pm
I trust our reporters, but I'd really like confirmation that this (that Super Heavy WILL be expended, not just most likely expended) is actually well-sourced information. Several other folks have said the FCC document mentions Super Heavy being expended and splashed, when in fact it refers specifically to landing and "touchdown", which is very different language than the "splashdown" used for Starship in the same section.Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.Not according to NSF article
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
And in case someone misreads this: I would bet money that Super Heavy will be expended this flight (i.e. that there won't be anything solid to land it on). But we do not have sourced information that *says* they will expend it. From what I can telling, this is something we are *inferring*, and we cannot yet 100% rule out that they may still hold out hope for landing the booster on something.
I agree.
We'll see if they will splashdown or not the SH. SpaceX many time has surprised us, doing things aiming very high or in a unconventinal way, but other time they go more "conventional". I hope to see both SH and SS recoverd, but maybe this isn't really the best thing for this test flight.
Post by: Robotbeat on 05/17/2021 07:18 pm
As far as I can tell, they don’t need the RVacs to reach orbit and land the ship without any payload. Because without payload, they can afford to partially fill Starship and still reach orbit and landing. I haven’t seen any calculations that show otherwise.Since the Starship will be expended, I think it's likely they'll only fly with 3 SL Raptors. They can add the 3 vacuum Raptors when they try to land the Starship.
Hopefully they successfully land the Super Heavy, so the test might only expend three Raptors.
They are trying to land starship. It'll just be in the ocean, but the landing profile will be the same as it would have been for a landingpad. So they will need those raptors.
No they do not need "those raptors" meaning Rvacs to land. 3 sea level engines are more than enough and include engine out redundancy.
They DO need the Rvacs to reach orbit as the Starship needs to carry enough propellant to achieve 9.x Km/sec orbital velocity allowing for gravity losses. Carrying the needed propellant mass means more Newtons force needed to move the Starship 2nd stage up to orbital velocity.
What’s the separation mass of SH? 400t? 3400t usable ascent propellant? 340s average ascent Isp for SH? If Starship has 150 tons of dry mass plus landing propellant... 350s ascent Isp... then with 850t usable ascent propellant (1000t total mass on Separation), it gets 10.6km/s delta-v.
3 Raptors each 200t thrust make 600 ton thrust. It’s not uncommon or unreasonable for upper stage engines to have half the thrust as the mass of the full upper stage, so 1000t wet mass being pushed by 600t thrust Raptors is no big problem for gravity losses.
https://www.google.com/search?q=350*9.8*ln%281000%2F150%29%2B340*9.8*ln%28%281000%2B3800%29%2F%281000%2B400%29%29 (https://www.google.com/search?q=350*9.8*ln%281000%2F150%29%2B340*9.8*ln%28%281000%2B3800%29%2F%281000%2B400%29%29)
Heck, even if you set the upper stage (Starship) to a T/W of 1:1, it still gets 9.7km/s delta v.
RVacs are not strictly necessary for reaching orbit on this flight (and people should stop claiming they are required, unless they have a much better argument), but I expect them to use them anyway.
Post by: Robotbeat on 05/17/2021 07:21 pm
Regular Raptor on the second stage still counts as a second stage Raptor engine...Vacuum raptors have nothing to do with landing. It's the SL engines which are used for landing.I wasn't saying the vacuum Raptors had anything to do with the landing. Just that if they hold off on installing the vacuum Raptors until they try landing (and recovering) the Starship, they won't have to intentionally expend any vacuum Raptors.
The vacuum engines are needed to get
1) Enough thrust
2) Good specific impulse.
Without any payload, Starship might be able to reach orbit with just 3 sea level engines, and might even have enough fuel left for the landing burn.
If we say they cost $1 million each, that's a $3 million saving by dropping them from this test flight. That's not huge of course, but these flights aren't making SpaceX any money. And having to replace them for a new flight might actually delay the test program, if availability is a challenge.
An interesting side note, using vacuum raptors on starship may fulfill some portion of a $67 million dollar contract with the DOD to create a second stage raptor engine.
https://spacenews.com/air-force-adds-more-than-40-million-to-spacex-engine-contract/ (https://spacenews.com/air-force-adds-more-than-40-million-to-spacex-engine-contract/)
Post by: oldAtlas_Eguy on 05/17/2021 07:29 pm
Post by: cscott on 05/17/2021 10:41 pm
Post by: oldAtlas_Eguy on 05/17/2021 10:51 pm
Post by: Cherokee43v6 on 05/17/2021 11:32 pm
What is the point of creating one-off frankenvehicles that require extra development expense and are a distraction from doing the work they actually need to do to fly SN/SS operationally?
Leaving off the RVACs means they have to write special software to control the vehicle that then has no application and becomes a dead-end for future development. It means recalculating how the entire stack behaves with the mass of the RVACs missing from their specific locations. It means that a significant portion of the data they retrieve has no value towards further development as it comes from a 'one-off special build'.
SpaceX is building an integrated system and things that are not going to be a part of that system are distractions.
Post by: Robotbeat on 05/18/2021 12:02 am
Post by: Nevyn72 on 05/18/2021 12:17 am
I suspect the static/test fire program with a whole gaggle of Raptors in close proximity to each other will end up being a longer and more problematic process than many are expecting... add into that teething problems with a whole new GSE setup and unfortunately delays are likely to be significant.
By the time the whole stack is ready to fly who knows what landing options may be available for SH offshore. ;)
Post by: kkattula on 05/18/2021 02:28 am
Costs of an SH and SS:
SH
Engines -> From $30M to $40M depending on number of engines used (18 vs 23)
Tank -> from $10M to $15M
Ancillary hardware etc. -> from $10M to $15M
Totals
Min = ~$50M
Max = ~$70M
SS
Engines -> from $8M to $10M
Tank and Fairing -> from $10M to $15M due to complexity of the nose cone shape and extra internal piping and header tanks + tiles attachments
Ancillary Hardware -> from $15M to $20M The fins complications and the tiles
Totals
Min = ~$33M
Max = ~$45M
Cost of flight hardware for orbital flight
Min =~$83M
Max = ~$115M
Or about 6 launches or more in a year without any recoveries for a total cost including all non flight hardware costs such as support GSE, tooling and other ground equipment fees and cryo costs. From a total spending of ~$1B.
I'm not convinced the costs will be anywhere near that high.
Raptors were estimated at around $2m each, BEFORE the spool up in production rate. They are likely well below $1M each by now.
Tanks are only a few $100K in stainless steel, and with the rate they're churning them out, labor costs can't be more than a few million.
So my guess is $10M to $15M for SS and $20M to $30M for SH. With those numbers reducing as they make more of them.
However, the unit cost is almost irrelevent, as the big spend is on the infrastructure to build Raptors, Starships & Super Heavies, then test, launch and land them. If they spend $1B this year and get one orbital launch, did it cost $1B per launch? That sort of calculation is almost meaningless until they reach steady state, if ever.
I prefer to look at it this way:
- They have invested in and established the capacity (infrastructure, supply chains and people) to build Raptor, Starships and Super Heavies.
- That capacity costs almost as much to sit idle as it does to make units.
- Using it builds experince and improves quality, at the minor additinal cost of some raw materials and power.
- The designs are not finalized yet, so current builds will not be of use when they eventually reach the operational designs.
So it makes sense to keep churning out prototypes and expending them in ways that inform the operational design. Or even discard them if they've already moved on. If they splash a SS and SH on the first orbital ettempt? No big deal, the new & improved versions will be just rolling out of the High Bay.
That said, I expect the SH will try to land on one of the drone ships, 20 km off Boca Chica. There could be a lot to learn by examining an intact, dry, booster, and the landing profile is relatively easy. Probably way too soon for one of the oil rigs to be ready though.
On the other hand, getting another droneship to the SS landing area would be very difficult & dangerous, with pretty low probabilty SS will make it that far intact, and be able to do the flip and stick the landing.
Post by: steveleach on 05/18/2021 07:05 am
Spot onCosts of an SH and SS:
SH
Engines -> From $30M to $40M depending on number of engines used (18 vs 23)
Tank -> from $10M to $15M
Ancillary hardware etc. -> from $10M to $15M
Totals
Min = ~$50M
Max = ~$70M
SS
Engines -> from $8M to $10M
Tank and Fairing -> from $10M to $15M due to complexity of the nose cone shape and extra internal piping and header tanks + tiles attachments
Ancillary Hardware -> from $15M to $20M The fins complications and the tiles
Totals
Min = ~$33M
Max = ~$45M
Cost of flight hardware for orbital flight
Min =~$83M
Max = ~$115M
Or about 6 launches or more in a year without any recoveries for a total cost including all non flight hardware costs such as support GSE, tooling and other ground equipment fees and cryo costs. From a total spending of ~$1B.
I'm not convinced the costs will be anywhere near that high.
Raptors were estimated at around $2m each, BEFORE the spool up in production rate. They are likely well below $1M each by now.
Tanks are only a few $100K in stainless steel, and with the rate they're churning them out, labor costs can't be more than a few million.
So my guess is $10M to $15M for SS and $20M to $30M for SH. With those numbers reducing as they make more of them.
However, the unit cost is almost irrelevent, as the big spend is on the infrastructure to build Raptors, Starships & Super Heavies, then test, launch and land them. If they spend $1B this year and get one orbital launch, did it cost $1B per launch? That sort of calculation is almost meaningless until they reach steady state, if ever.
I prefer to look at it this way:
- They have invested in and established the capacity (infrastructure, supply chains and people) to build Raptor, Starships and Super Heavies.
- That capacity costs almost as much to sit idle as it does to make units.
- Using it builds experince and improves quality, at the minor additinal cost of some raw materials and power.
- The designs are not finalized yet, so current builds will not be of use when they eventually reach the operational designs.
So it makes sense to keep churning out prototypes and expending them in ways that inform the operational design. Or even discard them if they've already moved on. If they splash a SS and SH on the first orbital ettempt? No big deal, the new & improved versions will be just rolling out of the High Bay.
That said, I expect the SH will try to land on one of the drone ships, 20 km off Boca Chica. There could be a lot to learn by examining an intact, dry, booster, and the landing profile is relatively easy. Probably way too soon for one of the oil rigs to be ready though.
On the other hand, getting another droneship to the SS landing area would be very difficult & dangerous, with pretty low probabilty SS will make it that far intact, and be able to do the flip and stick the landing.
Post by: oldAtlas_Eguy on 05/18/2021 04:42 pm
Which brings up the point on trying to save $3M or even $6M on the 3 RVACS is actually pointless vs the probability of getting a lot of data on the operation of RVACS in their normal operation regimes.Spot onCosts of an SH and SS:
SH
Engines -> From $30M to $40M depending on number of engines used (18 vs 23)
Tank -> from $10M to $15M
Ancillary hardware etc. -> from $10M to $15M
Totals
Min = ~$50M
Max = ~$70M
SS
Engines -> from $8M to $10M
Tank and Fairing -> from $10M to $15M due to complexity of the nose cone shape and extra internal piping and header tanks + tiles attachments
Ancillary Hardware -> from $15M to $20M The fins complications and the tiles
Totals
Min = ~$33M
Max = ~$45M
Cost of flight hardware for orbital flight
Min =~$83M
Max = ~$115M
Or about 6 launches or more in a year without any recoveries for a total cost including all non flight hardware costs such as support GSE, tooling and other ground equipment fees and cryo costs. From a total spending of ~$1B.
I'm not convinced the costs will be anywhere near that high.
Raptors were estimated at around $2m each, BEFORE the spool up in production rate. They are likely well below $1M each by now.
Tanks are only a few $100K in stainless steel, and with the rate they're churning them out, labor costs can't be more than a few million.
So my guess is $10M to $15M for SS and $20M to $30M for SH. With those numbers reducing as they make more of them.
However, the unit cost is almost irrelevent, as the big spend is on the infrastructure to build Raptors, Starships & Super Heavies, then test, launch and land them. If they spend $1B this year and get one orbital launch, did it cost $1B per launch? That sort of calculation is almost meaningless until they reach steady state, if ever.
I prefer to look at it this way:
- They have invested in and established the capacity (infrastructure, supply chains and people) to build Raptor, Starships and Super Heavies.
- That capacity costs almost as much to sit idle as it does to make units.
- Using it builds experince and improves quality, at the minor additinal cost of some raw materials and power.
- The designs are not finalized yet, so current builds will not be of use when they eventually reach the operational designs.
So it makes sense to keep churning out prototypes and expending them in ways that inform the operational design. Or even discard them if they've already moved on. If they splash a SS and SH on the first orbital ettempt? No big deal, the new & improved versions will be just rolling out of the High Bay.
That said, I expect the SH will try to land on one of the drone ships, 20 km off Boca Chica. There could be a lot to learn by examining an intact, dry, booster, and the landing profile is relatively easy. Probably way too soon for one of the oil rigs to be ready though.
On the other hand, getting another droneship to the SS landing area would be very difficult & dangerous, with pretty low probabilty SS will make it that far intact, and be able to do the flip and stick the landing.
Post by: lrk on 05/18/2021 06:31 pm
That said, I expect the SH will try to land on one of the drone ships, 20 km off Boca Chica. There could be a lot to learn by examining an intact, dry, booster, and the landing profile is relatively easy. Probably way too soon for one of the oil rigs to be ready though.
On the other hand, getting another droneship to the SS landing area would be very difficult & dangerous, with pretty low probabilty SS will make it that far intact, and be able to do the flip and stick the landing.
Landing on a droneship without the catch tower means the booster needs legs. Which would be more one-off development work that is not applicable long-term.
Post by: Robotbeat on 05/18/2021 11:30 pm
SpaceX sunk a ton of engineering into fairing recovery even though they knew it was only temporary until Starship is online.
I have a theory that Elon intentionally spouts out about their most Ioutlandish ideas and long-term proposals in order to make their near term stuff seem less plausible to their competitors, catching them off guard when they get steamrolled by a very real operational capability. He actually encourages the skepticism and the dismissivism to catch competitors off-guard.
Post by: DistantTemple on 05/18/2021 11:35 pm
That said, I expect the SH will try to land on one of the drone ships, 20 km off Boca Chica. There could be a lot to learn by examining an intact, dry, booster, and the landing profile is relatively easy. Probably way too soon for one of the oil rigs to be ready though.Accept it will not be real development work, because they don't need to take care with mass margins, etc, they just need some "knock them up in the field" basic legs. Some heavy girders that fold down like-but-unlike the F9 composite legs would do.
On the other hand, getting another droneship to the SS landing area would be very difficult & dangerous, with pretty low probabilty SS will make it that far intact, and be able to do the flip and stick the landing.
Landing on a droneship without the catch tower means the booster needs legs. Which would be more one-off development work that is not applicable long-term.
Post by: aero on 05/19/2021 12:58 am
Post by: su27k on 05/19/2021 04:00 am
Just wondering, how many launches of the SH/SS stack do you suppose they might want to make before the catch tower is completed?
From the most recent NSF Starship article (https://www.nasaspaceflight.com/2021/05/starship-sn15-reflight-road-orbit/):
Quote
While the SN20 and BN3 combo will be first in line for orbital flight, it’s expected that the subsequent boosters and ships will pair up accordingly, SN21 with BN4, SN22 with BN5, and SN23 with BN6. In addition, it’s understood that a major design upgrade is set to come with the SN24/BN7 pair.
From this it looks like they're planning at least 4 expendable SH launches, and the major upgrade by SN24/BN7 could very well be a SH that is catchable by the tower.
Post by: su27k on 05/19/2021 04:08 am
Post by: sebk on 05/19/2021 08:44 am
This may depend on the readiness state of RVacs. If SpaceX deems RVacs are too likely to jeopardize the mission they may skip them. It seems their primary goal is trying EDL -- this is the hardest next step for them, after all. RVac testing is a "drive by" secondary goal. If the engines are deemed good enough then sure, include them and have a good validation test on ascent. But if they assign too much probability of them failing and causing on-ascent RUD they would fly without them.
Post by: Mike_1179 on 05/19/2021 12:13 pm
User softwaresaur on reddit (https://old.reddit.com/r/spacex/comments/n26p13/rspacex_thread_index_and_general_discussion_may/gyj6a8d/) discovered a FCC filing for a Starlink Ku band ground station with a single off the shelf Cobham MK3 antenna in Honolulu, Hawaii (https://fcc.report/IBFS/SES-LIC-INTR2021-01908), this is different from regular Starlink ground stations which have 8 Ka band SpaceX antennas. Speculation is this ground station will be used to communicate with Starship during its flight towards splashdown site near Kauai.
The Starlink antenna on Starship is located on the leeward (dorsal) side presumably so it can talk upward to the Starlink constellation during entry. When would this ground station be in view of that antenna on Starship?
If not, then this Honolulu station would just be for talking to the constellation as it relays data down from Starship. So, then why not use a regular ground station, why a custom?
Post by: rsdavis9 on 05/19/2021 01:51 pm
They still show legs on the diagrams taped to the new parts.
SpaceX sunk a ton of engineering into fairing recovery even though they knew it was only temporary until Starship is online.
I have a theory that Elon intentionally spouts out about their most Ioutlandish ideas and long-term proposals in order to make their near term stuff seem less plausible to their competitors, catching them off guard when they get steamrolled by a very real operational capability. He actually encourages the skepticism and the dismissivism to catch competitors off-guard.
So f9 is 20t.
SH is 230t? 180t?
Any chance that the existing f9 legs could be used?
6 of them?
8 of them?
Are the current f9 legs over designed somewhat and can actually take a larger load?
How quick could they make an upgrade of the f9 legs for the larger loads?
EDIT: onespeed estimates 10.
https://forum.nasaspaceflight.com/index.php?topic=47179.msg2240197#msg2240197
Post by: TripD on 05/19/2021 02:03 pm
What's the weather like in Boca Chica in July? 8)
Post by: su27k on 05/19/2021 02:22 pm
User softwaresaur on reddit (https://old.reddit.com/r/spacex/comments/n26p13/rspacex_thread_index_and_general_discussion_may/gyj6a8d/) discovered a FCC filing for a Starlink Ku band ground station with a single off the shelf Cobham MK3 antenna in Honolulu, Hawaii (https://fcc.report/IBFS/SES-LIC-INTR2021-01908), this is different from regular Starlink ground stations which have 8 Ka band SpaceX antennas. Speculation is this ground station will be used to communicate with Starship during its flight towards splashdown site near Kauai.
The Starlink antenna on Starship is located on the leeward (dorsal) side presumably so it can talk upward to the Starlink constellation during entry. When would this ground station be in view of that antenna on Starship?
If not, then this Honolulu station would just be for talking to the constellation as it relays data down from Starship. So, then why not use a regular ground station, why a custom?
Pretty sure the ground station would just talk to the constellation which will relay the data from Starship. Not sure why they wouldn't use a regular ground station, maybe they're not ready to expand service to Hawaii yet? I don't know what is the fiber connection bandwidth between Hawaii and US mainland, it's possible the bandwidth is not sufficient to support a regular ground station offering commercial service, but it is sufficient for relaying some data from Starship test. They may be waiting for laser link to be operational before expanding Starlink service to Hawaii.
Post by: Robotbeat on 05/19/2021 03:20 pm
There are pictures of what they might look like. Probably, if SH has legs, they'll just be permanently welded ones like in the old renderings (but maybe simplified?). https://www.youtube.com/watch?v=C8JyvzU0CXUThey still show legs on the diagrams taped to the new parts.
SpaceX sunk a ton of engineering into fairing recovery even though they knew it was only temporary until Starship is online.
I have a theory that Elon intentionally spouts out about their most Ioutlandish ideas and long-term proposals in order to make their near term stuff seem less plausible to their competitors, catching them off guard when they get steamrolled by a very real operational capability. He actually encourages the skepticism and the dismissivism to catch competitors off-guard.
So f9 is 20t.
SH is 230t? 180t?
Any chance that the existing f9 legs could be used?
6 of them?
8 of them?
Are the current f9 legs over designed somewhat and can actually take a larger load?
How quick could they make an upgrade of the f9 legs for the larger loads?
EDIT: onespeed estimates 10.
https://forum.nasaspaceflight.com/index.php?topic=47179.msg2240197#msg2240197
Post by: aero on 05/19/2021 04:12 pm
I wonder if there will be any test flights after the booster landing tower is completed?
Post by: oldAtlas_Eguy on 05/19/2021 06:52 pm
It is a possibility this is what is sometimes called a suedosat. It would point at the location of final landing maneuvers which would take the vehicle out of connection to sats. If the location is on top of one of Hawaii's tall mountains such as next to an existing observatory where Internet broadband data speeds are available then it is a clincher.User softwaresaur on reddit (https://old.reddit.com/r/spacex/comments/n26p13/rspacex_thread_index_and_general_discussion_may/gyj6a8d/) discovered a FCC filing for a Starlink Ku band ground station with a single off the shelf Cobham MK3 antenna in Honolulu, Hawaii (https://fcc.report/IBFS/SES-LIC-INTR2021-01908), this is different from regular Starlink ground stations which have 8 Ka band SpaceX antennas. Speculation is this ground station will be used to communicate with Starship during its flight towards splashdown site near Kauai.
The Starlink antenna on Starship is located on the leeward (dorsal) side presumably so it can talk upward to the Starlink constellation during entry. When would this ground station be in view of that antenna on Starship?
If not, then this Honolulu station would just be for talking to the constellation as it relays data down from Starship. So, then why not use a regular ground station, why a custom?
Pretty sure the ground station would just talk to the constellation which will relay the data from Starship. Not sure why they wouldn't use a regular ground station, maybe they're not ready to expand service to Hawaii yet? I don't know what is the fiber connection bandwidth between Hawaii and US mainland, it's possible the bandwidth is not sufficient to support a regular ground station offering commercial service, but it is sufficient for relaying some data from Starship test. They may be waiting for laser link to be operational before expanding Starlink service to Hawaii.
ADDED: I stand corrected. It is at the exhibition hall in downtown Honolulu. It is possible that it is a setup for transmission of the Starship flight presentations to a crowd of reporters direct through the Starlink network point to point from wherever SpaceX Starship mission control is being done at. It would be a twofer. It demonstrates Starlink and shows off Starship at the same time.
Post by: Kiwi53 on 05/20/2021 03:52 am
I don't know what is the fiber connection bandwidth between Hawaii and US mainland, it's possible the bandwidth is not sufficient to support a regular ground station offering commercial service, but it is sufficient for relaying some data from Starship test. They may be waiting for laser link to be operational before expanding Starlink service to Hawaii.
Fibre/er capacity between Hawai'i & California is immense.
Apart from any US-specific cables, the 'Southern Cross' cable that connects Australia, New Zealand and the USA is a 'figure 8' with the cross-over in Hawai'i. It has a design capacity of >20Tb/sec and a lit capacity of 10Tb/sec.
I'm sure Verizon, a part owner, would rent SpaceX whatever capacity they needed.
https://en.wikipedia.org/wiki/Southern_Cross_Cable (https://en.wikipedia.org/wiki/Southern_Cross_Cable)
Post by: AstroStrike on 05/20/2021 03:54 am
Post by: Yggdrasill on 05/20/2021 06:57 am
From this it looks like they're planning at least 4 expendable SH launches, and the major upgrade by SN24/BN7 could very well be a SH that is catchable by the tower.Sticking with one design for the first four orbital flights does not mean expending everything. It could go something like this:
BN3/SN20: SH east coast splashdown and Starship west coast splashdown.
BN4/SN21: SH ASDS landing and Starship west coast splashdown.
BN5/SN22: SH RTLS landing and Starship east coast ASDS landing.
BN6/SN23: SH RTLS landing and Starship Boca Chica landing.
The question is really how fast SpaceX can get approval for landings with a greater damage potential. (And how well the SH/Starship performs, of course.)
Post by: RotoSequence on 05/20/2021 07:09 am
Sticking with one design for the first four orbital flights does not mean expending everything.
The Starship program doesn't have a history of completely changing their flight plans until a given build series accomplishes its test objectives, so I'd be surprised if they started making dramatic changes in testing before they start launching payloads.
Post by: Yggdrasill on 05/20/2021 07:30 am
The Starship program doesn't have a history of changing flight plans once a given build series accomplishes its test objectives, so I'd be surprised if they started changing that now.The previous test vehicles didn't have many options for fundamentally improving the outcome for SpaceX. SN5 and SN6 were only built to be able to do a short hop. SN8-SN11 and SN15 were only built to make higher altitude hops.
Also, we still don't know what SpaceX will do with SN15/SN16 now that SN15 has done a successful hop. It's entirely possible they change the flight plan for the next hop. However, the payoff for SpaceX would be significantly less for changing the flight plan for SN15/SN16 than it would be by changing the flight plan for the orbital flights. So, if they stick to the same flight plan for SN15/SN16 that doesn't mean they won't change the flight plan for the orbital flights.
Ideally, SpaceX will land both the SH and Starship at Boca Chica. This means they get experience landing the vehicles, and they get back the hardware for analysis or reflight. BN3/SN20 looks to be capable of this ideal outcome.
The reason why they don't plan on landing these vehicles at Boca Chica is probably because of the risk. But as they get more experience with these vehicles, risk goes down. As risk goes down, you can get approval for flights that are closer to the ideal outcome.
(I would think SpaceX actually could get approval to land the SH at Boca Chica already. But that they might not want to do that on the very first flight, with all the expensive infrastructure that is rapidly being built. If SH blows up on reentry, debris could go everywhere.)
Post by: WindyCity on 05/20/2021 07:36 am
Post by: Yggdrasill on 05/20/2021 07:50 am
Post by: DigitalMan on 05/20/2021 08:21 am
NET means NET. I think July is theoretically possible, but it'll more likely be later.
Where did NET come from? I know one of Chris' articles was specific NLT July 1. Certainly it is likely to change, for a lot of reasons.
https://www.nasaspaceflight.com/2021/03/starship-sn11-spacex-orbital-flight-summer/
Post by: kevinof on 05/20/2021 08:37 am
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021
NET means NET. I think July is theoretically possible, but it'll more likely be later.
Where did NET come from? I know one of Chris' articles was specific NLT July 1. Certainly it is likely to change, for a lot of reasons.
https://www.nasaspaceflight.com/2021/03/starship-sn11-spacex-orbital-flight-summer/
Post by: DigitalMan on 05/20/2021 08:42 am
July 20th was the start date from the FAA doc but it's a window that lasts 6 months. I doubt it will fly in July - maybe end of the summer.
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021NET means NET. I think July is theoretically possible, but it'll more likely be later.
Where did NET come from? I know one of Chris' articles was specific NLT July 1. Certainly it is likely to change, for a lot of reasons.
https://www.nasaspaceflight.com/2021/03/starship-sn11-spacex-orbital-flight-summer/
I thought the FCC doc said this:
Operation Start Date: 06/20/2021
Operation End Date: 12/20/2021
I was only asking because NLT was L2 before Chris put it in that article, and I'd like to read whatever it is that has a different date, since I haven't stumbled across it.
Post by: kevinof on 05/20/2021 08:43 am
July 20th was the start date from the FAA doc but it's a window that lasts 6 months. I doubt it will fly in July - maybe end of the summer.
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021NET means NET. I think July is theoretically possible, but it'll more likely be later.
Where did NET come from? I know one of Chris' articles was specific NLT July 1. Certainly it is likely to change, for a lot of reasons.
https://www.nasaspaceflight.com/2021/03/starship-sn11-spacex-orbital-flight-summer/
I thought the FCC doc said this:
Operation Start Date: 06/20/2021
Operation End Date: 12/20/2021
Post by: StarshipTrooper on 05/20/2021 01:47 pm
Do people really think that an orbital test flight in July is doable? The orbital launch site infrastructure is far from completion, yet alone tested and operational. Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"? The huge amount of work needed to be accomplished in just a few short weeks, assuming no weather or construction delays, makes a July orbital test flight in my mind highly unlikely. If it happened by the end of the year, I'd consider that an enormous achievement.It certainly does seem like the GSE is making slow progress. So far just 2 tanks have been mounted and none of the shells. Not all the bases have been formed and poured yet.
What do you think the minimal state of completion will the GSE need to be for an orbital launch? 4 tanks? 5 tanks?
Obviously they need a complete launch pad table. Probably the deluge system should be working.
Will the complete launch tower be needed to lift and mount the starship?
Post by: capoman on 05/20/2021 02:42 pm
They still show legs on the diagrams taped to the new parts.
SpaceX sunk a ton of engineering into fairing recovery even though they knew it was only temporary until Starship is online.
I have a theory that Elon intentionally spouts out about their most Ioutlandish ideas and long-term proposals in order to make their near term stuff seem less plausible to their competitors, catching them off guard when they get steamrolled by a very real operational capability. He actually encourages the skepticism and the dismissivism to catch competitors off-guard.
I don't think this is the case at all. Elon doesn't care about competition. He wants others to create cheap access to space also, as he think it's good for everyone to have that. Elon only wants cheap access to space to move us forward. He is only competing with himself and his own company.... eg Starship will compete (replace) F9 even though F9 FH is already beating other competition. Elon time is and always has been about motivating his teams to keep moving forward at lightning pace. Stretch goals.
Post by: capoman on 05/20/2021 02:49 pm
Do people really think that an orbital test flight in July is doable? The orbital launch site infrastructure is far from completion, yet alone tested and operational. Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"? The huge amount of work needed to be accomplished in just a few short weeks, assuming no weather or construction delays, makes a July orbital test flight in my mind highly unlikely. If it happened by the end of the year, I'd consider that an enormous achievement.
Maybe time for another poll. Personally, I think July is a stretch, but I think there's a pretty good chance it will fly within the six month window. There's a lot of pieces that have to fall into place, including FAA approval, which might be the biggest hurdle of them all.
Post by: tssp_art on 05/20/2021 03:01 pm
...Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"?
I agree that BN3 will need a static fire (at least one), but I don't think a "hop" for BN3 is necessary or likely. Its actual mission flight plan is "just" an extended "hop", not much different from the Falcon 9 booster - and a SH landing is not necessary for getting SS to orbit. Payloads can begin flying even if they are still losing SH boosters and SS second stages - just like every other launcher.
Post by: freddo411 on 05/20/2021 04:23 pm
Do people really think that an orbital test flight in July is doable? The orbital launch site infrastructure is far from completion, yet alone tested and operational. Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"? The huge amount of work needed to be accomplished in just a few short weeks, assuming no weather or construction delays, makes a July orbital test flight in my mind highly unlikely. If it happened by the end of the year, I'd consider that an enormous achievement.
I largely agree that a July orbital attempt is very, very unlikely. We are all familiar with Elon time ... this is just the latest example. I define Elon time as predicting success twice as fast as reality -- but reaching success at a later time is almost assured as long as work continues.
I don't expect a hop of BN3.
The FAA approvals have gotten more difficult and more time consuming to procure. SpaceX is adjusting and putting its plans out to the FAA well in advance of when they are ready to fly so that final approval and final readiness converge.
Post by: Jim on 05/20/2021 05:00 pm
The FAA approvals have gotten more difficult and more time consuming to procure. SpaceX is adjusting and putting its plans out to the FAA well in advance of when they are ready to fly so that final approval and final readiness converge.
They aren't procured. They are obtained. And SpaceX has nobody to blame but themselves.
Post by: VaBlue on 05/20/2021 05:08 pm
They aren't procured. They are obtained. And SpaceX has nobody to blame but themselves.
Who are they 'blaming' for anything? The complexity of the permits are increasing, but I haven't heard that SX is complaining about it? Who is complaining?
(Well, other than us - the people that want them flying once/week. Slackers need to get hot!)
Post by: Jim on 05/20/2021 05:10 pm
The complexity of the permits are increasing, ....
Due to SpaceX.
Post by: Alberto-Girardi on 05/20/2021 07:12 pm
Do people really think that an orbital test flight in July is doable? The orbital launch site infrastructure is far from completion, yet alone tested and operational. Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"? The huge amount of work needed to be accomplished in just a few short weeks, assuming no weather or construction delays, makes a July orbital test flight in my mind highly unlikely. If it happened by the end of the year, I'd consider that an enormous achievement.
I largely agree that a July orbital attempt is very, very unlikely. We are all familiar with Elon time ... this is just the latest example. I define Elon time as predicting success twice as fast as reality -- but reaching success at a later time is almost assured as long as work continues.
I don't expect a hop of BN3.
The FAA approvals have gotten more difficult and more time consuming to procure. SpaceX is adjusting and putting its plans out to the FAA well in advance of when they are ready to fly so that final approval and final readiness converge.
I too agree that a test in July is unlickely, but I think that late August is more reasonable. Anyways I hope before the school restart (here in Italy around the 10th of September).
Another reason because I don't expect bn3 doing an hop is because they will need legs, and more than for SS IIUC, because of the higher mass. But they have the same diameter, hence circonference, to place them on, which limits the number of legs. This isn't an impossible problem, but they will probably need redesigned lags, and this could take time.
Are the GSE tank shells needed for a test flight?
Post by: GalacticIntruder on 05/20/2021 07:20 pm
Post by: Jakusb on 05/20/2021 08:08 pm
The FAA has to advance to cope with this new increase requirement.
SpaceX is new, young and eagerly pushing many boundaries, that would likely not have moved at all if not done in this fashion.
Friction and some political statements should be taken with some grain of salt. Functional ‘angry/annoyed’ should not be mistaken for emotional uncontrolled harsh statements.
I think there is no blame to go around. It all is just a proces that needs to happen one way or another.
It will not happen without it or take decades.
All will be better after they resolved this into newer more agile ways of working. They will find each other halfway as with the amazing improvement like the AFTS did.
Post by: jrhan48 on 05/20/2021 08:11 pm
The longest pole in the tent is likely to be FAA approval, but not for any technical or safety reason related to the planned orbital flight, rather the history of the Boca site, and its existing environmental approvals.
The original EIS was for Falcon 9 and Falcon Heavy, at a launch cadence of once per month. The FAA agreed that the original EIS still covered sub-orbital flights of the Starship portion of the system NOT the SuperHeavy, and not orbital. For that, an environmental assessment is underway to determine if a modification to the EIS can be made without requiring a whole new EIS.
A whole new EIS would be a minimum delay of at least ~ 9 months and the worst case can take over 3 years (unlikely because they did the original EIS so have a starting point and a lot of information). This is all happening in response to lawsuits by the usual crowd who want to prevent anything related to space ever, or rent-seekers, hoping any settlement would pay them for their trouble.
Some justifiable resistance is also from a few locals who wich SpaceX never happened anywhere near their community, which is understandable.
In any case, it is the Environmental approvals that pose the longest pole in the tent for using Boca Chica as a space-port for the Starship system. None of these delays are due to anything SpaceX did or didn't do or to semi-expected prototype explosions. They are due to difficulty in the US of doing anything new and complexities of environmental laws and regulations.
Post by: Tangilinear Interjar on 05/20/2021 09:27 pm
You have to look at the whole ground facility as a singular complex machine, testing, verifying, validating (and troubleshooting, modifying, fixing) are going to have to happen before even a WDR on the booster can happen. Starting up that facility will be one hell of a job and I soooo wish I could be part of it!
Post by: WindyCity on 05/20/2021 11:26 pm
...Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"?
I agree that BN3 will need a static fire (at least one), but I don't think a "hop" for BN3 is necessary or likely. Its actual mission flight plan is "just" an extended "hop", not much different from the Falcon 9 booster - and a SH landing is not necessary for getting SS to orbit.
My reasoning with regard to a "hop" is that the vehicle's performance could be tested without loading the mass of propellant needed to push SS into orbit (assuming that they bypass a suborbital flight), which would run a higher risk of a catastrophic explosion if the liftoff and first minute of flight suffered a serious anomaly. A static fire wouldn't load the vehicle with as much stress as a short flight would.
Post by: tyrred on 05/21/2021 08:00 am
To anyone - when SpaceX applies for more complex permits to FAA... then FAA has more complexity to process per application... what is surprising about this?
Post by: ETurner on 05/21/2021 01:40 pm
Procure vs obtain - in your opinion, what's the difference, Jim?procure (https://www.dictionary.com/browse/procure) [ proh-kyoor, pruh- ]
1. to obtain or get by care, effort, or the use of special means: to procure evidence.
Post by: capoman on 05/21/2021 01:47 pm
Post by: novo2044 on 05/21/2021 02:28 pm
I'm going to lay my chips on August. Optimistic but ever since I saw the first visualizations of the bellyflop and thought "well there's no way they are going to use that" I've started hedging on the optimistic side.
Post by: Robotbeat on 05/21/2021 02:37 pm
If everything goes right, July isn’t literally impossible. But it could also be May 2022 by the time it finally launches.
Post by: tssp_art on 05/21/2021 02:41 pm
...Assuming that the GSE is ready in July, would BN3 be fully ready, meaning that its raptors have been tested in static fires successfully and the vehicle flown on a lower altitude "hop"?
I agree that BN3 will need a static fire (at least one), but I don't think a "hop" for BN3 is necessary or likely. Its actual mission flight plan is "just" an extended "hop", not much different from the Falcon 9 booster - and a SH landing is not necessary for getting SS to orbit.
My reasoning with regard to a "hop" is that the vehicle's performance could be tested without loading the mass of propellant needed to push SS into orbit (assuming that they bypass a suborbital flight), which would run a higher risk of a catastrophic explosion if the liftoff and first minute of flight suffered a serious anomaly. A static fire wouldn't load the vehicle with as much stress as a short flight would.
No question that a "hop" would be useful in retiring some risk. But is that risk retirement worth the price? If the "hop" went perfectly on ascent (likely - the forces are well understood) but not so perfect on the landing (also likely - it's harder than going up) they would lose a bunch of raptors and possibly damage some of the new Ground Support Equipment - or a drone ship depending on how they try to land the booster and assuming they aren't ready to "catch" it. All of that on a flight that could have boosted the first StarShip to orbit. It just doesn't feel like a good trade and I think SpaceX will reach farther on the next flight.
Post by: Tangilinear Interjar on 05/21/2021 03:26 pm
My understanding is that the GSE will hold enough for two complete launches. If that is the case, and my understanding is that water and nitrogen will be part of the GSE tanks there, it makes sense that the tank farm really only needs to be 2/3 complete to support a single launch. Likely 4 of 6 tanks required, and two unfinished ones could simply have the valves turned off that lead to them. If this is the case, the GSE is not as far off as it appears for a single test launch. The only caveat I can think of here is if all the tanks are required to load faster to reduce boiloff.
This was my point, a couple (2 maybe 3) tanks do not need to be fully operational but the tanks are really the easy part. They may happen to be the big and obvious part but just take a look at the months of work that went into just running electrical conduit. Every one of those conduit has wires run through them, attached to things on each side, and then tested, programmed etc. All of the piping that needs to be fit, welded, bolted, pressure tested etc.
Building the GSE system isn't rocket science, it's probably more like a petrochemical tank farm, but there is a lot of labor and complexity to building those things. In this case, everything between the tanks and the rocket must be complete and functioning, that is the real part of the GSE system, the tanks are just a simple part at one end of the process.
I just had a funny realization, each end of the GSE system is a nearly identical big tank, one sits all comfy in its nice insulated jacket, the other gets shot into space.
Post by: VaBlue on 05/21/2021 03:45 pm
Agreed that getting that many Raptors to simply fire together reliably might take quite a while. Could easily see issues related to that adding a good 6 months. We don’t know at this point. No one really does.
If everything goes right, July isn’t literally impossible. But it could also be May 2022 by the time it finally launches.
I don't see the firing of 28 Raptors in sync as being a large hurdle. They have plenty of experience in lighting off 27 Merlins that are synced up pretty well (FH). The SW base from Falcon was most likely modified for Raptor, and we've seen repeated firings of groups of 3 Raptors. Scaling up to 28, while not physically trivial, is probably a fairly easy set of variables within the code base. And that code is what will keep everything in sync - providing, of course, that the physical engines work as advertised. (And there's the rub...)
Will agree, though, that launch can be pushed back by any number of issues nobody has even dreamed up, yet. I'm not holding my breath for a July launch...
Post by: electricdawn on 05/21/2021 03:52 pm
But then, SpaceX has repeatedly been flying 27 Merlins, so...
Post by: Robotbeat on 05/22/2021 12:44 am
I don't mean in a showstopper sense, just in a raw numbers "this could take a while to get right" sense. Raptor is still a fairly new engine. 28 of them at once will probably cause quite a few aborted lift-offs in the early days. Just like with Falcon 9.Agreed that getting that many Raptors to simply fire together reliably might take quite a while. Could easily see issues related to that adding a good 6 months. We don’t know at this point. No one really does.
If everything goes right, July isn’t literally impossible. But it could also be May 2022 by the time it finally launches.
I don't see the firing of 28 Raptors in sync as being a large hurdle. They have plenty of experience in lighting off 27 Merlins that are synced up pretty well (FH). The SW base from Falcon was most likely modified for Raptor, and we've seen repeated firings of groups of 3 Raptors. Scaling up to 28, while not physically trivial, is probably a fairly easy set of variables within the code base. And that code is what will keep everything in sync - providing, of course, that the physical engines work as advertised. (And there's the rub...)
Will agree, though, that launch can be pushed back by any number of issues nobody has even dreamed up, yet. I'm not holding my breath for a July launch...
Post by: Nevyn72 on 05/22/2021 01:11 am
They'll probably won't even launch all Raptors at once - more like staggering them. All this within milliseconds of course. This to prevent resonances and other undesirable sh**. I think that this is not so much the problem. The problem will be more what happens when things go wrong. The software needs to be able to control 28 Raptors and handle any occurrence that might happen.
But then, SpaceX has repeatedly been flying 27 Merlins, so...
Those 27 Merlins weren't clustered together and had a lot less combined thrust.
The nearest equivalence in terms of engine positioning and total thrust would be Russia's N1, so...
Post by: punder on 05/22/2021 01:19 am
So, 50 years later, SpaceX can’t do better than a Soviet program that was absolutely screwed from 1965 on? Oh I see. No one will ever do hypersonic reentry of a booster. No one will ever recover or re-use a first-stage booster. No private company will ever fly a recoverable space capsule, much less re-use one. No American company will ever recapture the global launch market. And on, and on, and on... are you people even paying attention?They'll probably won't even launch all Raptors at once - more like staggering them. All this within milliseconds of course. This to prevent resonances and other undesirable sh**. I think that this is not so much the problem. The problem will be more what happens when things go wrong. The software needs to be able to control 28 Raptors and handle any occurrence that might happen.
But then, SpaceX has repeatedly been flying 27 Merlins, so...
Those 27 Merlins weren't clustered together and had a lot less combined thrust.
The nearest equivalence in terms of engine positioning and total thrust would be Russia's N1, so...
Post by: Alvian@IDN on 05/22/2021 02:23 am
And do note that 9 engines on Falcon 9 was considered just as crazy at the early daysSo, 50 years later, SpaceX can’t do better than a Soviet program that was absolutely screwed from 1965 on? Oh I see. No one will ever do hypersonic reentry of a booster. No one will ever recover or re-use a first-stage booster. No private company will ever fly a recoverable space capsule, much less re-use one. No American company will ever recapture the global launch market. And on, and on, and on... are you people even paying attention?They'll probably won't even launch all Raptors at once - more like staggering them. All this within milliseconds of course. This to prevent resonances and other undesirable sh**. I think that this is not so much the problem. The problem will be more what happens when things go wrong. The software needs to be able to control 28 Raptors and handle any occurrence that might happen.
But then, SpaceX has repeatedly been flying 27 Merlins, so...
Those 27 Merlins weren't clustered together and had a lot less combined thrust.
The nearest equivalence in terms of engine positioning and total thrust would be Russia's N1, so...
Post by: Robotbeat on 05/22/2021 03:00 am
BTW, I'm not too worried about supersonic flight on ascent. The main worry there on ascent is dynamic pressure, and they built a test frame for Starship for things like that, and so I think they have that handled. Separation is always kind of tricky, too, but not as crazy as a flip, which they managed first time.
Nah, I think just grinding through all the inevitable bugs of getting 28 high performance full flow staged combustion engines operating at the same time is likely to be something that could easily take 3-6 months to solve. I'm sure they'll solve it, though, and they'll probably even get to orbit soon after that.
Post by: steveleach on 05/22/2021 08:43 am
I'm going to have to jump in here.
An awful lot of people are here in the NSF forums because they are specifically interested in SpaceX and Starship, and this is the best source of high quality information and discourse on that subject. These people might go and look through the old threads on other topics every now and then, but that is going to be selective at best.
And in the SpaceX/Starship forum sections, Jim tends to come across as an obnoxious troll, and so people respond to him like they do to trolls everywhere. No-one is under any obligation to research the background and posting history of the people they are responding to.
There are other posters here that display an immense depth of knowledge with almost every single post they make, and they are invariably treated with the utmost respect. If Jim wants that respect then he can adjust his own posting behaviour so that he gets it; I suspect he simply doesn't care though.
Regardless, he doesn't need anyone to defend him, and I personally believe that many of his posts (including that one) don't deserve it.
Maybe the mods should just remove Jim's post and the entire response chain (including this). None of them are adding value to the discussion of the mission.
Post by: Chris Bergin on 05/22/2021 12:55 pm
As much as you may not like what Jim has to say at times (or more so how he says it - and even he gets trimmed when he's uncivil), those of us know him from the years here's been here and has openly stated his NASA career, he knows his stuff.
Post by: Nomadd on 05/22/2021 02:04 pm
Post by: Herb Schaltegger on 05/22/2021 02:36 pm
With no payload, only 3/4 of an orbit and resulting lower fuel load, maybe they'll still let it take off if a few Raptors don't light, or are a few percent off?
At first blush, my thinking is they will probably abort if any engine flat-out fails to ignite and ramp up to the nominal launch thrust level(*). One of the lesser-considered goals of a full stack launch will undoubtedly be gaining absolutely as much operational Raptor data they can all at once, especially in a large clustered configuration. If an engine fails to ignite and reach operating specs in the usual timeframe, the engineers will need to know why in case there’s some fault that might be shared by other engines, or an obscure issue with the vehicle.
(*) That said, I suspect the “nominal” thrust level and related parameters (chamber pressure, turbopump speeds, propellant flow rates …) might very well be more loosely constrained on the first developmental flight tests of so many engines at once as compared to later flights.
Post by: Robotbeat on 05/22/2021 02:38 pm
It’s weird saying that a private company has greater space vehicle manufacturing capacity than an entire supercontinent-spanning Superpower in the late 1960s early 70s, but it’s true. That’s what half a century of progress finally gets you.
I hope they bother to do as many static fires as it takes to get things to work smoothly at lift-off, though, something the N-1 was incapable of. That, combined with actual full acceptance testing of each engine at McGregor (something that the N-1’s NK-15s couldn’t do), should help a lot.
This really, really does seem to have a lot of resemblance to N-1, doesn’t it? 28 (vs 30) staged combustion engines, a hardware-rich approach, high similarity between stages (2nd stage of Starship has 6 similar engines whereas N-1 had 8... in both cases using same fuel and similar engines as the first stage). Being used for lunar missions with intent for later Mars missions.
And I have extremely high confidence it will eventually work where N-1 failed. I’m not even worried about it. The 24/7 streamlining high definition cameras covering all aspects of Starship building and testing is the polar opposite of the extreme secrecy of the N-1.
(I gotta say that I kind of liked the N-1, and I think people crap on it too much. It nearly worked, and it probably would have on the next launch.)
Post by: Herb Schaltegger on 05/22/2021 02:44 pm
… combined with actual full acceptance testing of each engine at McGregor (something that the N-1’s NK-15s couldn’t do), should help a lot.
This, absolutely. The NK-15’s were lot-tested and then they presumably just hoped for the best regarding the remainder.
Post by: StarshipTrooper on 05/22/2021 02:53 pm
A fascinating engineering problem!
Perhaps something like starting opposing pairs together with additional pairs coming online separated by milliseconds. Probably the critical gimbal engines first then the outer ring.
Anyone familiar with how the Falcon Heavy lights?
Post by: ugordan on 05/22/2021 03:01 pm
I wonder what the startup sequence would be like for a 28 engine cluster?
A fascinating engineering problem!
Perhaps something like starting opposing pairs together with additional pairs coming online separated by milliseconds. Probably the critical gimbal engines first then the outer ring.
Anyone familiar with how the Falcon Heavy lights?
F9 and by extension FH also uses staggered ignition of opposing outer engines on a given core. The shutdown sequence at MECO is the same.
First FH flight had the side boosters ignite first, followed by the center core a couple of seconds later. Block 5 FHs appear to ignite individual cores either simultaneously or virtually simultaneously.
I think it's a safe bet that SH will also use staggered opposing pair ignition.
Post by: punder on 05/22/2021 03:57 pm
(Thanks for trimming my rude response. Every now and then I come back to a previous post of mine and put my head in my hands... “I did it again.”
On the other hand, bullying behavior just really gets me going. Especially when it’s directed at newbies who haven’t fully acclimated to the site’s character.)
Post by: zubenelgenubi on 05/22/2021 07:01 pm
Agreed. And a small trim of posts was required.
As much as you may not like what Jim has to say at times (or more so how he says it - and even he gets trimmed when he's uncivil), those of us know him from the years here's been here and has openly stated his NASA career, he knows his stuff.
Can we get back on topic please?Moderator: Further thread trim.
Knock it off. Stop.
Post by: wannamoonbase on 05/22/2021 07:59 pm
The N-1 might have been a single flight away from success. We’ll never know. I’m 100% confident that SS/SH will succeed—just maybe not on my preferred schedule. :)
I love the N1 too, but even if it succeeded it was impressive than the Saturn V.
Not having LH2 engines hampers high energy performance.
I also think SS/SH will work. It’s just a matter of working the problems 1 at a time. How many tries, how many problems, we will know after it happens.
LCH4 seems to be a happy medium for performance, although I see room for a lot of LH2 for beyond LEO operations.
SS could provide a LH2 cargo service and do a strong business.
Edit: N1 would have been less impressive than Saturn V
Post by: jose m on 05/22/2021 08:06 pm
I put in some numbers, to help you notice the jump they have to make, for the starship to be orbital:
Speed max. SN15 in rise = 250 Km / h
Estimated necessary speed for orbital flight, 30,000 km / h
Mass (Weight) of Falcon 9 = 500 Ton. SS = 5,000 Ton (imagine 100 large trailers fully loaded, united and launched into space at 30 thousand km / h).
I hope you see that changing the line of software that says start 27 engines to start 28 engines is only part of the titanic task that SpaceX has.
Post by: Robotbeat on 05/23/2021 01:22 am
I worked on projects that involved large generator sets, common use equipment, but each start-up of a new plant was a major complex event. So when I read that they already have experience with 27 engines, putting one more is just one more line of code, ... etc. I think they are literary people, who never even changed a lamp in their house.Yeah, it’s a huge task with high likelihood of delays and headaches. But I also think SpaceX is prepared for it.
I put in some numbers, to help you notice the jump they have to make, for the starship to be orbital:
Speed max. SN15 in rise = 250 Km / h
Estimated necessary speed for orbital flight, 30,000 km / h
Mass (Weight) of Falcon 9 = 500 Ton. SS = 5,000 Ton (imagine 100 large trailers fully loaded, united and launched into space at 30 thousand km / h).
I hope you see that changing the line of software that says start 27 engines to start 28 engines is only part of the titanic task that SpaceX has.
Post by: EnricoR on 05/23/2021 12:43 pm
I worked on projects that involved large generator sets, common use equipment, but each start-up of a new plant was a major complex event. So when I read that they already have experience with 27 engines, putting one more is just one more line of code, ... etc. I think they are literary people, who never even changed a lamp in their house.Yeah, it’s a huge task with high likelihood of delays and headaches. But I also think SpaceX is prepared for it.
I put in some numbers, to help you notice the jump they have to make, for the starship to be orbital:
Speed max. SN15 in rise = 250 Km / h
Estimated necessary speed for orbital flight, 30,000 km / h
Mass (Weight) of Falcon 9 = 500 Ton. SS = 5,000 Ton (imagine 100 large trailers fully loaded, united and launched into space at 30 thousand km / h).
I hope you see that changing the line of software that says start 27 engines to start 28 engines is only part of the titanic task that SpaceX has.
And SH will not go at orbital speed.
Post by: VaBlue on 05/23/2021 01:35 pm
I worked on projects that involved large generator sets, common use equipment, but each start-up of a new plant was a major complex event. So when I read that they already have experience with 27 engines, putting one more is just one more line of code, ... etc. I think they are literary people, who never even changed a lamp in their house.
That's kind of a bold, condescending, and dismissive statement on a forum with a bunch of literal rocket scientists and assorted technical and manufacturing professional experts. And if you think that would be one line of code, you should stop commenting about SW.
Quote
I hope you see that changing the line of software that says start 27 engines to start 28 engines is only part of the titanic task that SpaceX has.
Nobody was saying anything about anything other than starting up 28 Raptor engines in those posts. Stop making up conversation threads that don't exist.
Post by: the_other_Doug on 05/23/2021 08:32 pm
I guess I'd be more likely to believe that the first SH stages will fly just fine had there been any 28-engine cluster test firings on the ground. Heck, the F-1 engines on the Saturn V were designed to handle the radiant heat and vibration from their neighboring engines, but you'll notice that a kludge -- thick thermal batting -- was plastered onto the outside of those engine bells after initial clustered test firings indicated that the extra protection and thermal coating was required to bring the engines within desired safety parameters. Again, yes, there has been more than 50 years of advancement in computer simulations. But the simulations are never any better than one's assumptions, and it was the sets of assumptions, and not failure of simulations, that caused the N-1 problems, and required a kludged-on layer of protection to be added onto the F-1s.
Besides, with the rather extreme replacement rate these Raptors seem to undergo during checkout and after static fires, once attached to the prototype Starships, it seems that the Raptors are also still in fairly early prototype stages themselves. So, the performance assumptions for the current version of the Raptor may be even more poorly defined than you might think.
Personally, I'd rather see SH stages sit on that orbital test mount and fire up their clusters for full-duration tests before bothering to mount a Starship on top. If for no other reason than to iron out all of the poorest assumptions before risking the loss of the R-Vacs that will likely be installed on any SS that gets put on top of an SH. Of course, that would take several months and endanger his build/launch/test site unnecessarily, and it seems Musk is in enough of a hurry that he doesn't want to go through that whole process. Still... even SpaceX might get surprised at the backlash if an SH blows up one or two km into the air. Because that would be, shall we say... a significant RUD. ;)
Post by: cwr on 05/23/2021 08:49 pm
The N-1's biggest issues were effects of vibration and heating on the closely clustered engines. Certainly, computer simulation has made great strides in predicting these interactions, but I will point out that the interaction of 28 such powerful engines, their exhaust impingements, etc., gets closer and closer to chaotic. And chaos theory is not a friendly taskmaster.
I agree that vibration and heating were big issues on N-1 but my impression is
that the worst issue was the fact that the engines on the 1st stage could only be
ignited once. This led to significant issues in the test plans., which meant that
the correctness of the plumbing and electrical wiring could not be verified
before launch.
This led to at least one case where an engine died on one launch and the S/W
sent the shutdown command to what was believed to be the opposite engine
so as to balance thrust but that shutdown command turned off a different set
of engines. Things cascaded from there as the S/W tried to correct for the
strange events that were occurring.
If a simple static fire had been possible a number of mistakes could have been
rectified before first flight. Who knows, just that one change may have seen
N-1 fly to orbit!
Carl
Post by: envy887 on 05/24/2021 02:11 pm
The N-1's biggest issues were effects of vibration and heating on the closely clustered engines. Certainly, computer simulation has made great strides in predicting these interactions, but I will point out that the interaction of 28 such powerful engines, their exhaust impingements, etc., gets closer and closer to chaotic. And chaos theory is not a friendly taskmaster.
I guess I'd be more likely to believe that the first SH stages will fly just fine had there been any 28-engine cluster test firings on the ground. Heck, the F-1 engines on the Saturn V were designed to handle the radiant heat and vibration from their neighboring engines, but you'll notice that a kludge -- thick thermal batting -- was plastered onto the outside of those engine bells after initial clustered test firings indicated that the extra protection and thermal coating was required to bring the engines within desired safety parameters. Again, yes, there has been more than 50 years of advancement in computer simulations. But the simulations are never any better than one's assumptions, and it was the sets of assumptions, and not failure of simulations, that caused the N-1 problems, and required a kludged-on layer of protection to be added onto the F-1s.
Besides, with the rather extreme replacement rate these Raptors seem to undergo during checkout and after static fires, once attached to the prototype Starships, it seems that the Raptors are also still in fairly early prototype stages themselves. So, the performance assumptions for the current version of the Raptor may be even more poorly defined than you might think.
Personally, I'd rather see SH stages sit on that orbital test mount and fire up their clusters for full-duration tests before bothering to mount a Starship on top. If for no other reason than to iron out all of the poorest assumptions before risking the loss of the R-Vacs that will likely be installed on any SS that gets put on top of an SH. Of course, that would take several months and endanger his build/launch/test site unnecessarily, and it seems Musk is in enough of a hurry that he doesn't want to go through that whole process. Still... even SpaceX might get surprised at the backlash if an SH blows up one or two km into the air. Because that would be, shall we say... a significant RUD. ;)
The marginal risk-reduction value of static fire time decreases significantly as the test gets longer. They would probably get 80% of the set of data from a 5-second test that they would from a 2 minute test. On the other hand, the work to build a test stand and flame trench that can take a 2-minute firing is massively larger than building a pad for a 5 second test.
Also, this booster probably isn't being reflown, and the next one will be built in a few months. At some point, it's faster and simpler to fly it than to test it longer on the ground. That way they get flight data too.
Post by: Robotbeat on 05/24/2021 02:59 pm
Post by: ChrML on 05/24/2021 03:33 pm
They'll probably won't even launch all Raptors at once - more like staggering them. All this within milliseconds of course. This to prevent resonances and other undesirable sh**. I think that this is not so much the problem. The problem will be more what happens when things go wrong. The software needs to be able to control 28 Raptors and handle any occurrence that might happen.The software for this is the easy part. Any software can easily be simulated, and likely a full flight simulation of any combination of failures gets run every time someone commits code. Each test includes arrangements/inputs, something happening, and then asserting the expected outcome (a so called "theory" in the software world).
But then, SpaceX has repeatedly been flying 27 Merlins, so...
The hard part is getting the Raptor so reliable that firing 28 Raptors does not abort the launch every time due to some error. And accounting for mechanical stresses and resonances. And unknowns, and things not though about not accounted for in the software.
Post by: Lars-J on 05/24/2021 06:13 pm
They'll probably won't even launch all Raptors at once - more like staggering them. All this within milliseconds of course. This to prevent resonances and other undesirable sh**. I think that this is not so much the problem. The problem will be more what happens when things go wrong. The software needs to be able to control 28 Raptors and handle any occurrence that might happen.The software for this is the easy part. Any software can easily be simulated, and likely a full flight simulation of any combination of failures gets run every time someone commits code. Each test includes arrangements/inputs, something happening, and then asserting the expected outcome (a so called "theory" in the software world).
But then, SpaceX has repeatedly been flying 27 Merlins, so...
The hard part is getting the Raptor so reliable that firing 28 Raptors does not abort the launch every time due to some error. And accounting for mechanical stresses and resonances. And unknowns, and things not though about not accounted for in the software.
Yes. And they know this, better than *anyone*.
BTW this concern about 28 raptors is so very much like the talk around this forum 10-12 years ago for the Falcon 9. 9 engines!?!?! There was no way that SpaceX would be able to make the F9 reliable, nor would they be able to reliably start them... They'll have to scrub so often that they would almost never launch on time.
I expect a campaign of test fires before the first orbital launch, with an increasing amount of engines. Just look at the Starship test vehicles. Does SpaceX strike you as a company reluctant to do static fires?
Post by: Robotbeat on 05/24/2021 06:57 pm
So that’s exact what I expect for 28 engines: difficulty at first but long-term no problem. Is this unreasonable?
Post by: Welsh Dragon on 05/24/2021 07:14 pm
Having 9 engines DID mean they had a lot of aborted liftoffs at first.Did they? Not being facetious but I genuinely don't remember many.
Post by: DigitalMan on 05/24/2021 07:16 pm
I expect a short learning curve for SH at this point.
Post by: ugordan on 05/24/2021 07:33 pm
Having 9 engines DID mean they had a lot of aborted liftoffs at first.Did they? Not being facetious but I genuinely don't remember many.
Did they ever... It felt like it was the order of the day back then. If the weather was perfect, the vehicle would abort with a 90% probability.
Here are just a few ones after a very quick search.
https://youtu.be/7Kq8rAcWiaY?t=60
https://www.youtube.com/watch?v=hheiByaxuVc
https://www.youtube.com/watch?v=ityLM2ogirk
Back then the prospect of getting an FH off the ground seemed almost ludicrous.
Post by: Lars-J on 05/24/2021 07:43 pm
Having 9 engines DID mean they had a lot of aborted liftoffs at first.Did they? Not being facetious but I genuinely don't remember many.
Did they ever... It felt like it was the order of the day back then. If the weather was perfect, the vehicle would abort with a 90% probability.
Your feelings are no substitute for data. Do you have anything other than 3 instances? That 90% probability figure is ludicrous. There were teething issues in the first few flights, but after that the engine failure ratio was not significantly different than other new LVs with new engines. And now I can't even recall the last launch abort due to an engine issue - can you?
Back then the prospect of getting an FH off the ground seemed almost ludicrous.
To some. To others the reduction in F9 engine start issues over time made it quite likely that it would not be a significant issue.
And that is my point. Now we have 28 (gasp!) engines, and shouts of "this is such a hard problem so why doesn't anyone tell SpaceX they don't know it yet?" (paraphrased) are rearing their heads again. :)
Post by: RedLineTrain on 05/24/2021 08:03 pm
https://forum.nasaspaceflight.com/index.php?topic=36507.0
Post by: ugordan on 05/24/2021 08:11 pm
Having 9 engines DID mean they had a lot of aborted liftoffs at first.Did they? Not being facetious but I genuinely don't remember many.
Did they ever... It felt like it was the order of the day back then. If the weather was perfect, the vehicle would abort with a 90% probability.
Your feelings are no substitute for data. Do you have anything other than 3 instances? That 90% probability figure is ludicrous.
Dude, chill. I lived through the era of the v1.0 and the initial v1.1s. No, I'm not going to waste time bringing up more pad aborts from then just to prove a point. And in case you didn't realize, that "90% probability" was tongue-in-cheek, as in the feeling (oh no, there goes that word again) of back in the day.
There were teething issues in the first few flights, but after that the engine failure ratio was not significantly different than other new LVs with new engines. And now I can't even recall the last launch abort due to an engine issue - can you?
Did I, at any point imply that the abort issues were not resolved eventually? My point was the "first few flights" spanned from 2010 to something like mid 2014 given the flight rate back then.
And who said anything about "engine failure ratio" in the first place? Your words. From what I remember from that time, the majority of the aborts were due to too conservative parameter settings rather than HW issues, but I guess that must have been a feeling as well.
Back then the prospect of getting an FH off the ground seemed almost ludicrous.
To some. To others the reduction in F9 engine start issues over time made it quite likely that it would not be a significant issue.
What part of "back then" did you not comprehend?
It always amuses me that still, to this day, even mentioning the fact that SpaceX had it a bit rough in the early F9 days will trigger a defensive knee-jerk reaction on this forum from someone, with a 100% probability (this one is not tongue-in-cheek).
Post by: electricdawn on 05/24/2021 08:21 pm
SpaceX is no god of machinery, but they have some of the best engineers in the business. They will sort it out eventually.
Post by: Robotbeat on 05/24/2021 08:26 pm
I both have no doubt they’re going to get Starship to orbit and no doubt that there’s a lot of work to do it.
I don’t feel the need to convince any one. I’ll just point back at this and say, I told you so.
SpaceX knows this. It’s not a mystery to them, either. They’ll attack it and get it solved. I’m not worried in the least, and I give it better than even odds of beating SLS to orbit.
Post by: RedLineTrain on 05/24/2021 08:30 pm
But I'm not sure that the engines will be the cause of the majority of scrubs. There's a smorgasbord of things that will be not quite right.
Post by: RAN on 05/24/2021 09:46 pm
Comparing engine counts of 9 and 28 and assume an individual engine has a 99% reliability (both during startup sequence and between startup and nominal engine cutoff).
For 9 engines requiring 9 to be green during startup to avoid a scrub, launches have a 8.6% scrub rate (1 - .99^9).
For 28 engines requiring 28 to launch, 24.5% scrub rate (1 - .99^28).
However during flight, we can still make orbit after losing 1 out of 9 (Falcon 9 has done this) or 3 out of 28 engines (assumption for Superheavy).
For 9 engines requiring 8+ to reach orbit, success rate is 99.65%
For 28 engines requiring 25+ to reach orbit, success rate is 99.98%
I used sequential and k out of n formulas from here: https://web.cortland.edu/matresearch/SerieslParallelSTART.pdf (https://web.cortland.edu/matresearch/SerieslParallelSTART.pdf)
Post by: AstroWare on 05/24/2021 10:34 pm
The relationship between engine counts and scrub chance / reliability to orbit seems similar to highly available software systems that are either sequential or k out of n parallel. A larger engine count will likely lead to higher scrub rate but also a higher reliability for reaching orbit.Does anyone care to speculate on if SpaceX will have to do opposing-pair shutdowns like N1? Especially for engine loss of the outer ring. (That would affect the calculations above)
Comparing engine counts of 9 and 28 and assume an individual engine has a 99% reliability (both during startup sequence and between startup and nominal engine cutoff).
For 9 engines requiring 9 to be green during startup to avoid a scrub, launches have a 8.6% scrub rate (1 - .99^9).
For 28 engines requiring 28 to launch, 24.5% scrub rate (1 - .99^28).
However during flight, we can still make orbit after losing 1 out of 9 (Falcon 9 has done this) or 3 out of 28 engines (assumption for Superheavy).
For 9 engines requiring 8+ to reach orbit, success rate is 99.65%
For 28 engines requiring 25+ to reach orbit, success rate is 99.98%
I used sequential and k out of n formulas from here: https://web.cortland.edu/matresearch/SerieslParallelSTART.pdf (https://web.cortland.edu/matresearch/SerieslParallelSTART.pdf)
Falcon doesn't because it can compensate by gimballing and throttling. Plus the much smaller diameter of the stage means less torque from the engine loss.
SH central cluster can gimbal, but the outer ring I believe is still planning to be non-gimballing. I don't remember if they are fixed or variable thrust but I'd assume they would keep them throttlable. Perhaps that is enough? Obviously it is better if they don't have to shutdown healthy engines...
Just curious!
Post by: Robotbeat on 05/25/2021 12:43 am
They might do it if they lose so many on one side that the angle of attack of the rocket with respect to the airstream becomes so extreme that there are structural issues.
Post by: chopsticks on 05/25/2021 01:58 am
Post by: TorenAltair on 05/25/2021 03:14 am
Post by: DreamyPickle on 05/25/2021 10:42 am
Also the N-1 was just one example of a many-engined rocket from 50 years ago. Similarities exist with the SuperHeavy but they're weak.
Remember how people kept bringing up the Space Shuttle as proof that Falcon 9 reusability can't work? Most of the shuttle's problems were actually specific to the shuttle itself and don't apply to reusable vehicles in general.
Post by: realnouns on 05/27/2021 06:52 pm
Might we come back to this specific mission, please? I think general technical discussions can find a lot of threads further down the forum.
Do we know that the first Superheavy booster flight will feature all 28 engines?
Also, does Starship's non-vacuum engines get used at all during flight, or just landing?
Post by: Lars-J on 05/27/2021 07:17 pm
Do we know that the first Superheavy booster flight will feature all 28 engines?
No, we do not know.
Also, does Starship's non-vacuum engines get used at all during flight, or just landing?
Yes the non-vacuum Raptors are used during ascent, they are the only main engines that can gimbal/steer. They are also needed for thrust-weight ratio reasons. All 6 Raptors will ignite after staging.
Post by: AC in NC on 05/28/2021 12:30 am
All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Post by: ThePonjaX on 05/28/2021 01:07 am
I like the idea of this been the first time we're going to see the vacuum raptor in action :)All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Post by: chopsticks on 05/28/2021 02:37 am
How could it be done otherwise and why? It just seems obvious to me that's what they would do. HOPEFULLY, all 6 will ignite and not just 4 or 5!All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Post by: Steven Pietrobon on 05/28/2021 07:33 am
All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Simulations show that three sea level Raptors on the second stage are sufficient to perform the flight. Whether SpaceX will add the three vacuum Raptors, we do not know.
Post by: Zed_Noir on 05/28/2021 02:21 pm
How could it be done otherwise and why? It just seems obvious to me that's what they would do. HOPEFULLY, all 6 will ignite and not just 4 or 5!All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Yeah. Don't think there is a current vacuum test chamber that is rated for 3 Vacuum Raptors & 3 sea level Raptors together. The inaugural Super Heavy orbital flight will permit SN20 to be a relatively cheap flying engine test stand.
Post by: realnouns on 05/28/2021 03:45 pm
Do we know that the first Superheavy booster flight will feature all 28 engines?
No, we do not know.
Depending if they're trying to actually land this thing on Phobos/Deimos, that's a lot of Raptor engines to dump in the ocean
Post by: ChrML on 05/28/2021 05:22 pm
So that’s exact what I expect for 28 engines: difficulty at first but long-term no problem. Is this unreasonable?I think it's reasonable. Every problem that occurs has some fix, and after a while all common problems will be eliminated and the vehicle is reliable. Raptor is a lot more complex than Merlin, but not impossible.
If it's a software problem, they add more theories to the software test setup to cover the problem, and that same problem will never happen again in a future iteration.
If it's a hardware problem I trust they have some other way of addressing it while making sure it doesn't happen again.
Post by: OTV Booster on 05/28/2021 08:04 pm
I wonder what the startup sequence would be like for a 28 engine cluster?Sounds like you just outlined a smart pre-flight test program. Maybe a series of one at a time static fires followed by lighting off combos and building to a full up static fire.
A fascinating engineering problem!
Perhaps something like starting opposing pairs together with additional pairs coming online separated by milliseconds. Probably the critical gimbal engines first then the outer ring.
Anyone familiar with how the Falcon Heavy lights?
Post by: OTV Booster on 05/28/2021 08:26 pm
OTOH, a rocket engine hits steady state in 2-3 seconds. From there on it's diminishing returns. Individual static tests on all the engines can all be done in one 60-80 second test. Purpose: manifold characterization. Are there anomalies that match up with specific manifold positions? Next up, get a sense of the interactions with different startup combinations and increased manifold flow rates. Validate the models. CFD is hard.The N-1's biggest issues were effects of vibration and heating on the closely clustered engines. Certainly, computer simulation has made great strides in predicting these interactions, but I will point out that the interaction of 28 such powerful engines, their exhaust impingements, etc., gets closer and closer to chaotic. And chaos theory is not a friendly taskmaster.
I guess I'd be more likely to believe that the first SH stages will fly just fine had there been any 28-engine cluster test firings on the ground. Heck, the F-1 engines on the Saturn V were designed to handle the radiant heat and vibration from their neighboring engines, but you'll notice that a kludge -- thick thermal batting -- was plastered onto the outside of those engine bells after initial clustered test firings indicated that the extra protection and thermal coating was required to bring the engines within desired safety parameters. Again, yes, there has been more than 50 years of advancement in computer simulations. But the simulations are never any better than one's assumptions, and it was the sets of assumptions, and not failure of simulations, that caused the N-1 problems, and required a kludged-on layer of protection to be added onto the F-1s.
Besides, with the rather extreme replacement rate these Raptors seem to undergo during checkout and after static fires, once attached to the prototype Starships, it seems that the Raptors are also still in fairly early prototype stages themselves. So, the performance assumptions for the current version of the Raptor may be even more poorly defined than you might think.
Personally, I'd rather see SH stages sit on that orbital test mount and fire up their clusters for full-duration tests before bothering to mount a Starship on top. If for no other reason than to iron out all of the poorest assumptions before risking the loss of the R-Vacs that will likely be installed on any SS that gets put on top of an SH. Of course, that would take several months and endanger his build/launch/test site unnecessarily, and it seems Musk is in enough of a hurry that he doesn't want to go through that whole process. Still... even SpaceX might get surprised at the backlash if an SH blows up one or two km into the air. Because that would be, shall we say... a significant RUD. ;)
The marginal risk-reduction value of static fire time decreases significantly as the test gets longer. They would probably get 80% of the set of data from a 5-second test that they would from a 2 minute test. On the other hand, the work to build a test stand and flame trench that can take a 2-minute firing is massively larger than building a pad for a 5 second test.
Also, this booster probably isn't being reflown, and the next one will be built in a few months. At some point, it's faster and simpler to fly it than to test it longer on the ground. That way they get flight data too.
At the same time build a methodology for fast testing iteration. Try to get 2-3 test sequences per day. Assuming no show stoppers testing might only take 2-3 weeks. Then replace some concrete and go for orbit.
Post by: OTV Booster on 05/28/2021 08:59 pm
Opinion follows.Do we know that the first Superheavy booster flight will feature all 28 engines?
No, we do not know.
Depending if they're trying to actually land this thing on Phobos/Deimos, that's a lot of Raptor engines to dump in the ocean
True that but... There's a question on how fast and how profound the raptors change. SX is happy to scrap partially built ships if they see no reason to test them. I think we've only seen one used raptor cycled back into use. Even if they save the raptors after an orbital flight would we expect to see them reused?
Same for the BN. It'll be a throw away for a while. It'll face mods. Maybe major mods. No biggie. As SX approaches operational with a more mature and less changing design (engine and airframe), we should see more emphasis on reusability. They may even do recovery and still not reuse.
Post by: rsdavis9 on 05/28/2021 09:19 pm
Same for the BN. It'll be a throw away for a while. It'll face mods. Maybe major mods. No biggie. As SX approaches operational with a more mature and less changing design (engine and airframe), we should see more emphasis on reusability. They may even do recovery and still not reuse.
After all you don't actually need to reuse a booster to know if it is reusable.
Recover engines.
Inspect.
No need to use it again at first.
Post by: Alberto-Girardi on 05/28/2021 09:28 pm
All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Simulations show that three sea level Raptors on the second stage are sufficient to perform the flight. Whether SpaceX will add the three vacuum Raptors, we do not know.
Thanks! I understood that all 6 raptors would be needed after separation, but this is wrong as you say. Are only 3 raptors needed only for this particular flight with no payload, with the operational launches needing 6 engines?
Post by: Lars-J on 05/28/2021 09:34 pm
All 6 Raptors will ignite after staging.Opinion or fact? ;) But I like the optimism and am pulling for you being right.
Simulations show that three sea level Raptors on the second stage are sufficient to perform the flight. Whether SpaceX will add the three vacuum Raptors, we do not know.
Thanks! I understood that all 6 raptors would be needed after separation, but this is wrong as you say. Are only 3 raptors needed only for this particular flight with no payload, with the operational launches needing 6 engines?
Operational launchers will certainly require all 6 engines. It is theoretically possible that a stripped down SN20 could make it to orbit with 3 engines only, but I personally consider this unlikely - for two reasons:
1) SN20 (or whatever will be the first orbital Starship) is unlikely to be as light as some people imagine
2) RVac engines appear to be deep into the testing phase, and why wouldn't they want to fire them on a real flight? They will want to retire as MUCH risk as possible on a first orbital attempt, especially if it is an expendable launch
Post by: punder on 05/31/2021 06:06 pm
Agree, but a lot of the “combo” testing has taken place already, with SN8 and subsequent flights, with lessons learned and subsequent model refinement each time.I wonder what the startup sequence would be like for a 28 engine cluster?Sounds like you just outlined a smart pre-flight test program. Maybe a series of one at a time static fires followed by lighting off combos and building to a full up static fire.
A fascinating engineering problem!
Perhaps something like starting opposing pairs together with additional pairs coming online separated by milliseconds. Probably the critical gimbal engines first then the outer ring.
Anyone familiar with how the Falcon Heavy lights?
And more generically, SpaceX must be far ahead of the industry baseline for this sort of modeling, having flown so many 9- and 27-engine clusters over the years. They didn’t have that knowledge base when they worked the bugs out of F9–they created it by doing so. So they have knowledge that no one else has (Rocket Lab included—similar issues but much lower energies). NASA most likely has studied the data for validation, but can’t apply it to anything of their own or pass it on to other industry players.
Still... as Elon says, “Excitement guaranteed!” ;D
Post by: Jansen on 06/04/2021 12:28 pm
Period from 20 June 2021 to 20 Dec 2021
https://apps.fcc.gov/els/GetAtt.html?id=275103
Post by: edzieba on 06/04/2021 12:45 pm
More FCC documents here: https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021 (https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021)
Some notable bits from the email chains:
- "Maximum flight altitude:380,160' AGL (0-72 miles)"
- 2GHz low bandwidth transceiver at base of Super Heavy, all other comms on Super Heavy and Starship are 2.4GHz (i.e. no Starlink)
- "This STA will expire as soon as launch has been completed or 10 December 2021, whichever occurs first."
- "One (1) or more of six (6) blackout zones (BOZs) MAY be imposed as follows: (1) 1500 nautical mile radius centered at 22N160W; (2) 1500 nautical mile radius centered at 33.25N119.57W; (3) 1500 nautical mile radius centered at 4.11N175.2W; (4) 1500 nautical mile radius centered at 57.46N152.38W; (5) 1500 nautical mile radius centered at 32.37N106.47W. (6) 1500 nautical mile radius centered at 57.34N7.35W. The final launch schedule for this SpaceX mission will ultimately determine which, if any BOZ will be implemented."
I've plotted those points on a map: https://www.google.com/maps/d/u/0/edit?mid=1AHv8RFOWWBvZB3JAtPSeeECCeLb1LuAF&usp=sharing (https://www.google.com/maps/d/u/0/edit?mid=1AHv8RFOWWBvZB3JAtPSeeECCeLb1LuAF&usp=sharing)
Point 1 is the expected Starship splashdown zone off of Kauai.
Point 3 is east of the Marshall Islands, and likely a contingency site that still has some EDL coverage from the RRBMDTS (Kwajalein range).
From there, things get interesting:
Point 2 is San Nicolas Island, off the coast of California, which hosts a USN base is and is part of the Pacific Missile Range.
Point 4 is the Pacific Spaceport Complex on Kodiak Island.
Point 5 White Sands missile range.
Point 6 is the RAF Deep Sea Range, South Uist lsland, off the north-west coast of Scotland.
Post by: Giovanni DS on 06/04/2021 12:47 pm
Post by: woods170 on 06/04/2021 01:10 pm
Is it safe to leave those raptors on the sea floor? I imagine those would be worth fishing out for some, not necessarily friendly, entity.
It is safe to leave them on the sea bed.
Same goes for the RS-25, the F-1 and even the RD-180. Apart from Jeff Bezos nobody has ever bothered to pick them up from the ocean floor. Not even the Chinese.
Also, why do people always assume that wreckage from engines is enough to reverse-engineer them?
I can tell you that it is not nearly enough to make a working clone.
Post by: edzieba on 06/04/2021 01:18 pm
Minor point, but many nations (including the US!) have indeed recovered spent ICBM stages to examine, and not because they want to replicate them (mainly to confirm models of adversary capability match actual adversary capability). Cost/benefit rarely works out, as 'benefit' is confirmation of existing estimates, and 'cost' is the potential of being caught in someone's territorial waters pilfering hardware, as well as high financial cost of deep-ocean search & recovery.Is it safe to leave those raptors on the sea floor? I imagine those would be worth fishing out for some, not necessarily friendly, entity.
It is safe to leave them on the sea bed.
Same goes for the RS-25, the F-1 and even the RD-180. Apart from Jeff Bezos nobody has ever bothered to pick them up from the ocean floor. Not even the Chinese.
Post by: Giovanni DS on 06/04/2021 01:23 pm
Also, why do people always assume that wreckage from engines is enough to reverse-engineer them?
I can tell you that it is not nearly enough to make a working clone.
Thanks, I understand your point about cloning, clearly cloning it is more about the production process than the engine itself.
I would look more for the detailed internal architecture, metals, etc. Not a rocket scientist but as a SW developer, having access to some code base for sure can speed up things even if you cannot use it as-is.
Raptor cycle is unlike any other engine as far I understood, perhaps there could be expensive lessons to be learned even from damaged engines.
Post by: mark_m on 06/04/2021 02:38 pm
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
Post by: rsdavis9 on 06/04/2021 02:51 pm
My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
Well it all depends on where the engines cutoff.
Currently the SECO second stage engine cutoff occurs over africa?
From that point you have to draw an ellipse around the earth.
The cutoff point can be the apogee or the perigee.
1. If the perigee then you have achieved orbit. Because it will come back around to the same point after achieving apogee 180 degrees around earth. (assumes cutoff is above the atmosphere)
2. If the apogee then it will have a perigee 180 degrees around earth and probably reenter because it will be further into the atmosphere than the cutoff point.
Of course a second engine start to change the orbit is possible.
So probably what they are doing is 2. Without another engine start to raise the orbit reentry will occur less than 180 degrees around the earth from the engine cutoff. Is the marshall islands less than 180 degrees? Remember to come down in hawaii the reentry starts further westward.
Post by: daedalus1 on 06/04/2021 02:51 pm
My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
If it reenters naturally after 3/4 of circumference, then it's suborbital. If it has to use engines to return (slow down), then it's orbital.
Post by: mark_m on 06/04/2021 03:02 pm
My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
If it reenters naturally after 3/4 of circumference, then it's suborbital. If it has to use engines to return (slow down), then it's orbital.
Let me restate my question. My understanding and paraphrasing of the claim is: If a body in free fall travels more than halfway around the globe without impacting, it will always make it all the way around (ignoring drag, etc.). My question is, is that a true statement?
Post by: eriblo on 06/04/2021 03:12 pm
A spacecraft can be injected at any point in its orbit, not just apogee or perigee. If you inject right "after" perigee in an elliptical orbit you will complete a large fraction of an orbit before reentering.My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
Well it all depends on where the engines cutoff.
Currently the SECO second stage engine cutoff occurs over africa?
From that point you have to draw an ellipse around the earth.
The cutoff point can be the apogee or the perigee.
1. If the perigee then you have achieved orbit. Because it will come back around to the same point after achieving apogee 180 degrees around earth. (assumes cutoff is above the atmosphere)
2. If the apogee then it will have a perigee 180 degrees around earth and probably reenter because it will be further into the atmosphere than the cutoff point.
Of course a second engine start to change the orbit is possible.
So probably what they are doing is 2. Without another engine start to raise the orbit reentry will occur less than 180 degrees around the earth from the engine cutoff. Is the marshall islands less than 180 degrees? Remember to come down in hawaii the reentry starts further westward.
Post by: daedalus1 on 06/04/2021 03:14 pm
My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
If it reenters naturally after 3/4 of circumference, then it's suborbital. If it has to use engines to return (slow down), then it's orbital.
Let me restate my question. My understanding and paraphrasing of the claim is: If a body in free fall travels more than halfway around the globe without impacting, it will always make it all the way around (ignoring drag, etc.). My question is, is that a true statement?
Someone might correct me on this, but my understanding is that in that circumstance the globe is centre of one of the two elliptical points. So it will not impact the surface.
Post by: edzieba on 06/04/2021 03:15 pm
Let me restate my question. My understanding and paraphrasing of the claim is: If a body in free fall travels more than halfway around the globe without impacting, it will always make it all the way around (ignoring drag, etc.). My question is, is that a true statement?No. You can have a trajectory that just clips the surface at perigee and is therefore suborbital, and there is no requirement for that to be no more than 1/2 the diameter of the orbited body.
However, the difference in delta-V between a suborbital trajectory that gets halfway around the planet before entering the atmosphere and an orbital trajectory is so small that you may as well produce that extra zephyr of a fart and go fully orbital. And with the practical requirements to avoid entering the atmosphere and that your initial launch trajectory starts your orbit from somewhere past perigee (because we launch with actual rockets rather than an instantaneous velocity impulse), you have to put a lot of work into trajectory shaping to avoid orbiting if you want to ballistically re-enter that far downrange.
Post by: Yggdrasill on 06/04/2021 03:49 pm
My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)I discussed that a bit here: https://forum.nasaspaceflight.com/index.php?topic=52134.msg2238213#msg2238213
Edziebas explanation above is good.
Post by: aero on 06/04/2021 06:49 pm
Maybe this need to be its own topic thread?
Post by: RAN on 06/04/2021 08:01 pm
Little change of subject, but shouldn't an orbital Starship be a named vehicle? Lindberg flew the "Spirit of Saint Louis," and all of the space shuttles were named, most aircraft are named, all boats and so on.
Maybe this need to be its own topic thread?
I would personally really like them to have names ;D very Culture-esque. no idea whether it will happen though
Post by: niwax on 06/04/2021 08:11 pm
Little change of subject, but shouldn't an orbital Starship be a named vehicle? Lindberg flew the "Spirit of Saint Louis," and all of the space shuttles were named, most aircraft are named, all boats and so on.
Maybe this need to be its own topic thread?
I would personally really like them to have names ;D very Culture-esque. no idea whether it will happen though
In a Culture way I thought they might want to give themselves names and this is literally what happened on the first try:
Post by: Surfdaddy on 06/04/2021 09:25 pm
I believe the low point of an Apollo moon orbit was quite low by earth standards, due to no atmosphere to worry about.
Post by: Joffan on 06/04/2021 11:15 pm
Post by: rakaydos on 06/04/2021 11:35 pm
Icarus flew too close to the sun and plummeted to earth. Daedelus survived the flight.Little change of subject, but shouldn't an orbital Starship be a named vehicle? Lindberg flew the "Spirit of Saint Louis," and all of the space shuttles were named, most aircraft are named, all boats and so on.I would personally really like them to have names ;D very Culture-esque. no idea whether it will happen though
Maybe this need to be its own topic thread?
Sounds like the first two test ships?
Post by: daedalus1 on 06/05/2021 06:46 am
Post by: su27k on 06/05/2021 11:15 am
Little change of subject, but shouldn't an orbital Starship be a named vehicle? Lindberg flew the "Spirit of Saint Louis," and all of the space shuttles were named, most aircraft are named, all boats and so on.
Maybe this need to be its own topic thread?
Old threads for this purpose:
ITS (Formerly known as MCT) Names? (https://forum.nasaspaceflight.com/index.php?topic=35208.0)
BFR/BFS/ITS Naming speculation thread (https://forum.nasaspaceflight.com/index.php?topic=43887.0)
Providing naming options for individual SpaceX Starships (https://forum.nasaspaceflight.com/index.php?topic=47557.0)
Since the first few orbital Starships have low chance of surviving the reentry, there's really no need to name them.
Post by: OTV Booster on 06/05/2021 02:40 pm
Sufficient to reverse engineer? No. Necessary? Probably not. Helpful? Yes. How many times has somebody here in NSF, especially the wiser more experienced members, itched to get their hands on an engine to verify a design speculation?Is it safe to leave those raptors on the sea floor? I imagine those would be worth fishing out for some, not necessarily friendly, entity.
It is safe to leave them on the sea bed.
Same goes for the RS-25, the F-1 and even the RD-180. Apart from Jeff Bezos nobody has ever bothered to pick them up from the ocean floor. Not even the Chinese.
Also, why do people always assume that wreckage from engines is enough to reverse-engineer them?
I can tell you that it is not nearly enough to make a working clone.
Worthwhile? Can only be decided by those with an interest and the capability.
Post by: OTV Booster on 06/05/2021 03:39 pm
Let me take a stab at this. First, some simplifications. Earth is a perfect sphere, and it has no atmosphere.My searching has failed me, but back during the discussion of "orbital" vs. "3/4 of the way around the Earth" someone made a statement that anything that goes more than halfway around the globe has to be "orbital". (I'm assuming this claim is only talking about a ballistic segment of the flight.)
IANARS, but naïvely this makes some intuitive sense to me—any trajectory that would intersect the Earth/planet/whatever would do so less than halfway around, right? But I didn't see any followup discussion, and I was wondering if that is really the case. Thanks for any elucidation!
If it reenters naturally after 3/4 of circumference, then it's suborbital. If it has to use engines to return (slow down), then it's orbital.
Let me restate my question. My understanding and paraphrasing of the claim is: If a body in free fall travels more than halfway around the globe without impacting, it will always make it all the way around (ignoring drag, etc.). My question is, is that a true statement?
The only reasons rockets initially go 'up' is clear the atmosphere. With no atmosphere it is more efficient to launch horizontal which is tangent to the surface.
Let's throw in two more simplification. First, the planet is not rotating. Second, instead of a rocket that adds impulsel over time, let's shoot the gizmo out of a cannon so all the impulse comes all at once. Shoot the gizmo. It hits some distance out. Remember, this is taking place on a sphere, so 'some distance out' is also some distance around the planet. This is suborbital.
Increase the firing charge and it goes further, but still hits. Keep increasing the firing charge and it can go further. It can go half way around, 3/4 around, 99.99999% around. This is all suborbital. On that last shot, the gizmo hits a little ways behind the cannons breach, but it didn't make it all around.
Increase the charge a bit more, move the cannon out of the way after firing so it doesn't get hit, and the gizmo will make it all the way around and pass through where the cannon was. It will keep going and will repeat it's trajectory. It is in orbit.
As a refinement, if the gizmo has a rocket engine, it can fire this at the high point of its orbit. This will be exactly 180deg from the cannon. If the rocket engine fires exactly right, the orbit will go from elliptical to circular with a radius exactly the same as that high point where the engines fired. As a point of interest, this is known as a Hohmann transfer orbit.
Rockets don't get all their impulse at one time and they have atmospheric issues. This muddies up any answer to your question but the above simplifications hopefully get to the heart of it.
Touching on an issue implied by this whole line of questions and putting the atmosphere back into play, the closer the gizmo gets to a full orbit, the closer the reentry velocity will be to orbital reentry velocity.
Warning: IAABAARS (I Am At Best An Amateur Rocket Scientist)
Post by: Greg Hullender on 06/05/2021 04:02 pm
It can go half way around, 3/4 around, 99.99999% around.Uh, actually, no. Look at the equation for an orbit: radius = p/(1 + ecc * cos(theta)) where radius is the distance from the center of the Earth, p is a constant (the semi-latus rectum of the orbit, but that's not important), ecc is the eccentricity, and theta is the angle between the cannon and the current position of the shell.
At 180°, the shell is at its apex (the perigee). But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Post by: cdebuhr on 06/05/2021 04:40 pm
This. To clarify a bit more, using and slightly extending OTVBooster's simplifying assumptions (no atmosphere, no planetary rotation, perfectly smooth and spherically symmetric planetary body, no mascons, no external gravitational perturbations all impulse delivered instantaneously at the moment of launch, and the "vehicle" is a point-like particle ... talk about spherical cows!), suborbital means the periapsis is below the planetary surface, while if periapsis is above the surface, you're orbital. That's pretty much it. Note that given the assumptions above, if you fire your projectile exactly tangent to the surface, then the point of launch will be either the periapsis, in which case you're orbital, or apoapsis, in which case you're not and the projectile will auger into the surface immediately. True tangent launch on a suborbital trajectory that goes anywhere is actually impossible. If you want to launch a suborbital projectile that goes halfway, 3/4, or even 99.99999% of the way around, you can either fire surface-parallel at non-zero elevation, or fire from the surface with an elevation angle raised amount above the surface-tangent.It can go half way around, 3/4 around, 99.99999% around.Uh, actually, no. Look at the equation for an orbit: radius = p/(1 + ecc * cos(theta)) where radius is the distance from the center of the Earth, p is a constant (the semi-latus rectum of the orbit, but that's not important), ecc is the eccentricity, and theta is the angle between the cannon and the current position of the shell.
At 180°, the shell is at its apex (the perigee). But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Post by: soyuzu on 06/05/2021 05:56 pm
But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
Post by: steveleach on 06/05/2021 08:26 pm
There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
Post by: ppb on 06/06/2021 02:31 am
In a Culture way I thought they might want to give themselves names and this is literally what happened on the first try:
Is Nomadd aware of this? That would be an entirely fitting name for SN20.
Post by: cdebuhr on 06/06/2021 03:09 am
While I suspect that your assessment of what this discussion really signifies is spot on, discussion of the "spherical cow" ideal case isn't totally useless. Ideal examples sit at the boundaries of what the physics will allow in theory, even in the most absurdly idealized case, and thus form the fundamental foundation upon which we layer the all the obnoxious intrusions of physical reality. They provide the starting point. Show me any high school physics text, and I'll show you a tome completely dedicated to the study of spherical cows. What physics student hasn't studied ideal harmonic oscillators based on mythical ideal springs?There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
All that said, I'm sure we'll all be much happier when rockets start flying again and we have something real to talk about!
Post by: cwr on 06/06/2021 03:27 am
There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
It seems to me that none of this discussion about sub-orbital versus orbital is because the participants
haven't read the SpaceX FCC application whose link is at the beginning of this thread.
In the "Flight Profile" section it says:
"The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate
approximately 170 seconds into flight. The Booster will then perform a partial return and land in the
Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying
between the Florida Straits. It will achieve orbit until performing a powered, targeted landing
approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing."
I'm surprised that the Soviet FOBS launches of the 60s wasn't mentioned in the discussion.
The payloads achieved orbit and were de-orbited before completing a full orbit, Just like Gagarin's
Vostok flight.
Carl
Post by: meekGee on 06/06/2021 04:27 am
There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
I think it's been explored often in ICBM circles, and is the original meaning of "suborbital".
The "Suborbital" that VG and BO/NS are doing is very very very suborbital. It's what a sounding rocket does. Calling it "suborbital" is charitable. I'm saying it because on the grand scheme of Earth, you can just approximate it with a parabola, since the gravity vector doesn't have time to shift. A true suborbital trajectory is elliptical.
... and, I like the energy definition of suborbital better, since there are orbital-energy trajectories that still intersect the surface of the Earth, and from a vehicle capability point of view, are still orbital. (e.g. "suborbital around the moon", as folks here often point out) - all that's gone with an energy-based definition.
Post by: OTV Booster on 06/06/2021 03:30 pm
So you're saying that in the idealized world described it is impossible to launch tangent and hit anywhere on the back 180?It can go half way around, 3/4 around, 99.99999% around.Uh, actually, no. Look at the equation for an orbit: radius = p/(1 + ecc * cos(theta)) where radius is the distance from the center of the Earth, p is a constant (the semi-latus rectum of the orbit, but that's not important), ecc is the eccentricity, and theta is the angle between the cannon and the current position of the shell.
At 180°, the shell is at its apex (the perigee). But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
My amateur status is more real than my math skills but I do have some conceptual questions. On a flat earth, a ballistic trajectory is a parabola. On a spherical earth it is something else. In that idealized earth the minimum viable orbital cannon shot would be the special case of an eclipse called a circle. Between the short round that almost follows a parabola and the circular orbit shot is something else, possibly an ellipse, but that is unclear to me.
Would the short round trajectory (not a parabola) be symmetrical? If it's a segment of an ellipse it would be. My gut says it would be a non-conic shape, but I don't really know. If the trajectory is non-conic it would have no symmetry and it should be possible to hit the back 180. It looks like my question hinges on 'not a parabola' being, or not being, an ellipse.
Post by: OTV Booster on 06/06/2021 03:39 pm
Hmmm. Maybe you just answered my 'not a parabola'/elliptical question.There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
I think it's been explored often in ICBM circles, and is the original meaning of "suborbital".
The "Suborbital" that VG and BO/NS are doing is very very very suborbital. It's what a sounding rocket does. Calling it "suborbital" is charitable. I'm saying it because on the grand scheme of Earth, you can just approximate it with a parabola, since the gravity vector doesn't have time to shift. A true suborbital trajectory is elliptical.
... and, I like the energy definition of suborbital better, since there are orbital-energy trajectories that still intersect the surface of the Earth, and from a vehicle capability point of view, are still orbital. (e.g. "suborbital around the moon", as folks here often point out) - all that's gone with an energy-based definition.
Post by: OTV Booster on 06/06/2021 03:40 pm
You take all the fun out of spherical cows 8)There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
It seems to me that none of this discussion about sub-orbital versus orbital is because the participants
haven't read the SpaceX FCC application whose link is at the beginning of this thread.
In the "Flight Profile" section it says:
"The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate
approximately 170 seconds into flight. The Booster will then perform a partial return and land in the
Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying
between the Florida Straits. It will achieve orbit until performing a powered, targeted landing
approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing."
I'm surprised that the Soviet FOBS launches of the 60s wasn't mentioned in the discussion.
The payloads achieved orbit and were de-orbited before completing a full orbit, Just like Gagarin's
Vostok flight.
Carl
Post by: meekGee on 06/06/2021 03:53 pm
Yes, correct.There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
It seems to me that none of this discussion about sub-orbital versus orbital is because the participants
haven't read the SpaceX FCC application whose link is at the beginning of this thread.
In the "Flight Profile" section it says:
"The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate
approximately 170 seconds into flight. The Booster will then perform a partial return and land in the
Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying
between the Florida Straits. It will achieve orbit until performing a powered, targeted landing
approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing."
I'm surprised that the Soviet FOBS launches of the 60s wasn't mentioned in the discussion.
The payloads achieved orbit and were de-orbited before completing a full orbit, Just like Gagarin's
Vostok flight.
Carl
The document does not describe a suborbital trajectory but an aborted orbital one.
The rest of the suborbital discussion is good, it just doesn't directly apply here. Probably.
Post by: Greg Hullender on 06/06/2021 09:22 pm
So you're saying that in the idealized world described it is impossible to launch tangent and hit anywhere on the back 180?Correct.
My amateur status is more real than my math skills but I do have some conceptual questions. On a flat earth, a ballistic trajectory is a parabola. On a spherical earth it is something else.It's a perfect ellipse. (Edit: or hyperbola. Or circle. etc. But always a conic.) If we know the muzzle velocity and the angle of elevation of the gun, we can compute the exact orbital elements, but it is always an ellipse. When the angle is zero (as in your example), the shell cannot impact the "back side" of the planet unless it passes through it first. If you use a different elevation of the gun, though, it's not hard to hit the other side.
Post by: Comga on 06/07/2021 03:37 am
There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
I think it's been explored often in ICBM circles, and is the original meaning of "suborbital".
The "Suborbital" that VG and BO/NS are doing is very very very suborbital. It's what a sounding rocket does. Calling it "suborbital" is charitable. I'm saying it because on the grand scheme of Earth, you can just approximate it with a parabola, since the gravity vector doesn't have time to shift. A true suborbital trajectory is elliptical.
... and, I like the energy definition of suborbital better, since there are orbital-energy trajectories that still intersect the surface of the Earth, and from a vehicle capability point of view, are still orbital. (e.g. "suborbital around the moon", as folks here often point out) - all that's gone with an energy-based definition.
Bingo
My opinion has been stated previously that the reason to call SS2 and New Shephard launches "sub-orbital" is to associate them with orbital flights, even by exclusion.
And an energy criterion for "orbital" is equivalent to a semi-major axis criterion.
If a trajectory is in an orbit with enough energy to go around the world, the semi-major axis of the path is greater than the radius of the Earth (plus some margin for the atmosphere.)
That means a free return trajectory around the Moon is clearly "orbital".
If Gargarin's Vostok, the FOBS, and Starship/Super Heavy Flight 1 need to perform retro-burns to bring them down either before or after they complete an orbit, they are "orbital"
Post by: OneSpeed on 06/07/2021 03:51 am
If Gargarin's Vostok, the FOBS, and Starship/Super Heavy Flight 1 need to perform retro-burns to bring them down either before or after they complete an orbit, they are "orbital"
The Starship/SuperHeavy first flight doesn't have to have a retro burn, because its ellipse can enter the sensible atmosphere at perigee. But that would still be a valid test of an orbital re-entry.
https://forum.nasaspaceflight.com/index.php?topic=47179.msg2240197#msg2240197
Post by: meekGee on 06/07/2021 03:56 am
Thx...There used to be a clear distinction between orbital & suborbital , a wide gulf between the two. A space launch vehicle was one or the other. But now SpaceX have, as they have with other industry terms like "flight proven", thrown themselves directly into the grey area and forced us to probe concepts that never had a clear boundary. This is what has lead us to strained definitions involving spherical cows in a vacuum.But because cos(-theta) = cos(theta), the orbit is symmetrical. (As if I needed to prove that.) :-) As a result, if it does not touch the ground in the first 180°, it will not touch the ground at all until it reaches the launch point.
Exactly, because orbit is symmetrical, if it touches the ground at some theta between 90-180°, then it must have travelled another theta above ground BEFORE the point of the cannon. So the angular distance between these two intersections with ground is 2theta, a value greater than 180°
I suspect this whole discussion is just a sign that we're all bored because not a lot is happening at the moment.
I think it's been explored often in ICBM circles, and is the original meaning of "suborbital".
The "Suborbital" that VG and BO/NS are doing is very very very suborbital. It's what a sounding rocket does. Calling it "suborbital" is charitable. I'm saying it because on the grand scheme of Earth, you can just approximate it with a parabola, since the gravity vector doesn't have time to shift. A true suborbital trajectory is elliptical.
... and, I like the energy definition of suborbital better, since there are orbital-energy trajectories that still intersect the surface of the Earth, and from a vehicle capability point of view, are still orbital. (e.g. "suborbital around the moon", as folks here often point out) - all that's gone with an energy-based definition.
Bingo
My opinion has been stated previously that the reason to call SS2 and New Shephard launches "sub-orbital" is to associate them with orbital flights, even by exclusion.
And an energy criterion for "orbital" is equivalent to a semi-major axis criterion.
If a trajectory is in an orbit with enough energy to go around the world, the semi-major axis of the path is greater than the radius of the Earth (plus some margin for the atmosphere.)
That means a free return trajectory around the Moon is clearly "orbital".
If Gargarin's Vostok, the FOBS, and Starship/Super Heavy Flight 1 need to perform retro-burns to bring them down either before or after they complete an orbit, they are "orbital"
Also, I just realized I said "in ICBM circles" on a trajectory discussion, and so I apologize. That door should remain closed.
And yes about association by exclusion, making "sub-" hint at "almost-"...
Shrug. It doesn't matter anymore. But I still expect one of these clowns to "welcome to the club" when Starship carries its first crew.
Post by: OTV Booster on 06/07/2021 04:29 pm
You've made my day. You helped me learn something. Thanks.So you're saying that in the idealized world described it is impossible to launch tangent and hit anywhere on the back 180?Correct.My amateur status is more real than my math skills but I do have some conceptual questions. On a flat earth, a ballistic trajectory is a parabola. On a spherical earth it is something else.It's a perfect ellipse. (Edit: or hyperbola. Or circle. etc. But always a conic.) If we know the muzzle velocity and the angle of elevation of the gun, we can compute the exact orbital elements, but it is always an ellipse. When the angle is zero (as in your example), the shell cannot impact the "back side" of the planet unless it passes through it first. If you use a different elevation of the gun, though, it's not hard to hit the other side.
Post by: capoman on 06/08/2021 12:13 pm
Post by: meekGee on 06/08/2021 03:53 pm
All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.Not sure about that..
Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.
The best definition is whether at insertion you had enough energy to ballistically go around the earth.
Post by: ppb on 06/08/2021 11:51 pm
I agree the speed/energy definition of full orbital is the simplest. At insertion above most of the atmosphere, flight path angle will be close to zero and inertial speed will be at least 7.8 km/s.All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.Not sure about that..
Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.
The best definition is whether at insertion you had enough energy to ballistically go around the earth.
Post by: meekGee on 06/09/2021 12:17 am
I think what I and several others were saying is that if you have a vehicle capable of such an orbit, then it should be considered orbital.I agree the speed/energy definition of full orbital is the simplest. At insertion above most of the atmosphere, flight path angle will be close to zero and inertial speed will be at least 7.8 km/s.All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.Not sure about that..
Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.
The best definition is whether at insertion you had enough energy to ballistically go around the earth.
Or rather the other way - it should not be considered "suborbital".
In other words: "It's not your impact point that defines you"
Post by: erictant on 06/09/2021 11:20 am
All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.Not sure about that..
Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.
I think we are really discussing the difference between the behaviour of Spherical Cows orbiting Billiard Balls and Real Rockets orbiting Planets.
Quote
The best definition is whether at insertion you had enough energy to ballistically go around the earth.
For the Cow, this will mean you stay in orbit forever. For the Rocket, you will immediately experience aerodynamic drag and effectively begin your deorbit manoeuvre. You are now in a region where you must balance drag and boost if you wish to maintain orbital velocity.
If you want to stay in orbit around your Planet you have to go higher to reduce the drag to a manageable level. The ISS is near the top of this region and is effectively deorbiting all the time and left to its own devices would re-enter. It is only kept there by regular orbit boosting burns.
SpaceX are deliberately exploiting the bottom edge of this region to allow for a controlled and predictable flight profile that does not require additional burns and all the complexities that entails. This allows them to maximise the chance of getting permits and also of being able to test high speed re-entry with a passive deorbit system.
So, yes, Starship will be orbital momentarily (English meaning) but will immediately start to deorbit so will not go all the way around.
Post by: meekGee on 06/09/2021 03:52 pm
All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.Not sure about that..
Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.
I think we are really discussing the difference between the behaviour of Spherical Cows orbiting Billiard Balls and Real Rockets orbiting Planets.QuoteThe best definition is whether at insertion you had enough energy to ballistically go around the earth.
For the Cow, this will mean you stay in orbit forever. For the Rocket, you will immediately experience aerodynamic drag and effectively begin your deorbit manoeuvre. You are now in a region where you must balance drag and boost if you wish to maintain orbital velocity.
If you want to stay in orbit around your Planet you have to go higher to reduce the drag to a manageable level. The ISS is near the top of this region and is effectively deorbiting all the time and left to its own devices would re-enter. It is only kept there by regular orbit boosting burns.
SpaceX are deliberately exploiting the bottom edge of this region to allow for a controlled and predictable flight profile that does not require additional burns and all the complexities that entails. This allows them to maximise the chance of getting permits and also of being able to test high speed re-entry with a passive deorbit system.
So, yes, Starship will be orbital momentarily (English meaning) but will immediately start to deorbit so will not go all the way around.
I don't think they're trying to naturally decay within one-half of an orbit - I think they specifically said they'll do a de-orbit burn.
They want to a) demonstrate orbital velocity and b) hit a specific landing zone.
Besides, natural decay within one-half of an orbit is really difficult and serves no useful purpose.
Post by: Greg Hullender on 06/09/2021 04:01 pm
So something like "a ballistic trajectory from ground to ground that leaves the atmosphere, does not enter the Van Allen belts, and subtends less than 180°."
To generalize that to bodies other than Earth, you could use something like "a ground-to-ground partial orbit (50% or less) with apapsis between 1.01 and 2 planetary radii."
Whether it's really worth trying to exclude very high orbits and/or orbits that go (say) 3/4 of the way around is debatable, of course, but I do think it's important to exclude things like mortar shells and basketballs. It's also a question whether you want to include things that merely go straight up and come straight down.
Post by: JaimeZX on 06/15/2021 05:18 am
If you impart the requisite 9km/s, you COULD fly to a stable orbit, but you can also impart this dV on a trajectory that will *not* result in an orbit. Hence "orbital class rocket" and the first SS/SH "orbital" flight that only goes 3/4 of the way around. It COULD go into a stable orbit, but they didn't point it in that direction... So still "orbital."
Post by: DavP on 06/15/2021 07:05 am
It shows what appears to be a countdown to the orbital test launch and the engine configuration of the rockets.
Also some of the engines are marked in green and others in white.
Post by: Skyrocket on 06/15/2021 08:19 am
Also some of the engines are marked in green and others in white.
The green engines are gimballed while the white are fixed.
Post by: RotoSequence on 06/15/2021 09:38 am
Also some of the engines are marked in green and others in white.
The green engines are gimballed while the white are fixed.
Out of frame here is a Starship shot, showing two green center engines and one white, and we know that all three gimbal.
Post by: kevinof on 06/15/2021 09:56 am
Landing engines? Would they be using that many on the booster for landing?Also some of the engines are marked in green and others in white.
The green engines are gimballed while the white are fixed.
Post by: Durham Park on 06/15/2021 10:05 am
Post by: NL-SpaceNews on 06/15/2021 10:14 am
This has been posted in another thread
It shows what appears to be a countdown to the orbital test launch and the engine configuration of the rockets.
Also some of the engines are marked in green and others in white.
Looks Like Elon is pushing for a pre - July 20th launch ;D
regards
Serge
Post by: DavP on 06/15/2021 11:02 am
I think green are engines shipped. You'll notice one of the inner three starship engines is white.
Yes. Engines shipped. That appears on the screen.
That countdown could be the deadline to have all the needed engines shipped
https://www.youtube.com/watch?v=mVosLGiOqmc&t=38s
Post by: envy887 on 06/15/2021 05:30 pm
All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.
Why not? That's purely a function of ballistic coefficient. If Starship would remain in orbit for 1.01 revs in the nose-prograde low-drag orientation, but changes to the nose-up high-drag orientation and decays in 0.99 revs, how is that intentional change in drag different from an intentional deorbit burn?
Post by: envy887 on 06/15/2021 05:34 pm
All of this could be understand with a bit of time in Kerbal Space Program, even in the tuturials, but the real answer is whether starship will need to do a deorbit burn? If so, it was orbital, if it was going to decay on the first trip around the earth without a deorbit burn, it's not orbital.Not sure about that..
Since there's no such thing as a gravitational decay in a two body classical system, then you're talking about aerodynamic decay, and then no, decay during the first orbit doesn't mean you weren't orbital, not any more than if you actively de-orbited.
I think we are really discussing the difference between the behaviour of Spherical Cows orbiting Billiard Balls and Real Rockets orbiting Planets.QuoteThe best definition is whether at insertion you had enough energy to ballistically go around the earth.
For the Cow, this will mean you stay in orbit forever. For the Rocket, you will immediately experience aerodynamic drag and effectively begin your deorbit manoeuvre. You are now in a region where you must balance drag and boost if you wish to maintain orbital velocity.
If you want to stay in orbit around your Planet you have to go higher to reduce the drag to a manageable level. The ISS is near the top of this region and is effectively deorbiting all the time and left to its own devices would re-enter. It is only kept there by regular orbit boosting burns.
SpaceX are deliberately exploiting the bottom edge of this region to allow for a controlled and predictable flight profile that does not require additional burns and all the complexities that entails. This allows them to maximise the chance of getting permits and also of being able to test high speed re-entry with a passive deorbit system.
So, yes, Starship will be orbital momentarily (English meaning) but will immediately start to deorbit so will not go all the way around.
I don't think they're trying to naturally decay within one-half of an orbit - I think they specifically said they'll do a de-orbit burn.
They want to a) demonstrate orbital velocity and b) hit a specific landing zone.
Besides, natural decay within one-half of an orbit is really difficult and serves no useful purpose.
It's not difficult at all to decay in 1/2 an orbit. Just set your perigee to around 70 km or so.
Post by: aero on 06/15/2021 06:11 pm
They already know that they can start the engines (sort of) and guide to a designated target landing zone.
Post by: DBMandrake on 06/17/2021 09:04 am
I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...I think green are engines shipped. You'll notice one of the inner three starship engines is white.
Yes. Engines shipped. That appears on the screen.
That countdown could be the deadline to have all the needed engines shipped
Post by: cwr on 06/17/2021 03:44 pm
I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...I think green are engines shipped. You'll notice one of the inner three starship engines is white.
Yes. Engines shipped. That appears on the screen.
That countdown could be the deadline to have all the needed engines shipped
Throughout my career, every manufacturing facility that I've known considered
"leaving our loading dock" as "shipped".
I've seen instances of the cargo part of a 6 wheeler loaded and pushed into the
parking lot to await it's front part and that was considered shipped!
So I would expect shipped meant left Hawthorne loading dock.
Carl
Post by: billh on 06/17/2021 04:50 pm
Just spitballing here, but I would guess "shipped" means "shipped" - i.e., finished manufacturing and left the factory. This display is in Hawthorne, after all.I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...I think green are engines shipped. You'll notice one of the inner three starship engines is white.
Yes. Engines shipped. That appears on the screen.
That countdown could be the deadline to have all the needed engines shipped
Post by: OTV Booster on 06/17/2021 05:25 pm
If the invoice says FOB (Freight On Board) it's considered shipped when it's loaded on the trailer. FOB is nearly, but not quite universal. Pushing a piece into the parking lot might make the internal paperwork look good but if the invoice is FOB and there is an issue, it will quickly becomes a bigger issue.I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...I think green are engines shipped. You'll notice one of the inner three starship engines is white.
Yes. Engines shipped. That appears on the screen.
That countdown could be the deadline to have all the needed engines shipped
Throughout my career, every manufacturing facility that I've known considered
"leaving our loading dock" as "shipped".
I've seen instances of the cargo part of a 6 wheeler loaded and pushed into the
parking lot to await it's front part and that was considered shipped!
So I would expect shipped meant left Hawthorne loading dock.
Carl
It's not just about shipping. Under FOB terms ownership and liability shifts to the receiver when it ships. This is covered in either the 'drayage' (maybe 'cartage') or 'warehousing' chapters of the Universal Commercial Code.
Please, oh please, don't ask for a tighter reference. The UCC is truly mind numbing.
Edit: The engines would be an internal transfer so ownership issues don't apply. I've done a lot of this type of move but never payed attention to the shipping terms.
Post by: DBMandrake on 06/18/2021 08:01 am
I agree. I guess my point was shipped from Hawthorne doesn't necessarily mean that it has arrived at Boca Chica and is ready and waiting because it first has to go to McGregor for test firings and validation, then ship from there to Boca Chica if the test firings are satisfactory.Just spitballing here, but I would guess "shipped" means "shipped" - i.e., finished manufacturing and left the factory. This display is in Hawthorne, after all.I wonder if "shipped" means the engines left Hawthorne for testing in McGregor, or whether it means they've completed testing and certification at McGregor and have been shipped to Boca Chica...I think green are engines shipped. You'll notice one of the inner three starship engines is white.
Yes. Engines shipped. That appears on the screen.
That countdown could be the deadline to have all the needed engines shipped
While we would hope that all the engines sent to McGregor now are passing their tests and being forwarded on that might not be the case, some may need to go back for rework or have replacements sent.
In short while that picture gives a good idea of the production rate of engines it doesn't really tell us how many engines are ready and waiting at Boca Chica.
Post by: oldAtlas_Eguy on 06/18/2021 04:06 pm
The real question are they hitting that expected or is it closer to the 1 engine every 2 days from a Elon tweet.
So if that video dates back to end of April first week of May. A much slower production rate of 24 engines in 50 days would be end of June first week of July. Currently the tea leaves are all saying that the first set will all be at Boca Chica by mid July. So the status info and production rate expectation and actual all add up to that the engines will be ready for install on flight vehicles in mid /late July.
Now still need the GSE and the FAA launch license + FCC approvals for the mission/flight experiment.
Post by: capoman on 06/22/2021 12:38 pm
Yes the expected production rate (shipped out the door from Hawthorn) as evidence from the poster is 24 engines in just less than 26 days!!!!
The real question are they hitting that expected or is it closer to the 1 engine every 2 days from a Elon tweet.
So if that video dates back to end of April first week of May. A much slower production rate of 24 engines in 50 days would be end of June first week of July. Currently the tea leaves are all saying that the first set will all be at Boca Chica by mid July. So the status info and production rate expectation and actual all add up to that the engines will be ready for install on flight vehicles in mid /late July.
Now still need the GSE and the FAA launch license + FCC approvals for the mission/flight experiment.
I suspect everything will be ready long before the FAA approves of the orbital flight. This might cause a window to allow another flight of Starship which will likely be easier to get approval for.
Post by: Lockne on 06/23/2021 10:28 am
Now still need the GSE and the FAA launch license + FCC approvals for the mission/flight experiment.
FCC approval has been granted. I don't think this has been posted in the update thread yet:
https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/0748-EX-ST-2021/275207
I suspect everything will be ready long before the FAA approves of the orbital flight. This might cause a window to allow another flight of Starship which will likely be easier to get approval for.
That's what I think too. I suspect that is why SN15 and SN16 are on hold, still hooked up to pressure lines, and not scrapped. The most important goal is getting the launch site ready. But if it is ready and the launch license for the full stack isn't there yet, they could resume testing SS rather quickly. The current license should allow for a max q test...I think they have the license for up to 30km suborbital flights with Starship? Of course they'll probably need a new launch clearance, I doubt the 'blanket clearance' for SN15-17 in case of a successful SN15 landing would apply to a different flight profile. But getting a launch clearance for such a test should be possible even without the environmental review being completed.
Also, I believe some SH testing should be possible with the current license too. Maybe not a 29 engine static fire, but possibly cryo or smaller cluster static fires, hot gas thruster tests, etc. So they could still proceed getting SH ready and taking the tank farm online. As long as they have their launch mount and GSE ready, they can continue working towards the orbital launch, while possibly resuming Starship testing. And once they got their launch license, they can proceed with that ASAP.
Post by: wannamoonbase on 06/23/2021 01:15 pm
Also, I believe some SH testing should be possible with the current license too. Maybe not a 29 engine static fire, but possibly cryo or smaller cluster static fires, hot gas thruster tests, etc. So they could still proceed getting SH ready and taking the tank farm online. As long as they have their launch mount and GSE ready, they can continue working towards the orbital launch, while possibly resuming Starship testing. And once they got their launch license, they can proceed with that ASAP.
Given the all new GSE, generators, electrical infrastructure, new launch structure and vehicles, they could probably tank and detain 10 to 20 times before getting things figured out to be smooth and efficient.
They have a lot of operational procedures to go through and refine, even for SpaceX it's going to take several months.
Then think about the fuel tank yard. All the liquid methane and Lox next to each other. Yikes!
Post by: dgkimpton on 06/24/2021 09:16 am
Quote
Scott Manley @DJSnMhttps://twitter.com/DJSnM/status/1407754444884742152?s=20
Starship test flights have all used compressed nitrogen for reaction control thrusters, this looks likely to be the hit has version. Little rocket motors using pressure fed Methalox in gas form - pressurized gas makes them easier to turn in and off for accurate control.
Quote
Elon Musk @elonmuskhttps://twitter.com/elonmusk/status/1407969457411067905?s=20
Cool, but an unnecessary complication for now. These are being removed to speed up time to orbital launch.
It's cool they're developing the hot gas thrusters, it's even more cool they aren't going to let that development get in the way of testing the rest of the booster.
Post by: Comga on 06/24/2021 10:13 pm
If we needed any more proof that SpaceX is running multiple development paths in parallel,QuoteScott Manley @DJSnMhttps://twitter.com/DJSnM/status/1407754444884742152?s=20 (https://twitter.com/DJSnM/status/1407754444884742152?s=20)
Starship test flights have all used compressed nitrogen for reaction control thrusters, this looks likely to be the hit has version. Little rocket motors using pressure fed Methalox in gas form - pressurized gas makes them easier to turn in and off for accurate controlQuoteElon Musk @elonmuskhttps://twitter.com/elonmusk/status/1407969457411067905?s=20 (https://twitter.com/elonmusk/status/1407969457411067905?s=20)
Cool, but an unnecessary complication for now. These are being removed to speed up time to orbital launch.
It's cool they're developing the hot gas thrusters, it's even more cool they aren't going to let that development get in the way of testing the rest of the booster.
Proof?
Whatever is being said is fairly garbled.
"...the hit has version"?
What's a guess as to what Manley meant?
And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?
Post by: freddo411 on 06/24/2021 10:35 pm
If we needed any more proof that SpaceX is running multiple development paths in parallel,QuoteScott Manley @DJSnMhttps://twitter.com/DJSnM/status/1407754444884742152?s=20 (https://twitter.com/DJSnM/status/1407754444884742152?s=20)
Starship test flights have all used compressed nitrogen for reaction control thrusters, this looks likely to be the hit has version. Little rocket motors using pressure fed Methalox in gas form - pressurized gas makes them easier to turn in and off for accurate controlQuoteElon Musk @elonmuskhttps://twitter.com/elonmusk/status/1407969457411067905?s=20 (https://twitter.com/elonmusk/status/1407969457411067905?s=20)
Cool, but an unnecessary complication for now. These are being removed to speed up time to orbital launch.
It's cool they're developing the hot gas thrusters, it's even more cool they aren't going to let that development get in the way of testing the rest of the booster.
Proof?
Whatever is being said is fairly garbled.
"...the hit has version"?
What's a guess as to what Manley meant?
And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?
Hot gas. Not “hit has”. Stupid auto correct
Post by: Lockne on 06/24/2021 10:44 pm
Proof?
Whatever is being said is fairly garbled.
"...the hit has version"?
What's a guess as to what Manley meant?
And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?
He's talking about RCS thrusters. 'Hit has version' = 'hot gas version'
The unnecessary complication Elon is referring to are the hot gas thrusters. Cold gas thrusters are a lot more simple and have been used on Starship so far. So after initially pushing for a first test of the hot gas thrusters during the first orbital attempt, it seems like they have now decided to play it safe and use cold gas thrusters instead, eliminating one unknown.
Yeah, the hot gas thrusters are often called methalox, even though that doesn't make much sense if they are indeed using gaseous oxygen. That said, I don't know if it's actually confirmed that they'll be using gaseous methane and oxygen. Cryogenic pressure-fed hot gas thrusters are a thing too.
The picture shows a SH forward dome, and the complex plumbing attached to it is an assembly of three hot gas RCS thrusters, one nozzle pointing left, one right, one towards the camera.
Post by: dgkimpton on 06/25/2021 08:42 am
Proof?
"...the hit has version"?
And what, specifically is that "unnecessary complication"?
RCS engines burning "methalox", which would actually be gaseous methane and oxygen?
And what is that complex bit of plumbing photographed by Kenniston?
Proof being the photo shows the Hot Gas version (which is what Manley was asking about) mounted to a SuperHeavy, and we now have confirmation from Elon that it will be unmounted and ordinary Nitrogen thrusters will be used instead. So clearly they are working on two different reaction control systems in parallel. Presumably, they hoped the Hot Gas version would be ready in time, but it has some kinks or unexpected complexity that makes it too much risk to fly with.
Post by: jpo234 on 06/25/2021 10:56 pm
Post by: IntoTheVoid on 06/26/2021 01:13 pm
The unnecessary complication Elon is referring to are the hot gas thrusters. Cold gas thrusters are a lot more simple and have been used on Starship so far. So after initially pushing for a first test of the hot gas thrusters during the first orbital attempt, it seems like they have now decided to play it safe and use cold gas thrusters instead, eliminating one unknown.
Yeah, the hot gas thrusters are often called methalox, even though that doesn't make much sense if they are indeed using gaseous oxygen. That said, I don't know if it's actually confirmed that they'll be using gaseous methane and oxygen. Cryogenic pressure-fed hot gas thrusters are a thing too.
The picture shows a SH forward dome, and the complex plumbing attached to it is an assembly of three hot gas RCS thrusters, one nozzle pointing left, one right, one towards the camera.
Proof being the photo shows the Hot Gas version (which is what Manley was asking about) mounted to a SuperHeavy, and we now have confirmation from Elon that it will be unmounted and ordinary Nitrogen thrusters will be used instead. So clearly they are working on two different reaction control systems in parallel. Presumably, they hoped the Hot Gas version would be ready in time, but it has some kinks or unexpected complexity that makes it too much risk to fly with.
I think people are failing to take into account other recent info and making the wrong conclusions.
Aside from the comment about the Hot Gas Thrusters, he also recently said that BN3 aka 'Booster 2' would be going to the Pad A test stand and that the next one would be the orbital booster. Thus, the actual implication, is not necessarily that the new thruster isn't ready for orbital flight. It is that the new thruster is an "unnecessary complication" on a ground test (hop test?) booster. Unstated, but also not unreasonable to consider, that perhaps they don't have enough of them to risk them before the orbital flight. But there is not (yet?) any implication that the hot gas thrusters will not be ready for the first orbital booster. It's just that this is not that booster, in spite of the common expectation that it was.
Post by: OTV Booster on 06/26/2021 08:21 pm
One complication is that the hot gas units seen are externally mounted. Production units will most likely be internal, especially if intended for orbit. Even if the basic design doesn't change the plumbing will probably be highly customized like the crazy wild plumbing under the hood of a late 1990's car.
The unnecessary complication Elon is referring to are the hot gas thrusters. Cold gas thrusters are a lot more simple and have been used on Starship so far. So after initially pushing for a first test of the hot gas thrusters during the first orbital attempt, it seems like they have now decided to play it safe and use cold gas thrusters instead, eliminating one unknown.
Yeah, the hot gas thrusters are often called methalox, even though that doesn't make much sense if they are indeed using gaseous oxygen. That said, I don't know if it's actually confirmed that they'll be using gaseous methane and oxygen. Cryogenic pressure-fed hot gas thrusters are a thing too.
The picture shows a SH forward dome, and the complex plumbing attached to it is an assembly of three hot gas RCS thrusters, one nozzle pointing left, one right, one towards the camera.
Proof being the photo shows the Hot Gas version (which is what Manley was asking about) mounted to a SuperHeavy, and we now have confirmation from Elon that it will be unmounted and ordinary Nitrogen thrusters will be used instead. So clearly they are working on two different reaction control systems in parallel. Presumably, they hoped the Hot Gas version would be ready in time, but it has some kinks or unexpected complexity that makes it too much risk to fly with.
I think people are failing to take into account other recent info and making the wrong conclusions.
Aside from the comment about the Hot Gas Thrusters, he also recently said that BN3 aka 'Booster 2' would be going to the Pad A test stand and that the next one would be the orbital booster. Thus, the actual implication, is not necessarily that the new thruster isn't ready for orbital flight. It is that the new thruster is an "unnecessary complication" on a ground test (hop test?) booster. Unstated, but also not unreasonable to consider, that perhaps they don't have enough of them to risk them before the orbital flight. But there is not (yet?) any implication that the hot gas thrusters will not be ready for the first orbital booster. It's just that this is not that booster, in spite of the common expectation that it was.
Post by: GHogan on 06/26/2021 10:22 pm
Post by: OTV Booster on 06/27/2021 06:21 pm
I first thought that the thrusters would go inside too. Then one of the renders showed the thrusters need to fire tangent to the hull. So they have to go outside.That would work on SH. F9 has external pods. How would that work on SS? It would be bad enough on the windward side but the side units would be really bad. They would be at exactly the place where the stagnation layer is thinnest and at its highest velocity.
Post by: Lars-J on 06/28/2021 04:41 am
I first thought that the thrusters would go inside too. Then one of the renders showed the thrusters need to fire tangent to the hull. So they have to go outside.Don’t take the renders as gospel at this point. And there is absolutely no requirement that thrusters need to be able to fire tangent to the hull. It may be the most efficient thruster placement in theory, but in practice there will be trade-offs to make, such as how to protect the thrusters from the re-entry heat.
Look at the Shuttle RCS, it had plenty of thrusters that did not fire tangentially to the hull due to the need for TPS on the bottom side.
Post by: OTV Booster on 06/28/2021 06:01 pm
The differences in shape of the shuttle and SS means that the RCS placement doesnt easily carry over, and the difference in aerodynamic control authority points up a (maybe) greater need for RCS authority.I first thought that the thrusters would go inside too. Then one of the renders showed the thrusters need to fire tangent to the hull. So they have to go outside.Don’t take the renders as gospel at this point. And there is absolutely no requirement that thrusters need to be able to fire tangent to the hull. It may be the most efficient thruster placement in theory, but in practice there will be trade-offs to make, such as how to protect the thrusters from the re-entry heat.
Look at the Shuttle RCS, it had plenty of thrusters that did not fire tangentially to the hull due to the need for TPS on the bottom side.
Looking at the shuttle nose, the side thrusters pierce a side that is tilted back slightly beyond vertical. They also pierce through the heatshield and call for custom tile shapes. There is some cosine loss because of their angle. They are also out of the shockwave and and the stagnation boundary layer which ITSM is the most important design parameter.
Moving this over to the SS (SH is not a problem) We're faced with a different airframe cross section. The midline of the cross section, or maybe slightly higher on the nose area, is where The shockwave is closest and the stagnation boundary layer is highest velocity. The closer the RCS engines are mounted behind this line, the shallower there firing angle can be or they risk exhaust impingement ripping tiles off. As they move back from the centerline the firing angle can get steeper, cosine losses less, and the cutout hole eclipse elongates.
This is some tight restraints. ISTM co-sign losses will be high.
Post by: Jim on 06/28/2021 11:24 pm
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Post by: envy887 on 06/28/2021 11:52 pm
No cosine losses since the other side fires at the same time
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Unless the thruster on the other side is firing exactly parallel to the one on this side, there will be cosine losses. The losses aren't large, though. At 15 degrees off centerline, nearly 97% of the thrust is going in the desired direction.
Post by: Jansen on 06/29/2021 06:31 am
Post by: meekGee on 06/29/2021 12:00 pm
And the one on the other side is rotated in the opposite way, so not parallel.No cosine losses since the other side fires at the same time
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Unless the thruster on the other side is firing exactly parallel to the one on this side, there will be cosine losses. The losses aren't large, though. At 15 degrees off centerline, nearly 97% of the thrust is going in the desired direction.
But agree cosine losses even for moderate angles are small and don't really matter here
Post by: edzieba on 06/29/2021 03:58 pm
Starship orbital flight information with StarlinkAh, SpaceX fuelling the Booster fate debate further. In addition to the "booster landing / Starship soft-landing" verbiage, there is now:
Quote from: STA Application
SpaceX intends demonstrate high data rate communications with Starship and the Super Heavy Booster on the ground at the launch site in Starbase, TX during launch, during booster recovery, in flight, and during reentry
Post by: steveleach on 06/29/2021 04:41 pm
Yep, another almost meaningless snippet that we will probably argue over in these forums for days, with all sides claiming it is evidence for their point of view.Starship orbital flight information with StarlinkAh, SpaceX fuelling the Booster fate debate further. In addition to the "booster landing / Starship soft-landing" verbiage, there is now:Quote from: STA ApplicationSpaceX intends demonstrate high data rate communications with Starship and the Super Heavy Booster on the ground at the launch site in Starbase, TX during launch, during booster recovery, in flight, and during reentry
It clearly means that the Starlink comms will be active for the entire time they are recovering the booster, therefore the booster must be intact the whole time, therefore it requires landing on a platform, therefore it requires legs.
Also, the fact that they specifically said "recovery" and not "landing" clearly indicates that it will be fished out of the water rather than landing on a platform, so it won't have any legs.
Post by: OTV Booster on 06/29/2021 05:22 pm
No cosine losses since the other side fires at the same timeJim, help me out here. I don't have the math but I work pretty well conceptually. Here's what I see with a simple model that ignores all issues discussed except thrust angle. If the thrusters are parallel their thrust adds together. No cosine loss. If they are both pointed outward and opposite each other, they null each other out. Cosine loss is 100%. If they are at 45 deg (cos 45deg=.707) They get ~30% cosine loss.
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I know you don't like being questioned, but what am I missing?
Post by: FutureSpaceTourist on 07/03/2021 08:21 am
Quote
UPDATE: As we learn more about @SpaceX’s plans for its first Superheavy launch, I’ll keep you updated to any design & mission updates/changes. What’s different with this infographic? This one goes to eleven. Plus some fin mods & no entry burn for the booster as stated by Elon.
https://twitter.com/infographictony/status/1411217349223469056
Quote
Also a version with less text.
Post by: Greg Hullender on 07/03/2021 04:52 pm
Post by: alugobi on 07/03/2021 06:26 pm
Quote
I'm sure they learn a lot more from actual recovered stages than they do from telemetry.First, they learn how to fly them and land them, telemetry teaching them that. Then, once they can regularly recover the booster and ship, then can learn from the hardware what to tweak going forward.
There are two phases to the development of the system. Some might occur simultaneously, but the flying and reentering part has to predominate in the early stages. I think that this how they're looking at it right now. The willingness to sacrifice Raptors to the deep suggests this approach, I believe.
Edit: clarity
Post by: OTV Booster on 07/03/2021 10:03 pm
I'll be very disappointed if SpaceX doesn't at least try to recover the upper and lower stages from this launch. If nothing else, I'm sure they learn a lot more from actual recovered stages than they do from telemetry.If one of the platforms is ready MAYBE they'll try to land the booster on it. IF it has actual landing legs. Otherwise, just land on the water like the early F9 landing tests.
For the SS, well, I will be gobsmacked if it makes it through the fireball. The heatshield is IMO the most difficult technical challenge and they've not even laid out an entire tile suite, even as a mock-up.
The most cost effective move would be to try to get some StarLink telemetry out before it disintegrated. That would be an extremely useful tool if they can make it work. That and some ships with good optics and maybe some good high frequency radar with enough resolution to maybe identify the pieces as they shed.
Post by: FutureSpaceTourist on 07/05/2021 12:01 pm
Quote
I took a look at what's know for the proposed marginal-orbit trajectory for the Starship/Super Heavy test flight. I came up with an OK fit with an orbit that is about 70 x 860 km x 26.4 deg. The relatively high apogee is needed to accomodate a low perigee and the range to HI
https://twitter.com/planet4589/status/1411781527869046785
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Here's some plots of the assumed trajectory superimposed on GoogleEarth:
twitter.com/planet4589/status/1411781897261355013
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And here is my fake TLE:
https://twitter.com/planet4589/status/1411782265525485569
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(Launch date of 0000 UTC Aug 1 is obviously arbitrary. Doubt it will be that soon!)
Post by: su27k on 08/24/2021 11:36 am
Quote from: The Honolulu Star-Advertiser
U.S. Indo-Pacific Command said the Navy's Pacific Missile Range Facility on Kauai "is in discussions (with SpaceX ) for limited support and use of their range " for the ocean landing.
Quote from: The Honolulu Star-Advertiser
PMRF "is included in discussions with SpaceX and the Federal Aviation Administration on plans for a mission to terminate in waters NW of Kauai, " spokesman Tom Clements said in a statement in response. "The FAA has the lead on licensing, including the environmental review, and public safety."
Clements said PMRF "is providing details on capabilities related to conducting a safe operation. All customers of PMRF must meet stringent safety requirements in order to receive our support."
Post by: Everything Space on 09/17/2021 05:27 pm
https://twitter.com/FAANews/status/1438920858433638408?
https://twitter.com/TGMetsFan98/status/1438916505559834629?
https://twitter.com/nextspaceflight/status/1438916710313054210?
Post by: Everything Space on 09/17/2021 05:48 pm
Edit to add: https://twitter.com/nextspaceflight/status/1438924994575097862?
Post by: geza on 01/16/2022 02:22 pm
I'll be very disappointed if SpaceX doesn't at least try to recover the upper and lower stages from this launch. If nothing else, I'm sure they learn a lot more from actual recovered stages than they do from telemetry.
Assume perfect landing of SH and/or SS to the water. Then, the question is, whether they can survive the belly flop into the water intact. (If I remember correctly, the Falcon 9 stages could not.) If anything remains floating, then SpaceX will be obliged to deal with it - otherwise it would become a navigation hazard. There are two options: (1) activation of the range safety explosives to guaranty sinking, or (2) sending boat(s) to tow it into harbor. The first option is the simpler, but the second one is the nicer.
Any thought?
Post by: Greg Hullender on 01/16/2022 03:09 pm
Post by: DanClemmensen on 01/16/2022 04:50 pm
An F9 booster is not designed for strong lateral forces. An SS is designed to withstand strong aerodynamic forces during re-entry. A properly-control flop is very likely to result in a floating SS, and if I were SpaceX, this would be part of the process for a crewed launch or in-flight abort.I'll be very disappointed if SpaceX doesn't at least try to recover the upper and lower stages from this launch. If nothing else, I'm sure they learn a lot more from actual recovered stages than they do from telemetry.
Assume perfect landing of SH and/or SS to the water. Then, the question is, whether they can survive the belly flop into the water intact. (If I remember correctly, the Falcon 9 stages could not.) If anything remains floating, then SpaceX will be obliged to deal with it - otherwise it would become a navigation hazard. There are two options: (1) activation of the range safety explosives to guaranty sinking, or (2) sending boat(s) to tow it into harbor. The first option is the simpler, but the second one is the nicer.
Any thought?
The SH is designed for RTLS, so they can splash it down in the ocean very close to the launch site. I suspect it's at least as likely to break up as an F9 booster, but it will be nearby and thus easier to recover fore analysis than a mid-ocean splashdown.
Post by: DreamyPickle on 07/06/2022 12:50 pm
Is it likely that the first orbital launch will carry actual starlinks for deployment?
I know that SN24 has the payload deployment mechanism ("pez dispenser") but don't know if they're going to try to launch an actual satellite. Since there are major changes in the new satellite version and they can't be launched with Falcon there is significant value in testing them on orbit as soon as possible, even if you lose a few of them. And failure on ascent hasn't even happened for any starship prototype yet.
Post by: Bob Niland on 07/06/2022 01:03 pm
The first launch is so far reported to be a fractional orbit, so won't get high enough to deploy any sort of sats.
Post by: DanClemmensen on 07/06/2022 01:12 pm
This might be a stupid question but recently I haven't followed SpaceX very closely so I don't know:The first flight will deliberately be not quite orbital. SN24 will re-enter the atmosphere and come down near Hawaii without need for a de-orbit burn even if for some reason something goes wrong and it cannot relight its engines. Good for safety, good for testing, bad for placing satellites into orbit.
Is it likely that the first orbital launch will carry actual starlinks for deployment?
I know that SN24 has the payload deployment mechanism ("pez dispenser") but don't know if they're going to try to launch an actual satellite. Since there are major changes in the new satellite version and they can't be launched with Falcon there is significant value in testing them on orbit as soon as possible, even if you lose a few of them. And failure on ascent hasn't even happened for any starship prototype yet.
Post by: crandles57 on 07/06/2022 01:47 pm
The first flight will deliberately be not quite orbital. SN24 will re-enter the atmosphere and come down near Hawaii without need for a de-orbit burn even if for some reason something goes wrong and it cannot relight its engines. Good for safety, good for testing, bad for placing satellites into orbit.
I haven't a clue really but ...
It would only take ullage release to circularise startship orbit, so that sounds like it wouldn't take much to circularise and achieve orbit. If they release Starlinks well before apogee when starship has necessary speed but wrong direction (gaining altitude) releasing starlinks into a more circular orbit direction and start the ion drives on the starlinks as soon as they possibly can, could that be enough to keep them in a low orbit? Even if possible, it would presumably take a lot of their fuel so they couldn't reach operational altitude, nor last very long, but for a bit of testing it could be useful?
If that is not possible, just testing the pez dispenser with dummy/mass simulator Starlinks might be useful?
Otherwise why put the pez dispenser in ship 24?
Post by: DanClemmensen on 07/06/2022 02:02 pm
If they circularize Starship's orbit they lose the failsafe re-entry and risk an uncontrolled reentry of the massive SS at a later time. If they were going to take that risk they would have put it in a higher orbit in the first place.The first flight will deliberately be not quite orbital. SN24 will re-enter the atmosphere and come down near Hawaii without need for a de-orbit burn even if for some reason something goes wrong and it cannot relight its engines. Good for safety, good for testing, bad for placing satellites into orbit.
I haven't a clue really but ...
It would only take ullage release to circularise startship orbit, so that sounds like it wouldn't take much to circularise and achieve orbit. If they release Starlinks well before apogee when starship has necessary speed but wrong direction (gaining altitude) releasing starlinks into a more circular orbit direction and start the ion drives on the starlinks as soon as they possibly can, could that be enough to keep them in a low orbit? Even if possible, it would presumably take a lot of their fuel so they couldn't reach operational altitude, nor last very long, but for a bit of testing it could be useful?
If that is not possible, just testing the pez dispenser with dummy/mass simulator Starlinks might be useful?
Otherwise why put the pez dispenser in ship 24?
I speculate without any input that they built SN24 as a full-up Starlink carrier because that's the most critical design for SpaceX. They want to test its launch, dispensing, and EDL performance. I also speculate that they will dispense a few dummy Starlinks, but I'm not sure about this because those are 1250 kg chunks that would come down in the same area that SN24 come down, or if they use thrusters would maybe come down in the wrong place. Maybe they could build dummies that will completely burn up, like with most of the mass being a bottle of water.
Post by: jketch on 07/06/2022 04:15 pm
If they circularize Starship's orbit they lose the failsafe re-entry and risk an uncontrolled reentry of the massive SS at a later time. If they were going to take that risk they would have put it in a higher orbit in the first place.The first flight will deliberately be not quite orbital. SN24 will re-enter the atmosphere and come down near Hawaii without need for a de-orbit burn even if for some reason something goes wrong and it cannot relight its engines. Good for safety, good for testing, bad for placing satellites into orbit.
I haven't a clue really but ...
It would only take ullage release to circularise startship orbit, so that sounds like it wouldn't take much to circularise and achieve orbit. If they release Starlinks well before apogee when starship has necessary speed but wrong direction (gaining altitude) releasing starlinks into a more circular orbit direction and start the ion drives on the starlinks as soon as they possibly can, could that be enough to keep them in a low orbit? Even if possible, it would presumably take a lot of their fuel so they couldn't reach operational altitude, nor last very long, but for a bit of testing it could be useful?
If that is not possible, just testing the pez dispenser with dummy/mass simulator Starlinks might be useful?
Otherwise why put the pez dispenser in ship 24?
I speculate without any input that they built SN24 as a full-up Starlink carrier because that's the most critical design for SpaceX. They want to test its launch, dispensing, and EDL performance. I also speculate that they will dispense a few dummy Starlinks, but I'm not sure about this because those are 1250 kg chunks that would come down in the same area that SN24 come down, or if they use thrusters would maybe come down in the wrong place. Maybe they could build dummies that will completely burn up, like with most of the mass being a bottle of water.
Yeah, it's easy to forget but an uncontrolled reentry of Starship would be terrible for SpaceX's reputation. When it reenters, it will be the second most massive artificial object to have ever reentered from orbit, second only to Mir. If it reenters in an uncontrolled manner, it will be largest such reentry ever. Skylab massed only 76 tons and its reentry is still talked about over 40 years later.
Post by: alugobi on 07/06/2022 04:26 pm
Quote
an uncontrolled reentry of Starship would be terrible for SpaceX's reputation.Only if it lands somewhere and hits something it shouldn't. The public memory is short, Skylab notwithstanding.
Still, anything about the flight that isn't perfect or as described by SX in advance will get hater headlines, only because much of the media is focused on Musk and not SpaceX. The public doesn't give a toss about space.
When a headline begins with "Elon Musk's SpaceX rocket...", or includes any use of the term 'billionaire', then you can bet it's not a friendly piece.
Post by: jpo234 on 07/07/2022 11:19 am
https://twitter.com/SciGuySpace/status/1544742740201803785
Post by: FutureSpaceTourist on 07/09/2022 05:14 am
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SpaceX has submitted new FCC filings for Starlink communications during the Starship orbital test flight. Multiple terminals will be mounted on the ship and the booster to ensure clear views with the constellation through all phases of flight. https://apps.fcc.gov/oetcf/els/reports/ViewExhibitReport.cfm?id_file_num=1169-EX-ST-2022&application_seq=116809
https://twitter.com/nextspaceflight/status/1545593415596797952
Quote
Flight profile details:
- Booster will either do a partial return and land in the Gulf of Mexico or do a full return with a catch attempt
- Ship will reach about 250 km in altitude, then powered landing in the Pacific
twitter.com/nextspaceflight/status/1545593776256692225
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Starlink will allow "high-data rate communications" and remove telemetry blackouts during reentry.
https://twitter.com/nextspaceflight/status/1545594349395668993
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Super Heavy catch attempt profile.
Post by: OneSpeed on 07/09/2022 10:45 am
Post by: JayWee on 07/09/2022 12:56 pm
Post by: Clavin on 07/09/2022 01:37 pm
I've tried to fiddle with Google Earth to get similar view as in the SuperHeavy catch profile and it looks like it's going to stage around 150km downrange. Isn't that very very early? A partial fuel load?or a very steep trajectory.
Post by: crandles57 on 07/09/2022 01:42 pm
I've tried to fiddle with Google Earth to get similar view as in the SuperHeavy catch profile and it looks like it's going to stage around 150km downrange. Isn't that very very early? A partial fuel load?or a very steep trajectory.
How far downrange should we be expecting? Bigger & more powerful rocket = earlier staging ?
Post by: AlesH on 07/09/2022 03:13 pm
I've tried to fiddle with Google Earth to get similar view as in the SuperHeavy catch profile and it looks like it's going to stage around 150km downrange. Isn't that very very early? A partial fuel load?From the picture, I personally estimate a stagging downrange to be around 60 km and a maximum RTLS downrange less than 150 km. This is quite a bit more than for the Falcon 9, which usually has a RTLS stagging downrange around 40 km and a maximum RTLS downrange around 80 km (according to my own simulations and according to https://flightclub.io/ simulations).
Post by: JayWee on 07/09/2022 04:45 pm
Duh, thanks. For some reason I was thinking of the ASDS barge location when thinking about it. So it's not that different after all.I've tried to fiddle with Google Earth to get similar view as in the SuperHeavy catch profile and it looks like it's going to stage around 150km downrange. Isn't that very very early? A partial fuel load?From the picture, I personally estimate a stagging downrange to be around 60 km and a maximum RTLS downrange less than 150 km. This is quite a bit more than for the Falcon 9, which usually has a RTLS stagging downrange around 40 km and a maximum RTLS downrange around 80 km (according to my own simulations and according to https://flightclub.io/ simulations).
Post by: SPKirsch on 07/20/2022 05:44 pm
SpaceX filed an extension for the Starship first launch (the previous permit expires Sept. 1).
1230-EX-ST-2022 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=117025&RequestTimeout=1000)
New operation end date: March 1, 2023
Post by: FutureSpaceTourist on 08/15/2022 07:47 pm
Quote
“We are so close” here’s my (unofficial) infographic detailing what to expect from the 1st flight of @SpaceX’s fully stacked #starship. Stay up-to-date with changes I may need to make as we approach the imminent launch. Thanks to @LunarCaveman for helping me fine tune the details
Post by: darkenfast on 08/16/2022 12:50 am
Post by: kdhilliard on 08/16/2022 01:00 am
Nice work, Tony! Spotted a minor typo: Paragraph labelled "Boostback burn" has the Booster peaking at over 20km. Should that be 200?20km is certainly too low, but 200km seems too high, at least compared to what we've seen with Falcon 9 boosters.
Have we ever seen any numbers on the subject from SpaceX?
We do have a 3D booster trajectory on pg. 3 of this (https://apps.fcc.gov/els/GetAtt.html?id=273481) FCC exhibit. Perhaps it would be possible to recreate the Google Earth angle and magnification and extract something from that plot.
Post by: OneSpeed on 08/16/2022 05:04 am
Nice work, Tony! Spotted a minor typo: Paragraph labelled "Boostback burn" has the Booster peaking at over 20km. Should that be 200?20km is certainly too low, but 200km seems too high, at least compared to what we've seen with Falcon 9 boosters.
Have we ever seen any numbers on the subject from SpaceX?
We do have a 3D booster trajectory on pg. 3 of this (https://apps.fcc.gov/els/GetAtt.html?id=273481) FCC exhibit. Perhaps it would be possible to recreate the Google Earth angle and magnification and extract something from that plot.
It is possible.
A separate nit, the second engine start (SES) appears only to light the vacuum Raptors, which have no gimbal. This is unlikely from a control authority perspective, as well as increasing gravity losses.
Post by: FutureSpaceTourist on 09/22/2022 05:45 pm
twitter.com/yasin_shafiei/status/1572562946387218438QuoteHi Elon. Can you please give us some updates about orbital flight date? I can’t wait to see this launch 😀
https://twitter.com/elonmusk/status/1572563987258290177QuoteLate next month maybe, but November seems highly likely. We will have two boosters & ships ready for orbital flight by then, with full stack production at roughly one every two months.
twitter.com/bnordhaug/status/1572564338577379328QuoteSo booster 7 will be first to fly? (hopefully)
https://twitter.com/elonmusk/status/1572564908381999105QuoteThat’s the plan. We’re taking a little risk there, as engine isolation was done as retrofit, so not as good as on Booster 9.
Post by: FutureSpaceTourist on 10/31/2022 02:28 pm
https://twitter.com/sciguyspace/status/1587100031999676416QuoteRight now the schedule would lead to "an early December" launch of Starship and Super Heavy. NASA's Mark Kirasich said he does not believe SpaceX will attempt to recover the Super Heavy first stage on that test flight.
Post by: alugobi on 10/31/2022 03:13 pm
Post by: ZachS09 on 10/31/2022 03:21 pm
I think December is pretty ambitious.
Maybe launch it on the two-year anniversary of SN8?
Post by: Oersted on 11/04/2022 07:36 pm
Post by: FutureSpaceTourist on 12/08/2022 06:06 pm
Quote
Based on a couple of conversations, I think SpaceX has a reasonable chance of making Starship's orbital launch during the first quarter of 2023. No guarantees, and there still is a lot of work to do. But they're making progress.
https://twitter.com/sciguyspace/status/1600907257365106690
Quote
One thing I would note: SpaceX has moved on the from the "cowboy" phase of development in South Texas, when there was a higher tolerance of risk and failure during Starship prototype testing. With the expensive launch tower, they taking more time to increase chances of success.
Post by: aero on 12/09/2022 12:27 am
Post by: DanClemmensen on 12/09/2022 12:36 am
Well that and the simple fact that the upcoming orbital flight had better be a success. They are taking the extra time to assure themselves of probable success. The last little bits take time anyway.I don't see that. I think they need a high probability of a non-destructive launch. A post-launch failure that does not damage the launch site would not be a big problem. It's still a problem, of course, because they only have 5 launches per year.
Post by: alugobi on 12/09/2022 12:50 am
Post by: ZachS09 on 12/09/2022 12:53 am
If they can clear the pad on that first launch, and get it out over the water, then I think they'll declare victory. Everything else will be gravy after that.
But this an orbital test flight, not a pad clearance test flight. I can’t see orbit insertion being a bonus because that’s the primary mission goal.
However, I agree that the landing phases of both Super Heavy and Starship are bonuses.
Post by: Vahe231991 on 12/12/2022 01:03 am
Quote
Starship orbital launch will slip into 2023. SpaceX has not said anything official, but based on a couple of conversations, I think SpaceX has a reasonable chance of making Starship's orbital launch during the first quarter of 2023. There are no guarantees, and there still is a lot of work to do. But the company is making progress. I can say for certain that an orbital launch attempt this year is off the table.
Protect the tower, please ... Another thing I would note is that SpaceX has moved on from the "cowboy" phase of rocketry development in South Texas, when there was a higher tolerance of risk and failure during Starship prototype testing in 2021. This means the company is moving more slowly and deliberately. With the expensive launch tower, in particular, it is taking more time to increase its chances of success with the first launch of the Super Heavy booster and its Starship upper stage.
Post by: zubenelgenubi on 12/15/2022 02:25 am
latest NET date for Starship appears to be January 20.
2044-EX-ST-2022 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=120347&RequestTimeout=1000)
Post by: FutureSpaceTourist on 01/08/2023 07:10 am
Quote
We have a real shot at late February. March launch attempt appears highly likely.
Post by: Vahe231991 on 01/15/2023 11:46 pm
Cross-post:January 20 is merely the start date of the requested period of operation, which according to the cited document ends July 20.latest NET date for Starship appears to be January 20.
2044-EX-ST-2022 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=120347&RequestTimeout=1000)
Post by: Alexphysics on 01/16/2023 12:16 am
Post by: FutureSpaceTourist on 02/05/2023 06:17 am
Quote
If remaining tests go well, we will attempt a Starship launch next month
Post by: FutureSpaceTourist on 02/11/2023 01:24 pm
https://twitter.com/elonmusk/status/1624412830446534656QuoteThis test is at ~50% throttle. Launch attempt next month will be at ~90%.
P.S. To state the obvious, Elon still talking about next month suggests SpaceX are happy with the static fire (or at least not expecting any significant delays arising from the static fire)
Post by: FutureSpaceTourist on 02/13/2023 12:09 pm
Quote
Hmnnnn…
March 11?
https://wccftech.com/spacex-starship-launch-date-potentially-revealed-in-nasa-calendar/
Very much a NET date I assume (from NASA's WB-57 calendar)
Edit to add: consistent with Elon yesterday (so still Elon time?)
https://twitter.com/elonmusk/status/1624898503267983360QuoteStarship orbital launch attempt soon!
Post by: Orbiter on 02/13/2023 12:13 pm
https://twitter.com/rocketrick/status/1625115510508773376QuoteHmnnnn…
March 11?
https://wccftech.com/spacex-starship-launch-date-potentially-revealed-in-nasa-calendar/
Very much a NET date I assume (from NASA's WB-57 calendar)
I wouldn't read too much into it, those dates also have Crew-6 launching on the 18th (when it's the 26th) and are likely out-of-date.
Post by: Alexphysics on 02/13/2023 02:35 pm
Post by: GewoonLukas_ on 02/13/2023 02:36 pm
Yes that date has been there for well over two weeks by now and several other dates are wrong as indicated above.
It also says "placeholder"
Post by: alugobi on 02/13/2023 04:16 pm
They're also digging out concrete outside the blast area directly below the engines, on the back side if looking at it from the tank farm. This might be only surface replacement after the static fire, or it might be trenching out for water lines coming from the new deluge system being installed.
Figure that into a launch date.
Post by: PM3 on 02/14/2023 07:24 am
Post by: daedalus1 on 02/14/2023 07:54 am
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
Post by: PM3 on 02/14/2023 08:20 am
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
[Edit: corrected typos in video title]
Post by: daedalus1 on 02/14/2023 08:27 am
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explanes updated to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
Haven't seen the video, but that is only 67 mph which would mean the low point of the orbit will dip into the atmosphere.
Post by: eriblo on 02/14/2023 02:24 pm
There is no updated information regarding the trajectory and the logic behind it remains the same.Haven't seen the video, but that is only 67 mph which would mean the low point of the orbit will dip into the atmosphere.Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explanes updated to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
The 30 m/s number is the difference between the assumed perigee inside the atmosphere and one that would clear it with some resonable guess for the apogee (we do not know exactly what they plan).
The absolutely lowest orbit that can do this trajectory will have an extremely shallow reentry angle which means that you might miss the landing with 1000s of km if you miss the engine shutdown by a fraction of a second or have the wrong thermosphere density numbers.
Increasing the apogee steepens the reentry angle and gives more margin while reducing the difference with regard to the lowest possible circular orbit.
Depending on the trajectory chosen there might be a lower energy circular orbit that would make it around at least once.
Post by: Hog on 02/17/2023 06:19 pm
STS-93-Columbia launched and reached orbit carrying the heaviest payload carried by STS . the CHANDRA telescope and its Inertial Upper Stage weighed 22,780kg/50,222lbs, OV-101 Columbia, weighed 122,534 kg/270,142 lb at liftoff.
At main engine start a gold pin used to block the engines oxidizer post was blasted from the Main Combustion Chamber and tearing into 3 of the 1080 stainless tubes that comprise the nozzle's regenerative cooling capability.
This leaking fuel forced that engine's #2 engine controller to increase oxidizer flow from its nominal 6.03:! O/F ratio, which then resulted in a LOX low level cutoff at MECO(Main Engine Cut Off) some 8-1/2 minutes later. This early cut off resulted in an orbital velocity which was 15 ft/s (4.6 m/s) lower than expected. "The vehicle safely achieved its intended orbit and completed the mission as planned."
It should be noted however that if 5 of the 1080 stainless steel regenerative cooling tubes are damaged within close proximity Loss of Crew/Vehicle(LOCV) is probable. Thankfully just 3 tubes were ruptured.
So STS-93 experienced a 15 ft/s or 4.6 m/s underspeed vs. the 30 m/s or 108 feet/second velocity for Starship
Attachments
1) pic of the STS-93 Space Shuttle Main Engines(SSME) RS-25 engines with the damage on the inside of the Right (#3) engine visible as the brighter spot along the inner wall of the nozzle.
Post by: FutureSpaceTourist on 02/18/2023 02:53 am
Quote
From what I hear, everything is on track for a March launch attempt as far as the FAA is concerned.
Post by: FutureSpaceTourist on 02/21/2023 05:01 pm
Quote
Gary Henry, senior advisor for national security space solutions at SpaceX, says at a Space Mobility panel that both the Starship booster and pad are in "good shape" after static fire test earlier this month. The test was the "last box to check" before the first orbital launch.
https://twitter.com/jeff_foust/status/1628092269872947201
Quote
He adds the company still needs an FAA launch license but expects that in the "very near future." Tells the audience to expect some "must-see TV" sometime in March.
Post by: FutureSpaceTourist on 02/22/2023 05:46 pm
Quote
Starship's Orbital Test Flight milestones to launch, and the countdown by the numbers, with analysis from Adrian Beil (@BCCarCounters).
Starship's big day is *potentially* just weeks away!
https://twitter.com/nasaspaceflight/status/1628440975470108673
Quote
And here's Adrian with the overview in video form, with additional visuals:
https://youtu.be/eIz1Q2gcc18
Post by: Comga on 02/22/2023 07:35 pm
0421-EX-ST-2023 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=122165&RequestTimeout=1000) Starship Orbital Test Flight
Operation Start Date (NET) March 15
Post by: Vahe231991 on 02/22/2023 08:23 pm
[Feb 22]
Quote
ORLANDO — SpaceX’s static-fire test of nearly all the engines in its Starship booster earlier this month was “the last box to check” before the vehicle’s first orbital launch attempt, likely some time in March, a company official said Feb. 21.
Speaking on a panel at the Space Mobility conference here about “rocket cargo” delivery, Gary Henry, senior advisor for national security space solutions at SpaceX, said both the Super Heavy booster and its launch pad were in good shape after the Feb. 9 test, clearing the way for an orbital launch that is still pending a Federal Aviation Administration launch license.
[…]
[FST edit: I deleted most of the quoted material. We can’t quote large parts of other news sites copyrighted articles.]
Post by: FutureSpaceTourist on 02/22/2023 10:00 pm
Quote
Got an email “SpaceX Opens Accreditation for Starship Flight Test”
We’re getting close!
Post by: scr00chy on 02/22/2023 11:38 pm
Cross-post:0421-EX-ST-2023 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=122165&RequestTimeout=1000) Starship Orbital Test Flight
Operation Start Date (NET) March 15
Is this just another extension of that FCC licence they've had for a few years now, or is this something else?
Post by: realnouns on 02/23/2023 01:33 pm
Cross-post:0421-EX-ST-2023 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=122165&RequestTimeout=1000) Starship Orbital Test Flight
Operation Start Date (NET) March 15
Is this just another extension of that FCC licence they've had for a few years now, or is this something else?
It seems more like fine tuning. The superseded FCC app had an OSD of March 1st. This updated app has the following new language, "adding an updated power level for two antennas at the Boca Chica TX site". That and moving the OSD to March 15th are the only changes.
Post by: FutureSpaceTourist on 03/07/2023 06:58 pm
Quote
Elon Musk at a Morgan Stanley conference says again that Starship's first full-stack test launch from Texas will happen "hopefully in the next month or so, we'll have our first attempt." Adds "80 percent chance of reaching orbit this year"
Post by: pb2000 on 03/07/2023 07:36 pm
Post by: Robotbeat on 03/07/2023 07:41 pm
So translated from Elon time, to normal time, does that mean NET June?We’re still at NET March. NET.
Post by: pb2000 on 03/07/2023 10:19 pm
"hopefully in the next month or so" implies that March is already out, even without taking into account the 'Elon Time' multiplier (which varies from 1.1x to infinity).So translated from Elon time, to normal time, does that mean NET June?We’re still at NET March. NET.
Post by: eriblo on 03/07/2023 10:51 pm
No, it implies uncertainty in the outcome with a March launch not yet being ruled out. He did not say "hopefully next month..." or "hopefully in a month..."."hopefully in the next month or so" implies that March is already out, even without taking into account the 'Elon Time' multiplier (which varies from 1.1x to infinity).So translated from Elon time, to normal time, does that mean NET June?We’re still at NET March. NET.
Post by: pb2000 on 03/07/2023 11:18 pm
No, it implies uncertainty in the outcome with a March launch not yet being ruled out. He did not say "hopefully next month..." or "hopefully in a month...".English can be pretty ambiguous at times, but that phrasing generally means a minimum of 30 days.
Post by: Ken the Bin on 03/07/2023 11:38 pm
No, it implies uncertainty in the outcome with a March launch not yet being ruled out. He did not say "hopefully next month..." or "hopefully in a month...".English can be pretty ambiguous at times, but that phrasing generally means a minimum of 30 days.
Right, so Elon was effectively saying "hopefully in the next 30 days or so", which includes the rest of March.
Post by: eeergo on 03/08/2023 07:50 am
No, it implies uncertainty in the outcome with a March launch not yet being ruled out. He did not say "hopefully next month..." or "hopefully in a month...".English can be pretty ambiguous at times, but that phrasing generally means a minimum of 30 days.
Right, so Elon was effectively saying "hopefully in the next 30 days or so", which includes the rest of March.
If the quote is accurate, saying "next month" on March 7th does not mean "NLT April 8th". It means the next month that goes after March, "hopefully", "or so". So NET April is pretty unambiguous taking the tweet at face value.
The need for a water deluge has been pretty evident for a long time now. While they may have data that encourages them one might not be needed, they have never fired 33 engines for an extended period of time at close to full thrust - not even close: closest has been around half of that, and heat fluxes/dissipation/plume collimation effects do not necessarily allow for a simple extrapolation from existing data. However, despite having been willfully pushed aside in certain circles, a water deluge right next to the protected terrain the environmental assessment does not allow construction on, necessarily implies runoff water flowing into it towards the greater area. This necessitates both permits and physical regulation of runoff contaminants, as well as possibly provisions against erosion on the built-up area in SpaceX's interest. This, and even minimal functional testing, evidently needs more than a week to complete - and can't be sidelined once work on it breaks ground. There are even pipes being delivered to the site! Furthermore, the water desalination plant that was the cause of most of the kerfuffle around the environmental assessment in the past (and with it, its power needs and associated impacts) is no longer in the cards, so water supply is also a focus point - depending on the deluge system's flow, extra storage might even need to be installed beyond what already exists around the propellant storage area.
Clinging against all evidence to a March 20th date that is clearly unfeasible from many fronts is quite an acute case of go-fever.
Post by: Vultur on 03/08/2023 02:34 pm
"In the next month" would mean *within* the next ~30 days (so definitely not ruling out March: "in *a* month" = 'a month from now' provably would) but "or so" makes it vague enough that precise parsing is likely not relevant.
IMO late March is still the 'plan of record' but there is doubt about meeting it (there is still no launch license...)
Post by: alugobi on 03/08/2023 04:02 pm
You'll get some pushback on that, but you know that. (not from me)
The need for a water deluge has been pretty evident for a long time now. While they may have data that encourages them one might not be needed, they have never fired 33 engines for an extended period of time at close to full thrust - not even close: closest has been around half of that, and heat fluxes/dissipation/plume collimation effects do not necessarily allow for a simple extrapolation from existing data.
However, it's clear that they're going to build a deluge system. Why would they launch without one, when both Musk and Shotwell have said upfront that the big win for them is not destroying the pad?
If what Musk just said is shorthand for "we're going to build the water system first", then it will be longer than a month. If that's not the case, then we should quit trying to interpret these pronouncements, because most of the time they're not accurate and it just makes for a bunch of rhetorical wrestling over vague language.
Post by: realnouns on 03/08/2023 04:22 pm
And: We're building deluge, because it will accelerate future turnaround times, so we don't need to make as many repairs.
....I'm currently reading Liftoff, and SpaceX has always moved with haste. No reason both of the above can't be true.
Post by: Robotbeat on 03/08/2023 04:27 pm
Could be a case of: We're launching without deluge. It won't destroy the launch site, like a RUD would. If NASA wasn't also saying it, just Elon, I would be more skeptical.100% this.
And: We're building deluge, because it will accelerate future turnaround times, so we don't need to make as many repairs.
....I'm currently reading Liftoff, and SpaceX has always moved with haste. No reason both of the above can't be true.
Post by: AS_501 on 03/09/2023 06:46 pm
https://www.independent.co.uk/space/spacex-starship-launch-date-elon-musk-b2297482.html
I'm glad he's stating this because he said something similar prior to the first FH launch in 2018. ;)
Post by: Lee Jay on 03/11/2023 02:09 am
It's a very vague phrase that I don't think much can be read into, except that Elon isn't certain/confident of March.
"In the next month" would mean *within* the next ~30 days (so definitely not ruling out March: "in *a* month" = 'a month from now' provably would) but "or so" makes it vague enough that precise parsing is likely not relevant.
IMO late March is still the 'plan of record' but there is doubt about meeting it (there is still no launch license...)
I think the quote means, "we're planning a first attempt in the next 30 days but don't know how it will go or how many attempts it will take to get to release of the hold down clamps."
Post by: chopsticks on 03/11/2023 03:22 am
I think the quote means, "we're planning a first attempt in the next 30 days but don't know how it will go or how many attempts it will take to get to release of the hold down clamps."
Hold down clamps? Huh?
Post by: Vahe231991 on 03/11/2023 03:33 am
Musk is setting low expectations for a successful SS/SH first launch:Elon Musk raised the possibility that the first Falcon Heavy launch might end in failure, but that launch ended up exceeding Musk's expectations and lofting a car into orbit, leaving its launch site unscathed. We'll see how the liftoff sequence for the first Starship launch plays out.
https://www.independent.co.uk/space/spacex-starship-launch-date-elon-musk-b2297482.html
I'm glad he's stating this because he said something similar prior to the first FH launch in 2018. ;)
Post by: realnouns on 03/13/2023 04:52 pm
Cross-post:0421-EX-ST-2023 (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=122165&RequestTimeout=1000) Starship Orbital Test Flight
Operation Start Date (NET) March 15
This FCC App was "Denied/Dismissed"
Quote
This refers to application, File No. 0421-EX-ST-2023, for an experimental authorization.
You are advised that the Commission is unable to grant your application for the facilities requested. NTIA objected due to harmful interference anticipated to federal space systems as a result of the increased ERP.
Post by: alugobi on 03/13/2023 09:28 pm
Post by: FutureSpaceTourist on 03/15/2023 06:22 pm
Quote
SpaceX's Tom Ochinero: "so close" to launching Starship; waiting for FAA license so we can announce launch date.
Post by: Hog on 03/16/2023 03:04 pm
The 20(IIRC) Stage-0 hold down clamps that support the mass of the entire stack until launch. You can start the stage-1 engines but until the clamps release the stack's going no where.I think the quote means, "we're planning a first attempt in the next 30 days but don't know how it will go or how many attempts it will take to get to release of the hold down clamps."
Hold down clamps? Huh?
Think of a SH booster engine start without a launch similarly to a STS(shuttle) RSLS(Redundant Set Launch Sequencer) abort. The 3 RS25s lit at T minus 6.6 seconds and if they didn't register at least 90% thrust, or if other Launch Commit Criterion were not met, the 3 liquid engines shut down, the 2 solids never fired, the 8 SRB pyro holdowns remained intact and the stack was left to twang back and forth in a most anti-climactic fashion.
Post by: FutureSpaceTourist on 03/16/2023 10:53 pm
Quote
SpaceX will be ready to launch Starship in a few weeks, then launch timing depends on FAA license approval.
Assuming that takes a few weeks, first launch attempt will be near end of third week of April, aka …
Post by: pb2000 on 03/17/2023 01:02 am
And to think y'all doubted me."hopefully in the next month or so" implies that March is already out, even without taking into account the 'Elon Time' multiplier (which varies from 1.1x to infinity).So translated from Elon time, to normal time, does that mean NET June?We’re still at NET March. NET.
So going on the easy assumption this slips further, we got may 4th and june 9th (not applicable to the D/M/Y folks) as backup dates.
Post by: kevin-rf on 03/17/2023 07:48 pm
(sorry, just want to see it launch on my birthday)
Post by: Darkseraph on 03/17/2023 08:38 pm
Aim for the 26th, Aim for the 26th!!!
(sorry, just want to see it launch on my birthday)
By coincidence, that's Alien Day!
Quote
Alien Day is an annual promotional event dedicated to the Alien franchise, held on April 26. It is officially organized and promoted by 20th Century Fox. The date is a reference to the moon on which Aliens is set — April 26, 4 / 26, LV- 426 .
Post by: Zed_Noir on 03/18/2023 04:06 am
Minor correction.Aim for the 26th, Aim for the 26th!!!
(sorry, just want to see it launch on my birthday)
By coincidence, that's Alien Day!QuoteAlien Day is an annual promotional event dedicated to the Alien franchise, held on April 26. It is officially organized and promoted by20th Century FoxDisney. The date is a reference to the moon on which Aliens is set — April 26, 4 / 26, LV- 426 .
Post by: Vahe231991 on 03/19/2023 02:39 am
Post by: alugobi on 03/19/2023 03:21 pm
Post by: FutureSpaceTourist on 03/20/2023 04:46 pm
Post by: erv on 03/23/2023 11:20 pm
https://twitter.com/WarshipCam/status/1638968486431977485
(https://twitter.com/WarshipCam/status/1638968486431977485)
Post by: Alexphysics on 03/23/2023 11:45 pm
Probably have nothing to do with the topic of this thread whatsoever.
https://twitter.com/WarshipCam/status/1638968486431977485
(https://twitter.com/WarshipCam/status/1638968486431977485)
Correct, doesn't have anything to do with Starship. See here: https://twitter.com/Marco_Langbroek/status/1638204692671995905
Post by: catdlr on 03/24/2023 12:31 am
Probably have nothing to do with the topic of this thread whatsoever.
Could also be for upcoming hypersonic testing out of VSFB (The one that was canceled last month at the cape)
The subject subject starts at 25 seconds into video
https://youtu.be/m-Rnm1ynWTU
https://youtu.be/iVfA-gEaPlM
Post by: FutureSpaceTourist on 03/28/2023 05:38 pm
Quote
For Starship's orbital test flight, it may take multiple attempts to reach liftoff.
Sawyer Rosenstein (@thenasaman) takes a look at other past and present super-heavy rockets, and the scrubs and aborts that could appear on Starship launch day:
https://www.nasaspaceflight.com/2023/03/starship-aborts-scrubs/
Post by: FutureSpaceTourist on 03/29/2023 06:37 pm
Quote
This tracks with what I’ve heard. Unless there’s an unforeseen problem, SpaceX should have the launch license for the Starship debut launch by April 14 or thereabouts. Then again, there always could be last-minute checks that cause delays.
Post by: AndyH on 04/01/2023 02:35 am
Quote
From: <[email protected]>
Date: Fri, Mar 31, 2023, 10:19 PM
Subject: NAVAREA IV 372/23(11,28).
To: <[email protected]>
250611Z MAR 23
NAVAREA IV 372/23(11,28).
GULF OF MEXICO.
TEXAS.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
1125Z TO 1710Z DAILY 06 THRU 12 APR
IN AREAS BOUND BY
25-57.00N 097-12.00W, 26-02.00N 097-12.00W,
26-06.00N 096-46.00W, 26-05.00N 095-44.00W,
25-57.00N 093-13.00W, 25-43.00N 092-44.00W,
25-33.00N 092-44.00W, 25-32.00N 093-07.00W,
25-47.00N 095-14.00W, 25-52.00N 096-17.00W,
25-53.00N 096-46.00W.
2. HAZARDOUS OPERATIONS, SPACE DEBRIS
1255Z TO 1710Z DAILY 06 THRU 12 APR
IN AREAS BOUND BY
25-57.00N 097-12.00W, 26-02.00N 097-12.00W,
26-03.00N 097-07.00W, 26-07.00N 096-59.00W,
26-10.00N 096-49.00W, 26-32.00N 096-25.00W,
26-42.00N 095-34.00W, 26-42.00N 092-53.00W,
26-08.00N 091-05.00W, 25-32.00N 090-24.00W,
24-37.00N 084-52.00W, 24-30.00N 084-52.00W,
25-09.00N 090-30.00W, 24-55.00N 091-06.00W,
25-09.00N 092-53.00W, 25-14.00N 093-53.00W,
24-58.00N 094-40.00W, 25-12.00N 096-10.00W,
25-54.00N 097-04.00W
2.CANCEL THIS MSG 121810Z APR 23.//
No idea why this was dated 25 Mar.
Post by: Ken the Bin on 04/01/2023 03:18 am
Quote from: NGA
291338Z MAR 23
HYDROPAC 1098/23(GEN).
NORTH PACIFIC.
HAWAII TO MARSHALL ISLANDS.
DNC 12, DNC 13.
1. HAZARDOUS OPERATIONS, SPACE DEBRIS
1255Z TO 1850Z DAILY 06 THRU 12 APR
IN AREA BOUND BY
22-09.00N 167-02.00W, 19-50.00N 174-26.00W,
18-19.00N 179-59.90W, 15-00.00N 173-24.00E,
11-44.00N 167-39.00E, 11-18.00N 167-54.00E,
13-44.00N 174-11.00E, 16-08.00N 179-30.00W,
18-10.00N 173-45.00W, 20-13.00N 167-33.00W,
21-52.00N 162-27.00W, 22-26.00N 160-32.00W,
23-04.00N 157-57.00W, 23-36.00N 155-42.00W,
24-05.00N 154-01.00W, 24-24.00N 153-16.00W,
24-43.00N 152-44.00W, 24-49.00N 152-48.00W,
24-41.00N 154-58.00W, 24-08.00N 158-18.00W,
23-21.00N 162-33.00W.
2. CANCEL THIS MSG 121950Z APR 23.//
Quote from: NGA
291338Z MAR 23
NAVAREA XII 176/23(GEN).
NORTH PACIFIC.
HAWAII TO MARSHALL ISLANDS.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
1125Z TO 1850Z DAILY 06 THRU 12 APR
IN AREA BOUND BY
23-49.00N 157-42.00W, 23-30.00N 157-37.00W,
23-40.00N 156-57.00W, 23-58.00N 157-03.00W.
2. HAZARDOUS OPERATIONS, SPACE DEBRIS
1255Z TO 1850Z DAILY 06 THRU 12 APR
IN AREA BOUND BY
22-09.00N 167-02.00W, 19-50.00N 174-26.00W,
18-19.00N 179-59.90W, 15-00.00N 173-24.00E,
11-44.00N 167-39.00E, 11-18.00N 167-54.00E,
13-44.00N 174-11.00E, 16-08.00N 179-30.00W,
18-10.00N 173-45.00W, 20-13.00N 167-33.00W,
21-52.00N 162-27.00W, 22-26.00N 160-32.00W,
23-04.00N 157-57.00W, 23-36.00N 155-42.00W,
24-05.00N 154-01.00W, 24-24.00N 153-16.00W,
24-43.00N 152-44.00W, 24-49.00N 152-48.00W,
24-41.00N 154-58.00W, 24-08.00N 158-18.00W,
23-21.00N 162-33.00W.
3. CANCEL THIS MSG 121950Z APR 23.//
Post by: alugobi on 04/01/2023 03:26 am
Post by: Ken the Bin on 04/01/2023 04:22 am
Does this mean that they have a licence?
Not necessarily. Other launches have had notices issued in advance of the launch license.
But if SpaceX doesn't already have the FAA launch license, they must have reason to believe that they'll receive it soon.
Post by: Galactic Penguin SST on 04/01/2023 04:57 am
Post by: OneSpeed on 04/01/2023 05:08 am
No idea why this was dated 25 Mar.
In addition to the notice posted above, there are these two also ...
LHA and Space Debris maps from the NGA notices. Edit: added splashdown area.
Post by: mlindner on 04/01/2023 08:47 pm
Edit: This post is asking if this confirms there is no attempt to land the booster on the ocean in the Gulf.
Post by: southshore26 on 04/01/2023 08:51 pm
Post by: kevinof on 04/01/2023 09:05 pm
So am I correct in assuming that this shows that there will be no attempt to land the booster?
Correct. Plan was always to splash both on the first attempt. Booster in the gulf and SS in Pacific.
Post by: Aphelios on 04/01/2023 09:30 pm
https://www.navcen.uscg.gov/sites/default/files/pdf/lnms/lnm0813g2023.pdf page 49
Post by: FutureSpaceTourist on 04/01/2023 10:31 pm
Quote
A booster on the mount, and a rocket at the pad. It is almost time for someone to hold Starship's beer.
https://arstechnica.com/science/2023/04/spacex-moves-starship-to-launch-site-and-liftoff-could-be-just-days-away/
https://twitter.com/elonmusk/status/1642273756289671170
Quote
More than days away, but hopefully not many weeks away
Post by: FutureSpaceTourist on 04/01/2023 10:40 pm
Quote
Based on the NOTAMs and Marco's estimate, here is a rendering of the Starship near-orbital test flight trajectory (1/n)
Quote
.... SE over the Atlantic...
Quote
.. over Namibia and the Indian Ocean
Quote
... past Indonesia and on to the Pacific ...
Quote
... and then reentry at first perigee for debris impact 250 km NNE of Honolulu
Quote
Zoom in on impact area
Post by: mlindner on 04/01/2023 11:07 pm
There was never a plan for this booster to land anywhere other than the Gulf of Mexico
To be clear, and I've edited my post as such (I've been here a while, please assume normal assumptions of people asking questions on this forum), I was asking if this confirms there is no attempt for ocean landing in the Gulf of Mexico. As there doesn't seem to be any specific landing area like there is for Hawaii. It was always very obvious that there was no chance for a land landing.
Post by: alugobi on 04/01/2023 11:54 pm
So, a "soft" landing, or a fast, hard one. What do you think they'll do?
Edit: My own guess? After we saw video and pics of that series of buoys that they had stacked around the site somewhere, I had the idea that they were going to put those out in the Gulf where they intend to boost back to. And those will have cameras and other telemetry recording devices for recording the return to the surface. So I vote "soft" landing, like they did with F9 several times.
Post by: jpo234 on 04/03/2023 08:40 am
twitter.com/sciguyspace/status/1642271784270536706I haven't seen this mentioned, but Eric Berger's article includes a link to the WB-57 schedule (https://airbornescience.nasa.gov/aircraft_detailed_cal/2023-04?aircraft_id=36) that shows April 10th and 11th reserved for "Imaging"...QuoteA booster on the mount, and a rocket at the pad. It is almost time for someone to hold Starship's beer.
https://arstechnica.com/science/2023/04/spacex-moves-starship-to-launch-site-and-liftoff-could-be-just-days-away/
https://twitter.com/elonmusk/status/1642273756289671170QuoteMore than days away, but hopefully not many weeks away
Post by: geza on 04/03/2023 10:13 am
There was never a plan for this booster to land anywhere other than the Gulf of Mexico
I am surprised because there was quite specific talk here about SH boostback and offshore soft landing. In conjunction of an FCC submission it was even assumed that landing attempt & catch at the launch site was also in the cards. All of these were baseless speculation?
Post by: jpo234 on 04/03/2023 11:11 am
An "offshore soft landing" would be in the Gulf of Mexico, so I don't see a contradiction.There was never a plan for this booster to land anywhere other than the Gulf of Mexico
I am surprised because there was quite specific talk here about SH boostback and offshore soft landing. In conjunction of an FCC submission it was even assumed that landing attempt & catch at the launch site was also in the cards. All of these were baseless speculation?
Post by: kevinof on 04/03/2023 11:24 am
NSF is great at going “what if…” and adding lots of speculation. The only plan I’ve ever heard from SpaceX was no boostback, splash the booster in the gulf but attempt a soft splash to see how far they get. No way they are risking a boostback and catch on a first flight.There was never a plan for this booster to land anywhere other than the Gulf of Mexico
I am surprised because there was quite specific talk here about SH boostback and offshore soft landing. In conjunction of an FCC submission it was even assumed that landing attempt & catch at the launch site was also in the cards. All of these were baseless speculation?
Post by: eriblo on 04/03/2023 12:03 pm
Original FCC exhibit 0748-EX-ST-2021NSF is great at going “what if…” and adding lots of speculation. The only plan I’ve ever heard from SpaceX was no boostback, splash the booster in the gulf but attempt a soft splash to see how far they get. No way they are risking a boostback and catch on a first flight.There was never a plan for this booster to land anywhere other than the Gulf of Mexico
I am surprised because there was quite specific talk here about SH boostback and offshore soft landing. In conjunction of an FCC submission it was even assumed that landing attempt & catch at the launch site was also in the cards. All of these were baseless speculation?
Quote
Flight ProfileUpdated FCC exhibit 1169-EX-ST-2022
The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate approximately 170 seconds into flight. The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore.
Quote
FLIGHT PROFILEThere has been no mention of anything other than a boost back.
The Starship-Super Heavy test flight will originate from Starbase, TX. The booster stage will separate and will then perform a partial return and land in the Gulf of Mexico or return to Starbase and be caught by the launch tower.
Post by: crandles57 on 04/03/2023 12:25 pm
NSF is great at going “what if…” and adding lots of speculation. The only plan I’ve ever heard from SpaceX was no boostback, splash the booster in the gulf but attempt a soft splash to see how far they get. No way they are risking a boostback and catch on a first flight.There was never a plan for this booster to land anywhere other than the Gulf of Mexico
I am surprised because there was quite specific talk here about SH boostback and offshore soft landing. In conjunction of an FCC submission it was even assumed that landing attempt & catch at the launch site was also in the cards. All of these were baseless speculation?
There was a document from SpaceX
This time around, SpaceX says that the Super Heavy booster will “will separate[,] perform a partial return[,] and land in the Gulf of Mexico or return to Starbase and be caught by the launch tower.”
Note the "or", so AFAIK it was never confirmed that they would as some media indicated. This always seemed an unlikely possibility to me as they will surely want to see that they can control its positioning before risking the tower. I think this should be viewed more like someone covering all eventualities than a serious plan to do it. So perhaps not completely baseless speculation but catch attempt always a pretty unlikely eventuality.
Post by: Vettedrmr on 04/03/2023 12:38 pm
This always seemed an unlikely possibility to me as they will surely want to see that they can control its positioning before risking the tower.
I agree, but for a different reason. They won't have had a chance to inspect the launch facilities before the booster lands, so they'll have little information on how it survived the first launch.
Post by: Tangilinear Interjar on 04/03/2023 03:22 pm
That part of the system is critical for catching the booster.
Post by: kevinof on 04/03/2023 04:24 pm
Original FCC exhibit 0748-EX-ST-2021NSF is great at going “what if…” and adding lots of speculation. The only plan I’ve ever heard from SpaceX was no boostback, splash the booster in the gulf but attempt a soft splash to see how far they get. No way they are risking a boostback and catch on a first flight.There was never a plan for this booster to land anywhere other than the Gulf of Mexico
I am surprised because there was quite specific talk here about SH boostback and offshore soft landing. In conjunction of an FCC submission it was even assumed that landing attempt & catch at the launch site was also in the cards. All of these were baseless speculation?QuoteFlight ProfileUpdated FCC exhibit 1169-EX-ST-2022
The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate approximately 170 seconds into flight. The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore.QuoteFLIGHT PROFILEThere has been no mention of anything other than a boost back.
The Starship-Super Heavy test flight will originate from Starbase, TX. The booster stage will separate and will then perform a partial return and land in the Gulf of Mexico or return to Starbase and be caught by the launch tower.
Post by: FutureSpaceTourist on 04/04/2023 02:34 am
Quote
Buoy update: this is the grid conformation for SpaceX' PATON buoys for the first Starbase OFT flight. Stay out of area please.
Guaranteed excitement. @LunarCaveman @InfographicTony
@SpaceX @DrSianProctor
@SpaceOffshore @cnunezimages
@LabPadre @RGVaerialphotos
@elonmusk
Post by: FutureSpaceTourist on 04/04/2023 02:45 am
Quote
Vehicles: B7/S24
Projected date: NET April 10, 2023
Key milestones to watch the rest of the way now live on nextspaceflight.com/starship and the Next Spaceflight app.
Post by: Chris Bergin on 04/04/2023 04:15 am
Update thread for the launch:
https://forum.nasaspaceflight.com/index.php?topic=58568.0
(Opened when Ship 24 is stacking).
Post by: FutureSpaceTourist on 04/04/2023 07:03 am
Quote
Regarding the launch license, there is no known reason why SpaceX cannot launch within days of receiving it. If you wait for it, you may be planning too late! That is why we are now going with April 10. If they get the license this week. Early next is possible.
https://twitter.com/nextspaceflight/status/1643147019522043904
Quote
That said, due to the nature of the beast, do not be surprised if there are considerable delays. Plan accordingly!
Post by: FutureSpaceTourist on 04/04/2023 10:58 pm
Quote
In the event of a scrubbed launch attempt for the first Starship Orbital Flight Test, it will take at least 3 days to top off the Orbital Tank Farm.
This is based on the number of tankers needed to refill the storage tanks after the Wet Dress Rehearsal
https://twitter.com/thetimellis/status/1643359449657245699
Quote
I’d also imagine fuel conditioning with subcooled and methane could be a factor too. Speculation, but from experience with methane we saw this too.
twitter.com/csi_starbase/status/1643370758322700290
Quote
Hi Tim! Are you able to expand on this a little more? I've actually been really curious about this topic.
https://twitter.com/thetimellis/status/1643384699849678848
Quote
Talked about it a little in our Terran 1 launch thread, but tldr if they are using liquid natural gas and not pure methane (likely, because it’s so much cheaper, but I don’t know for sure) then it has a small but significant quantity of other longer chain hydrocarbons like ethane, butane, propane, etc that will preferentially boil off slower than methane, so methane concentration goes down in ground storage tanks over time, and you must take this into account for recycle attempts on scrubs for the rocket. Depends on GSE design, there are ways to mitigate this and I have no clue if they have, but just mentioning it’s a factor. Subcooling also adds complexity to this to get temperatures right, but does help freeze out some contaminants.
Post by: kraisee on 04/05/2023 03:27 am
Quote
The real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
Post by: Robotbeat on 04/05/2023 04:21 am
Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
Post by: M.E.T. on 04/05/2023 06:21 am
Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
https://twitter.com/peterrhague/status/1643284717922553856?s=46&t=cXe8daS2G2wE0oO0kwAwjQ
https://twitter.com/tobyliiiiiiiiii/status/1643407600275587072?s=46&t=cXe8daS2G2wE0oO0kwAwjQ
Interesting. So get the license, fuel up and GO, while the lawsuit is still being prepped. I like it.
Post by: FutureSpaceTourist on 04/05/2023 08:53 am
https://twitter.com/spmttracker/status/1643509033360412673
Quote
Last evening a single SPMT was moved to the Launch Complex to later take the Raptor Installation Platform back to the Shipyard.
📷: @LabPadre
Post by: sferrin on 04/05/2023 12:33 pm
Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
And if you follow the money. . .
Post by: Herb Schaltegger on 04/05/2023 12:45 pm
Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
And if you follow the money. . .
So? Have you? Followed the money, that is? What does your financial research and investigation reveal? Or is this some kind of conspiratorial shadow-chasing?
Post by: darthguili on 04/05/2023 12:57 pm
Let's all take a higher road please.
Post by: plank on 04/05/2023 01:33 pm
Post by: Robotbeat on 04/05/2023 02:03 pm
This could/will be a historic moment for spaceflight and I expect more from this forum than some low level conspiracy BS.I agree largely, but I do think it’s a real risk… in which case the solution is to SHUT UP ABOUT IT ON SOCIAL MEDIA!! :) (I keep thinking about these tweets… “stop giving them ideas!!” And luckily hardly anyone reads into the depths of these forums, so we’re safe here except from other space nerds.)
Let's all take a higher road please.
Post by: Robotbeat on 04/05/2023 02:05 pm
Post by: FutureSpaceTourist on 04/05/2023 02:19 pm
Quote
With the Starship launch getting closer, it’s time to go over previous rockets, and how SpaceX can learn from them to prevent scrubs!
Link: youtu.be/KGhwD0b_m1E
Hosted and written by @thenasaman
Produced by @kmreed
Edited by @dpoddolphinpro
https://youtu.be/KGhwD0b_m1E
Post by: Robotbeat on 04/05/2023 02:31 pm
Post by: FutureSpaceTourist on 04/05/2023 02:35 pm
Quote
With Starship’s launch finally getting closer, many have been wondering about the onboard cameras. There are many on Starship and Superheavy, and while we don’t know about all of them, let’s look at the ones we do. (1/11)
📸 @CosmicalChief
All renders provided by @ChameleonCir
Quote
Starting on the Ship, there is a downwards-facing camera located on the underside of one of the forward flaps. This will give a nice extended view out from the side of the vehicle. You may remember seeing a similar view on SN15's flight test. (2/11)
📸 @RGVaerialphotos
https://twitter.com/ringwatchers/status/1643609367944613891
Quote
There are 2 more cameras located on the side of the Ship, embedded in this triangular block. One is watching a forward flap, and the other is watching an aft flap. These cameras will likely be useful during the reentry phase. (3/11)
📸 @RGVaerialphotos
Quote
2 more are located on the side of the Ship facing outwards. It's unclear what these are watching, but they should provide some cool views. You can just see the lenses behind the transparent covers. (4/11)
📸 @RGVaerialphotos
https://twitter.com/ringwatchers/status/1643609669179416578
Quote
Moving down the Ship further, there are internal tank cameras confirmed to be in the CH4 tank of the vehicle. It's not entirely clear if there is one in the LOX tank, but it may look like the pictured render. (5/11)
📸 @RGVaerialphotos
Quote
Inside the skirt, there is at least 1 camera positioned to watch the 6 Raptor engines during the flight. This view was seen a lot on the Suborbital Flight Tests, and that view certainly hasn't gone away. (6/11)
📸 @SpaceX
https://twitter.com/ringwatchers/status/1643609839828979714
Quote
Now, these are just the confirmed cameras on the Ship. There are likely others in the skirt, Payload Bay, and other areas, but we can only confirm that once we see evidence of them. Either way, let's move on to the Superheavy Booster. (7/11)
Quote
There is a camera placed inside the Booster's interstage that can see both stages of the vehicle. This may be one of the angles we see during stage separation on ascent. (8/11)
📸 @SpaceX
https://twitter.com/ringwatchers/status/1643610134239748096
Quote
Another camera is located above one of the Booster's grid fins and load points. This view is at an angle and should look something like this. During the descent, this may be one of the views we get to see. (9/11)
📸 @RGVaerialphotos @SpaceX
Quote
Like the Ship, the Booster also has internal tank cameras. One is confirmed to be in the CH4 tank, and it remains unconfirmed if others are in the LOX tank or other areas. The LOX tank render pictured is speculative, as with the Ship. (10/11)
📸 @SpaceX
https://twitter.com/ringwatchers/status/1643610435290103810
Quote
These are many of the onboard cameras that we know of, but there are certainly many more that have gone unnoticed. Remember that many of these may be kept as engineering cameras only, but we can hope for as many views as possible! (11/11)
Post by: kevinof on 04/05/2023 02:36 pm
Clickbait title!! (I clicked LOL.)
Post by: Oersted on 04/05/2023 03:25 pm
Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
I would guess an environmental group focused on protecting the AMAZON.... Or an affiliated group with a similar ORIGIN... Hint, hint, wink, wink....
(Just kidding)
Post by: DanClemmensen on 04/05/2023 03:45 pm
You might want to take a look at the 19,000 or so comments submitted by the public on the PEA. A large number of them were form letters submitted by Sierra Club members opposing launch operations on environmental grounds.Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
I would guess an environmental group focused on protecting the AMAZON.... Or an affiliated group with a similar ORIGIN... Hint, hint, wink, wink....
(Just kidding)
Post by: alugobi on 04/05/2023 04:12 pm
Post by: xvel on 04/05/2023 04:31 pm
You might want to take a look at the 19,000 or so comments submitted by the public on the PEA. A large number of them were form letters submitted by Sierra Club members opposing launch operations on environmental grounds.
Weren't they all the same? That's called spam in my dictionary, they proved back then that they are a joke, they have no real arguments so they can't stop it, but they can delay it using legal means.
Post by: DanClemmensen on 04/05/2023 05:06 pm
This specific type of spam is usually called "astroturfing". Not all of the comments were these form letters: some were a lot more thoughtful. Not all of the comments were driven by Sierra Club, either. There was at least one other environmental group and probably quite a few unaffiliated environmentalists. However, none of those other folks are likely to be organized enough to file a lawsuit. I hope that any judge that sees such a suit will use the results of the PEA as a basis to refuse to issue a preliminary injunction. There were legitimate environmental concerns, and they were carefully considered and addressed.You might want to take a look at the 19,000 or so comments submitted by the public on the PEA. A large number of them were form letters submitted by Sierra Club members opposing launch operations on environmental grounds.
Weren't they all the same? That's called spam in my dictionary, they proved back then that they are a joke, they have no real arguments so they can't stop it, but they can delay it using legal means.
Post by: RDMM2081 on 04/05/2023 05:15 pm
Post by: xvel on 04/05/2023 05:39 pm
Post by: Lee Jay on 04/05/2023 05:49 pm
There were legitimate environmental concerns, and they were carefully considered and addressed.
How do we know that they were addressed? We know they were mentioned in the document, but I haven't seen anything on them being addressed.
Post by: chopsticks on 04/05/2023 05:57 pm
There were legitimate environmental concerns, and they were carefully considered and addressed.
How do we know that they were addressed? We know they were mentioned in the document, but I haven't seen anything on them being addressed.
The fact that a mitigated FONSI was issued would imply that they have been addressed but not all taken care of. A launch license would indicate that they have worked through any remaining issues as I understand it.
Post by: Robotbeat on 04/05/2023 06:05 pm
(Then again, the long PEA process also helped spin up a whole bunch of people to be against the launch. A lower profile PEA would have posed less risk.)
Post by: DanClemmensen on 04/05/2023 06:11 pm
The PEA was written by SpaceX. It laid out the mitigations that SpaceX proposed to do. I do not know that they have actually done them, but do not think they would propose things that they did not intend to carry out.There were legitimate environmental concerns, and they were carefully considered and addressed.
How do we know that they were addressed? We know they were mentioned in the document, but I haven't seen anything on them being addressed.
Post by: joncz on 04/05/2023 06:15 pm
Post by: Robotbeat on 04/05/2023 06:30 pm
Yup. And the funny thing about US environmental review is that you don’t actually have to eliminate negative environmental effects. You just have to STUDY them and have sufficient paperwork. (And likewise, it doesn’t matter if the environmental effects are zero or are otherwise mitigated if there isn’t enough studying/paperwork.) Really kind of messed up, a worship of process over actual results.There were legitimate environmental concerns, and they were carefully considered and addressed.
How do we know that they were addressed? We know they were mentioned in the document, but I haven't seen anything on them being addressed.
The fact that a mitigated FONSI was issued would imply that they have been addressed but not all taken care of. A launch license would indicate that they have worked through any remaining issues as I understand it.
It’s why fossil fuel companies can extract as much fossil fuel as they want regardless of climate consequences as long as the paperwork is done, and yet renewable energy projects can be blocked by Koch funded groups who sue on the basis of not enough studying done…
Post by: Herb Schaltegger on 04/05/2023 06:42 pm
Post by: craiglv2 on 04/05/2023 07:56 pm
Post by: Robotbeat on 04/05/2023 08:06 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.fr, I hear that kind of objection to Boca Chica all the time and it’s abundantly clear that the vast majority of such people have virtually no background knowledge on spacelaunch and just jumped on this recently. (Unfortunately, you’ll also have some people who really ought to know better boost those takes.)
Post by: wannamoonbase on 04/05/2023 08:11 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
Keep in mind that CCSFB and KSC had several communities on them before they were taken over and rolled into the wildlife refuge.
It wouldn't exist if it wasn't for the need for the large unpopulated areas.
I lived and worked there for 2.5 years, never should have left. Despite the oppressive summers it's a magical place for the rockets and wildlife.
Maybe Boca Chica could benefit from this in a similar way.
Post by: Herb Schaltegger on 04/05/2023 08:16 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
That's why just claiming some kind of "environmental" basis for any putative legal action is specious. My suggestion above is the kind of specific and focused approach someone would have to take if they want to challenge a lawfully-granted license; they would have to argue with some degree of particularity that there was a flaw in the licensing process or - more likely - that one of the preconditions for grant of a license was not met. Failing to meet one of the environmental mitigations promised in the finding of Mitigated FONSI could be such a basis.
Post by: mrhuggy on 04/05/2023 08:39 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
Keep in mind that CCSFB and KSC had several communities on them before they were taken over and rolled into the wildlife refuge.
It wouldn't exist if it wasn't for the need for the large unpopulated areas.
I lived and worked there for 2.5 years, never should have left. Despite the oppressive summers it's a magical place for the rockets and wildlife.
Maybe Boca Chica could benefit from this in a similar way.
I remember watching a small documentary about the wildlife refuge and about the people who lived there and had to leave. One of the person in it actually grew up there before his family was moved out, he later went into orbit with NASA and now runs NASA, Bill Nelson.
Post by: wannamoonbase on 04/05/2023 09:31 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
Keep in mind that CCSFB and KSC had several communities on them before they were taken over and rolled into the wildlife refuge.
It wouldn't exist if it wasn't for the need for the large unpopulated areas.
I lived and worked there for 2.5 years, never should have left. Despite the oppressive summers it's a magical place for the rockets and wildlife.
Maybe Boca Chica could benefit from this in a similar way.
I remember watching a small documentary about the wildlife refuge and about the people who lived there and had to leave. One of the person in it actually grew up there before his family was moved out, he later went into orbit with NASA and now runs NASA, Bill Nelson.
Great story, I didn't know that one.
I use to roam around on my lunch hours and follow some of the old roads to where the trailers were located. That was all Pre 9/11 and afterward it felt like less of a good idea to randomly wonder around a military installation.
Dodging the gators warming themselves on the road is a great memory, as is the 8 foot diamond back rattle snake crossing the road. Epic place.
Post by: sferrin on 04/05/2023 09:58 pm
Bit of a knee-jerk don't you think? How, exactly, would I follow the money of something that hasn't happened yet?Eric Berger says:I would expect it's neither, but an outside environmental group. If it happens.QuoteThe real risk I have heard about is a last-minute civil lawsuit. In this scenario, the FAA issues the license and a civil suit is immediately filed for environmental reasons. It is possible a judge would issue a temporary injunction.
So who is behind this possible lawsuit? I'd guess either Boca Chica locals, or one of SpX's competitors trying to harm their efforts. Anyone know more?
Ross.
And if you follow the money. . .
So? Have you? Followed the money, that is? What does your financial research and investigation reveal? Or is this some kind of conspiratorial shadow-chasing?
Post by: Lee Jay on 04/05/2023 10:36 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
That's why just claiming some kind of "environmental" basis for any putative legal action is specious. My suggestion above is the kind of specific and focused approach someone would have to take if they want to challenge a lawfully-granted license; they would have to argue with some degree of particularity that there was a flaw in the licensing process or - more likely - that one of the preconditions for grant of a license was not met. Failing to meet one of the environmental mitigations promised in the finding of Mitigated FONSI could be such a basis.
That's what they would have to argue to win, not to file. To file, they need nothing but the filing fee and paperwork. To get an injunction, they need more but not as much as they'd need to win.
Post by: FutureSpaceTourist on 04/05/2023 11:53 pm
Quote
Hoppy has got just about the best seat in the house for the upcoming launch. I think he will get to witness quite a bit of history on the making.
#Starbase #Starship #SpaceX
📸 Me for WAI Media @FelixSchlang
Maybe some camera adjustment getting ready for launch?
Post by: FutureSpaceTourist on 04/06/2023 12:13 am
Quote
Diagram #34 | 5th April, 2023 | "Soon™"
Useful summary of tests so far with the vehicles on right-hand side of the graphic
Post by: FutureSpaceTourist on 04/06/2023 01:25 am
Quote
Happy First Contact Day! As Troi said to Data and Picard - would you three like to be alone? Hey, it's a Titan! And here I am w/ a Titan IV years ago. Now it's Falcons and Starships.
Spending time now working on webcast rehearsals for first test flight of Starship.
Post by: Herb Schaltegger on 04/06/2023 01:54 am
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
That's why just claiming some kind of "environmental" basis for any putative legal action is specious. My suggestion above is the kind of specific and focused approach someone would have to take if they want to challenge a lawfully-granted license; they would have to argue with some degree of particularity that there was a flaw in the licensing process or - more likely - that one of the preconditions for grant of a license was not met. Failing to meet one of the environmental mitigations promised in the finding of Mitigated FONSI could be such a basis.
That's what they would have to argue to win, not to file. To file, they need nothing but the filing fee and paperwork. To get an injunction, they need more but not as much as they'd need to win.
To get an injunction, they’d need SUBSTANTIALLY more than the filing fee. Have you ever tried to get an injunction from a judge about anything? Because I have, and trust me, most judges don’t grant them willy-nilly. Typically, the movant has to make a prima facile showing of some kind of irreparable or irreversible harm if the injunction is not granted, and that is not an easy burden.
Post by: edzieba on 04/06/2023 07:02 am
Post by: envy887 on 04/06/2023 01:12 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
That's why just claiming some kind of "environmental" basis for any putative legal action is specious. My suggestion above is the kind of specific and focused approach someone would have to take if they want to challenge a lawfully-granted license; they would have to argue with some degree of particularity that there was a flaw in the licensing process or - more likely - that one of the preconditions for grant of a license was not met. Failing to meet one of the environmental mitigations promised in the finding of Mitigated FONSI could be such a basis.
Even arguing based on the mitigated FONSI that a precondition for grant of a license was not met would be difficult, since most of the required mitigations are not specifically preconditions to launch but rather relate to construction activities, or to continuing mitigations already in process, or to post-anomaly restoration.
There's very little in the way of "SpaceX shall do this activity before launch" in the FONSI - I only saw 2 items like this: contracting a qualified biologist to evaluate vegetation and habitat in the week before launch, and coordinating with local oil and gas companies prior to launch. Unless SpaceX is doing nothing at all regarding the mitigations, I doubt there's much to go after there.
Post by: Herb Schaltegger on 04/06/2023 01:25 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.
That's why just claiming some kind of "environmental" basis for any putative legal action is specious. My suggestion above is the kind of specific and focused approach someone would have to take if they want to challenge a lawfully-granted license; they would have to argue with some degree of particularity that there was a flaw in the licensing process or - more likely - that one of the preconditions for grant of a license was not met. Failing to meet one of the environmental mitigations promised in the finding of Mitigated FONSI could be such a basis.
Even arguing based on the mitigated FONSI that a precondition for grant of a license was not met would be difficult …
.
Exactly. This entire topic sounds like typical tech-nerd guys’ ingrained fear of a legal system they don’t understand, taking an off-hand remark (“Well, someone might file for an injunction …”) and overstating the real risks involved.
As a tech-nerd guy who is also a lawyer, nothing is more personally frustrating to me than when nerds freak out about legal issues, and when lawyers fail (or refuse to try) to understand technology.
Post by: envy887 on 04/06/2023 01:31 pm
In regards to lawsuits: because of the bass-ackwards way NEPA works, anyone wanting to file for an injunction would have to wait for the FAA to issue a Launch License. The proposed issuance of a Launch License is the federal action that triggered the NEPA process, and the sole purpose of the EA was to produce a public document of the environmental impacts of that federal action, in order to arm other agencies and the public with the information needed to contest actions (remember, a EA/EIS is not an 'approval' in any way shape or form, the sole enforcement mechanism is through lawsuits, not through environmental regulations or standards). Until the FAA actually issue the Launch License, that federal action has not occurred, so there is nothing to challenge.
The NEPA process also arms the FAA (as the agency completing the Federal action), because it is designed to discover all potentially relevant impacts, via the processes of interagency communication and public comment, so that FAA isn't blindsided with new considerations when it issues a license. Unless something truly new comes up, the FAA and SpaceX are already prepared to show how they evaluated a specific impact and why it isn't significant. These processes are pretty well-established and quite thorough, so something actually new isn't all that likely to come up.
Post by: Vahe231991 on 04/06/2023 02:39 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.When weighing whether to approve a license for Starship to construct Starbase, why didn't the FAA take note of the fact that the space launch facilities in Cape Canaveral are partly shared with the Merritt Island National Refuge?
Post by: whitelancer64 on 04/06/2023 03:11 pm
Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.When weighing whether to approve a license for Starship to construct Starbase, why didn't the FAA take note of the fact that the space launch facilities in Cape Canaveral are partly shared with the Merritt Island National Refuge?
NASA was established in 1958, and NASA began buying land for the Launch Operations Center (later the Kennedy Space Center) in 1962.
The Merritt Island National Wildlife Refuge was established in 1963, largely as a buffer zone around NASA's launch operations complex. It wasn't a wildlife refuge before NASA started plans to build there, and also the environmental regulations didn't exist then. NEPA (National Environmental Policy Act) was enacted in 1970.
Post by: Chris Bergin on 04/06/2023 04:13 pm
https://www.youtube.com/watch?v=acxnPFOV9jU
Post by: DanClemmensen on 04/06/2023 05:01 pm
More generally, a lot of things that dramatically reduce the human population density end up being beneficial to wildlife. This includes weapons testing ranges, the Chernobyl disaster, offshore wind farms that keep fishing boats out, etc. Starbase/SpaceX will likely have this effect on much of the environmentally-sensitive acreage of the BC area. The area paved or occupied by structures was already mostly paved or occupied by structures.NASA was established in 1958, and NASA began buying land for the Launch Operations Center (later the Kennedy Space Center) in 1962.Who would ever approve a rocket launch site at a wildlife refuge? Oh, I almost forgot that Cape Canaveral has shared the Merritt Island National Wildlife Refuge for 70 years.When weighing whether to approve a license for Starship to construct Starbase, why didn't the FAA take note of the fact that the space launch facilities in Cape Canaveral are partly shared with the Merritt Island National Refuge?
The Merritt Island National Wildlife Refuge was established in 1963, largely as a buffer zone around NASA's launch operations complex. It wasn't a wildlife refuge before NASA started plans to build there, and also the environmental regulations didn't exist then. NEPA (National Environmental Policy Act) was enacted in 1970.
Post by: pb2000 on 04/06/2023 07:06 pm
So with the closure canceled on Monday are we calling this NET 18th now? Could argue that "~" means ± a couple days, but lets be realistic here, launch schedules almost always move to the right.QuoteStarship fully stacked at Starbase. Team is working towards a launch rehearsal next week followed by Starship’s first integrated flight test ~week later pending regulatory approval
Post by: GewoonLukas_ on 04/06/2023 07:19 pm
So with the closure canceled on Monday are we calling this NET 18th now? Could argue that "~" means ± a couple days, but lets be realistic here, launch schedules almost always move to the right.QuoteStarship fully stacked at Starbase. Team is working towards a launch rehearsal next week followed by Starship’s first integrated flight test ~week later pending regulatory approval
I'd say "No Earlier Then the week of April 17th" would be more appropriate
Post by: JAFO on 04/06/2023 07:37 pm
More generally, a lot of things that dramatically reduce the human population density end up being beneficial to wildlife. This includes weapons testing ranges, the Chernobyl disaster, offshore wind farms that keep fishing boats out, etc. Starbase/SpaceX will likely have this effect on much of the environmentally-sensitive acreage of the BC area. The area paved or occupied by structures was already mostly paved or occupied by structures.
GA airports are lusted after by real estate developers and loved/hated by environmentalists. They hate the leaded fuel GA piston airplanes burn and the "elites" who can afford to fly them, but love all the open space reserved for wildlife.
If I'm working late on my plane I love to go out and listen to the noise from the wildlife. Once I heard some coyotes howl from across the runway to the north, another one answered from the east, then another one howled from behind me in the direction of my hangar. I beat feet back very quickly and kept the door closed the rest of that night.
Post by: pedz on 04/07/2023 01:34 pm
https://twitter.com/alexphysics13/status/1643406331741708289QuoteThis advisory is normally updated every few hours (it says at the end when the next update will happen). It has been updated just a few minutes ago and it shows a new window for Starship's first orbital test flight from 7AM CDT to 11AM CDT
Is it possible to get these FAA updates directly? Are they on a web site somewhere? I plan to drive down (again) to watch the launch and record it (video and photos). I was there for two weeks early March hoping it would go at that time but (obviously) it didn’t.
I don’t want to drive down on Sunday for nothing so I’d like to have a pretty good feel of the expected launch. I’ve come across April 10th as well as April 17th in various places.
I will, of course, watch this thread.
Post by: dwheeler on 04/07/2023 02:38 pm
Is it possible to get these FAA updates directly? Are they on a web site somewhere?
There's a link in that tweet: https://www.fly.faa.gov/adv/adv_spt.jsp (https://www.fly.faa.gov/adv/adv_spt.jsp)
Post by: pedz on 04/07/2023 03:44 pm
Is it possible to get these FAA updates directly? Are they on a web site somewhere?
There's a link in that tweet: https://www.fly.faa.gov/adv/adv_spt.jsp (https://www.fly.faa.gov/adv/adv_spt.jsp)
Ahh!! My bad. I kept trying that link but it wasn't really the link but the image of the tweet...
Thank you
Post by: JDTractorGuy on 04/07/2023 04:49 pm
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Post by: sferrin on 04/07/2023 04:53 pm
Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Post by: EspenU on 04/07/2023 04:53 pm
Folks,Nope. Both will be ditched. They will attempt to bring Starship through reentry and "land" in the water.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Post by: DanClemmensen on 04/07/2023 05:08 pm
There was an extensive discussion about this about 18 months ago. We assume they intend to do the same maneuver they will need as part of a chopsticks landing, but over empty ocean, reaching a zero-velocity vertical orientation just above the sea surface. The question: what happens next? if they simply cut off the engines, the booster (in the gulf of Mexico) and an hour later the Starship (off Hawaii) will fall into the water. These are big and relatively fragile structures. They will probably crumple, take on water, and sink: think of a 22-story building and a 16-story building made of steel so thin that it can buckle if not pressurized. There are several possible tricks that might mitigate this, but we have no reason to believe SpaceX intends to do any of them.Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Post by: LinuxForAll on 04/07/2023 05:44 pm
Post by: InterestedEngineer on 04/07/2023 05:49 pm
There was an extensive discussion about this about 18 months ago. We assume they intend to do the same maneuver they will need as part of a chopsticks landing, but over empty ocean, reaching a zero-velocity vertical orientation just above the sea surface. The question: what happens next? if they simply cut off the engines, the booster (in the gulf of Mexico) and an hour later the Starship (off Hawaii) will fall into the water. These are big and relatively fragile structures. They will probably crumple, take on water, and sink: think of a 22-story building and a 16-story building made of steel so thin that it can buckle if not pressurized. There are several possible tricks that might mitigate this, but we have no reason to believe SpaceX intends to do any of them.Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Been hashed over so many times, and you didn't present the counter hypothesis, that
1. Falcon-9 has had successful landings on the ocean and didn't break up
2. The math shows that there's a good possibility of intact survival
Why don't you link to the thread instead of just presenting one side of it and causing the argument all over again
Post by: Malisk on 04/07/2023 06:11 pm
By happy coincidence, I am going to be in Hawaii on starting April 17th visiting the islands Oahu and Kauai. If I go to the north shore when the water landing is attempted, is there a chance that I may be able to catch a glimpse of the water landing off in the distance, or it is still going to be too far away?
according to this (https://twitter.com/Alexphysics13/status/1642028439539425283?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1642028439539425283%7Ctwgr%5E5112f6a66ff3f80761d27099d221107588c353a0%7Ctwcon%5Es1_&ref_url=https%3A%2F%2Fforum.nasaspaceflight.com%2Findex.php%3Ftopic%3D58288.400), the landing will be 200km+ North of Honolulu but the inbound path is ~100km-200km northwest of Kauai. Using a site like this (http://www.ringbell.co.uk/info/hdist.htm)you can see that at best you will be able to see the ship while it is 3km+ above sea level. Just the fact that it will be 200km a way though means you likely could not see it with the naked eye at all.
Post by: Robotbeat on 04/07/2023 06:29 pm
Just like with Falcon 9, will *probably* crumple, but they *might not*. Therefore they’ll need a plant to either tow them to shore or to sink them. No one has made a strong enough argument to me that sinking is assured, ie that they won’t need the ability to tow or sink them. Marine safety considerations means we can’t count on them for sure crumpling.There was an extensive discussion about this about 18 months ago. We assume they intend to do the same maneuver they will need as part of a chopsticks landing, but over empty ocean, reaching a zero-velocity vertical orientation just above the sea surface. The question: what happens next? if they simply cut off the engines, the booster (in the gulf of Mexico) and an hour later the Starship (off Hawaii) will fall into the water. These are big and relatively fragile structures. They will probably crumple, take on water, and sink: think of a 22-story building and a 16-story building made of steel so thin that it can buckle if not pressurized. There are several possible tricks that might mitigate this, but we have no reason to believe SpaceX intends to do any of them.Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Post by: Herb Schaltegger on 04/07/2023 06:55 pm
Post by: KSHavre on 04/07/2023 06:59 pm
Just like with Falcon 9, will *probably* crumple, but they *might not*. Therefore they’ll need a plant to either tow them to shore or to sink them. No one has made a strong enough argument to me that sinking is assured, ie that they won’t need the ability to tow or sink them. Marine safety considerations means we can’t count on them for sure crumpling.There was an extensive discussion about this about 18 months ago. We assume they intend to do the same maneuver they will need as part of a chopsticks landing, but over empty ocean, reaching a zero-velocity vertical orientation just above the sea surface. The question: what happens next? if they simply cut off the engines, the booster (in the gulf of Mexico) and an hour later the Starship (off Hawaii) will fall into the water. These are big and relatively fragile structures. They will probably crumple, take on water, and sink: think of a 22-story building and a 16-story building made of steel so thin that it can buckle if not pressurized. There are several possible tricks that might mitigate this, but we have no reason to believe SpaceX intends to do any of them.Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Would they be able to use the explosives for safeing a wayward rocket, to make big holes in the tanks?
Post by: edzieba on 04/07/2023 08:08 pm
Like with Falcon 9, if the vehicle survives tipover intact (more probable than not with Falcon 9 ocean landings that did not cut engines at altitude, unknown for Starship or Super Heavy) it will not take long for wave action to break up the stage once it has depressurised.
Post by: Slothman on 04/07/2023 08:32 pm
Post by: John Santos on 04/07/2023 08:47 pm
You all assume that the heatshield holds.If the heat shield does not hold, then the issue of floating debris (a hazard to navigation) is moot. No one is assuming that the heat shield holds, but no one is assuming it fails, either.
Post by: DanClemmensen on 04/07/2023 09:51 pm
You all assume that the heatshield holds.There are two "landings". The booster landing does not depend on a heat shield. SS needs its TPS to work (and also lots of other stuff) to survive re-entry. A landing failure of SS would still be a spectacularly successful test flight.
Post by: TheRadicalModerate on 04/07/2023 10:03 pm
You all assume that the heatshield holds.If the heat shield does not hold, then the issue of floating debris (a hazard to navigation) is moot. No one is assuming that the heat shield holds, but no one is assuming it fails, either.
Tiles + insulating blanket will likely float. Tiles + blanket + skin might float in some cases, if the pieces of debris were small. Tiles + blanket + skin + stringer will probably sink.
Post by: TheRadicalModerate on 04/07/2023 10:07 pm
You all assume that the heatshield holds.There are two "landings". The booster landing does not depend on a heat shield. SS needs its TPS to work (and also lots of other stuff) to survive re-entry. A landing failure of SS would still be a spectacularly successful test flight.
A nit to pick: The booster needs TPS as well. It's just not as extensive as the Starship, and it's considerably less exotic.
Post by: envy887 on 04/07/2023 10:10 pm
Just like with Falcon 9, will *probably* crumple, but they *might not*. Therefore they’ll need a plant to either tow them to shore or to sink them. No one has made a strong enough argument to me that sinking is assured, ie that they won’t need the ability to tow or sink them. Marine safety considerations means we can’t count on them for sure crumpling.There was an extensive discussion about this about 18 months ago. We assume they intend to do the same maneuver they will need as part of a chopsticks landing, but over empty ocean, reaching a zero-velocity vertical orientation just above the sea surface. The question: what happens next? if they simply cut off the engines, the booster (in the gulf of Mexico) and an hour later the Starship (off Hawaii) will fall into the water. These are big and relatively fragile structures. They will probably crumple, take on water, and sink: think of a 22-story building and a 16-story building made of steel so thin that it can buckle if not pressurized. There are several possible tricks that might mitigate this, but we have no reason to believe SpaceX intends to do any of them.Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Superheavy going for a chopstick landing will come to a stop and cut it's engines while still some 50 meters in the air. Without the chopsticks to land in, it will fall that distance to the surface, and I don't see any way it can survive that, water or no water.
I could see it maybe surviving a zero-zero landing. But why would SpaceX do a zero-zero landing when that's not the intended mode of operation?
Post by: TheRadicalModerate on 04/07/2023 11:01 pm
Superheavy going for a chopstick landing will come to a stop and cut it's engines while still some 50 meters in the air. Without the chopsticks to land in, it will fall that distance to the surface, and I don't see any way it can survive that, water or no water.
I could see it maybe surviving a zero-zero landing. But why would SpaceX do a zero-zero landing when that's not the intended mode of operation?
I'd feel confident that if you twiddled the guidance parameter that specified 0m/s at 50m to be 0m/s at 2m, you'd have proven your landing regime worked, and it was time to try the chopsticks, set at 50/0, your next flight.
I keep wondering if you really tune the system to be at 0m/s and hovering just as the hard points reach the height of the chopstick catch rails. I suspect that it'll be more reliable to have something analogous to a hoverslam, with things programmed to be at maybe -1m/s when the hard points should be scraping past the catch rails. Seems a lot more likely to have reliable contact--which stays reliable as the engines shut down. If you're hovering, the possibility of an upward bounce during shutdown could ruin your day.
Post by: Robotbeat on 04/08/2023 12:48 am
If they want to recover it for inspection.Just like with Falcon 9, will *probably* crumple, but they *might not*. Therefore they’ll need a plant to either tow them to shore or to sink them. No one has made a strong enough argument to me that sinking is assured, ie that they won’t need the ability to tow or sink them. Marine safety considerations means we can’t count on them for sure crumpling.There was an extensive discussion about this about 18 months ago. We assume they intend to do the same maneuver they will need as part of a chopsticks landing, but over empty ocean, reaching a zero-velocity vertical orientation just above the sea surface. The question: what happens next? if they simply cut off the engines, the booster (in the gulf of Mexico) and an hour later the Starship (off Hawaii) will fall into the water. These are big and relatively fragile structures. They will probably crumple, take on water, and sink: think of a 22-story building and a 16-story building made of steel so thin that it can buckle if not pressurized. There are several possible tricks that might mitigate this, but we have no reason to believe SpaceX intends to do any of them.Folks,I thought the idea was both stages soft land at sea. Whether they get towed back in I've never seen mentioned one way or another. I can't imagine them just leaving them floating around at sea though.
I apologize if I'm asking a question that's already been answered, but reading the article posted on NSF I'm a bit confused. Are they not going to attempt recovery of the booster or starship? I was under the impression that they would at least attempt to recover the upper stage. Any clarification appreciated!
Superheavy going for a chopstick landing will come to a stop and cut it's engines while still some 50 meters in the air. Without the chopsticks to land in, it will fall that distance to the surface, and I don't see any way it can survive that, water or no water.
I could see it maybe surviving a zero-zero landing. But why would SpaceX do a zero-zero landing when that's not the intended mode of operation?
Post by: envy887 on 04/08/2023 01:51 am
If they want to recover it for inspection.
That would be an immensely challenging task. Is there any evidence that they are planning to attempt it?
Post by: Robotbeat on 04/08/2023 01:54 am
Not really. Was done for SRBs. For Shuttle and Ariane 5. Doable if it does survive somehow. Don't know if they'll want to.If they want to recover it for inspection.
That would be an immensely challenging task....
Post by: envy887 on 04/08/2023 02:53 am
Not really. Was done for SRBs. For Shuttle and Ariane 5. Doable if it does survive somehow. Don't know if they'll want to.If they want to recover it for inspection.
That would be an immensely challenging task....
Despite the fact that the SRBs were much smaller and much sturdier, recovery was still very challenging, requiring dedicated support hardware, ships, crews, and training. Have we seen any of those?
Post by: Vahe231991 on 04/08/2023 03:05 am
Post by: Alvian@IDN on 04/08/2023 03:13 am
Is Elon Musk open to having the first orbital flight of the Starship make two or three orbits, given that the purpose of the first Starship launch will be to test the in-space behavior of the second stage of the Starship? This possibility shouldn't be ruled out because the first and only orbital flight of the Buran made two orbits before the Buran returned to Earth.You don't want a 120+ ton space debris circling around and or raining down the populated areas just because the first-time space propulsion is having a failure at deorbit
There's plenty of next vehicles waiting in line to do that, once the orbital burn & reentry stage is more proven. It's afterall, still their objective
Post by: Eer on 04/08/2023 03:22 am
Is Elon Musk open to having the first orbital flight of the Starship make two or three orbits, given that the purpose of the first Starship launch will be to test the in-space behavior of the second stage of the Starship? This possibility shouldn't be ruled out because the first and only orbital flight of the Buran made two orbits before the Buran returned to Earth.No, it is not given that the purpose of the first test flight is to test the in-space behavior of the second stage.
The purpose of the first flight is to test out the gse and first stage to get the stack off the pad and safely away from the gse. If that succeeds, try to make it to maxq. If it survives that, make it to MECO without tumbling out of control. Then stage separation. If it makes it that far it will be a stunning success for flight 1.
After that, if second stage engines light and doesn’t lose control, that’s a bonus, surely. Also, if booster reorienta itself and approximates a stable return trajectory…good. If the booster makes a soft approach to a zero vertical and horizontal vector some distance above the water, that is another huge success. Ditto Re-entry of the second stage towards the test range north of Hawaii. The whole idea of the low altitude perigee is to be absolutely darned sure it doesn’t get stuck in orbit if the engines can’t relight to bring it down.
Iteration is a different approach to retiring risk.
Post by: TheRadicalModerate on 04/08/2023 03:32 am
Is Elon Musk open to having the first orbital flight of the Starship make two or three orbits, given that the purpose of the first Starship launch will be to test the in-space behavior of the second stage of the Starship? This possibility shouldn't be ruled out because the first and only orbital flight of the Buran made two orbits before the Buran returned to Earth.
The reason not to do this is because you leave a big mess if the Starship can't deorbit or otherwise fails after getting to space. If you're in a suborbital trajectory (even if you've achieved orbital energy--it's just a matter of eccentricity), then almost everything will reenter.¹ The suborbital trajectory also gives you a good chance of getting some hypersonic data even if the propulsion system doesn't restart.
The purpose of the test is not to test the in-space behavior of Starship. The purpose of the test is to get Starship to space in the first place. Anything beyond that is gravy.
_________
¹If the Starship explodes near apogee, then some debris will have its perigee raised enough to be in a stable orbit. But explosions aren't very energetic, and most debris will decay fairly quickly. If it collides with something, that's a different story.
Post by: alugobi on 04/08/2023 03:35 am
The flight plan is already published.
Post by: baking on 04/08/2023 04:17 am
The purpose of the first flight is to test out the gse and first stage to get the stack off the pad and safely away from the gse. If that succeeds, try to make it to maxq. If it survives that, make it to MECO without tumbling out of control. Then stage separation. If it makes it that far it will be a stunning success for flight 1.I've been trying to focus my thoughts on this flight in a similar manner. Clearing the pad moving the debris field over water would be a success, in that the next launch could proceed without substantial rebuilding of stage zero. Some repairs are to be expected, but we hope for no major delays.
Stage separation would be an unqualified success. Everything after that is pure gravy.
My gut is telling me there is a 1/3 chance of failure at the pad or near the ground, 1/3 chance failure during ascent, and a 1/3 chance of making it to stage separation. I hope I'm being too pessimistic, but I would like to hear some other educated estimates.
Post by: daedalus1 on 04/08/2023 06:17 am
Is Elon Musk open to having the first orbital flight of the Starship make two or three orbits, given that the purpose of the first Starship launch will be to test the in-space behavior of the second stage of the Starship? This possibility shouldn't be ruled out because the first and only orbital flight of the Buran made two orbits before the Buran returned to Earth.
What for? It wouldn't be anywhere near a landing area.
Post by: dnavas on 04/08/2023 02:55 pm
My gut is telling me there is a 1/3 chance of failure at the pad or near the ground, 1/3 chance failure during ascent, and a 1/3 chance of making it to stage separation. I hope I'm being too pessimistic, but I would like to hear some other educated estimates.
Not to be a downer, but that seems to me an over-estimate of the likelihood of leaving the pad.
There hasn't been an entirely successful 33 engine start yet, and nothing anywhere close to full thrust.
We're talking about a repaired booster running engines that are regularly swapped out on a brand new architecture built by a company that prefers to fail fast.
I have every confidence that SpaceX will figure this out, but there will be a full exploration of the space of outcomes first.
All mho, and very definitely not an educated estimate!
Post by: Jeff Lerner on 04/08/2023 03:15 pm
because if not, I suspect there will be several attempts/aborts, etc before we see liftoff .
For me, just getting off the pad and away from Stage 0 represents a huge success…having the OLM and GSE survive to live to fight another day is critical to keep the program moving along.
IMHO, anything positive that happens after that is gravy for this booster/ship combo…
Post by: Lee Jay on 04/08/2023 03:19 pm
Does SpaceX commit to release of clamps and launch with less than 33 engines running at full power ??…
because if not, I suspect there will be several attempts/aborts, etc before we see liftoff .
For me, just getting off the pad and away from Stage 0 represents a huge success…having the OLM and GSE survive to live to fight another day is critical to keep the program moving along.
IMHO, anything positive that happens after that is gravy for this booster/ship combo…
Remember, booster hasn't flown at all. Personally, I'd add a mostly-successful first stage flight to just getting off the pad as a measure of success, for at least two reasons. First, booster needs to prove it can fly under control with Starship on top. Second, if it just gets off the pad and nothing more, that means it could fall back fully-fueled onto the area and cause a lot of damage.
Post by: daedalus1 on 04/08/2023 03:55 pm
Post by: whitelancer64 on 04/08/2023 04:28 pm
It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Post by: matthewkantar on 04/08/2023 04:43 pm
Post by: Alberto-Girardi on 04/08/2023 05:19 pm
If I recall correctly, all Raptor powered launches so far have nailed the going up part. I feel pretty good about their chances from liftoff to staging. Stage sep concept is new/never been done, if they get past that, man, they are in business.
I agree with you. If they launch it means that all engines have lighted correctly. Even the comparatively unreliable raptor 1 used in the suborbital campaign has never had a failure (directly resulting in ascent failure) on ascent. This is because, i suppose, once the engine (and this might apply to a lot of systems in general) is in a stady state (eg full power) it is much less likely to have a failure than during a state transition (eg. engine ignition), but they will launch only after this "state transition". The staging worries me because it seems to involve a peculiar flip maneuver to separate the stack, given that there isn't any mechanical device to separate it.
We know that the stack is connected by protrusions on SH that fit in slots on the ship. Does anyone know if the system that keeps that connection firm is a kind of "claw" or pin in the ship or is a pin located in the protrusion?
edit: forgot what chopsticks later pointed out
Post by: chopsticks on 04/08/2023 05:24 pm
If I recall correctly, all Raptor powered launches so far have nailed the going up part.
SN15 had an early shutdown on one of the engines. (The one that didn't relight)
SN11 had an engine fire which fried the avionics which led to a hard start and RUD. It kept running until shutdown though.
Post by: joek on 04/08/2023 05:24 pm
It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
...
With or without nominal starship payload? Musk stated ~1.5 TWR; think we know "T" (give-or-take), but he did not state "W". Might be quite a bit more margin with zero starship payload, as we might expect for first test flight?
Post by: DanClemmensen on 04/08/2023 05:28 pm
If I recall correctly, all Raptor powered launches so far have nailed the going up part. I feel pretty good about their chances from liftoff to staging. Stage sep concept is new/never been done, if they get past that, man, they are in business.
Reminder: reliability of .99 (example) for each engine is a reliability of .99^^33=0.71 that all 33 Raptors will start.
Post by: sferrin on 04/08/2023 05:36 pm
If you go by the only example we have, where they succeeded in lighting 31/33, that gives it a 13% chance of lighting off all 33. Of course they know why those two engines didn't fire, and have almost certainly mitigated those factors, so we'll see.If I recall correctly, all Raptor powered launches so far have nailed the going up part. I feel pretty good about their chances from liftoff to staging. Stage sep concept is new/never been done, if they get past that, man, they are in business.
Reminder: reliability of .99 (example) for each engine is a reliability of .99^^33=0.71 that all 33 Raptors will start.
Post by: joek on 04/08/2023 05:51 pm
Reminder: reliability of .99 (example) for each engine is a reliability of .99^^33=0.71 that all 33 Raptors will start.
True, and that undoubtedly will factor into their launch decision. Expect they have enough experience to determine start reliability to a high level of confidence. (Whereas we have only one public data point based on previous all-up test showing 31/33.)
Expect launch commit criteria is going to depend on several factors, of which number of engines starts is one, but not the only. That said, hope and expect they are shooting for 100%.
But we don't know what their test criteria-priorities are. Might be that they're ok with less than 100% if it accelerates starship tests. Or maybe getting the booster ironed out is a priority. Hard to tell from our (public) vantage.
Post by: alugobi on 04/08/2023 06:25 pm
Post by: Alberto-Girardi on 04/08/2023 07:28 pm
Reminder: reliability of .99 (example) for each engine is a reliability of .99^^33=0.71 that all 33 Raptors will start.
True, and that undoubtedly will factor into their launch decision. Expect they have enough experience to determine start reliability to a high level of confidence. (Whereas we have only one public data point based on previous all-up test showing 31/33.)
I wonder if they could do a static fire as part of the launch rehersal. They haven't said "wet dress rehersal" which has a specific and established meaning.
AFAIK all the closures/notices for a static fire/wdr are the same, apart from the overpressure notice, which might not be necesary given that they might want to evacuate the village as it would happen during a real launch. So we can't rule that out yet.
Post by: meekGee on 04/08/2023 07:59 pm
It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
Post by: AU1.52 on 04/08/2023 08:57 pm
It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
Post by: meekGee on 04/08/2023 09:23 pm
I was talking about this specific flight, where the risk of every ignition is high, and priority is to risk the OLM as little as possible, and when a partial flight is also pretty much considered a success.It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
Later on the considerations change.
Post by: VLN on 04/09/2023 01:58 am
By happy coincidence, I am going to be in Hawaii on starting April 17th visiting the islands Oahu and Kauai. If I go to the north shore when the water landing is attempted, is there a chance that I may be able to catch a glimpse of the water landing off in the distance, or it is still going to be too far away?
{snip}
... at best you will be able to see the ship while it is 3km+ above sea level. Just the fact that it will be 200km a way though means you likely could not see it with the naked eye at all.
If the landing burn begins above 3km, you could see that part. (It also would be visible all the way down if you're in an aircraft at 10,000 ft or more.)
From the eastern suburbs of Los Angeles we can see a Falcon 9 entry burn with the naked eye from more than 240 km.
The main impediment is clouds and haze near the horizon.
So I'd recommend that you at least set up a chair in a dark spot, keep the livestream audio in your ear so you know when it's coming, and see what you see. Bring enough beverages.
Post by: TrueBlueWitt on 04/09/2023 02:54 am
It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
Another question here. Raptors at 90% at liftoff. If they lose engines, will they allow the other engines to throttle higher to makeup the difference?
Post by: joek on 04/09/2023 08:07 am
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
Based on first order BOTE calc. Given: Raptor 2 thrust = 230t (100%); TWR = 1.5 ...
= SS payload 150t requires 33 Raptors @100% thrust.
= SS payload 0t requires 32 Raptors @100% thrust.
= SS payload 0t requires 31.9 Raptors @90% thrust.
... so not much room to maneuver based on those simple pro-forma calcs. You effectively need 32 Raptors regardless of scenario.
That said, for this test, the TWR might be relaxed as they don't plan on recovering the booster, so they might make it up with a longer booster burn with fewer engines or lower thrust (and thus the booster travels farther down range).
Post by: Chinakpradhan on 04/09/2023 09:53 am
https://twitter.com/thePrimalSpace/status/1644973813325524992?s=20
Post by: FutureSpaceTourist on 04/09/2023 11:39 am
Quote
Overnight this happened. Pic 1 shows a metal plate, apparently securing objects to the chopstick stabilisation pin socket on Booster 7, before being removed (pic 2) presumably after adhesive had dried. @elonmusk Are you going to attempt a catch maybe?
@LabPadre #Rover2Cam
We know no catch attempt this flight; other ideas?
Post by: saturnsky on 04/09/2023 12:59 pm
Post by: baking on 04/09/2023 01:47 pm
Any suggestions for viewing and photography for the interested civilian????Everyday Astronaut just put up a video on the subject:
https://www.youtube.com/watch?v=aWvHrih-Juk
Post by: Kaputnik on 04/09/2023 02:47 pm
Post by: kevinof on 04/09/2023 03:15 pm
Any chance of seeing this from the Caribbean?Northern Caribbean maybe. I am going from Antiqua to Bahamas and hope to catch it on the way.
Post by: RedLineTrain on 04/09/2023 07:41 pm
New NGA notices. Note that these do not cancel the existing notices. (NAVAREA XII 189/23 being canceled by NAVAREA XII 191/23 was a new notice that came out shortly before, so I'm not posting 189/23.)
For completeness, added maps of the research buoys, and a global ground track.
Post by: OTV Booster on 04/09/2023 09:11 pm
Or, what if they decide to reduce propellant because there's no payload? All of a sudden there's a stack even more tolerant of engine loss on the booster.It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
They get some points for form but most of the points are for performance. I can hear it now. The booster launches on 31 engine and goes on for a flawless seperation and faux landing. The ship goes on to successful EDL and a faux landing. And all the SX haters will make noise about is the engine out problem.
Yeah, they'll loose a few point here. So what.
PS. That's not a prediction, just a what if...
Post by: Alberto-Girardi on 04/09/2023 09:20 pm
Or, what if they decide to reduce propellant because there's no payload? All of a sudden there's a stack even more tolerant of engine loss on the booster.It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
They get some points for form but most of the points are for performance. I can hear it now. The booster launches on 31 engine and goes on for a flawless seperation and faux landing. The ship goes on to successful EDL and a faux landing. And all the SX haters will make noise about is the engine out problem.
Yeah, they'll loose a few point here. So what.
PS. That's not a prediction, just a what if...
I have heard many times in the NSF streams and I agree with the opinion that loading less propellant is not a good idea. You want a test flight that accurately rappresents a "normal" flight. Having non full tanks at the start changes a variable. I remember, but i am not sure ( i hope someone can confirm or disprove me), that on Falcon 9 flights they do NOT change the amount of loaded propellant even if the payload is lighter, they simply stop the burn before ( i assume the 2nd stage burn given that the first can't have too much propellant before landing, because the drag wouldn't slow it down enough). They do this beacuse the vehicle has been caracterazed to a high precision on THAT fuel load, and you don't want to mess with that.
Again I can't quote any source, but I think I heard that on a NSF stream.
Post by: Kaputnik on 04/09/2023 09:44 pm
Or, what if they decide to reduce propellant because there's no payload? All of a sudden there's a stack even more tolerant of engine loss on the booster.It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
They get some points for form but most of the points are for performance. I can hear it now. The booster launches on 31 engine and goes on for a flawless seperation and faux landing. The ship goes on to successful EDL and a faux landing. And all the SX haters will make noise about is the engine out problem.
Yeah, they'll loose a few point here. So what.
PS. That's not a prediction, just a what if...
I have heard many times in the NSF streams and I agree with the opinion that loading less propellant is not a good idea. You want a test flight that accurately rappresents a "normal" flight. Having non full tanks at the start changes a variable. I remember, but i am not sure ( i hope someone can confirm or disprove me), that on Falcon 9 flights they do NOT change the amount of loaded propellant even if the payload is lighter, they simply stop the burn before ( i assume the 2nd stage burn given that the first can't have too much propellant before landing, because the drag wouldn't slow it down enough). They do this beacuse the vehicle has been caracterazed to a high precision on THAT fuel load, and you don't want to mess with that.
Again I can't quote any source, but I think I heard that on a NSF stream.
AIUI it's generally not even possible to part fill because the vehicle's sensors are not configured that way. I think it was Jim who explained this and it wasn't Falcon specific.
Post by: meekGee on 04/09/2023 10:02 pm
If the payload is light, you still fly full for exactly that reason, and you additionally get more fault tolerance.Or, what if they decide to reduce propellant because there's no payload? All of a sudden there's a stack even more tolerant of engine loss on the booster.It doesn't need all 33 engines to climb from the pad. 2 or 3 less I remember seeing somewhere.
If my math is right, Super Heavy could lose up to 8 engines at liftoff and still make it off the pad, i.e., TWR is >1
However, that would look a lot like that Astra launch that went sideways. It wouldn't get very far and there'd likely be considerable damage to the OLM and surrounding ground equipment.
It can lose 2 or 3 engines at liftoff and still make it to orbit. Losing engines later in the flight is less of an issue.
That said, I think that SpaceX will not release the hold-down clamps without all 33 engines running and healthy.
Every launch attempt is a risk. This has to be factored in when deciding whether to commit or abort if n<33.
IMO, you get the most bang for the buck if you allow flight with n>=32.
The impact is the least possible, and the odds of it occurring are the highest.
If you're allowing flight with n=31, you have to think what if the failures are correlated, and also you can have more asymmetrical thrust, and we know B7 is less tolerant of that.
So maybe ok to go with n=31 only if the failed engines are on opposite sides or some similar criteria.
What if you were not carrying 150 tons to orbit? How many engines would you need then? What if any payload / mass simulation would S24 contain if any?
They get some points for form but most of the points are for performance. I can hear it now. The booster launches on 31 engine and goes on for a flawless seperation and faux landing. The ship goes on to successful EDL and a faux landing. And all the SX haters will make noise about is the engine out problem.
Yeah, they'll loose a few point here. So what.
PS. That's not a prediction, just a what if...
I have heard many times in the NSF streams and I agree with the opinion that loading less propellant is not a good idea. You want a test flight that accurately rappresents a "normal" flight. Having non full tanks at the start changes a variable. I remember, but i am not sure ( i hope someone can confirm or disprove me), that on Falcon 9 flights they do NOT change the amount of loaded propellant even if the payload is lighter, they simply stop the burn before ( i assume the 2nd stage burn given that the first can't have too much propellant before landing, because the drag wouldn't slow it down enough). They do this beacuse the vehicle has been caracterazed to a high precision on THAT fuel load, and you don't want to mess with that.
Again I can't quote any source, but I think I heard that on a NSF stream.
Basically there is no advantage in ever underfilling the first stage, and it only adds complications.
Post by: FutureSpaceTourist on 04/09/2023 10:29 pm
Quote
There's something wonderful about a LOX Tanker decorated in Shuttle, supplying the Starbase Tank Farm for Starship!
nsf.live/starbase
Post by: MdBee on 04/10/2023 12:07 am
It feels to me like having as much daylight as possible at both hopeful ends of this test flight might be helpful for diagnosis if anything is off-norminal... (let alone any cool soft-landing footage potentially!). Thoughts or corrections?
Post by: sferrin on 04/10/2023 02:10 am
75% believe that's just good design with an unfortunate appearance. 25% think it's part Elon prank. :o
Post by: alphacentauri on 04/10/2023 02:56 am
(shifting this from another discussion thread) Quick question about the 7/24 OFT scheduling. As a non-US person, can somebody confirm my timezone maths, that the current suggested launch windows (12Z-15Z) are roughly dawn-till-midmorning in TX, and it would be night-till-barely-dawn at the wet-LZ near HI? IIUC, 16Z is 06HI, about 20min before sunrise there - anything much earlier is still dark. This is noting of course the TX-HI flight time of ~60-90min...Your time zone observations are correct. My guess is they don't expect the ship to survive reentry so it doesn't matter that the landing zone will be dark. They probably chose the time to favor best conditions for launch in TX without worrying about HI. There may be other considerations to prefer a morning launch instead of an afternoon launch, perhaps likelihood of better weather?
It feels to me like having as much daylight as possible at both hopeful ends of this test flight might be helpful for diagnosis if anything is off-norminal... (let alone any cool soft-landing footage potentially!). Thoughts or corrections?
Post by: Alberto-Girardi on 04/10/2023 07:02 am
(shifting this from another discussion thread) Quick question about the 7/24 OFT scheduling. As a non-US person, can somebody confirm my timezone maths, that the current suggested launch windows (12Z-15Z) are roughly dawn-till-midmorning in TX, and it would be night-till-barely-dawn at the wet-LZ near HI? IIUC, 16Z is 06HI, about 20min before sunrise there - anything much earlier is still dark. This is noting of course the TX-HI flight time of ~60-90min...Your time zone observations are correct. My guess is they don't expect the ship to survive reentry so it doesn't matter that the landing zone will be dark. They probably chose the time to favor best conditions for launch in TX without worrying about HI. There may be other considerations to prefer a morning launch instead of an afternoon launch, perhaps likelihood of better weather?
It feels to me like having as much daylight as possible at both hopeful ends of this test flight might be helpful for diagnosis if anything is off-norminal... (let alone any cool soft-landing footage potentially!). Thoughts or corrections?
considering they launched SN11 in an extremely thick fog I would say that the do not care enough about landing visuals to change the launch window that apparently is good for them. After all they still will have the telemetry and inboard footage that might tell them more than a splashdown video that might not even exist since the distance from the island. (I don't know if they can get a boat close due to the closure).
Post by: Robotbeat on 04/10/2023 08:14 am
Post by: edzieba on 04/10/2023 12:03 pm
Post by: plank on 04/10/2023 12:17 pm
Post by: sdsds on 04/10/2023 09:55 pm
For completeness, added maps of the research buoys, and a global ground track.
I note with interest the hazard area maps don't seem to cover a case where the booster under-performs but Starship separates and then targets a disposal location in either the mid-Atlantic or Indian Ocean. Am I missing something?
I'm also curious about speculation (informed or otherwise) about when after liftoff the vehicle will begin to pitch towards its intended trajectory. Approximately what length below the booster is the supersonic exhaust flow expected to extend? Would the vehicle begin to pitch at about that altitude?
Post by: Herb Schaltegger on 04/10/2023 11:21 pm
Approximately what length below the booster is the supersonic exhaust flow expected to extend?
That's not how supersonic flow works. Perhaps you can be more precise in your question.
Post by: TheRadicalModerate on 04/10/2023 11:52 pm
For completeness, added maps of the research buoys, and a global ground track.
I note with interest the hazard area maps don't seem to cover a case where the booster under-performs but Starship separates and then targets a disposal location in either the mid-Atlantic or Indian Ocean. Am I missing something?
I'm also curious about speculation (informed or otherwise) about when after liftoff the vehicle will begin to pitch towards its intended trajectory. Approximately what length below the booster is the supersonic exhaust flow expected to extend? Would the vehicle begin to pitch at about that altitude?
The launch hazard area extends all the way to the Florida Keys. If there's that serious an underperformance or Starship fails to start up, they'll destroy the Starship and it'll fall into that area.
I suspect that the landing hazard area going as far west as the Marshalls probably handles 95% of the cases where the Starship itself underperforms.
As for pitchover, they're going to be lofting the hell out of the thing, so there's no need for an early pitchover. T/W=1.5 means that the vehicle should be 100m above the tower (145m high) in exactly 10s. If that's too extreme an exhaust load, I guess they could pitch over sooner, but that seems like a terrible idea on a first launch. It takes 7.6s to clear the tower, and you certainly wouldn't want to pitch before then.
Post by: CameronD on 04/10/2023 11:59 pm
The launch hazard area extends all the way to the Florida Keys. If there's that serious an underperformance or Starship fails to start up, they'll destroy the Starship and it'll fall into that area.
I suspect that the landing hazard area going as far west as the Marshalls probably handles 95% of the cases where the Starship itself underperforms.
I guess that also means a ridiculously-high likelihood of a vessel incursion and resulting launch hold on this first one.
Let's hope not, but either way: LOOK OUT BELOW!!
Post by: TheRadicalModerate on 04/11/2023 01:44 am
If you go by the only example we have, where they succeeded in lighting 31/33, that gives it a 13% chance of lighting off all 33. Of course they know why those two engines didn't fire, and have almost certainly mitigated those factors, so we'll see.If I recall correctly, all Raptor powered launches so far have nailed the going up part. I feel pretty good about their chances from liftoff to staging. Stage sep concept is new/never been done, if they get past that, man, they are in business.
Reminder: reliability of .99 (example) for each engine is a reliability of .99^^33=0.71 that all 33 Raptors will start.
Sounds like we’ve almost got the ingredients for a good old fashioned frequentist vs. bayesian smack down.
Post by: FutureSpaceTourist on 04/11/2023 03:29 am
https://twitter.com/nasaspaceflight/status/1645619546823221248
Quote
If this scene becomes a reality for the test flight, SpaceX will have seriously overachieved!
I'd take a launch and some good first stage action to get away from potentially damaging the launch site.
Some nice downrange - I'll take it.
Maybe lose a few engines - keep calm; she can keep going.
MaxQ - it's getting tasty now! Lots of useful data.
Staging - hey, we're winning now! Booster's going into the drink as planned.
Ship ignition - we've got RVacs firing in space!
Ship re-entry - TPS data!
Ship survives and lands near Hawaii - faints.
Seriously though. Launch, clear the launch site. Anything else is a bonus.
Post by: TheRadicalModerate on 04/11/2023 03:50 am
The launch hazard area extends all the way to the Florida Keys. If there's that serious an underperformance or Starship fails to start up, they'll destroy the Starship and it'll fall into that area.
I suspect that the landing hazard area going as far west as the Marshalls probably handles 95% of the cases where the Starship itself underperforms.
I guess that also means a ridiculously-high likelihood of a vessel incursion and resulting launch hold on this first one.
Let's hope not, but either way: LOOK OUT BELOW!!
There are two different classes contained in the notice to mariners:
1) Hazardous operations, rocket launching
2) Hazardous operations, space debris
Anybody know how they're each treated as launch criteria? If SpaceX has to wait until a sizable chunk of the maritime traffic in the Gulf of Mexico gets the word to cease north-south operations and actually obeys it, they're going to be waiting a while.
Post by: billh on 04/11/2023 03:51 am
Video of the same rainbowThe rocket at the end of the rainbow!
https://www.youtube.com/shorts/mOwBHnMb6-k
Post by: TheRadicalModerate on 04/11/2023 03:52 am
twitter.com/ercxspace/status/1645564399556661248
https://twitter.com/nasaspaceflight/status/1645619546823221248
Is it just me, or do the two guys in the Zodiac look like they need to be hefting harpoons?
Post by: billh on 04/11/2023 03:58 am
Call me Ishmael.twitter.com/ercxspace/status/1645564399556661248
https://twitter.com/nasaspaceflight/status/1645619546823221248
Is it just me, or do the two guys in the Zodiac look like they need to be hefting harpoons?
Post by: OneSpeed on 04/11/2023 12:14 pm
I note with interest the hazard area maps don't seem to cover a case where the booster under-performs but Starship separates and then targets a disposal location in either the mid-Atlantic or Indian Ocean. Am I missing something?
...
If the booster dramatically under-performs, then I'd suggest that SESU will be aborted, and the ship either be terminated or re-enter ballistically. Even if the booster performs perfectly, then my simulation suggests that with a maximum of 90% thrust, and no payload, the ship would only reach about 600km downrange ballistically. I've added the ground track of that scenario to the LHA map.
Post by: whitelancer64 on 04/11/2023 04:37 pm
*snip*
It feels to me like having as much daylight as possible at both hopeful ends of this test flight might be helpful for diagnosis if anything is off-norminal... (let alone any cool soft-landing footage potentially!). Thoughts or corrections?
Video of an anomaly is almost always far less helpful than the data from the thousands of onboard sensors. While we would all love to see a clear video stream of the launch, the reality is that telemetry is much more important.
Post by: wannamoonbase on 04/11/2023 05:19 pm
*snip*
It feels to me like having as much daylight as possible at both hopeful ends of this test flight might be helpful for diagnosis if anything is off-norminal... (let alone any cool soft-landing footage potentially!). Thoughts or corrections?
Video of an anomaly is almost always far less helpful than the data from the thousands of onboard sensors. While we would all love to see a clear video stream of the launch, the reality is that telemetry is much more important.
100% agree, the resolution of telemetry will exceed video, especially after the first few miles.
However, daylight on the pacific re-entry area might be really helpful.
Post by: Vettedrmr on 04/11/2023 05:24 pm
Video of an anomaly is almost always far less helpful than the data from the thousands of onboard sensors. While we would all love to see a clear video stream of the launch, the reality is that telemetry is much more important.
But it's not an either/or. There's no outside pressure to launch, so why not wait for good visual weather?
Post by: whitelancer64 on 04/11/2023 05:33 pm
*snip*
It feels to me like having as much daylight as possible at both hopeful ends of this test flight might be helpful for diagnosis if anything is off-norminal... (let alone any cool soft-landing footage potentially!). Thoughts or corrections?
Video of an anomaly is almost always far less helpful than the data from the thousands of onboard sensors. While we would all love to see a clear video stream of the launch, the reality is that telemetry is much more important.
100% agree, the resolution of telemetry will exceed video, especially after the first few miles.
However, daylight on the pacific re-entry area might be really helpful.
If they were doing a recovery, then I'd agree, but there is no planned recovery for either booster or Starship, and an intact landing for either is very unlikely.
Post by: alphacentauri on 04/11/2023 07:58 pm
If they were doing a recovery, then I'd agree, but there is no planned recovery for either booster or Starship, and an intact landing for either is very unlikely.According to the materials SpaceX released today, they will not even attempt a vertical landing of Starship. The diagram shows it landing horizontally on the Pacific Ocean. Apparently, they will let it "float" horizontally until splashdown, with no landing burn.
Post by: Alberto-Girardi on 04/11/2023 08:01 pm
Things are starting to feel real!
The news from NSF Alex that there would not be a WDR is confirmed.
Also we have an official countdown. It feels a little bit strange, it is the end of us being totally blind and having to figure out everything, like it was done during the suborbital campaign ( i will never forget how beautiful it was that a few guys could figure out starship launch time precise to the second only watching other tests.). Not to say that we won't have anything to do, obviusly.
Interesting things I noted:
- raptor ignition sequence is going to start at t-8 s. It will be long, similar to the Saturn V or Shuttle one, compared to Falcon 9 or other rockets. I hope the commentator calls out "ignition sequence start"like in Apollo 11.
-what is "Fluid interfaces begin ventdown"? at t -40s? could be ship qd disconnect?
Post by: Alberto-Girardi on 04/11/2023 08:11 pm
Post by: neoforce on 04/11/2023 08:15 pm
Chris' tweet and the post here https://forum.nasaspaceflight.com/index.php?topic=47352.msg2473864#msg2473864 includes the graphic. But when I go to the page on spacex at https://www.spacex.com/launches/mission/?missionId=starship-flight-test it has the countdown/timeline but not the graphic?
EDIT: never mind, was just me
Post by: kevinof on 04/11/2023 08:16 pm
Is it just me, or did spacex update their page and remove the graphic?I see the graphic and timeline(https://uploads.tapatalk-cdn.com/20230411/f89a615fbd50079b04d8d8cd35b136e9.jpg)
Chris' tweet and the post here https://forum.nasaspaceflight.com/index.php?topic=47352.msg2473864#msg2473864 includes the graphic. But when I go to the page on spacex at https://www.spacex.com/launches/mission/?missionId=starship-flight-test it has the countdown/timeline but not the graphic?
Post by: neoforce on 04/11/2023 08:18 pm
Is it just me, or did spacex update their page and remove the graphic?I see the graphic and timeline
Chris' tweet and the post here https://forum.nasaspaceflight.com/index.php?topic=47352.msg2473864#msg2473864 includes the graphic. But when I go to the page on spacex at https://www.spacex.com/launches/mission/?missionId=starship-flight-test it has the countdown/timeline but not the graphic?
Thanks, its just me... tried it from another computer/browser and i see it. Either a browser or proxy issue.
Post by: Malisk on 04/11/2023 08:19 pm
Post by: TheRadicalModerate on 04/11/2023 08:23 pm
If they were doing a recovery, then I'd agree, but there is no planned recovery for either booster or Starship, and an intact landing for either is very unlikely.According to the materials SpaceX released today, they will not even attempt a vertical landing of Starship. The diagram shows it landing horizontally on the Pacific Ocean. Apparently, they will let it "float" horizontally until splashdown, with no landing burn.
I'd be extremely surprised if they didn't do the flip maneuver. There's no reason not to gather more landing data, especially since there have been so many changes since the SNxx series of tests. I suspect the graphics designer simply didn't want to make the chart too busy.
Post by: Nomadd on 04/11/2023 08:31 pm
So the ship is 'landing' horizontally? That's not really a landing and more like a belly flop, right? Is it known why it wouldn't attempt to move vertical and repulsively land?.If it's a marine sanctuary, there could be a problem with firing engines into the water. But that shouldn't prevent them from igniting to go vertical. They might want to hit horizontal to insure breakup and sinking.
Post by: Robotbeat on 04/11/2023 08:33 pm
So the ship is 'landing' horizontally? That's not really a landing and more like a belly flop, right? Is it known why it wouldn't attempt to move vertical and repulsively land?.Possibilities
1) graphic designer forgot
2) they decided they didn’t want to bother doing all the mods needed to enable a successful flip. Remember, this is probably the most challenging part of the whole mission for the suborbital tests, and it failed multiple times in multiple ways. They may have just deleted those mitigations on this vehicle since it was already tested on suborbital flights and this is an old design of Starship anyway.
3) they want to do sideways landing now. If they’re already potentially adding auxiliary thrusters for the Moon, they could just avoid flipping at all for Earth landings. This would be the first we’ve heard about it.
I’d say 2 is more likely than 1, and 3 is by far the least likely.
Post by: chariotoffire on 04/11/2023 08:47 pm
If they were doing a recovery, then I'd agree, but there is no planned recovery for either booster or Starship, and an intact landing for either is very unlikely.According to the materials SpaceX released today, they will not even attempt a vertical landing of Starship. The diagram shows it landing horizontally on the Pacific Ocean. Apparently, they will let it "float" horizontally until splashdown, with no landing burn.
I'd be extremely surprised if they didn't do the flip maneuver. There's no reason not to gather more landing data, especially since there have been so many changes since the SNxx series of tests. I suspect the graphics designer simply didn't want to make the chart too busy.
The timeline shows a landing burn for the booster but not the ship. I don't think they're going to try the flip.
Post by: FutureSpaceTourist on 04/11/2023 08:48 pm
Quote
The NSF team is live discussing the release of the flight profile for SpaceX's Starship Flight Test!
https://youtu.be/mhJRzQsLZGg
Post by: Alberto-Girardi on 04/11/2023 09:06 pm
So the ship is 'landing' horizontally? That's not really a landing and more like a belly flop, right? Is it known why it wouldn't attempt to move vertical and repulsively land?.Possibilities
1) graphic designer forgot
2) they decided they didn’t want to bother doing all the mods needed to enable a successful flip. Remember, this is probably the most challenging part of the whole mission for the suborbital tests, and it failed multiple times in multiple ways. They may have just deleted those mitigations on this vehicle since it was already tested on suborbital flights and this is an old design of Starship anyway.
3) they want to do sideways landing now. If they’re already potentially adding auxiliary thrusters for the Moon, they could just avoid flipping at all for Earth landings. This would be the first we’ve heard about it.
I’d say 2 is more likely than 1, and 3 is by far the least likely.
I think the most likey is 2. It is interesting what Nomadd metioned. Maybe due to the provisional payload bay design s24 can't handle a flip. Also I would mention that the flip maneuver WAS NOT tested completely successfully, in fact spacex said a few weeks ago that pressure was lost in a header tank. They still have to do it perfectly.
If 3 is true it is a little bit disappointg, the fun of Starship for me was also the challenge of the incredible flip maneuver, but we have already a lot of reason to think that they need a flip to have good efficiency on the landing.
Post by: TheRadicalModerate on 04/11/2023 09:14 pm
2) they decided they didn’t want to bother doing all the mods needed to enable a successful flip. Remember, this is probably the most challenging part of the whole mission for the suborbital tests, and it failed multiple times in multiple ways. They may have just deleted those mitigations on this vehicle since it was already tested on suborbital flights and this is an old design of Starship anyway.
S24 has the methane header tank in the nose, doesn't it? Why wouldn't they want to field-test its dynamics--especially since that's a known problem area with the flip maneuver?
Post by: philw1776 on 04/11/2023 09:23 pm
So the ship is 'landing' horizontally? That's not really a landing and more like a belly flop, right? Is it known why it wouldn't attempt to move vertical and repulsively land?.Possibilities
1) graphic designer forgot
2) they decided they didn’t want to bother doing all the mods needed to enable a successful flip. Remember, this is probably the most challenging part of the whole mission for the suborbital tests, and it failed multiple times in multiple ways. They may have just deleted those mitigations on this vehicle since it was already tested on suborbital flights and this is an old design of Starship anyway.
3) they want to do sideways landing now. If they’re already potentially adding auxiliary thrusters for the Moon, they could just avoid flipping at all for Earth landings. This would be the first we’ve heard about it.
I’d say 2 is more likely than 1, and 3 is by far the least likely.
Curse you for reviving that topic with option 3.
Post by: Slothman on 04/11/2023 09:30 pm
Post by: alugobi on 04/11/2023 10:04 pm
Post by: Herb Schaltegger on 04/11/2023 10:22 pm
They might think that they've fixed the door for max-q stress, but aren't confident about torque on the frame during a flip.
There will be no "torque" on the frame (torsion). The only stresses on the airframe for the flip will be in tension and compression modes. Presuming a belly-entry, the door will be on the leeward side of the structure and thus should face predominantly compression forces from a flip. That door structure will face far more compression on launch than it will during the flip.
Post by: JCopernicus on 04/11/2023 10:28 pm
Post by: wolfi44 on 04/11/2023 10:36 pm
https://twitter.com/spacex/status/1645875678657810439QuoteTeams are focused on launch readiness ahead of Starship’s first integrated flight test as soon as next week, pending regulatory approval – no launch rehearsal this week spacex.com/launches/
Will they skip the WDR ?
Post by: gemmy0I on 04/11/2023 10:36 pm
1. Something in their simulations/modeling has told them conclusively that S24 can't or almost certainly won't successfully pull off the flip-and-burn maneuver. Basically, there's some known deficiency in the design (perhaps structural, but I suspect more likely "plumbing-related", i.e. header-tank/pressurization issues of the sort S15 had) that falls short of the needs of this maneuver, so they left if off the flight plan because they don't expect to learn anything from it. Save it for a future ship (probably S28) that has the necessary design improvements. If true, this would fit neatly with the decision long ago to remove the heat-shield tiles and flaps entirely from S26 and S27 and just fly them expendable. S26 and S27 are from the same design generation as S24, so S28 is their next real opportunity to fix big design issues.
Incidentally, since any design issues in S24 should be shared by S25, if they fly S25, they'll likely use the same flight profile: no landing burn, just focus on testing ascent, re-entry, and atmospheric control through the transonic regime (none of which could be tested with S15 and earlier since they didn't go supersonic).
2. They know that if S24 makes a successful water landing, it'll likely survive the subsequent tip-over, leaving them with a giant, floating stainless-steel whale in the middle of the ocean that they have to dispose of lest it become a marine hazard. Belly-flopping at terminal velocity should guarantee a "clean" breakup (see SN9). They've been through this before with that one Falcon 9 that survived a water landing and had to be demolished with explosive charges by frogmen (not, as the early sensational rumors reported, "used as target practice by the Air Force" ;) ). That kind of operation with human divers in close proximity to a building-sized object "flopping" unpredictably in the waves is surely extremely hazardous - the sort of thing you do when you have no other choice, but you don't want to make a habit of risking when you can avoid it. That's a fast way to get a workers'-comp/wrongful-death lawsuit and a ton of bad publicity.
I'd consider #1 the more likely deciding factor, because I suspect if they thought they could actually get good data on a flip-and-burn landing, they'd try their best to do it (despite the risk of a tricky cleanup; if they expected that to be an issue, there are ways they can mitigate the challenge through engineering, e.g. by leaving the FTS armed and detonating it as soon as the landing burn ends). As we now know, S15's landing burn was far from 100% successful, and its safe touchdown was more of a "fluke" than a true success - so this absolutely remains on their list of things that need to be tested and proven out. I can't imagine them not giving it another shot with S24 unless they didn't think it would teach them anything worthwhile.
Post by: TheRadicalModerate on 04/11/2023 10:38 pm
They might think that they've fixed the door for max-q stress, but aren't confident about torque on the frame during a flip.
What's the worst that can happen? The Starship just destroys itself ten seconds earlier. A belly-flop into the Pacific Ocean at ~100m/s (can't remember the exact number) isn't going to leave much to examine.
Post by: sdsds on 04/11/2023 10:39 pm
I note with interest the hazard area maps don't seem to cover a case where the booster under-performs but Starship separates and then targets a disposal location in either the mid-Atlantic or Indian Ocean. [...]
If the booster dramatically under-performs, then I'd suggest that SESU will be aborted [...]
Thanks very much for your analysis. It adds quite a bit of clarity to a scenario that seems at best quite murky!
Thinking about the SpaceX test objective priorities, demonstrating stage separation followed by Starship in-flight engine startup seem like items that must be fairly high up the list. Yet even optimistically the lack of flight history for a booster powered by a cluster of Raptor-2 engines makes the likelihood of booster under-performance seem non-negligible.
(Fully recognizing this isn't a "Poll" thread I nonetheless attach a graphic guess at the likelihood of how many booster engines lose thrust — either through commanded shutdowns or RUD/fratricide events — at some time before the intended amount of propellant is expended. The modal value is 8, based on a Poisson distribution with μ = 8.5.)
Sounds like we’ve almost got the ingredients for a good old fashioned frequentist vs. bayesian smack down.
Oh yes, in so many ways! ;)
Post by: envy887 on 04/11/2023 11:30 pm
I note with interest the hazard area maps don't seem to cover a case where the booster under-performs but Starship separates and then targets a disposal location in either the mid-Atlantic or Indian Ocean. [...]
If the booster dramatically under-performs, then I'd suggest that SESU will be aborted [...]
Thanks very much for your analysis. It adds quite a bit of clarity to a scenario that seems at best quite murky!
Thinking about the SpaceX test objective priorities, demonstrating stage separation followed by Starship in-flight engine startup seem like items that must be fairly high up the list. Yet even optimistically the lack of flight history for a booster powered by a cluster of Raptor-2 engines makes the likelihood of booster under-performance seem non-negligible.
(Fully recognizing this isn't a "Poll" thread I nonetheless attach a graphic guess at the likelihood of how many booster engines lose thrust — either through commanded shutdowns or RUD/fratricide events — at some time before the intended amount of propellant is expended. The modal value is 8, based on a Poisson distribution with μ = 8.5.)Sounds like we’ve almost got the ingredients for a good old fashioned frequentist vs. bayesian smack down.
Oh yes, in so many ways! ;)
The most likely outcomes would seem to be either 0 or 33 the engines shutting down early.
Post by: BenW on 04/11/2023 11:37 pm
2. They know that if S24 makes a successful water landing, it'll likely survive the subsequent tip-over, leaving them with a giant, floating stainless-steel whale in the middle of the ocean that they have to dispose of lest it become a marine hazard. Belly-flopping at terminal velocity should guarantee a "clean" breakup (see SN9).
They could probably "have it both ways" if they wanted, by attempting the flip maneuver at say 3km altitude, then turning off the engines to ensure that it still impacts the ocean at near-terminal velocity. But agreed that it doesn't make sense to do it if they've predetermined it's incapable, or if the design of S28+ is so different that they wouldn't learn anything by S24/S25 trying it.
Post by: JWC on 04/11/2023 11:43 pm
Post by: Kspbutitscursed on 04/12/2023 12:49 am
WEN HOP
Nah just kidding
what are the chances of booster 9 being caught by the chopstix and what are the chances of it being recovered.
Post by: Eer on 04/12/2023 12:58 am
Question:
WEN HOP
Nah just kidding
what are the chances of booster 9 being caught by the chopstix and what are the chances of it being recovered.
I believe the answer to both of your questions is zero.
B9 is not flying back to the launch site, so won't be caught by chopsticks.
It looks like from the marine alerts that it will attempt a near landing above water out at sea. We've not seen anything to indicate they plan to tow it back to shore.
Post by: Kspbutitscursed on 04/12/2023 01:03 am
did you mean Booster 7Question:
WEN HOP
Nah just kidding
what are the chances of booster 9 being caught by the chopstix and what are the chances of it being recovered.
I believe the answer to both of your questions is zero.
B9 is not flying back to the launch site, so won't be caught by chopsticks.
It looks like from the marine alerts that it will attempt a near landing above water out at sea. We've not seen anything to indicate they plan to tow it back to shore.
becaus i was talkig about IFT-2
Post by: Herb Schaltegger on 04/12/2023 01:19 am
did you mean Booster 7Question:
WEN HOP
Nah just kidding
what are the chances of booster 9 being caught by the chopstix and what are the chances of it being recovered.
I believe the answer to both of your questions is zero.
B9 is not flying back to the launch site, so won't be caught by chopsticks.
It looks like from the marine alerts that it will attempt a near landing above water out at sea. We've not seen anything to indicate they plan to tow it back to shore.
becaus i was talkig about IFT-2
That's off-topic for this thread. Perhaps consider a different one for that discussion.
Post by: Kspbutitscursed on 04/12/2023 01:25 am
oops i thought i was in the discussion thread 25 sorrydid you mean Booster 7Question:
WEN HOP
Nah just kidding
what are the chances of booster 9 being caught by the chopstix and what are the chances of it being recovered.
I believe the answer to both of your questions is zero.
B9 is not flying back to the launch site, so won't be caught by chopsticks.
It looks like from the marine alerts that it will attempt a near landing above water out at sea. We've not seen anything to indicate they plan to tow it back to shore.
becaus i was talkig about IFT-2
That's off-topic for this thread. Perhaps consider a different one for that discussion.
Post by: darkenfast on 04/12/2023 02:53 am
So the ship is 'landing' horizontally? That's not really a landing and more like a belly flop, right? Is it known why it wouldn't attempt to move vertical and repulsively land?.If it's a marine sanctuary, there could be a problem with firing engines into the water. But that shouldn't prevent them from igniting to go vertical. They might want to hit horizontal to insure breakup and sinking.
The Ship is landing (or impacting), in a U.S. Navy open-ocean test range north of Hawaii, in very deep water. The Booster, on the other hand is landing somewhere off the south Texas coast, and I'm not sure of what the Marine Sanctuary boundaries are.
Post by: GmP on 04/12/2023 06:43 am
Post by: TomH on 04/12/2023 10:40 am
Post by: woods170 on 04/12/2023 11:52 am
The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
Post by: geza on 04/12/2023 02:02 pm
The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Post by: Herb Schaltegger on 04/12/2023 02:06 pm
The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Planning for it requires software validation, flight dynamics and CFD simulations, and who knows how much other testing and preparatory work. That all takes time and resources away from work on earlier, more significant milestones for this first flight test.
Post by: MichaelBlackbourn on 04/12/2023 02:08 pm
Post by: wannamoonbase on 04/12/2023 02:10 pm
...But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
A simple explanation maybe that they consider Starship surviving to make a landing attempt to be a low probability and not worth the effort to include it in the plan.
Post by: WisRich on 04/12/2023 02:17 pm
Just thinking out load.
Post by: kevinof on 04/12/2023 02:26 pm
I think until we see it or don’t on the day no one can say right now. It makes sense they don’t want to clutter the conversation about ‘crash it into the water’ with lingo about landing it. Best to keep the plan simple ‘we’re gonna lose it’ and then do the flip anyway. I doubt how you crash it into the water in the last 500m makes any difference to launch licences.Very sensible post there but this is NSF and wild speculation is just another day on this site
Post by: MichaelBlackbourn on 04/12/2023 02:49 pm
Maybe it's a safety issue. If it were to survive the landing, there might be some residual fuel in the tanks, leaving recovery team members exposed to a potential bobbing bomb.
Just thinking out load.
Then the navy gets target practice. It’s happened before.
Post by: jstrotha0975 on 04/12/2023 02:54 pm
Maybe it's a safety issue. If it were to survive the landing, there might be some residual fuel in the tanks, leaving recovery team members exposed to a potential bobbing bomb.
Just thinking out load.
Then the navy gets target practice. It’s happened before.
The Navy would most likely use divers with explosives if they get involved.
Post by: MichaelBlackbourn on 04/12/2023 03:04 pm
Maybe it's a safety issue. If it were to survive the landing, there might be some residual fuel in the tanks, leaving recovery team members exposed to a potential bobbing bomb.
Just thinking out load.
Then the navy gets target practice. It’s happened before.
The Navy would most likely use divers with explosives if they get involved.
It was an Air Force air strike last time. So probably not divers.
https://www.thedrive.com/the-war-zone/18343/did-the-u-s-air-force-bomb-a-rogue-spacex-booster-rocket
Post by: sferrin on 04/12/2023 03:20 pm
Post by: Lee Jay on 04/12/2023 03:22 pm
So...any word on the FAA license?
Soon.
Post by: Cheapchips on 04/12/2023 03:23 pm
If it comes to rest at catch arm height and then cuts it's engines, it'll fall 40m? Presumably that's enough of a fall to produce a violent end.
Post by: WisRich on 04/12/2023 03:45 pm
Do we think that the booster's 'water landing' will be a simulated tower landing?
If it comes to rest at catch arm height and then cuts it's engines, it'll fall 40m? Presumably that's enough of a fall to produce a violent end.
Interestingly, I was reading the test launch summary from SpaceX and in regards to the tower it says:
"...the launch and catch tower is designed to support vehicle integration, launch, and catch of the Super heavy rocket booster. For the first flight, the team will not attempt a vertical landing of Starship or catch of the Super Heavy Booster.."
I thought Starship was to be caught by the tower. This passage indicates otherwise. I guess I overlooked that small detail.
Post by: KilroySmith on 04/12/2023 03:50 pm
I thought Starship was to be caught by the tower. This passage indicates otherwise. I guess I overlooked that small detail.
Well, Starship is going to be landing south of Hawaii, and the Tower is in Texas, so unless they extend the chopsticks dramatically the tower ain't gonna be catching Starship this flight.
By next year at this time, I expect to have seen both Booster and Starship landings. But neither one is going to happen this month. Hopefully there'll be video of the Booster attempting a water landing, but I'm not expecting to see much in the way of video of the Starship impacting other than perhaps a long-distance shot from an airplane.
Post by: JWC on 04/12/2023 03:50 pm
Post by: Herb Schaltegger on 04/12/2023 04:23 pm
What if the current prototypes have negative payload? A year of adding structural reinforcements eating up all the margins until they were forced to drop the landing fuel. Without that fuel they now have margin to pull off this flight plan.
Starship should be able to loft 100 tons or more to orbit in a fully-reusable configuration. There is no way they have “negative margin” no matter how over-built Ship 24 and Booster 7 might be compared to later models.
Post by: jon.amos on 04/12/2023 04:27 pm
Post by: maquinsa on 04/12/2023 04:31 pm
They are not going to recover it even if it gets to that point so why test something that has already been?
Edited
Post by: mpusch on 04/12/2023 04:32 pm
It was an Air Force air strike last time. So probably not divers.
https://www.thedrive.com/the-war-zone/18343/did-the-u-s-air-force-bomb-a-rogue-spacex-booster-rocket
Not to go down this rabbit hole too far, but according to Spacex:
Quote
"While the Falcon 9 first stage for the GovSat-1 mission was expendable, it initially survived splashdown in the Atlantic Ocean. However, the stage broke apart before we could complete an unplanned recovery effort for this mission. Reports that the Air Force was involved in SpaceX's recovery efforts are categorically false."
Post by: alugobi on 04/12/2023 04:33 pm
Post by: rsnellenberger on 04/12/2023 04:36 pm
I haven't seen it mentioned already, but S24 will be the last Ship that uses hydraulic gimbeling, so the whole "test like you fly" argument really doesn't apply as far as the flip maneuver goes. The belly landing eliminates the need to make any particular effort to keep the hydraulic systems operational through the coast phase and re-entry, whereas the "elonerons" (sp?) will be operating off batteries as they will in future Ships.The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Post by: dodageka on 04/12/2023 04:40 pm
Post by: uhuznaa on 04/12/2023 04:51 pm
What if the current prototypes have negative payload? A year of adding structural reinforcements eating up all the margins until they were forced to drop the landing fuel. Without that fuel they now have margin to pull off this flight plan.
I'm sure that their dry mass is higher than they wanted it to be right now, but negative payload would mean it would be higher by 100 or 150 tons. Not very probable.
What I could imagine is that they have thermal problems and that 90 minutes after launch and after reentry and hypersonic flight they know they would have some serious boil-off problems with the propellants in the nose tanks. This is something I always wondered about as soon as they moved their header tanks into the nose from within the main tanks for center of gravity reasons.
Well, or this is just some unlucky wording on their mission page. Just like the graphic that has the booster boost itself down instead of back...
Anyway, getting the ship far enough in one piece and in controlled descent to bellyflop into the water will be a huge success already.
Post by: WisRich on 04/12/2023 04:54 pm
I haven't seen it mentioned already, but S24 will be the last Ship that uses hydraulic gimbeling, so the whole "test like you fly" argument really doesn't apply as far as the flip maneuver goes. The belly landing eliminates the need to make any particular effort to keep the hydraulic systems operational through the coast phase and re-entry, whereas the "elonerons" (sp?) will be operating off batteries as they will in future Ships.The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Wait, what? No more gimbling? Well that's interesting. I'm looking forward to seeing the new flip maneuver.
Post by: EspenU on 04/12/2023 04:59 pm
Wait, what? No more gimbling? Well that's interesting. I'm looking forward to seeing the new flip maneuver.No more hydraulic gimbaling. They will be using electric gimbal going forward.
Post by: sferrin on 04/12/2023 05:00 pm
So...any word on the FAA license?
Soon.
Post by: jjerjackson on 04/12/2023 05:03 pm
Wait, what? No more gimbling? Well that's interesting. I'm looking forward to seeing the new flip maneuver.
As I understand it they will gimble, but it will be with electric actuators instead of the current hydraulic.
Respectfully,
James
Post by: joek on 04/12/2023 05:03 pm
Wait, what? No more gimbling? Well that's interesting. I'm looking forward to seeing the new flip maneuver.No more hydraulic gimbaling. The new gimbaling is electro-mechanical.
Post by: joek on 04/12/2023 05:13 pm
In the very beginning of the thread there was a discussion why, in the FCC application, SpaceX wrote of a “Booster touchdown” and a “Ship splashdown”. Back then some people thought that this might suggest an actual landing of a booster on a barge, but ist thought that SpaceX just didn’t pay close attention to their wording. That’s what I still believe as well, but in the light of the new information it makes you wonder whether SpaceX already back then decided against the bellyflop on the first flight
Don't think there is much to read into those tea leaves (or additional Kremlinology required). It leaves SpaceX room to maneuver and is consistent with the PEA...
Quote
c A Starship landing could occur at the VLA, on a floating platform in the Gulf of Mexico, or on a floating platform in the Pacific Ocean. Alternatively, SpaceX could expend Starship in the Gulf of Mexico or Pacific Ocean. Further environmental review of landing at sites not described in this document would be necessary if proposed in the future.... if SpaceX made more progress in other areas then we might be seeing different; a lot has changed in the intervening 12 months including (reportedly) pulling back on some test objectives for this first flight.
d A Super Heavy landing is part of a launch, as it would occur shortly after takeoff. Super Heavy could land at the VLA or on a floating platform in the Gulf of Mexico. Alternatively, SpaceX could expend Super Heavy in the Gulf of Mexico. Further environmental review of landing at sites not described in this document would be necessary if proposed in the future.
Post by: StuffOfInterest on 04/12/2023 05:16 pm
Post by: Vettedrmr on 04/12/2023 05:20 pm
...SpaceX already back then decided against the bellyflop on the first flight
The "bellyflop" (i.e. the really high AoA) flight regime is required for re-entry; what's being discussed here is whether S24 will attempt the pitch up to vertical for a powered landing or not.
Post by: whitelancer64 on 04/12/2023 05:31 pm
If S24 is going to be doing a bellyflop all the way to the water, has anyone estimated what the terminal velocity will be?
Approximately 75 - 90 m/s, or about 270 - 324 kph / 167 - 200 mph, depending on its angle of attack and the position of the flaperons.
Post by: whitelancer64 on 04/12/2023 05:34 pm
"I want to believe"So...any word on the FAA license?
Soon.
Historically, launch licenses for new LVs are only granted a few days before the first launch attempt.
Post by: Oersted on 04/12/2023 05:36 pm
Post by: StevenOBrien on 04/12/2023 05:38 pm
https://www.spacex.com/launches/mission/?missionId=starship-flight-test
Post by: Hog on 04/12/2023 05:47 pm
"For the first flight test, the team will not attempt a vertical landing of Starship"As mentioned in post #747.
https://www.spacex.com/launches/mission/?missionId=starship-flight-test
Post by: edzieba on 04/12/2023 05:50 pm
Flipping and soft-landing risks Starship surviving. Not flipping and hitting the water belly-first at terminal velocity mitigates that risk.
Post by: joek on 04/12/2023 06:09 pm
Historically, launch licenses for new LVs are only granted a few days before the first launch attempt.
Post by: geza on 04/12/2023 06:35 pm
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?I haven't seen it mentioned already, but S24 will be the last Ship that uses hydraulic gimbeling, so the whole "test like you fly" argument really doesn't apply as far as the flip maneuver goes. The belly landing eliminates the need to make any particular effort to keep the hydraulic systems operational through the coast phase and re-entry, whereas the "elonerons" (sp?) will be operating off batteries as they will in future Ships.
For me, this is the winning explanation, thanks.
Post by: DanClemmensen on 04/12/2023 06:38 pm
Performing the flip & soft landing means Starship may end up floating in the Pacific neat Kauai. That's a headache for everyone: you now have a huge floating uncontrolled object, with ordinance (the FTS charges) and pressurised elements (headers, any RCS tankage) that may or may not discharge as intended, and may at any time break up from wave action or may drift, depending on uncontrollable weather conditions. Even if a salvage team were standing by with the vessels and equipment needed to drag Starship... somewhere, it'd be no easy task to actually wrangle it safely.It's a Navy test range. The Navy would probably enjoy having a nice target to sink.
Flipping and soft-landing risks Starship surviving. Not flipping and hitting the water belly-first at terminal velocity mitigates that risk.
Post by: uhuznaa on 04/12/2023 06:50 pm
"For the first flight test, the team will not attempt a vertical landing of Starship"
https://www.spacex.com/launches/mission/?missionId=starship-flight-test
Yes, but this is mentioned purely in the context of the launch tower. Also the graphic on this page shows the booster basically doing the boost back burn in the wrong direction. I really wouldn't read too much into these words. Whoever did this page knows more about web design than about rockets.
And anyway it doesn't matter. If they manage to get the thing through all this and to a controlled descent onto the water this test will be more successful than anyone can realistically hope for. I mean, if everything will work out to this extent the landing maneuver will be a piece of cake later.
It's just that we're all stoked up and are looking for anything to talk about... nothing wrong with that too.
Post by: sdsds on 04/12/2023 07:26 pm
[...] guess at the likelihood of how many booster engines lose thrust — either through commanded shutdowns or RUD/fratricide events — at some time before the intended amount of propellant is expended.
The most likely outcomes would seem to be either 0 or 33 the engines shutting down early.
Yes, I see your point and am highly confident SpaceX has extensively analyzed those cases both internally and with external review, particularly from the perspective of safety. If zero or some small number of Booster 7 Raptors lose thrust it seems highly likely the first stage flight profile will proceed on track, with stage separation within some defined "box" of flight parameters (speed, down-range distance, altitude, etc.). My guess is that the vehicle has plenty of performance margin, and even losing thrust from as many as six Raptors (depending on when the events occur) could still result in a "nominal" stage shutdown, perhaps a few seconds later than listed on the timeline. That's not based on any analysis of Booster 7; just on observations about how spaceflight performance margins in general seem to work.
On the pessimistic side, SpaceX must equally have a carefully reviewed plan if all 33 engines shut down early. The likely action would be termination of the entire flight, without attempting to have Ship 24 "escape" off the failed booster. Presumably all the propellant gets burned at altitude and the structural debris impacts in the hazard area. Again total guesswork has me thinking that 10 or more Raptor shutdowns, particularly early in the ascent, lead to this same outcome.
The gray zone for me is thus loss of thrust from 7, 8, or 9 Raptors. Some unexpected common mode failure could lead to this outcome, or a RUD/fratricide event. These seem like cases where one might expect to see Booster 7 burn to depletion yet fail to reach the nominal stage shutdown parameter box. Is this where a Ship 24 escape trajectory that ends with a propellant-depleted splashdown in the Gulf makes sense? Or am I misinterpreting OneSpeed's data?
Post by: TomH on 04/12/2023 07:32 pm
Historically, launch licenses for new LVs are only granted a few days before the first launch attempt.
You have the implied causality backwards. The more accurate relationship is: Most new LVs are launched within a few days of being granted a launch license.
Post by: TomH on 04/12/2023 07:38 pm
The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Neither of you is thinking about the fact that they are landing near a marine sanctuary. If they burn off all the residuals, they can crash with less toxic chemicals. If they did the flip, they'd have more toxins remaining. So you can't definitively say Nope, because you don't know with certainty.
Post by: jpo234 on 04/12/2023 08:06 pm
If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Post by: Robotbeat on 04/12/2023 08:26 pm
It occurs to me that the first crewed flights of Starship could happen Yuri-style where they just eject after Starship gets subsonic…If S24 is going to be doing a bellyflop all the way to the water, has anyone estimated what the terminal velocity will be?
Approximately 75 - 90 m/s, or about 270 - 324 kph / 167 - 200 mph, depending on its angle of attack and the position of the flaperons.
LOL
Post by: Elvis in Space on 04/12/2023 08:33 pm
If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Last time I was there, Texas was already awash in natural gas and oxygen. I doubt even the critters would notice.
Post by: sferrin on 04/12/2023 08:35 pm
What's the difference between a permit and a license, and how could SpaceX launch legally without either?Historically, launch licenses for new LVs are only granted a few days before the first launch attempt.
Nit: Expect this is a permit (not license). In any case, FAA has historically lagged and not unusual to see nothing published of until after the event. Not holding my breath we will see such from the FAA before this attempt.
Post by: uhuznaa on 04/12/2023 08:42 pm
If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Last time I was there, Texas was already awash in natural gas and oxygen. I doubt even the critters would notice.
I'm pretty sure the FAA has this nicely covered. Both the ship and booster will have methane and oxygen, some hydraulic fluids and probably some Tesla's worth of batteries on board. All of this will land in the sea one way or another anyway though. Not nothing, but also not much, really. Not even hypergolic RCS.
Post by: jpo234 on 04/12/2023 08:57 pm
But these wouldn't burn off in a landing burn...some hydraulic fluids and probably some Tesla's worth of batteries on board.If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Post by: whitelancer64 on 04/12/2023 09:00 pm
Historically, launch licenses for new LVs are only granted a few days before the first launch attempt.
You have the implied causality backwards. The more accurate relationship is: Most new LVs are launched within a few days of being granted a launch license.
It is both. You can't launch without the FAA approval, but you can't get the FAA approval without being ready for launch.
Post by: Oersted on 04/12/2023 09:50 pm
It occurs to me that the first crewed flights of Starship could happen Yuri-style where they just eject after Starship gets subsonic…If S24 is going to be doing a bellyflop all the way to the water, has anyone estimated what the terminal velocity will be?
Approximately 75 - 90 m/s, or about 270 - 324 kph / 167 - 200 mph, depending on its angle of attack and the position of the flaperons.
LOL
Thanks for referencing Gagarin in this thread. Today is the anniversary of his flight.
Post by: joek on 04/12/2023 10:04 pm
What's the difference between a permit and a license, and how could SpaceX launch legally without either?SpaceX could not legally launch without one of them...
- Vehicle Operator Licenses (https://www.faa.gov/space/licenses/operator_licenses_permits); current licenses here (https://www.faa.gov/data_research/commercial_space_data/licenses/).
- Experimental Permits for Reusable Suborbital Rockets (https://www.faa.gov/space/licenses/experimental-permits-reusable-suborbital-rockets); current permits here (https://www.faa.gov/data_research/commercial_space_data/permits/).
Just reviewed CFR's again (been a while) and looks like this will need a license as it involves orbital vehicle and parameters which exceed permit allowance.
Also likely why previous SS/hopper tests were under license rather than permit. Apologies to @whitelancer64 et. al. for the nit; previous post updated.
Post by: joek on 04/12/2023 10:21 pm
It is both. You can't launch without the FAA approval, but you can't get the FAA approval without being ready for launch.
Well... sorry to nit again, but you can get a license without being ready for launch; plenty of precedent for that. Expect that when we see the FAA license it will be one of those "LRLO" (launch reentry launch operator) or similar which allows a number of flights of the same type. But could be wrong; might be an "LLS" (launch license specific), but that historically does not allow for reentry (which SS would require).
Or I may be way off the map. Keeping track of FAA's license-permit-whatever designations drives me nuts. Think maybe does not matter any more; just read the license (whenever we see it) and ignore the FAA's designation-acronym-de-jour.
Post by: AU1.52 on 04/12/2023 11:15 pm
Post by: CameronD on 04/12/2023 11:56 pm
If the launch is April 17th I will likely miss it. Very unfortunate timing for me - if it launches Monday Z-up, I will running Y-east to the center of Boston for 26.2 miles from mid morning through early pm.
Priorities.. But don't worry, it'll be all over Youtube and there'll be other launches to watch :)
Post by: alugobi on 04/12/2023 11:58 pm
Post by: FutureSpaceTourist on 04/13/2023 12:13 am
Quote
Shoutout to this employee that just single handedly moved part of the QD structure away from Starship.
📸: NSF Live
I wouldn’t stand there during launch though …
Post by: spacenut on 04/13/2023 12:19 am
Post by: TomH on 04/13/2023 01:49 am
If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Last time I was there, Texas was already awash in natural gas and oxygen. I doubt even the critters would notice.
SS is supposed to land on the margin of a marine sanctuary in Hawaii.
Post by: TomH on 04/13/2023 01:56 am
But these wouldn't burn off in a landing burn...some hydraulic fluids and probably some Tesla's worth of batteries on board.If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
What I am saying is that they may burn them off prior to reentry, with nothing more than RCS prop remaining. The SS then belly flops with no prop available to do the landing burn. This might possibly eliminate environmental concerns related to landing on the periphery of an environmentally protected area. If this had been one of the sticking points in getting the permit/license. Getting rid of the prop ahead of time and eliminating the flip/landing burn may have eliminated that sticking point. SX can attempt that on a subsequent flight, perhaps away from protected areas.
Post by: russianhalo117 on 04/13/2023 02:03 am
More specifically into one of the weapons and missile impact test ranges controlled by the Kauai Test Facility (KTF) (Pacific Missile Range Facility (PMRF)) centrally based from their installation at Barking Sands, Kauai, Hawaii.If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Last time I was there, Texas was already awash in natural gas and oxygen. I doubt even the critters would notice.
SS is supposed to land on the margin of a marine sanctuary in Hawaii. Keep up!
Post by: InterestedEngineer on 04/13/2023 04:45 am
More specifically into one of the weapons and missile impact test ranges controlled by the Kauai Test Facility (KTF) (Pacific Missile Range Facility (PMRF)) centrally based from their installation at Barking Sands, Kauai, Hawaii.If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Last time I was there, Texas was already awash in natural gas and oxygen. I doubt even the critters would notice.
SS is supposed to land on the margin of a marine sanctuary in Hawaii. Keep up!
Is there anything preventing a foreign ship from entering those waters?
I'm not a maritime law expert by any stretch of the imagination but I thought the exclusion zone was only about 20 miles or so (aka the horizon)
Post by: woods170 on 04/13/2023 08:11 am
...But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
A simple explanation maybe that they consider Starship surviving to make a landing attempt to be a low probability and not worth the effort to include it in the plan.
You're spot on.
Post by: kevinof on 04/13/2023 09:36 am
Foreign boats could enter this zone and basically give the finger the the U.S. Navy or CG but that's probably not a smart move. Most sailors would keep well away. There are different rules for controlling airspace.
More specifically into one of the weapons and missile impact test ranges controlled by the Kauai Test Facility (KTF) (Pacific Missile Range Facility (PMRF)) centrally based from their installation at Barking Sands, Kauai, Hawaii.If they burn off all the residuals, they can crash with less toxic chemicals.What toxic chemicals?
Last time I was there, Texas was already awash in natural gas and oxygen. I doubt even the critters would notice.
SS is supposed to land on the margin of a marine sanctuary in Hawaii. Keep up!
Is there anything preventing a foreign ship from entering those waters?
I'm not a maritime law expert by any stretch of the imagination but I thought the exclusion zone was only about 20 miles or so (aka the horizon)
Post by: sferrin on 04/13/2023 01:22 pm
Post by: envy887 on 04/13/2023 01:31 pm
Is there anything preventing a foreign ship from entering those waters?No, but other than observing the EDL sequence (which they could just as easily do from outside the area) there's nothing useful to be gained from going there. They can't legally recover and keep a foreign spacecraft.
Post by: Bob Shaw on 04/13/2023 02:29 pm
Post by: eriblo on 04/13/2023 02:39 pm
Starship isn’t a nationally-owned vehicle, but is a private one. Do the rules re salvage apply as with ships it it falls in the sea? IIRC SpaceX claimed ownership of a fairing which washed ashore as debris in the English Channel a few years ago (pre recovery efforts).Maritime salvage laws do not apply to space hardware. It remains the property and responsibility of whomever launched it.
Post by: launchwatcher on 04/13/2023 02:44 pm
Starship isn’t a nationally-owned vehicle, but is a private one. Do the rules re salvage apply as with ships it it falls in the sea? IIRC SpaceX claimed ownership of a fairing which washed ashore as debris in the English Channel a few years ago (pre recovery efforts).See Articles VI and VIII of the outer space treaty, which doesn't make a distinction between nationally-owned and privately owned objects. As I read it, anything launched by an entity under US jurisdiction remains under US jurisdiction and if recovered by another party to the treaty must be returned to the US.
Quote
Article VI
States Parties to the Treaty shall bear international responsibility for national activities in outer space, including the Moon and other celestial bodies, whether such activities are carried on by governmental agencies or by non-governmental entities, and for assuring that national activities are carried out in conformity with the provisions set forth in the present Treaty. The activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty. ... (text about international missions trimmed) ...
Article VIII
A State Party to the Treaty on whose registry an object launched into outer space is carried shall retain jurisdiction and control over such object, and over any personnel thereof, while in outer space or on a celestial body. Ownership of objects launched into outer space, including objects landed or constructed on a celestial body, and of their component parts, is not affected by their presence in outer space or on a celestial body or by their return to the Earth. Such objects or component parts found beyond the limits of the State Party to the Treaty on whose registry they are carried shall be returned to that State Party, which shall, upon request, furnish identifying data prior to their return.
Post by: Vahe231991 on 04/13/2023 05:05 pm
Starship isn’t a nationally-owned vehicle, but is a private one. Do the rules re salvage apply as with ships it it falls in the sea? IIRC SpaceX claimed ownership of a fairing which washed ashore as debris in the English Channel a few years ago (pre recovery efforts).Let's hope that if the Starship upper stage falls into the sea after completing one orbit and re-entering the earth's atmosphere the Chinese don't get their hands on the Starship stage and reverse-engineer it to create a huge Starship-like reusable spacecraft to be potentially used for military purposes.
Post by: philw1776 on 04/13/2023 05:22 pm
Starship isn’t a nationally-owned vehicle, but is a private one. Do the rules re salvage apply as with ships it it falls in the sea? IIRC SpaceX claimed ownership of a fairing which washed ashore as debris in the English Channel a few years ago (pre recovery efforts).Let's hope that if the Starship upper stage falls into the sea after completing one orbit and re-entering the earth's atmosphere the Chinese don't get their hands on the Starship stage and reverse-engineer it to create a huge Starship-like reusable spacecraft to be potentially used for military purposes.
Day 0 of the Cetian space program as whales steal raptor tech to jump start their effort
Post by: JamesH65 on 04/13/2023 05:54 pm
Starship isn’t a nationally-owned vehicle, but is a private one. Do the rules re salvage apply as with ships it it falls in the sea? IIRC SpaceX claimed ownership of a fairing which washed ashore as debris in the English Channel a few years ago (pre recovery efforts).Let's hope that if the Starship upper stage falls into the sea after completing one orbit and re-entering the earth's atmosphere the Chinese don't get their hands on the Starship stage and reverse-engineer it to create a huge Starship-like reusable spacecraft to be potentially used for military purposes.
The Chinese are quite capable of doing all this off their own back. No need to reverse engineer, although that might make things faster. Which would only be the engines anyway, and the secret sauce in there is, I suspect, a lot in software (timing etc).
Post by: sebk on 04/13/2023 05:59 pm
Could this be poopy news?
$SPCE news FAA shoots down launch of SpaceX Starship, IBD reports
https://www.investors.com/news/technology/spacex-faa-blows-out-candle-on-company-starship/
The article contains some utter nonsense, confusing PEA which concluded last year (in May, indeed) with launch license. The author clearly has no clue what he's talking about.
Post by: 2megs on 04/13/2023 06:04 pm
Could this be poopy news?
$SPCE news FAA shoots down launch of SpaceX Starship, IBD reports
https://www.investors.com/news/technology/spacex-faa-blows-out-candle-on-company-starship/
Has Investors Business Daily, in the past, been a good source of inside scoops about SpaceX or the FAA, before other sources had covered it?
If not (and I'm pretty sure they haven't been), I wouldn't give that much importance unless you start hearing the same elsewhere.
In the next week we can expect a lot of low-quality "journalists" trying to turn the rising interest in Starship into clickbait. Please let's not treat it as an UPDATE! every time their content mills churn out some more pulp.
Post by: TheRadicalModerate on 04/13/2023 07:09 pm
Could this be poopy news?
$SPCE news FAA shoots down launch of SpaceX Starship, IBD reports
https://www.investors.com/news/technology/spacex-faa-blows-out-candle-on-company-starship/
The article contains some utter nonsense, confusing PEA which concluded last year (in May, indeed) with launch license. The author clearly has no clue what he's talking about.
Sounds a lot like GPT-3 might have written this and failed to notice that the FAA environmental review delays were all from 2022.
Post by: Alberto-Girardi on 04/13/2023 07:38 pm
IIRC Falcon Heavy test flight was late into the window because they had problems with weather, can we extrapolate something from there on how spacex handles this kind of things?
Anyway even if they launch exaclty at the start I wouldn't miss it (in Italy it will be 2 pm at 1200Z), but I would miss the fueling due to school.
Post by: alugobi on 04/13/2023 07:51 pm
Post by: ChrisC on 04/13/2023 08:12 pm
(road closure notice from Cameron County)
https://www.cameroncountytx.gov/order-closing-boca-chica-beach-and-state-hwy-4-april-17-2023-with-alternative-date-of-april-18-2023-or-april-19-2023-2/
The notice quotes "C.S.T." times, not "Central" or "CT". It's one thing to hear average yahoos make this mistake, but official sources? Sad trombone :( (See my sig below. And get off my lawn!)
Post by: peregrinus on 04/13/2023 08:30 pm
"For the first flight test, the team will not attempt a vertical landing of Starship"
https://www.spacex.com/launches/mission/?missionId=starship-flight-test
Also the graphic on this page shows the booster basically doing the boost back burn in the wrong direction.
I might be wrong, but just curious. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
Post by: whitelancer64 on 04/13/2023 09:07 pm
"For the first flight test, the team will not attempt a vertical landing of Starship"
https://www.spacex.com/launches/mission/?missionId=starship-flight-test
Also the graphic on this page shows the booster basically doing the boost back burn in the wrong direction.
I might be wrong, but just curious. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
The image has been corrected. The original had the flamey end on the wrong side of the booster.
Post by: MoodyBlues on 04/13/2023 09:57 pm
(road closure notice from Cameron County)
https://www.cameroncountytx.gov/order-closing-boca-chica-beach-and-state-hwy-4-april-17-2023-with-alternative-date-of-april-18-2023-or-april-19-2023-2/
The notice quotes "C.S.T." times, not "Central" or "CT". It's one thing to hear average yahoos make this mistake, but official sources? Sad trombone :( (See my sig below. And get off my lawn!)
https://www.timeanddate.com/time/zones/cst
maybe you're on the wrong lawn... ;)
Post by: sdsds on 04/13/2023 10:05 pm
[...]. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
The image has been corrected. The original had the flamey end on the wrong side of the booster.
Roger that: flamey end now looks good!
Is there information/discussion about how many engines will/would be used for the boost back burn?
Post by: kessdawg on 04/13/2023 10:06 pm
Post by: pedz on 04/13/2023 10:37 pm
I plan to have two cameras. I sure wish I could get closer than the 6+ miles. The rocket is more than half the view finder with a 500mm lens but the haze is going to produce less than spectacular images and footage. We'll see how it goes.
One question: The FAA advisory is for 1200Z. That is Zulu -- right? or GMT / UTC? Which translates into 7 a.m. local time. Am I doing all that right?
I assume there will not be any real published launch time by SpaceX. ?
Post by: FutureSpaceTourist on 04/14/2023 04:13 am
Quote
Here is my NEW updated 2.0 (unofficial) infographic poster with all the information you need to know about the upcoming #SpaceX #Starship Orbital Flight Test (I removed the "flip and burn" maneuver). A big thank you to @LunarCaveman. Now all good to go!
Post by: pedz on 04/14/2023 04:34 am
Post by: Alvian@IDN on 04/14/2023 04:47 am
I don't know if this is right or not... 3B you have "All 13 gimbaled Raptor engines..." ... Are 20 of the engines not gimbaled or is that suppose to be "All 33 gimbaled Raptor engines" ?Two clusters, inner & outer. The inner (13 engines) will gimbal, the outer (20 engines) will not
Post by: Slothman on 04/14/2023 07:44 am
With a mature rocket like the F9, with no other constraints, it will almost always launch on the minute. With a prototype, not so likely. Expect scrubs and holds while they tune the system.
Also weather, as illustrated by today's transporter mission scrub
Post by: Eer on 04/14/2023 11:30 am
Haven't heard about when they plan to restack, other than L-2 mentioned earlier - that may have been the destack target.
I wonder if they'll stack (lift), load (prop) and go (launch) Monday morning? Audacious, but maybe they're getting comfortable with the lift and alignment process - or maybe they're just waiting for the NASA guests to assemble before the lift.
I need more coffee...my mind is wandering.
Post by: JCopernicus on 04/14/2023 01:34 pm
[...]. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
The image has been corrected. The original had the flamey end on the wrong side of the booster.
Roger that: flamey end now looks good!
Is there information/discussion about how many engines will/would be used for the boost back burn?
The graphic implies the booster does two flip manuevers, (one not show to put the engines facing down again). Is that how it works or is the graphic still wrong as to the positioning?
Post by: pedz on 04/14/2023 02:10 pm
I looked for “flames end” in Wikipedia and didn’t see it. 🤷♂️ 😊[...]. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
The image has been corrected. The original had the flamey end on the wrong side of the booster.
Roger that: flamey end now looks good!
Is there information/discussion about how many engines will/would be used for the boost back burn?
The graphic implies the booster does two flip manuevers, (one not show to put the engines facing down again). Is that how it works or is the graphic still wrong as to the positioning?
Post by: whitelancer64 on 04/14/2023 02:44 pm
[...]. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
The image has been corrected. The original had the flamey end on the wrong side of the booster.
Roger that: flamey end now looks good!
Is there information/discussion about how many engines will/would be used for the boost back burn?
The graphic implies the booster does two flip manuevers, (one not show to put the engines facing down again). Is that how it works or is the graphic still wrong as to the positioning?
The first one is called a "flip" because it's a pretty aggressive maneuver; the faster they can do the boostback burn, the less fuel they need to use to do it. After the boostback burn, a much slower rotation will orient the rocket to the correct angle for its glide path.
This is pretty much exactly what the Falcon 9 booster does now. It should look pretty much the same from the ground and on the webcasts.
Post by: JCopernicus on 04/14/2023 03:01 pm
[...]. How is the boost back burn illustrated in the wrong direction? Isn't the burn pointing in the correct direction to remove horizontal velocity? https://sxcontent9668.azureedge.us/cms-assets/assets/SPACEX_STARSHIP_INFOGRAPHIC_041223_web_096b650bff.png
The image has been corrected. The original had the flamey end on the wrong side of the booster.
Roger that: flamey end now looks good!
Is there information/discussion about how many engines will/would be used for the boost back burn?
The graphic implies the booster does two flip manuevers, (one not show to put the engines facing down again). Is that how it works or is the graphic still wrong as to the positioning?
The first one is called a "flip" because it's a pretty aggressive maneuver; the faster they can do the boostback burn, the less fuel they need to use to do it. After the boostback burn, a much slower rotation will orient the rocket to the correct angle for its glide path.
This is pretty much exactly what the Falcon 9 booster does now. It should look pretty much the same from the ground and on the webcasts.
Thanks, just realized my confusion. Falcon 9 has two flip maneuvers, one for the barge, and one when they get back to land.
The SS Booster they're showing is like a hybrid of the two since they're not going back.
Post by: testguy on 04/14/2023 04:08 pm
Post by: alugobi on 04/14/2023 04:20 pm
Notice that I did write, "with no other constraints". Weather is certainly one of them.With a mature rocket like the F9, with no other constraints, it will almost always launch on the minute. With a prototype, not so likely. Expect scrubs and holds while they tune the system.
Also weather, as illustrated by today's transporter mission scrub
Post by: golosio on 04/14/2023 04:29 pm
https://twitter.com/infographictony/status/1646701133803520000Very nice poster! Can I ask if we have an estimate of the speed at stage separation, and of the maximum speed of Starship in the orbit?QuoteHere is my NEW updated 2.0 (unofficial) infographic poster with all the information you need to know about the upcoming #SpaceX #Starship Orbital Flight Test (I removed the "flip and burn" maneuver). A big thank you to @LunarCaveman. Now all good to go!
Post by: alastairmayer on 04/14/2023 04:38 pm
Take this as pure speculation, I am NOT a lawyer. There was some speculation a while back that an injunction stopping Star Ship launch may happen due to environmental issues. I would think you can't get an injunction without a launch license in place. Therefore, might SpaceX try to delay the license until late Friday after the courts are closed and try to get a launch off on Monday before the courts reopen?
IANAL either, but an emergency injunction can theoretically be obtained by finding an appropriate judge willing to issue one, even after hours. Mind, if you're disturbing a judge on his days off, you'd better have a pretty solid case, and since the FAA already went through the environmental evaluation last year, good luck with that.
Post by: geza on 04/14/2023 04:47 pm
Post by: joek on 04/14/2023 04:53 pm
When the licence is issued, it is public immediately?No. Publication on FAA public site often lags well behind issuance (could be days-weeks).
Post by: Fireworking on 04/14/2023 05:11 pm
When the licence is issued, it is public immediately?No. Publication on FAA public site often lags well behind issuance (could be days-weeks).
Which could mean the only way we can tell when they have the license, aside from a tweet, would be when they arm the FTS?
Post by: Hog on 04/14/2023 05:29 pm
Does that really help? Is there any sort of external cue that the FTS is armed? Liftoff is a surefire external cue.When the licence is issued, it is public immediately?No. Publication on FAA public site often lags well behind issuance (could be days-weeks).
Which could mean the only way we can tell when they have the license, aside from a tweet, would be when they arm the FTS?
Post by: geza on 04/14/2023 05:54 pm
Does that really help? Is there any sort of external cue that the FTS is armed? Liftoff is a surefire external cue.When the licence is issued, it is public immediately?No. Publication on FAA public site often lags well behind issuance (could be days-weeks).
Which could mean the only way we can tell when they have the license, aside from a tweet, would be when they arm the FTS?
Do we know for sure that the licence has not been issued yet?
Post by: Fireworking on 04/14/2023 06:23 pm
Does that really help? Is there any sort of external cue that the FTS is armed? Liftoff is a surefire external cue.When the licence is issued, it is public immediately?No. Publication on FAA public site often lags well behind issuance (could be days-weeks).
Which could mean the only way we can tell when they have the license, aside from a tweet, would be when they arm the FTS?
Well of course the only way to be sure of a license is when they launch, but I think if they arm the FTS they will rather promptly commence restacking. If we're looking for external cues we could just look for when a cherrypicker goes over to that side of the ship. (unless they no longer arm them by hand)
By now i wouldn't be surprised if they already have the license.
Post by: ChrisC on 04/14/2023 08:39 pm
Post by: WisRich on 04/14/2023 09:55 pm
It's happening. :)
https://www.youtube.com/watch?v=0qgET1Zhpb8
Post by: sferrin on 04/14/2023 09:55 pm
Post by: TomH on 04/14/2023 10:03 pm
Post by: jackvancouver on 04/14/2023 10:23 pm
Post by: Herb Schaltegger on 04/14/2023 10:55 pm
Post by: Revolver Ocelot on 04/14/2023 10:57 pm
Post by: jpo234 on 04/14/2023 10:59 pm
So what is everyone’s prediction for how the flight will go?Up and then down again.
Post by: Nevyn72 on 04/14/2023 11:02 pm
So what is everyone’s prediction for how the flight will go?Up and then down again.
The first part of that is yet TBD....
Post by: sferrin on 04/14/2023 11:05 pm
If the fire starts it'll go up for sure. How fast and how high would be the question. ;)So what is everyone’s prediction for how the flight will go?Up and then down again.
The first part of that is yet TBD....
Post by: jpo234 on 04/14/2023 11:06 pm
As Niels Bohr said:So what is everyone’s prediction for how the flight will go?Up and then down again.
The first part of that is yet TBD....
Quote
Prediction is very difficult, especially if it's about the future.
Post by: Vahe231991 on 04/14/2023 11:25 pm
Given that Elon Musk hinted at the possibility that the first Falcon Heavy might fail, only to see that prediction dashed after the first Falcon Heavy launch reached orbit, I think the first Starship launch will smoothly lift off from the launch pad, reach max Q over the Gulf of Mexico, and put the Starship stage into a stable orbit three or four seconds after the first stage separates.If the fire starts it'll go up for sure. How fast and how high would be the question. ;)So what is everyone’s prediction for how the flight will go?Up and then down again.
The first part of that is yet TBD....
Post by: alugobi on 04/14/2023 11:32 pm
Post by: xvel on 04/14/2023 11:46 pm
Post by: Jim on 04/14/2023 11:54 pm
nd put the Starship stage into a stable orbit three or four seconds after the first stage separates.
It will be far from orbital at that point. Starship has burn to near depletion to go into orbit.
Also separation has not been demonstrated
Post by: whitelancer64 on 04/15/2023 12:18 am
As Niels Bohr said:So what is everyone’s prediction for how the flight will go?Up and then down again.
The first part of that is yet TBD....QuotePrediction is very difficult, especially if it's about the future.
I fully expect that there will be a scrub or two (but that won't preclude me having a launch webcast on in the background to keep an eye on).
However, once they open the launch clamps with the engines running, I expect it will most likely clear the pad with minimal problems. They could easily lose an engine or two or three on ascent, and I'm not sure how visible that will be to us. The big milestones in my book are stage separation and the in-flight ignition of Starship's engines. Anything that happens after that is pure gravy as far as I'm concerned.
"Excitement Guaranteed"
Post by: TomH on 04/15/2023 01:13 am
Take this as pure speculation, I am NOT a lawyer. There was some speculation a while back that an injunction stopping Star Ship launch may happen due to environmental issues. I would think you can't get an injunction without a launch license in place. Therefore, might SpaceX try to delay the license until late Friday after the courts are closed and try to get a launch off on Monday before the courts reopen?
IANAL either, but an emergency injunction can theoretically be obtained by finding an appropriate judge willing to issue one, even after hours. Mind, if you're disturbing a judge on his days off, you'd better have a pretty solid case, and since the FAA already went through the environmental evaluation last year, good luck with that.
Have heard from other sources that license had been ready for a day or two. And, indeed, announcement was made at end of the day on a Friday. Further, the LV should be propped and ready first thing Monday. Though the above theory is speculation, the current timing certainly matches the the theory thus far.
Post by: catdlr on 04/15/2023 02:32 am
A 122 page document has been published by the FAA in relation to the launch license: https://www.faa.gov/media/27236
I've only skimmed through it, but there's a lot of detailed information relating to the test flight (specifically the "landings" and their environmental impact) that I'm sure will be of interest.
One excerpt on page 3 seems to suggest that Ship 25 is being skipped in favor of S26:QuoteSpaceX also proposes to add an area southwest of Hawaii, uprange of the passive descent ocean
landing area, to account for the potential Starship debris field for the second and third launches of
Starship that are not configured to survive atmospheric reentry.QuoteSpaceX would expend Starship (break up upon atmospheric entry) following the second and third launches.]
So the second and third are the two SS's that are bare (no thermal tiles and flaps)??
Post by: joek on 04/15/2023 02:35 am
IANAL either, but an emergency injunction can theoretically be obtained by finding an appropriate judge willing to issue one, even after hours. Mind, if you're disturbing a judge on his days off, you'd better have a pretty solid case, and since the FAA already went through the environmental evaluation last year, good luck with that.
As noted in the update thread (@SteveObrien) (https://forum.nasaspaceflight.com/index.php?topic=58568.msg2475118#msg2475118), there is also an updated WRITTEN RE‐EVALUATION OF THE 2022 FINAL PROGRAMMATIC ENVIRONMENTAL ASSESSMENT (https://www.faa.gov/media/27236), 14-Apr-2023 (today).
Any challenge is going to have to address that, not just the older PEA, WR's, etc.
edit: p.s. interesting aside... that WR was signed 2023.04.14 16:30.04-4'00'; launch license signed 2023.04.14 17:32:34 -04'00'.
Post by: FutureSpaceTourist on 04/15/2023 02:44 am
Quote
Welp I was going to sleep but instead spent about an hour reading through this 122 page PDF that came out today along with the license. This is a re-evaluation of the PEA specific for the flight profile of the first few flights of Starship, cool stuff.
faa.gov/media/27236
Quote
Some of the stuff that I found interesting:
- Second and Third flights of Starship will be with S26 and S27 (expected but now comfirmed)
- Super Heavy will be landing on the surface of the ocean. SpaceX will NOT recover it and will instead try to sink it in any way possible
https://twitter.com/alexphysics13/status/1647065239802847237
Quote
- Ship 24 will have onboard flight recorders to be retrieved for data. This we kinda guessed from the hardware installed on its exterior but now it's confirmed.QuoteAs part of that study, they needed to study the way the transfer tube on Starship may be damaged due to sudden impacts. Something that they had previous experienced with SN10's hard landing- A lot went into figuring out the impact to marine life due to Ship 24's impact with the water
https://twitter.com/alexphysics13/status/1647065254285721600
Quote
Lastly, the document was signed just this afternoon which makes me think was the "hold up" for the FAA to finally wrap up and grant the license.
https://twitter.com/alexphysics13/status/1647068584747597824
Quote
An extra thought from this is...
This document covers the FireX system on the pad and it's supposed to be at least the first three flights. It doesn't mention the deluge system SpaceX is building so it makes me think this system may not debut until the fourth flight 🤔
Post by: FutureSpaceTourist on 04/15/2023 03:39 am
Quote
In addition to everything else, SpaceX confirmed in an email that it will allow accredited press to set remote cameras about 500 feet away from the launch mount! Should result in some amazing photos if the dust clouds aren't too awful :)
Post by: Cabbage123 on 04/15/2023 03:50 am
Has that always been the plan, or was there previously speculation of a controlled landing for S24 too?
Why no soft landing for S24? Would it have sufficient propellant left?
Post by: tenkendojo on 04/15/2023 04:10 am
Post by: joek on 04/15/2023 04:41 am
Seems like a controlled ocean landing for B7, but a terminal velocity impact for S24. Is that right?
Has that always been the plan, or was there previously speculation of a controlled landing for S24 too?
Why no soft landing for S24? Would it have sufficient propellant left?
Yes to B7 controlled landing. As to the S24, quite a bit of discussion upthread starting around post #734 (https://forum.nasaspaceflight.com/index.php?topic=53846.msg2474017#msg2474017).
Post by: TomH on 04/15/2023 06:05 am
Post by: Zed_Noir on 04/15/2023 06:31 am
Do we have any information on drone boats or airborne small drones near the two landing zones to take photos/video or record any other data?The Starship splashdown zone is in the Pacific Missile Range Facility (aka Barking Sands) that have the most extensive optical tracking and imaging capabilities that the DoD can get theirs hands on. Also the venerable nuke sniffer aircraft (aka WB-57 Canberra) will get tracking footage of the reenty from high altitude. Of course we might never get to see all the images acquire by the DoD.
Post by: PM3 on 04/15/2023 06:34 am
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
[Edit: corrected typos in video title]
Confirmation that this will be a suborbital flight:
"The Starship upper stage will fire its engines until 9 minutes and 20 seconds after liftoff. That will place the vehicle on a “nearly orbital” trajectory, an FAA official said on background, reaching a peak altitude of about 235 kilometers before reentering."
https://spacenews.com/faa-issues-license-for-first-starship-integrated-test-flight/
Post by: tyrred on 04/15/2023 06:49 am
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
[Edit: corrected typos in video title]
Confirmation that this will be a suborbital flight:
"The Starship upper stage will fire its engines until 9 minutes and 20 seconds after liftoff. That will place the vehicle on a “nearly orbital” trajectory, an FAA official said on background, reaching a peak altitude of about 235 kilometers before reentering."
https://spacenews.com/faa-issues-license-for-first-starship-integrated-test-flight/
What a scoop - confirmation that the Orbital Test Flight isn't actually going to orbit?
Why ever would they call it test flight, then?
We need confirmation its not actually even a test, pronto!
;)
Post by: daedalus1 on 04/15/2023 07:03 am
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
[Edit: corrected typos in video title]
Confirmation that this will be a suborbital flight:
"The Starship upper stage will fire its engines until 9 minutes and 20 seconds after liftoff. That will place the vehicle on a “nearly orbital” trajectory, an FAA official said on background, reaching a peak altitude of about 235 kilometers before reentering."
https://spacenews.com/faa-issues-license-for-first-starship-integrated-test-flight/
What a scoop - confirmation that the Orbital Test Flight isn't actually going to orbit?
Why ever would they call it test flight, then?
We need confirmation its not actually even a test, pronto!
;)
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Post by: PM3 on 04/15/2023 07:14 am
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Nope. The perigee of a "nearly orbital trajectory" is not in the atmosphere but below sea level.
The confusion was caused by SpaceX calling it an "Orbital Flight Test". But they have stopped doing so - it now is just the "Starship Flight Test" on the SpaceX website (https://www.spacex.com/launches/mission/?missionId=starship-flight-test) and on the mission patch.
Post by: FutureSpaceTourist on 04/15/2023 08:17 am
Post by: steveleach on 04/15/2023 09:11 am
Sorry, are you saying that the documents show that S24 will have a perigee below sea level, or that the definition of a "nearly orbital trajectory" is that the perigee is below sea level?That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Nope. The perigee of a "nearly orbital trajectory" is not in the atmosphere but below sea level.
The confusion was caused by SpaceX calling it an "Orbital Flight Test". But they have stopped doing so - it now is just the "Starship Flight Test" on the SpaceX website (https://www.spacex.com/launches/mission/?missionId=starship-flight-test) and on the mission patch.
Post by: FutureSpaceTourist on 04/15/2023 09:50 am
https://youtu.be/Z_YaxHqXjSo
https://youtu.be/Y4J7wLD6dBs
Post by: envy887 on 04/15/2023 11:48 am
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Nope. The perigee of a "nearly orbital trajectory" is not in the atmosphere but below sea level.
The confusion was caused by SpaceX calling it an "Orbital Flight Test". But they have stopped doing so - it now is just the "Starship Flight Test" on the SpaceX website (https://www.spacex.com/launches/mission/?missionId=starship-flight-test) and on the mission patch.
The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
You're not helping resolve the confusion by using the less accurate term.
Post by: meekGee on 04/15/2023 11:53 am
Only because they're near circular. If you fly straight up half way towards the moon, with almost escape speed... Still suborbital?That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Nope. The perigee of a "nearly orbital trajectory" is not in the atmosphere but below sea level.
The confusion was caused by SpaceX calling it an "Orbital Flight Test". But they have stopped doing so - it now is just the "Starship Flight Test" on the SpaceX website (https://www.spacex.com/launches/mission/?missionId=starship-flight-test) and on the mission patch.
The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
The "sub" denotes that orbital velocity was not achieved, like an intercontinental trajectory.
Post by: Legios on 04/15/2023 12:22 pm
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
[Edit: corrected typos in video title]
Confirmation that this will be a suborbital flight:
"The Starship upper stage will fire its engines until 9 minutes and 20 seconds after liftoff. That will place the vehicle on a “nearly orbital” trajectory, an FAA official said on background, reaching a peak altitude of about 235 kilometers before reentering."
https://spacenews.com/faa-issues-license-for-first-starship-integrated-test-flight/
What a scoop - confirmation that the Orbital Test Flight isn't actually going to orbit?
Why ever would they call it test flight, then?
We need confirmation its not actually even a test, pronto!
;)
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Wouldn't that just be a ballistic trajectory ala an ICBM.
SpaceX is just not performing a circularization burn. But just because it has the energy for orbit, if it doesn't circularize, it's not orbital
Post by: sebk on 04/15/2023 12:35 pm
Is the plan still to stay slightly below orbital velocity for safety reasons? To avoid the necessity of a deorbiting burn?Technically it's not going to be below orbital velocity, it's just that the low point of the orbit is within the upper atmosphere .
So what does the "30 meters per second difference" refer to, that Tim Dodd mentioned in the video "Elon Musk explains updates to Starship and Starbase" (at 23:10)? Not 30 m/s below orbital velocity? Or is that information outdated?
[Edit: corrected typos in video title]
Confirmation that this will be a suborbital flight:
"The Starship upper stage will fire its engines until 9 minutes and 20 seconds after liftoff. That will place the vehicle on a “nearly orbital” trajectory, an FAA official said on background, reaching a peak altitude of about 235 kilometers before reentering."
https://spacenews.com/faa-issues-license-for-first-starship-integrated-test-flight/
What a scoop - confirmation that the Orbital Test Flight isn't actually going to orbit?
Why ever would they call it test flight, then?
We need confirmation its not actually even a test, pronto!
;)
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Wouldn't that just be a ballistic trajectory ala an ICBM.
SpaceX is just not performing a circularization burn. But just because it has the energy for orbit, if it doesn't circularize, it's not orbital
Nope, it's not an ICBM like trajectory at all. ICBMs dont fly more than half around the globe.
The orbit here is about 50x235km it's perigee is above surface level, but within the atmosphere. And energetically it's equivalent to 142x142km circular orbit which for a vehicle the size and mass of Starship would decay in significantly more than once around (less streamlined and with lower ballistic coefficient SkyLab started it's last full circle at ~135km)
Post by: sebk on 04/15/2023 12:43 pm
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Nope. The perigee of a "nearly orbital trajectory" is not in the atmosphere but below sea level.
The confusion was caused by SpaceX calling it an "Orbital Flight Test". But they have stopped doing so - it now is just the "Starship Flight Test" on the SpaceX website (https://www.spacex.com/launches/mission/?missionId=starship-flight-test) and on the mission patch.
You're contradicting oneself.
The problem is Starship Integrated Test Flight will have its perigee significantly above the sea level.
There's simply no way to have single burn launch to 235km apogee and do 3/4 of the whole circle with perigee below the sea level. Perigee must be around 50km up.
So this is a murky territory with perigee in the atmosphere and the actual energy high enough for a full circle: it's 142x142km circular orbit equivalent which would take noticeably more than a full circle to decay.
Post by: PM3 on 04/15/2023 12:44 pm
The orbit here is about 50x235km it's perigee is above surface level, but within the atmosphere. And energetically it's equivalent to 142x142km circular orbit which for a vehicle the size and mass of Starship would decay in significantly more than once around (less streamlined and with lower ballistic coefficient SkyLab started it's last full circle at ~135km)
The whole flight is within the atmosphere, which reaches much higher than 235 km. Therefore the notion of Starship "entering atmosphere" at some point on this flight does not make sense.
And orbital velocity is only horizontal velocity. A hyperbolic suborbital flight that has the same kinetic energy like some circular orbital flight is still a suborbital flight.
Can you please quote the source for the 50 km perigee?
There's simply no way to have single burn launch to 235km apogee and do 3/4 of the whole circle with perigee below the sea level. Perigee must be around 50km up.
This is totally wrong.
Post by: Orbiter on 04/15/2023 01:00 pm
There's simply no way to have single burn launch to 235km apogee and do 3/4 of the whole circle with perigee below the sea level. Perigee must be around 50km up.
Not true. You can have perigee points below sea level and achieve a very high apogee.
Post by: Herb Schaltegger on 04/15/2023 01:11 pm
The orbit here is about 50x235km it's perigee is above surface level, but within the atmosphere. And energetically it's equivalent to 142x142km circular orbit which for a vehicle the size and mass of Starship would decay in significantly more than once around (less streamlined and with lower ballistic coefficient SkyLab started it's last full circle at ~135km)
The whole flight is within the atmosphere, which reaches much higher than 235 km. Therefore the notion of Starship "entering atmosphere" at some point on this flight does not make sense.
Only the most tenuous bits of the atmosphere reach so high, and if you’re going to play that game, there’s plenty of scattered gas and dust molecules along with stray solar protons streaming throughout the inner solar system too … but 253 km is still a vacuum for all intents and purposes.
Post by: sebk on 04/15/2023 01:11 pm
There's simply no way to have single burn launch to 235km apogee and do 3/4 of the whole circle with perigee below the sea level. Perigee must be around 50km up.
Not true. You can have perigee points below sea level and achieve a very high apogee.
Yes. High is a keyword here. To get perigee below the sea level and do 3/4 of the circle you have to have your apogee above
Post by: sferrin on 04/15/2023 01:11 pm
Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
https://youtu.be/Z_YaxHqXjSo (https://youtu.be/Z_YaxHqXjSo)
https://youtu.be/Y4J7wLD6dBs (https://youtu.be/Y4J7wLD6dBs)
Post by: eriblo on 04/15/2023 01:13 pm
Some candidates:
Specific energy >= -μ/2R (lowest circular orbit above the surface).
Specific energy >= -μ/2r for some r>R.
Perigee above surface.
Perigee above some height h.
r and h could be 50 km, 80 km, 100 km or some spacecraft dependent value guaranteeing more than a full orbit is possible.
Post by: FutureSpaceTourist on 04/15/2023 01:13 pm
https://twitter.com/csi_starbase/status/1647215514186334208
Quote
Here is another angle showing what appears to be some kind of electrical short resulting in an object falling into the base of the tower.
🎥@LabPadre
At least it seems far enough away from Starship to not have damaged it.
Post by: sferrin on 04/15/2023 01:15 pm
Post by: Ben Baley on 04/15/2023 01:16 pm
Doesn’t sound or look great:
https://youtu.be/Z_YaxHqXjSo
https://youtu.be/Y4J7wLD6dBs
Any more info on what happened?
This is concerning for a few reasons, even a small object falling that distance could easily damage the systems on the launch tower, and there's the risk to anyone working below, the last thing we want to see is having the flight delayed for an OSHA investigation.
Post by: jimvela on 04/15/2023 01:17 pm
It will be interesting to see how much activity there is around the tower in the next couple of days.
Post by: FutureSpaceTourist on 04/15/2023 01:21 pm
Quote
Appears to be the elevator failing, they are using manbaskets to bring people up to the SQD level.
Post by: Slothman on 04/15/2023 01:23 pm
But perception can be deceiving especially not knowing from which distance the audio was taken. There was certainly a thud at the end
Post by: pedz on 04/15/2023 01:31 pm
What does the green text say up in the right top corner?
I'll be on Long Island probably or I might go over to the Fisherman Statue.
Post by: minusYcore on 04/15/2023 01:44 pm
Discussion about suborbital/orbital or not first need to decide on the definition of orbital as there is not one that is obvious and universally used.US Federal definition of suborbital is a trajectory whose vacuum instantaneous impact point does not leave the Earth's surface. Mount Everest is under 9km tall, so a rocket with perigee of >9km (worst case) is orbital (or one way to deep space).
Some candidates:
Specific energy >= -μ/2R (lowest circular orbit above the surface).
Specific energy >= -μ/2r for some r>R.
Perigee above surface.
Perigee above some height h.
r and h could be 50 km, 80 km, 100 km or some spacecraft dependent value guaranteeing more than a full orbit is possible.
https://www.law.cornell.edu/uscode/text/51/50902#24 (https://www.law.cornell.edu/uscode/text/51/50902#24)
Post by: sebk on 04/15/2023 01:44 pm
The orbit here is about 50x235km it's perigee is above surface level, but within the atmosphere. And energetically it's equivalent to 142x142km circular orbit which for a vehicle the size and mass of Starship would decay in significantly more than once around (less streamlined and with lower ballistic coefficient SkyLab started it's last full circle at ~135km)
The whole flight is within the atmosphere, which reaches much higher than 235 km. Therefore the notion of Starship "entering atmosphere" at some point on this flight does not make sense.
This is a useless semantic game. By that logic International Space Station is not a space station at all. And none of the satellites in LEO is in space. In fact even GEO is doubdful as the traces of Earth's atmosphere stretch above 100000km.
And for practical spaceflight purposes reentering atmosphere is defined as passing entry interface which happens at 120 to 130km up. i.e. at the altitude where effects of the atmosphere like heating are large enough.
And orbital velocity is only horizontal velocity. A hyperbolic suborbital flight that has the same kinetic energy like some circular orbital flight is still a suborbital flight.
Wrong. Doubly so.
1. Elliptic orbits do have significant vertical components except at peri- and apo-apses.
2. Hyperbolic flight is never suborbital. All suborbital flights are elliptic.
Can you please quote the source for the 50 km perigee?
Jonathan McDowell estimated it at 50km.
But this actually comes from pretty basic geometric considerations and requirements for rocket burnout to happen above the commonly understood atmosphere. See below.
There's simply no way to have single burn launch to 235km apogee and do 3/4 of the whole circle with perigee below the sea level. Perigee must be around 50km up.
This is totally wrong.
Nope. You are totally wrong.
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Rocket's SECO must happen at least 80km up (realistically it'd be 120+, but let's get to the extreme) or it will fall down without even crossing the Atlantic. If you want your perigee to be the lowest possible and you're flying 3/4 around the globe, at SECO you should insert into an orbit about 1/8 of the circle (45°) past the perigee. And you're 80km up. If the perigee is 0, then from the simple geometry apogee would be more than 4x80 i.e. 320km (it would be 320km if the orbit were exactly circular, but such would be non-physical, as it must be slightly elongated, so it's in fact more than 320km.
Starship published apogee is 235km. To keep perigee at 0 the SECO would have to happen at... 59km. That's totally unworkable.
Realistically even 50km is somewhat low. With 235km apogee it would mean SECO at 96km which would be low but not impossibly (I didn't see SECOs happening below 115km).
Post by: Alvian@IDN on 04/15/2023 01:45 pm
If that's the elevator, it is hard to believe the tower would be fully usable for a launch attempt with it out of service- even if there wasn't anything else damaged during the event.Manlifts can still be used for access which they're doing it right now
It will be interesting to see how much activity there is around the tower in the next couple of days.
Once again a classic "let's put the delay speculation as a fact"
Post by: sanman on 04/15/2023 01:51 pm
The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Planning for it requires software validation, flight dynamics and CFD simulations, and who knows how much other testing and preparatory work. That all takes time and resources away from work on earlier, more significant milestones for this first flight test.
Are you sure that's the long and the short of it? What if they did attempt that tailsitter flip landing maneuver without the preparatory work? They'd be no worse off than the current scenario where they don't attempt it at all. After all, the flip maneuver is taking place at the tail end of the descent anyway. So I don't see what they have to lose by attempting that flip maneuver, even without the preparatory work. Just do it the exact same way you did it for SN15, if need be.
Post by: sferrin on 04/15/2023 01:53 pm
Post by: Herb Schaltegger on 04/15/2023 01:59 pm
Feel free to explain that to Gwynne Shotwell, the flight test operational planning team and the FAA. :) Because they are pointedly NOT doing that, they are belly-flopping, assuming the vehicle survives its “passive re-entry” as described in the 122 page Written Re-Evaluation document filed by the FAA last night. They are also expending the Ships for flights 2 and 3 by tumbling during entry to ensure breakup prior to attempting a landing.The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Planning for it requires software validation, flight dynamics and CFD simulations, and who knows how much other testing and preparatory work. That all takes time and resources away from work on earlier, more significant milestones for this first flight test.
Are you sure that's the long and the short of it? What if they did attempt that tailsitter flip landing maneuver without the preparatory work? They'd be no worse off than the current scenario where they don't attempt it at all. After all, the flip maneuver is taking place at the tail end of the descent anyway. So I don't see what they have to lose by attempting that flip maneuver, even without the preparatory work. Just do it the exact same way you did it for SN15, if need be.
But I’m sure your reasoning will be compelling enough to make them toss out their well-laid plans and just wing it. :)
Post by: minusYcore on 04/15/2023 02:02 pm
The changes to the flight plan may be to eliminate some minor issues that SpaceX feels the FAA is still not satisfied with.
Nope, that's not it. When Gwynne took over some months ago SpaceX did a thorough review of this test flight. Since then a number of test objectives have been moved from this test flight to future ones.
But, why? Flip & landing was already demonstrated by SN15. What was wrong about leaving this maneuver in the flight plan?
Planning for it requires software validation, flight dynamics and CFD simulations, and who knows how much other testing and preparatory work. That all takes time and resources away from work on earlier, more significant milestones for this first flight test.
Are you sure that's the long and the short of it? What if they did attempt that tailsitter flip landing maneuver without the preparatory work? They'd be no worse off than the current scenario where they don't attempt it at all. After all, the flip maneuver is taking place at the tail end of the descent anyway. So I don't see what they have to lose by attempting that flip maneuver, even without the preparatory work. Just do it the exact same way you did it for SN15, if need be.
If flip and landing worked, they would need to dispose of the ship. Instead, they are keeping 14 metric tons of propellant as ballast and planning for the ship to explode on impact and sink.
Post by: FutureSpaceTourist on 04/15/2023 02:06 pm
(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=58568.0;attach=2175230;image)
What does the green text say up in the right top corner?
It says: designated viewing zone for mariners
Clearer image attached
Post by: edzieba on 04/15/2023 02:27 pm
Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Nope. You are totally wrong.
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Post by: jimvela on 04/15/2023 02:46 pm
If that's the elevator, it is hard to believe the tower would be fully usable for a launch attempt with it out of service- even if there wasn't anything else damaged during the event.Manlifts can still be used for access which they're doing it right now
It will be interesting to see how much activity there is around the tower in the next couple of days.
Once again a classic "let's put the delay speculation as a fact"
Manlifts can be used for access, as we are seeing.
They would not be adequate for any day-of-launch tower activities, nor will inspection and repair access for the tower be quick -if- that was the elevator falling and thus man lift or crane access is the best they can do.
I speculated that the tower might not be usable for a launch event in the near term -if- the elevator fell.
That long drop with sparks and the thud at the end at least represents a reasonable possibility as an elevator failure/fall event.
It is certainly not clear what happened.
I did not speculate further on repair / recovery actions and on what timeline.
I noted that it will be interesting to observe the response over the next couple of days.
If I were to speculate further, it would be:
+ if the elevator fell, I speculate that the launch attempt will not happen in the coming week. Multiple practical reasons. I could be proved very wrong.
+ if it wasn't the elevator that fell, and whatever it was can be easily repaired, then we should know that before end of day Sunday.
+ if it wasn't the elevator that fell, I'm still very skeptical that a Monday launch attempt is still in the cards for an event where they are clearly unable to access the tower with the elevator. There's no way a not-functional elevator would be a valid state for the launch support equipment during a launch attempt.
+ I bet this picks up the discussion volume considerably over the weekend.
Post by: chopsticks on 04/15/2023 02:48 pm
Please stop with your conspiracy theories.Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
https://youtu.be/Z_YaxHqXjSo (https://youtu.be/Z_YaxHqXjSo)
https://youtu.be/Y4J7wLD6dBs (https://youtu.be/Y4J7wLD6dBs)
Post by: minusYcore on 04/15/2023 02:54 pm
In terms of Starship though, that isn't happening. It has one ascent acceleration phase and no powered descent acceleration.Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Nope. You are totally wrong.
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Quote
Starship: For the first launch, after ascent engine cutoff, Starship would vent residual main tank propellant during the in-space coast phase of the launch at or above 120 kilometers AGL.
Following the in-space coast phase, Starship would begin its passive descent.
Post by: sferrin on 04/15/2023 03:03 pm
Sorry if reality triggered you. No way anybody is just going to crack a beer and give a thumbs up for Monday after something like that.Please stop with your conspiracy theories.Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Post by: kdhilliard on 04/15/2023 03:10 pm
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch ... you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.... for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Sure, but your example trajectory would have its perigee <1/2 an orbit away from SECO, right?
Post by: Lee Jay on 04/15/2023 03:11 pm
Something can fall down the shaft and damage the elevator, but having the whole car fall is protected against by like octuple redundancy.
Post by: sferrin on 04/15/2023 03:26 pm
Is there some reason to believe whatever fell is the elevator? It's almost impossible for an elevator to fall.Somebody else suggested elevator counterweights. (Which makes more sense given how solid the final impact sounded.) In either case though it's because of the location of what was visible. What else goes that high up the center of the tower and is that heavy?
Something can fall down the shaft and damage the elevator, but having the whole car fall is protected against by line octuple redundancy.
Post by: minusYcore on 04/15/2023 03:34 pm
I believe they are speaking of a non-Hohmann orbit burn. So rather than applying deltaV at perigee/apogee perpendicular to the major axis, they raise both nodes simultaneously by accelerating at, for example, the midpoint with thrust parallel to the major axis.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch ... you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.... for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Sure, but your example trajectory would have its perigee <1/2 an orbit away from SECO, right?
Post by: launchwatcher on 04/15/2023 04:07 pm
I don't have a good sense of the mass of the object(s) that fell.Is there some reason to believe whatever fell is the elevator? It's almost impossible for an elevator to fall.Somebody else suggested elevator counterweights. (Which makes more sense given how solid the final impact sounded.) In either case though it's because of the location of what was visible. What else goes that high up the center of the tower and is that heavy?
Something can fall down the shaft and damage the elevator, but having the whole car fall is protected against by line octuple redundancy.
Pure speculation: it could be something not intended to be permanently part of the tower, like tools/equipment temporarily positioned in the tower for work. Rolling tool chest, gas cylinders for welding, etc., that got away from workers clearing the tower ahead of Monday's launch window.
Post by: eriblo on 04/15/2023 04:25 pm
The discussion is about the orbit that Starship follows after the insertion burn ends until it reenters the atmosphere (assuming no further burns).I believe they are speaking of a non-Hohmann orbit burn. So rather than applying deltaV at perigee/apogee perpendicular to the major axis, they raise both nodes simultaneously by accelerating at, for example, the midpoint with thrust parallel to the major axis.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch ... you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.... for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Sure, but your example trajectory would have its perigee <1/2 an orbit away from SECO, right?
By comparing to a circle it should be fairly obvious even without doing any math that for a majority of the orbit to be above a certain altitude the highest point must be much higher above this altitude than the lowest point is below it.
Example: Take a LEO at 120 km altitude. Shift it to one side by 120 km. It is now a reasonable approximation for an orbit with a 0 km perigee and a 240 km apogee and only half of it is going to be above 120 km.
Post by: Jim on 04/15/2023 04:27 pm
Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Doesnt have be OSHA. SpaceX could do it themselves
Post by: alastairmayer on 04/15/2023 04:30 pm
[...] Just do it the exact same way you did it for SN15, if need be.
They can't. S24 hardware is different from SN15 hardware, so they'd have to re-write the control software. There's no point in doing that for this test, since later ships have different hardware from S24.
Post by: Jim on 04/15/2023 04:30 pm
Post by: alastairmayer on 04/15/2023 04:36 pm
Wonderful. Now OSHA will shut it down for three weeks for an "investigation".Please stop with your conspiracy theories.
So, where was the ULA sniper positioned? ::)
Post by: ThatOldJanxSpirit on 04/15/2023 04:39 pm
orbital flight with making less than one orbitJim, you are well aware how small the delta is.
Post by: llanitedave on 04/15/2023 04:40 pm
Shocking reveal: It was Tim Dodd all along.Wonderful. Now OSHA will shut it down for three weeks for an "investigation".Please stop with your conspiracy theories.
So, where was the ULA sniper positioned? ::)
Post by: Lee Jay on 04/15/2023 04:52 pm
Is there some reason to believe whatever fell is the elevator? It's almost impossible for an elevator to fall.Somebody else suggested elevator counterweights. (Which makes more sense given how solid the final impact sounded.) In either case though it's because of the location of what was visible. What else goes that high up the center of the tower and is that heavy?
Something can fall down the shaft and damage the elevator, but having the whole car fall is protected against by line octuple redundancy.
A counter weight was my first thought. It's generating so many sparks that it's hard to believe it's a box or something falling and hitting things. More like sliding. And a counter weight doesn't have all the protections a car does.
I had to commission a custom elevator once. One of the last things we had to do was put 133% of the car's rated load in the car, and "cut the cables" (we didn't actually cut them, we just released them). The car fell about an inch or two before the brakes caught it. And oh boy, was getting them to release after re-attaching the cables a fun time. Take all the load off and start the wrestling match.
Post by: jon.amos on 04/15/2023 04:58 pm
Post by: plank on 04/15/2023 04:59 pm
Post by: Lee Jay on 04/15/2023 05:01 pm
Pure speculation but those sparks look electrical to me. Could someone have lost control of or otherwise caused a running genset used for weldinng to fall? We know they are welding at height and local generator makes more sense than permanently installed power to support.
It does? On a tower that size with that many already-existing high-power devices (winches, hydraulics, and so on), it makes more sense to me to put outlets everywhere for this sort of thing (i.e. 480V three-phase 100A Hubbells or similar). Where I work, we have them all over the place, including on towers way smaller than this one.
Post by: edzieba on 04/15/2023 05:14 pm
Post by: Slothman on 04/15/2023 05:18 pm
Gentlemen, please: the OLIT has stairs. Even if whatever falling doodad prevents use of the elevator, do you really think there are no SpaceXers willing to risk thigh chafing to perform any tasks out of manlift reach in order to avoid a delay?
It's not the grunt's willingness to grind that matters, it's the willingness of the company to let this go uninvestigated until the conclusion of the flight test or their willingness to get this i vestigated and cleared out before continuing to use stage 0.
Post by: kevinof on 04/15/2023 05:25 pm
You’ve obviously never worked in construction or health and safety. If there was no injuries then all SpaceX have to do is cease using that piece of equipment and carry out their own investigation, add remedial measures and fix. It shouldn’t prevent anything else from going ahead. That’s assuming nobody was injured and there is no further risk of injury.Gentlemen, please: the OLIT has stairs. Even if whatever falling doodad prevents use of the elevator, do you really think there are no SpaceXers willing to risk thigh chafing to perform any tasks out of manlift reach in order to avoid a delay?
It's not the grunt's willingness to grind that matters, it's the willingness of the company to let this go uninvestigated until the conclusion of the flight test or their willingness to get this i vestigated and cleared out before continuing to use stage 0.
Post by: jon.amos on 04/15/2023 05:26 pm
Pure speculation but those sparks look electrical to me. Could someone have lost control of or otherwise caused a running genset used for weldinng to fall? We know they are welding at height and local generator makes more sense than permanently installed power to support.
It does? On a tower that size with that many already-existing high-power devices (winches, hydraulics, and so on), it makes more sense to me to put outlets everywhere for this sort of thing (i.e. 480V three-phase 100A Hubbells or similar). Where I work, we have them all over the place, including on towers way smaller than this one.
I wouldn't want to leave power in places not routinely accessed. The power on the tower has got to be protected a bit more that a standard industrial outlet. And those outlets would need to be marine grade due to location. Most of those that i am familiar with are plastic, I don't know how they stand up in that acoustic environment. This was speculation so I am likely entirely wrong.
Post by: matthewkantar on 04/15/2023 05:38 pm
And there it is. Wonder if it was the elevator. Launch ain't happening this week. >:(
Best to cancel the whole program, butter fingers company obviously not going to hunt.
Post by: dnavas on 04/15/2023 05:44 pm
If there was no injuriesFrom your lips to God's ears, as they say.
Post by: sferrin on 04/15/2023 05:45 pm
No but they will have to do a bunch of inspections to make sure nothing propellant, electrical, or hydraulic related was damaged. Kind of important, no? ::)And there it is. Wonder if it was the elevator. Launch ain't happening this week. >:(
Best to cancel the whole program, butter fingers company obviously not going to hunt.
Post by: Tywin on 04/15/2023 05:48 pm
That's just confusion over whether th 'trajectory' skims the top of the atmosphere or not. It is orbital velocity but the low point is in the atmosphere - as explained multiple times here and elsewhere.
Nope. The perigee of a "nearly orbital trajectory" is not in the atmosphere but below sea level.
The confusion was caused by SpaceX calling it an "Orbital Flight Test". But they have stopped doing so - it now is just the "Starship Flight Test" on the SpaceX website (https://www.spacex.com/launches/mission/?missionId=starship-flight-test) and on the mission patch.
You are right...
Post by: Tywin on 04/15/2023 05:52 pm
Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
https://youtu.be/Z_YaxHqXjSo (https://youtu.be/Z_YaxHqXjSo)
https://youtu.be/Y4J7wLD6dBs (https://youtu.be/Y4J7wLD6dBs)
Do you prefer a fatal accident or injury?
Post by: Tywin on 04/15/2023 05:53 pm
Discussion about suborbital/orbital or not first need to decide on the definition of orbital as there is not one that is obvious and universally used.
Some candidates:
Specific energy >= -μ/2R (lowest circular orbit above the surface).
Specific energy >= -μ/2r for some r>R.
Perigee above surface.
Perigee above some height h.
r and h could be 50 km, 80 km, 100 km or some spacecraft dependent value guaranteeing more than a full orbit is possible.
Then I can say that New Shepard is orbital? ::)
Post by: Tywin on 04/15/2023 05:54 pm
And there it is. Wonder if it was the elevator. Launch ain't happening this week. >:(
Safety FIRST!!!
Post by: FutureSpaceTourist on 04/15/2023 05:56 pm
Quote
I still get nervous even for other people’s rocket launches. The knowledge that all your work could go up in a giant explosion is a special kind of frisson.
But for everyone that has ever drawn a spark of inspiration from visions of humanity expanding into space:This is the Way.
https://twitter.com/elonmusk/status/1647297173157978112
Quote
I still have launch PTSD from early Falcon days. My limbic system twists my guts into a knot as we get closer to launch.
Post by: Slothman on 04/15/2023 05:57 pm
That's what I'm saying. What they *have* to do doesn't necessarily match with what they want to do or should do considering all eyes on them.You’ve obviously never worked in construction or health and safety. If there was no injuries then all SpaceX have to do is cease using that piece of equipment and carry out their own investigation, add remedial measures and fix. It shouldn’t prevent anything else from going ahead. That’s assuming nobody was injured and there is no further risk of injury.Gentlemen, please: the OLIT has stairs. Even if whatever falling doodad prevents use of the elevator, do you really think there are no SpaceXers willing to risk thigh chafing to perform any tasks out of manlift reach in order to avoid a delay?
It's not the grunt's willingness to grind that matters, it's the willingness of the company to let this go uninvestigated until the conclusion of the flight test or their willingness to get this i vestigated and cleared out before continuing to use stage 0.
Post by: Tywin on 04/15/2023 06:00 pm
Sorry if reality triggered you. No way anybody is just going to crack a beer and give a thumbs up for Monday after something like that.Please stop with your conspiracy theories.Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
ERGGGG?
Post by: Tywin on 04/15/2023 06:04 pm
Gentlemen, please: the OLIT has stairs. Even if whatever falling doodad prevents use of the elevator, do you really think there are no SpaceXers willing to risk thigh chafing to perform any tasks out of manlift reach in order to avoid a delay?
It's not the grunt's willingness to grind that matters, it's the willingness of the company to let this go uninvestigated until the conclusion of the flight test or their willingness to get this i vestigated and cleared out before continuing to use stage 0.
Exactly
Post by: sferrin on 04/15/2023 06:27 pm
How'd you get that from my statement?Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Do you prefer a fatal accident or injury?
Post by: Tywin on 04/15/2023 06:29 pm
How'd you get that from my statement?Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Do you prefer a fatal accident or injury?
Because, OSHA exists for a very clear reason...
Post by: Lee Jay on 04/15/2023 06:32 pm
Gentlemen, please: the OLIT has stairs. Even if whatever falling doodad prevents use of the elevator, do you really think there are no SpaceXers willing to risk thigh chafing to perform any tasks out of manlift reach in order to avoid a delay?
I work with wind energy. The tallest tower I've climbed is 80 meters (I've gone up 135m in a basket). It's a workout, for sure, but what you do is plan the trip up to be once up to get a job done, and never plan more than 2 trips up per day (ideally, not more than one a day). It's doable, but it's unpleasant. Where it becomes not doable is if you need heavy stuff to come up with you and your cargo lifting device is broken. Even that 80m tower I climbed had a winch-driven cargo basket.
If SpaceX personnel need to go up, they can go. If they need to take heavy stuff with them, the elevator is the way to go. If they don't have it or at least some sort of cargo lifting device, that could well be a show-stopper until they can fix what's broken or rig a temporary solution for lifting heavy stuff inside the tower.
Post by: pedz on 04/15/2023 06:38 pm
That point is only 4 miles away rather than 6 miles which is the distance from Port Isabel. But, you would be shooting straight into the rising sun -- although that could look cool if done properly.
As I recall, there is still a lot of scrub at that point and you can't actually see the launch site except whatever pokes out above the scrub.
Post by: Jimmy_C on 04/15/2023 07:46 pm
Sheriffs are closing the road around the launch site for potential Ship 24 stacking.
https://twitter.com/VickiCocks15/status/1647306355395510272
Referring to the above: Because Starship is being stacked with presumably explosive ordnance installed for the FTS, I suspect they are planning to proceed with the launch in the near future in spite of whatever happened on the tower. However I could be wrong.
Post by: Slothman on 04/15/2023 07:46 pm
More questions about the "Starbase Launch Keep Out Zone": Is Highway 4 closed before or after the border patrol check point? The diagram has two "Check Point". One is next to Richardson Avenue. Is it possible for me to get at that point with my cameras? Is it possible to see the launch pad from that point?
That point is only 4 miles away rather than 6 miles which is the distance from Port Isabel. But, you would be shooting straight into the rising sun -- although that could look cool if done properly.
As I recall, there is still a lot of scrub at that point and you can't actually see the launch site except whatever pokes out above the scrub.
As far as I'm aware, general public has to stay out of the outer checkpoint (and will be escorted if found between outer and inner checkpoint) while spacex personnel is allowed between the checkpoints, but nobody past the inner checkpoint(Eichorn Blvd.?) Tim dodd's boca chica visiting guide had some mention of that
Post by: Lee Jay on 04/15/2023 07:53 pm
Post by: meekGee on 04/15/2023 08:02 pm
I think they'll need to have a rationale.That's what I'm saying. What they *have* to do doesn't necessarily match with what they want to do or should do considering all eyes on them.You’ve obviously never worked in construction or health and safety. If there was no injuries then all SpaceX have to do is cease using that piece of equipment and carry out their own investigation, add remedial measures and fix. It shouldn’t prevent anything else from going ahead. That’s assuming nobody was injured and there is no further risk of injury.Gentlemen, please: the OLIT has stairs. Even if whatever falling doodad prevents use of the elevator, do you really think there are no SpaceXers willing to risk thigh chafing to perform any tasks out of manlift reach in order to avoid a delay?
It's not the grunt's willingness to grind that matters, it's the willingness of the company to let this go uninvestigated until the conclusion of the flight test or their willingness to get this i vestigated and cleared out before continuing to use stage 0.
For example, if it was the counterweight(s) and if the fall path remained contained, (and the car remained latched) then it can be argued that the backup systems worked and so there's no damage expected outside of the elevator system.
Maybe look for why the counterweight separated, to make sure it wasn't caused by something outside the elevator system.
Both things can be done today towards a Monday launch.
If they find something wrong, plenty time to stand down on Sunday.
Post by: sferrin on 04/15/2023 08:08 pm
No SS. I work in manufacturing. I know all about OSHA.How'd you get that from my statement?Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Do you prefer a fatal accident or injury?
Because, OSHA exists for a very clear reason...
Post by: meekGee on 04/15/2023 08:10 pm
orbital flight with making less than one orbitThat's exactly what it is.
People calling it suborbital are the same people calling a 100 (82...) km up-and-down hop "going to space"
Using legalese to intentionally miss the point is all fun and games, but has never helped anyone do anything constructive.
Not even repeating that likely this is a fully-legal orbital flight too, because that hair splitting is entirely inconsequential.
Post by: meekGee on 04/15/2023 08:20 pm
I mean we're watching a giant rocket being put together as if nothing. Wham bam thank you ma'am. Lego rocket FTW.
And it just seems natural, we almost take it for granted.
Post by: TheRadicalModerate on 04/15/2023 08:23 pm
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch ... you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.... for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Sure, but your example trajectory would have its perigee <1/2 an orbit away from SECO, right?
No, it's more complicated than that. If you're trying to maximize energy, yes, your burnout would be at either perigee or apogee, with a flight path angle of zero. But you can also have burnouts with non-zero flight path angles, where the apse line is somewhere else. This is pretty likely when you're aiming for a particular spot in the Pacific, which is roughly 85% of an orbit. I also did a rough Google Earth propagation of the NOTMAR debris hazard box (azimuth = ~93º) and an energy-maximized orbit would cross a few hundred km below the Big Island, not north of Kauai, where the landing zone is. Some of that is because of Earth's rotation, but I suspect that there's some RAAN rotation baked in there as well, which is yet another indication of a funny flight path angle at burnout.
Discussion about suborbital/orbital or not first need to decide on the definition of orbital as there is not one that is obvious and universally used.US Federal definition of suborbital is a trajectory whose vacuum instantaneous impact point does not leave the Earth's surface. Mount Everest is under 9km tall, so a rocket with perigee of >9km (worst case) is orbital (or one way to deep space).
Some candidates:
Specific energy >= -μ/2R (lowest circular orbit above the surface).
Specific energy >= -μ/2r for some r>R.
Perigee above surface.
Perigee above some height h.
r and h could be 50 km, 80 km, 100 km or some spacecraft dependent value guaranteeing more than a full orbit is possible.
https://www.law.cornell.edu/uscode/text/51/50902#24 (https://www.law.cornell.edu/uscode/text/51/50902#24)
Unfortunately there's no definition for "vacuum instantaneous impact point", which is a bit ambiguous. Does this mean the impact point if Earth had no atmosphere, or the ground track expected from an uncontrolled reentry?
I'm gonna guess that the orbit is actually about 235 x 100km, since things with perigees below the Karman Line are going to reenter is short order (i.e. a fraction of an orbit). That would be a semi-major axis (altitude) of 168km, and also the equivalent circular orbit. That's probably OK for an orbit or two, but not much more than that.
Update:
I found a set of USSF range safety manuals:
Volume 1 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v1/sscman91-710v1.pdf) (range safety and requirements procedures)
Volume 2 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v2/sscman91-710v2.pdf) (flight safety requirements)
Volume 3 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v3/sscman91-710v3.pdf) (ground support systems)
Volume 4 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v4/sscman91-710v4.pdf) (flight safety, FTS, etc.)
Volume 5 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v5/sscman91-710v5.pdf) (reentry vehicle location)
Volume 6 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v6/sscman91-710v6.pdf) (personnel safety)
Volume 7 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v7/sscman91-710v7.pdf) (glossary)
Sadly, while there's a definition of instantaneous impact point, there's still no definition of the "vacuum" version of that term. However, in volume 2 (p. 81) (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v2/sscman91-710v2.pdf), there's a time-of-flight definition that's as follows:
Quote
Time of flight (2D) remaining to instantaneous vacuum impact point in seconds (TIIP).
Definition. The time of flight is the flight time remaining to an instantaneous vacuum
impact point assuming that all vehicle thrust is terminated at some time after launch.
The instantaneous vacuum impact point is a Keplerian solution only. The
instantaneous impact point is the location at which the vehicle would meet the
spheroid and is measured in the downrange direction from the launch point in the
flight plane.
So I think that makes the "suborbital" definition the atmosphere-free version, which invalidates my guess.
Update to the Update:
Here's an FAA rulemaking for reusable suborbital vehicles (https://spaceref.com/status-report/faa-experimental-permits-for-reusable-suborbital-rockets/) with the following definition:
Quote
The reusable suborbital rocket must also be flown on a suborbital trajectory, which the CSLAA defines as the intentional flight path of a launch vehicle, reentry vehicle, or any portion thereof, whose vacuum instantaneous impact point (the location on Earth where a vehicle would impact if it were to fail, calculated in the absence of atmospheric drag effects) does not leave the surface of the Earth.
Done deal. So if SpaceX and/or the FAA is calling the flight suborbital, then the perigee is consistent with lithobraking.
Post by: pedz on 04/15/2023 08:28 pm
More questions about the "Starbase Launch Keep Out Zone": Is Highway 4 closed before or after the border patrol check point? The diagram has two "Check Point". One is next to Richardson Avenue. Is it possible for me to get at that point with my cameras? Is it possible to see the launch pad from that point?
That point is only 4 miles away rather than 6 miles which is the distance from Port Isabel. But, you would be shooting straight into the rising sun -- although that could look cool if done properly.
As I recall, there is still a lot of scrub at that point and you can't actually see the launch site except whatever pokes out above the scrub.
As far as I'm aware, general public has to stay out of the outer checkpoint (and will be escorted if found between outer and inner checkpoint) while spacex personnel is allowed between the checkpoints, but nobody past the inner checkpoint(Eichorn Blvd.?) Tim dodd's boca chica visiting guide had some mention of that
Thank you. I watched that video and saw that but later in the same video he says “this is where the check point is” and it is at Starbase itself. Slightly confusing.
Post by: DigitalMan on 04/15/2023 08:39 pm
Post by: Tywin on 04/15/2023 08:53 pm
No SS. I work in manufacturing. I know all about OSHA.How'd you get that from my statement?Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Do you prefer a fatal accident or injury?
Because, OSHA exists for a very clear reason...
I was working in construction, so I know OSHA well too....
Post by: Tywin on 04/15/2023 08:54 pm
orbital flight with making less than one orbitThat's exactly what it is.
People calling it suborbital are the same people calling a 100 (82...) km up-and-down hop "going to space"
Using legalese to intentionally miss the point is all fun and games, but has never helped anyone do anything constructive.
Not even repeating that likely this is a fully-legal orbital flight too, because that hair splitting is entirely inconsequential.
We can twist reality as much as we want at our will, but the definitions are clear...
Post by: meekGee on 04/15/2023 09:15 pm
orbital flight with making less than one orbitThat's exactly what it is.
People calling it suborbital are the same people calling a 100 (82...) km up-and-down hop "going to space"
Using legalese to intentionally miss the point is all fun and games, but has never helped anyone do anything constructive.
Not even repeating that likely this is a fully-legal orbital flight too, because that hair splitting is entirely inconsequential.
We can twist reality as much as we want at our will, but the definitions are clear...
You're not listening.
The definitions are clear, and yet you can apply them to arrive at the wrong conclusions.
This flight is equivalent to any LEO flight (sans circularization) and entirely different from what's normally referred to as a suborbital flight.
Plus, reading upthread, it may even formally be fully orbital, depending on the flavor of the definition.
THAT is the reality. Good luck with the hair splitting - it doesn't change a thing except give some folks the illusion that a certain suborbital launcher is "ready to catch up" or even "leap frog" SpaceX.
Post by: Alberto-Girardi on 04/15/2023 09:20 pm
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch ... you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.... for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Sure, but your example trajectory would have its perigee <1/2 an orbit away from SECO, right?
No, it's more complicated than that. If you're trying to maximize energy, yes, your burnout would be at either perigee or apogee, with a flight path angle of zero. But you can also have burnouts with non-zero flight path angles, where the apse line is somewhere else. This is pretty likely when you're aiming for a particular spot in the Pacific, which is roughly 85% of an orbit. I also did a rough Google Earth propagation of the NOTMAR debris hazard box (azimuth = ~93º) and an energy-maximized orbit would cross a few hundred km below the Big Island, not north of Kauai, where the landing zone is. Some of that is because of Earth's rotation, but I suspect that there's some RAAN rotation baked in there as well, which is yet another indication of a funny flight path angle at burnout.Discussion about suborbital/orbital or not first need to decide on the definition of orbital as there is not one that is obvious and universally used.US Federal definition of suborbital is a trajectory whose vacuum instantaneous impact point does not leave the Earth's surface. Mount Everest is under 9km tall, so a rocket with perigee of >9km (worst case) is orbital (or one way to deep space).
Some candidates:
Specific energy >= -μ/2R (lowest circular orbit above the surface).
Specific energy >= -μ/2r for some r>R.
Perigee above surface.
Perigee above some height h.
r and h could be 50 km, 80 km, 100 km or some spacecraft dependent value guaranteeing more than a full orbit is possible.
https://www.law.cornell.edu/uscode/text/51/50902#24 (https://www.law.cornell.edu/uscode/text/51/50902#24)
Unfortunately there's no definition for "vacuum instantaneous impact point", which is a bit ambiguous. Does this mean the impact point if Earth had no atmosphere, or the ground track expected from an uncontrolled reentry?
I'm gonna guess that the orbit is actually about 235 x 100km, since things with perigees below the Karman Line are going to reenter is short order (i.e. a fraction of an orbit). That would be a semi-major axis (altitude) of 168km, and also the equivalent circular orbit. That's probably OK for an orbit or two, but not much more than that.
Update:
I found a set of USSF range safety manuals:
Volume 1 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v1/sscman91-710v1.pdf) (range safety and requirements procedures)
Volume 2 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v2/sscman91-710v2.pdf) (flight safety requirements)
Volume 3 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v3/sscman91-710v3.pdf) (ground support systems)
Volume 4 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v4/sscman91-710v4.pdf) (flight safety, FTS, etc.)
Volume 5 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v5/sscman91-710v5.pdf) (reentry vehicle location)
Volume 6 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v6/sscman91-710v6.pdf) (personnel safety)
Volume 7 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v7/sscman91-710v7.pdf) (glossary)
Sadly, while there's a definition of instantaneous impact point, there's still no definition of the "vacuum" version of that term. However, in volume 2 (p. 81) (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v2/sscman91-710v2.pdf), there's a time-of-flight definition that's as follows:QuoteTime of flight (2D) remaining to instantaneous vacuum impact point in seconds (TIIP).
Definition. The time of flight is the flight time remaining to an instantaneous vacuum
impact point assuming that all vehicle thrust is terminated at some time after launch.
The instantaneous vacuum impact point is a Keplerian solution only. The
instantaneous impact point is the location at which the vehicle would meet the
spheroid and is measured in the downrange direction from the launch point in the
flight plane.
So I think that makes the "suborbital" definition the atmosphere-free version, which invalidates my guess.
Update to the Update:
Here's an FAA rulemaking for reusable suborbital vehicles (https://spaceref.com/status-report/faa-experimental-permits-for-reusable-suborbital-rockets/) with the following definition:QuoteThe reusable suborbital rocket must also be flown on a suborbital trajectory, which the CSLAA defines as the intentional flight path of a launch vehicle, reentry vehicle, or any portion thereof, whose vacuum instantaneous impact point (the location on Earth where a vehicle would impact if it were to fail, calculated in the absence of atmospheric drag effects) does not leave the surface of the Earth.
Done deal. So if SpaceX and/or the FAA is calling the flight suborbital, then the perigee is consistent with lithobraking.
Great find. But have the FAA or SpaceX ever called the flight suborbita?
Post by: meekGee on 04/15/2023 09:27 pm
Neither is obliged to follow any guidelines.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch ... you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.... for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Sure, but your example trajectory would have its perigee <1/2 an orbit away from SECO, right?
No, it's more complicated than that. If you're trying to maximize energy, yes, your burnout would be at either perigee or apogee, with a flight path angle of zero. But you can also have burnouts with non-zero flight path angles, where the apse line is somewhere else. This is pretty likely when you're aiming for a particular spot in the Pacific, which is roughly 85% of an orbit. I also did a rough Google Earth propagation of the NOTMAR debris hazard box (azimuth = ~93º) and an energy-maximized orbit would cross a few hundred km below the Big Island, not north of Kauai, where the landing zone is. Some of that is because of Earth's rotation, but I suspect that there's some RAAN rotation baked in there as well, which is yet another indication of a funny flight path angle at burnout.Discussion about suborbital/orbital or not first need to decide on the definition of orbital as there is not one that is obvious and universally used.US Federal definition of suborbital is a trajectory whose vacuum instantaneous impact point does not leave the Earth's surface. Mount Everest is under 9km tall, so a rocket with perigee of >9km (worst case) is orbital (or one way to deep space).
Some candidates:
Specific energy >= -μ/2R (lowest circular orbit above the surface).
Specific energy >= -μ/2r for some r>R.
Perigee above surface.
Perigee above some height h.
r and h could be 50 km, 80 km, 100 km or some spacecraft dependent value guaranteeing more than a full orbit is possible.
https://www.law.cornell.edu/uscode/text/51/50902#24 (https://www.law.cornell.edu/uscode/text/51/50902#24)
Unfortunately there's no definition for "vacuum instantaneous impact point", which is a bit ambiguous. Does this mean the impact point if Earth had no atmosphere, or the ground track expected from an uncontrolled reentry?
I'm gonna guess that the orbit is actually about 235 x 100km, since things with perigees below the Karman Line are going to reenter is short order (i.e. a fraction of an orbit). That would be a semi-major axis (altitude) of 168km, and also the equivalent circular orbit. That's probably OK for an orbit or two, but not much more than that.
Update:
I found a set of USSF range safety manuals:
Volume 1 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v1/sscman91-710v1.pdf) (range safety and requirements procedures)
Volume 2 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v2/sscman91-710v2.pdf) (flight safety requirements)
Volume 3 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v3/sscman91-710v3.pdf) (ground support systems)
Volume 4 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v4/sscman91-710v4.pdf) (flight safety, FTS, etc.)
Volume 5 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v5/sscman91-710v5.pdf) (reentry vehicle location)
Volume 6 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v6/sscman91-710v6.pdf) (personnel safety)
Volume 7 (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v7/sscman91-710v7.pdf) (glossary)
Sadly, while there's a definition of instantaneous impact point, there's still no definition of the "vacuum" version of that term. However, in volume 2 (p. 81) (https://static.e-publishing.af.mil/production/1/ssc/publication/sscman91-710v2/sscman91-710v2.pdf), there's a time-of-flight definition that's as follows:QuoteTime of flight (2D) remaining to instantaneous vacuum impact point in seconds (TIIP).
Definition. The time of flight is the flight time remaining to an instantaneous vacuum
impact point assuming that all vehicle thrust is terminated at some time after launch.
The instantaneous vacuum impact point is a Keplerian solution only. The
instantaneous impact point is the location at which the vehicle would meet the
spheroid and is measured in the downrange direction from the launch point in the
flight plane.
So I think that makes the "suborbital" definition the atmosphere-free version, which invalidates my guess.
Update to the Update:
Here's an FAA rulemaking for reusable suborbital vehicles (https://spaceref.com/status-report/faa-experimental-permits-for-reusable-suborbital-rockets/) with the following definition:QuoteThe reusable suborbital rocket must also be flown on a suborbital trajectory, which the CSLAA defines as the intentional flight path of a launch vehicle, reentry vehicle, or any portion thereof, whose vacuum instantaneous impact point (the location on Earth where a vehicle would impact if it were to fail, calculated in the absence of atmospheric drag effects) does not leave the surface of the Earth.
Done deal. So if SpaceX and/or the FAA is calling the flight suborbital, then the perigee is consistent with lithobraking.
Great find. But have the FAA or SpaceX ever called the flight suborbita?
The trajectory is known and agreed upon.
It's categorization as "orbital" or not is purely marketing. There's reasons to go either way.
My guess is that there's enough obvious achievement that there's no reason for SpaceX to get into the distraction of arguing semantics.
Post by: DigitalMan on 04/15/2023 09:48 pm
Obvious minimum requirements for a first test flight in my opinion are being tested. (1) Achieving orbital velocity (2) Affects of reentry at the required entry velocity.
Sure there are other things they could add, like the flip-landing, but there is a trail of ships waiting to fly. Obvious reason for less than one orbit is risk and desire to observe entry performance from a location with adequate instrumentation.
Post by: alugobi on 04/15/2023 09:50 pm
Post by: rcoppola on 04/15/2023 09:53 pm
After that...it's all good.
Post by: joek on 04/15/2023 09:56 pm
Great find. But have the FAA or SpaceX ever called the flight suborbita?
FWIW... The FAA launch license is neutral. The FAA WR (published concurrently), refers to "Starship Orbital Test Flight...", and also specifically refers to booster as suborbital.
Think most of us know what a significant effort this is and what it portends--whether or not this first attempt succeeds. Trolls, ankle biters and barnyard lawyers trying to minize that based on questionable self-serving interpretations just makes them look small and is a distraction.
Post by: baking on 04/15/2023 09:56 pm
Thank you. I watched that video and saw that but later in the same video he says “this is where the check point is” and it is at Starbase itself. Slightly confusing.There is a checkpoint at Starbase, but that is only for non-flight tests such as cryo-tests, wet dress rehearsals, and static fires, etc. Anything that leaves the ground (intentionally) requires FAA approval and they have a larger exclusion zone.
Post by: joek on 04/15/2023 10:17 pm
There is a checkpoint at Starbase, but that is only for non-flight tests such as cryo-tests, wet dress rehearsals, and static fires, etc. Anything that leaves the ground (intentionally) requires FAA approval and they have a larger exclusion zone.
FYI, per FAA license additional stipulations kick in well before anything might leave the ground (emphasis added)...
Quote from: FAA launch license VOL 23-129
“Pre-flight ground operations” shall mean Space Exploration Technologies, Corp.’s pre-flight preparations of the Starship-Super Heavy vehicle at Boca Chica, Texas, beginning at the start of Autonomous Flight Termination System ordnance installation for the Starship upper stage vehicle or Super Heavy booster vehicle, whichever occurs first.... including $48M liability coverage from those pre-flight operations. (Actual flight is $500M.)
Post by: ChrisC on 04/15/2023 10:44 pm
There is one overriding requirement...Clear. The. Tower. After that...it's all good.
Ah yes, thanks for the reminder, I wanted to whine about this. Hey NSF guys, I was really surprised that, in your recent launch sequence video (https://youtube.com/watch?v=tHa-37Bcg_Q), scripted by Alex, you did not call out the point at which the stack will have flown far enough to eliminate any chance of damaging the launch pad. That's the first major milestone that us armchair veterans will be watching for, and it typically occurs at around 25 seconds into flight. At that point, with the altitude and more important the beginning of pitch over, the Instantaneous Impact Point (IIP) (https://www.google.com/search?q=instantaneous+impact+point&tbm=isch) will be "outside the fenceline", and a couple more seconds after that it'll be across the beach and in the water. It's what we were watching for during the first Falcon Heavy launch, and it's the point when Elon ran outside with a big ass grin on his face :)
Just "clearing the tower" isn't enough. Once the IIP is in the water, we can breathe easy and everything after that is gravy -- max q, staging, RVac ignition, orbit*, entry, splashdown. Put that mention of IIP into your timeline and coverage!
* OMG would you all please stop with the orbital semantics. Didn't we already do this six months ago when the Hawaii target was first news?
Post by: TheRadicalModerate on 04/15/2023 11:22 pm
Great find. But have the FAA or SpaceX ever called the flight suborbita?
FWIW... The FAA launch license is neutral. The FAA WR (published concurrently), refers to "Starship Orbital Test Flight...", and also specifically refers to booster as suborbital.
Think most of us know what a significant effort this is and what it portends--whether or not this first attempt succeeds. Trolls, ankle biters and barnyard lawyers trying to minize that based on questionable self-serving interpretations just makes them look small and is a distraction.
The booster is clearly suborbital, both legally and physically.
There are rules for orbital flights, and slightly different rules for suborbital ones. I haven't waded through the permit yet, so I don't know if there's any verbiage in there that sheds light on the issue.
Another issue: I'd guess that SpaceX would like to be as gentle on the tiles as possible, in the interest of getting as much hypersonic data before a failure as possible. That implies hitting entry interface with as modest an amount of energy as possible. If that requires giving the aforementioned ankle-biters something to chew on, so be it. But I have to admit that I would smile if I saw their tears.
FWIW: I vote for calling any spacecraft with a specific orbital energy greater than -30MJ/kg "orbital". By that definition, 235km x 0km isn't orbital.
Post by: joek on 04/16/2023 12:19 am
There are rules for orbital flights, and slightly different rules for suborbital ones. I haven't waded through the permit yet, so I don't know if there's any verbiage in there that sheds light on the issue.
...
Good luck. Was hoping there would be more specifics in the launch license, but it is pretty generic. FAA appears to have moved to an inclusive "VOL" (vehicle operator license) recently. All the specifics we use to see in previous licenses (e.g., LLS or permits) is not exposed, but buried in per-flight paperwork that is not public. More specific information is in the latest WR published concurrently with the license, but doubt that is going to convince doubters whether Starship trajectory is "orbital". (In any case, past caring about that debate.)
Post by: meekGee on 04/16/2023 12:37 am
Another issue: I'd guess that SpaceX would like to be as gentle on the tiles as possible, in the interest of getting as much hypersonic data before a failure as possible. That implies hitting entry interface with as modest an amount of energy as possible. If that requires giving the aforementioned ankle-biters something to chew on, so be it. But I have to admit that I would smile if I saw their tears.
I think they plan to use the tiles as a backup tracking mechanism, in case they lose telemetry and radar contact.
Post by: Fireworking on 04/16/2023 01:43 am
If it was the elevator falling, Ok, big deal, the elevator doesn't work. The elevator is used for when workers need to make it to the top of the tower. however, starship is currently ready for launch, meaning they dont have a need to travel up and down the tower, and if they do they won't be carrying much equipment. The elevator won't be needed for a launch.
If, however, a pipe that carries methane/lox was ruptured due to the object falling, then either way the best way to check for leaks is to use the pipes, and in this case they could just proceed with the launch as planned, and if something leaks then they can scrub.
I don't think this is such a big deal that they will scrub the launch to do a thorough investigation. Maybe this will happen after the launch, but given that Starship is already fully prepared for launch, including being stacked on the booster, there really isn't another need for the tower except for the fueling of the upperstage, but like i said, if something leaks they can scrub from there.
Personally it doesn't seem like a big enough deal to scrub the launch so far in advance.
Post by: FutureSpaceTourist on 04/16/2023 02:07 am
Quote
SpaceX is projecting things onto the Mega Bay. Looks like a calibration alignment grid ahead of whatever they plan to project.
nsf.live/starbase
Post by: FutureSpaceTourist on 04/16/2023 07:03 am
Quote
Just another night at Mega Bay🚀
Post by: FutureSpaceTourist on 04/16/2023 07:31 am
Quote
Hey, I know that shape!
https://twitter.com/nasaspaceflight/status/1647429205947211778
Quote
Elon, get off the projector controls! 😅
Post by: faramund on 04/16/2023 07:39 am
:) :) :)
Post by: PM3 on 04/16/2023 07:41 am
Think most of us know what a significant effort this is and what it portends--whether or not this first attempt succeeds. Trolls, ankle biters and barnyard lawyers trying to minize that based on questionable self-serving interpretations just makes them look small and is a distraction.
I think ANYONE here knows and respects what an enournous effort this is. Everything is awesome about this rocket and the first launch and the prospect of enabling humanity to live among the stars.
Seeking for correct information and terms regarding the upcoming launch, writing the right things into the history books - e. g. if it is an orbital or suborbital flight - does not impede the respect for SpaceX's achievements. It actually honours Elon's habit to alway be as honest as possible.
Post by: Slothman on 04/16/2023 08:21 am
It actually honours Elon's habit to alway be as honest as possible.XD
I mean.. appreciate Elon as much as you want for the development of starship,it's great.. but that statement is just objectively ridiculous.
Post by: CMac on 04/16/2023 12:04 pm
Joking aside, there was some informative bits in the midst of it.
Post by: Alberto-Girardi on 04/16/2023 12:10 pm
This now is feeling very real.
Post by: sebk on 04/16/2023 12:53 pm
Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Nope. You are totally wrong.
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Wrong. As I wrote, this applies to everything behaving like a rocket. In fact, it'd be more doable with a space gun (realistically it must be either some type of EM gun or nuclear) than with a rocket: guns always have perigee below ground level, you must raise it later. And no rocket burns for tens of minutes. The longest ascent burns approaches 20m and it takes less than 1/10 of the full circle to ascent. Way too little to cut the exoatmospheric part of the flight below half circle which would be required to play games with lowering perigee without raising apogee.
And yes, you can insert into an apogee of an orbit, that's not a problem at all (and rockets without upper stage restart capability did this in the past). The thing is, you can't then have the perigee not only under ground but even in the significant atmosphere (i.e. below 90km) and do a 270° around the Earth. If you wanted to go for less than half circle, then you're free to do so. But with 270° flight you're limited by the reality that perigee is necessarily 180° from the apogee. If you insert to an overhead apogee, your perigee will be at the antipode of your launch site, 180° away. Obviously, you're not doing 270° if your perigee is only 180° away and underground. It must be above the ground, and significantly at that.
The way to have the lowest perigee (if this is your particular goal; it's not even Starship goal to begin with) while keeping apogee below the set level (235km here) is to have it roughly half-way between your splashdown/landing site and your launch site (give or take 5°). Apogee then must be about half way of your flight.
Post by: clongton on 04/16/2023 01:48 pm
The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
Why not just say "orbital velocity on a suborbital trajectory".
Post by: clongton on 04/16/2023 01:56 pm
ICBMs dont fly more than half around the globe.
They do if you don't want the target to see them coming. For example a Eurasian nation that wants to hit something in North America could launch due south, over the South Pole, and the ICBM would approach the target from the south, a direction that is not being monitored for ICBMs.
Just correcting the misstatement. Back to the topic now.
Post by: Legios on 04/16/2023 01:57 pm
Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Nope. You are totally wrong.
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Wrong. As I wrote, this applies to everything behaving like a rocket. In fact, it'd be more doable with a space gun (realistically it must be either some type of EM gun or nuclear) than with a rocket: guns always have perigee below ground level, you must raise it later. And no rocket burns for tens of minutes. The longest ascent burns approaches 20m and it takes less than 1/10 of the full circle to ascent. Way too little to cut the exoatmospheric part of the flight below half circle which would be required to play games with lowering perigee without raising apogee.
And yes, you can insert into an apogee of an orbit, that's not a problem at all (and rockets without upper stage restart capability did this in the past). The thing is, you can't then have the perigee not only under ground but even in the significant atmosphere (i.e. below 90km) and do a 270° around the Earth. If you wanted to go for less than half circle, then you're free to do so. But with 270° flight you're limited by the reality that perigee is necessarily 180° from the apogee. If you insert to an overhead apogee, your perigee will be at the antipode of your launch site, 180° away. Obviously, you're not doing 270° if your perigee is only 180° away and underground. It must be above the ground, and significantly at that.
The way to have the lowest perigee (if this is your particular goal; it's not even Starship goal to begin with) while keeping apogee below the set level (235km here) is to have it roughly half-way between your splashdown/landing site and your launch site (give or take 5°). Apogee then must be about half way of your flight.
Too many mental gymnastics going on in this thread. It is a suborbital ballistic trajectory, period.
But, it's not a bad thing. It's by design. SpaceX does not want to risk a huge piece of space junk orbiting and then reentering out of control. It is a responsible course of action for an initial test flight of all-new hardware.
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
Too me, orbital is simple. Orbits are when the path is stable due simply to physics. No additional forces are required. (Yes, station keeping in LEO is required to overcome drag...but it's negligible for the sake of this argument.) If the perigee is low enough that atmospheric drag will cause re-entry, then by definition it is not orbital.
Post by: mikelepage on 04/16/2023 01:59 pm
I wonder if SpaceX Will attempt to catch Starship upper stage in the future? The reason I say this is because of the way they word it on the website. Only mentioning catching Super heavy and not Starship.
I think part of the issue has always been leg design with a wide enough stance (especially on the heat shield side). There’s a whole thread about this elsewhere on the forum which maybe is worth updating.
They may want to get data on how a simply-shaped heat shield performs during reentry before they even go to the effort of designing the more complex shapes that you would need to shield extendable (F9-style) legs.
Post by: Zed_Noir on 04/16/2023 02:20 pm
<snip>Will take a shot at a description. Called it a retarded orbital flight. Think the Starship have enough delta-V left to make orbit, otherwise they wouldn't be venting the propellants out after engine cutoff. So it appears that SpaceX applied a vector change just before engine cutoff to attained a revised trajectory that result in atmosphere reentry later.
The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
<snip>
It is somewhat similar to deploying a tail retardation device on a piece of ordnance that is drop by a fast strike aircraft at low altitude. So said ordnance slow down enough to gave a safe horizontal separation from the departing aircraft before going boom.
Post by: GORDAP on 04/16/2023 02:36 pm
The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
Why not just say "orbital velocity on a suborbital trajectory".
The European Space Agency had a (failed) launch some years back that in fact had orbital energy, but alas not quite the right trajectory, hence a crash. In what I think was a brilliant (and accurate) attempt at face saving, they said the craft had entered an Earth Intersecting Orbit (EIO) :-) I nominate 'Earth Intersecting Orbit' as our descriptor for the upcoming flight.
Post by: joek on 04/16/2023 02:41 pm
Too me, orbital is simple. Orbits are when the path is stable due simply to physics. No additional forces are required. (Yes, station keeping in LEO is required to overcome drag...but it's negligible for the sake of this argument.) If the perigee is low enough that atmospheric drag will cause re-entry, then by definition it is not orbital.
This debate has little-nothing to do with physics, but legal or quasi-legal definitions of "orbital". You can speculate either way depending on your interpretation of various references. And even given those references, you can't really call it unless you know details about the trajectory and what happens when--which we do not have.
For example...
Quote from: 14 CFR § 401.7 - Definitions.
Suborbital trajectory means the intentional flight path of a launch vehicle, reentry vehicle, or any portion thereof, whose vacuum instantaneous impact point does not leave the surface of the Earth.
Deorbit means the flight of a vehicle that begins with the final command to commit to a perigee below 70 nautical miles (approximately 130 kilometers), and ends when all vehicle components come to rest on the Earth.
That is only a small selection of various sources-references. E.g., We could have a "suborbital" trajectory by definition #1, yet have a "deorbit"--which implies orbit--by definition #2 (e.g., if it were commanded later in flight).
Tempest in a teapot. People will cherry pick and speculate based on their preferences; not worth wasting more time on this. We'll know when the dust has settled.
Post by: meekGee on 04/16/2023 02:42 pm
Have the Karmens stopped fighting about orbital/suborbital?Good morning!
Joking aside, there was some informative bits in the midst of it.
And, no.
21 hours to go.
Post by: PM3 on 04/16/2023 03:02 pm
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
Post by: rsdavis9 on 04/16/2023 03:09 pm
Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
Might they try an in orbit engine restart to test this?
Post by: DanClemmensen on 04/16/2023 03:15 pm
That's why they are using the free-return trajectory: it wil hist the landing zone without ever relighting after SECO. It does not explain why they are not at least trying for a sea-level vertical landing. You don't need high confidence for that. You just need to believe it has a chance of working. The published plan is for the belly flop to end in a small explosion. Worst case if relight failed during a flip-and-land would be a bigger explosion (more propellant) out there in the middle of the ocean.Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
Post by: joek on 04/16/2023 03:16 pm
Have the Karmens stopped fighting about orbital/suborbital?
...
They're still debating based on focus group feedback from recent appearances, and of course their personal opinions...
An orbital launch is like totally slaying the runway. When a rocket reaches orbit, it's going super fast, cruising around Earth without falling back. It's like rocking an outfit that's meant to keep all eyes on you, making a major statement.
On the flip side, a suborbital launch is like a quick flex. The rocket goes up into space but doesn't have enough speed to stay in orbit, so it comes back down to Earth after a hot minute. It's like wearing an outfit that's just meant for a brief strut on the runway, showing off your style and then dipping out.
So, basically, an orbital launch keeps the rocket orbiting Earth like a total boss, while a suborbital launch sends the rocket into space for a brief moment before it comes back down. Just like the vibes on the runway, the main difference is how long they're meant to stay in the limelight.
YMMV :)
Post by: joek on 04/16/2023 03:21 pm
That's why they are using the free-return trajectory: it wil hist the landing zone without ever relighting after SECO. It does not explain why they are not at least trying for a sea-level vertical landing. You don't need high confidence for that. You just need to believe it has a chance of working. The published plan is for the belly flop to end in a small explosion. Worst case if relight failed during a flip-and-land would be a bigger explosion (more propellant) out there in the middle of the ocean.Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
Worst case is much worse than that, which is why they may have deferred on any entry-landing gymnastics. Potentially a *lot* more review and approvals.
Post by: meekGee on 04/16/2023 03:23 pm
I vote for this.The confusion is because we don't have a good word to describe trajectories that have orbital speed and energy but also have a velocity vector direction that will result in entering the atmosphere before a complete revolution.
Such trajectories are much better described as "orbital" than "suborbital", but neither is completely accurate.
Why not just say "orbital velocity on a suborbital trajectory".
The European Space Agency had a (failed) launch some years back that in fact had orbital energy, but alas not quite the right trajectory, hence a crash. In what I think was a brilliant (and accurate) attempt at face saving, they said the craft had entered an Earth Intersecting Orbit (EIO) :-) I nominate 'Earth Intersecting Orbit' as our descriptor for the upcoming flight.
Post by: Herb Schaltegger on 04/16/2023 03:35 pm
ICBMs dont fly more than half around the globe.
They do if you don't want the target to see them coming. For example a Eurasian nation that wants to hit something in North America could launch due south, over the South Pole, and the ICBM would approach the target from the south, a direction that is not being monitored for ICBMs.
Just correcting the misstatement. Back to the topic now.
Fractional Orbit Bombardment. IIRC, the Soviets were afraid the Shuttle was a first strike FOBS [size=78%]disguised as a white project, now the US is worried about China using hypersonic glide weapons doing the same thing.[/size]
Is China gliding toward a FOBS capability?
https://www.iiss.org/online-analysis/online-analysis//2021/10/is-china-gliding-toward-a-fobs-capability (https://www.iiss.org/online-analysis/online-analysis//2021/10/is-china-gliding-toward-a-fobs-capability)
Please take this geopolitical stuff to the Policy Forum, not this thread. It's messy enough with all the pissing at each other regarding the definitions of "orbital" and "suborbital."
Post by: robot_enthusiast on 04/16/2023 03:37 pm
The Written Reevaluation to the PEA that was released alongside the license makes it clear that a significant amount of thought went into minimizing the environmental impact at the splashdown zone. Ensuring a full breakup of the vehicle and minimizing propellant load at the time of impact are both important for that. As soon as they have SECO they will be venting the tanks to ensure the propellant has time to fully boil off.Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
Post by: alugobi on 04/16/2023 04:03 pm
Post by: getitdoneinspace on 04/16/2023 04:10 pm
https://www.youtube.com/watch?v=4TKJUJy7LhU
Post by: woods170 on 04/16/2023 04:29 pm
No but they will have to do a bunch of inspections to make sure nothing propellant, electrical, or hydraulic related was damaged. Kind of important, no? ::)And there it is. Wonder if it was the elevator. Launch ain't happening this week. >:(
Best to cancel the whole program, butter fingers company obviously not going to hunt.
Already done.
The incident looked a lot more spectacular than it was because: night.
The incident also sounded a lot more spectacular than it was because: night (less activity, less background noise)
OHSA is not involved because: No people were harmed.
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
Post by: Alberto-Girardi on 04/16/2023 05:00 pm
No but they will have to do a bunch of inspections to make sure nothing propellant, electrical, or hydraulic related was damaged. Kind of important, no? ::)And there it is. Wonder if it was the elevator. Launch ain't happening this week. >:(
Best to cancel the whole program, butter fingers company obviously not going to hunt.
Already done.
The incident looked a lot more spectacular than it was because: night.
The incident also sounded a lot more spectacular than it was because: night (less activity, less background noise)
OHSA is not involved because: No people were harmed.
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
Good to hear that, still it was pretty clear that everything was ok since they stacked.
Still it seems that the failure disbled in some way the elevator, since it doesn't seem to have been used.
https://twitter.com/VickiCocks15/status/1647377008077201410
Post by: ZachS09 on 04/16/2023 05:35 pm
Post by: alastairmayer on 04/16/2023 05:39 pm
(emphasis added)That's why they are using the free-return trajectory: it wil hist the landing zone without ever relighting after SECO. It does not explain why they are not at least trying for a sea-level vertical landing. You don't need high confidence for that. You just need to believe it has a chance of working.The published plan is for the belly flop to end in a small explosion. Worst case if relight failed during a flip-and-land would be a bigger explosion (more propellant) out there in the middle of the ocean.Plus, the fact that Starship is not going to try a controlled landing indicates that S24 is either not prepped to relight its engines or that SpaceX is still not confident that S24 will relight reliably. Either way, without relight, it is impossible to raise the perigee enough to maintain an orbit.
The sentence fatted by me is the actual reason why SpaceX chose the suborbital trajectory. Starship has the capability to go orbital, but for safety reasons it will not do so on its first spaceflight.
You also need to rewrite the flip-and-land software to account for all the changes since SN15, which are considerable both in hardware and mission profile. All for a one-time attempt (because future hardware and mission profiles will be different again) that S24 may not even survive to try. SpaceX (wisely, IMHO) decided it wasn't worth the trouble.
Post by: meekGee on 04/16/2023 06:04 pm
Lighten up.. he was just offering another term (Fractional Orbit) and giving a tiny but of (otherwise) interesting context.ICBMs dont fly more than half around the globe.
They do if you don't want the target to see them coming. For example a Eurasian nation that wants to hit something in North America could launch due south, over the South Pole, and the ICBM would approach the target from the south, a direction that is not being monitored for ICBMs.
Just correcting the misstatement. Back to the topic now.
Fractional Orbit Bombardment. IIRC, the Soviets were afraid the Shuttle was a first strike FOBS [size=78%]disguised as a white project, now the US is worried about China using hypersonic glide weapons doing the same thing.[/size]
Is China gliding toward a FOBS capability?
https://www.iiss.org/online-analysis/online-analysis//2021/10/is-china-gliding-toward-a-fobs-capability (https://www.iiss.org/online-analysis/online-analysis//2021/10/is-china-gliding-toward-a-fobs-capability)
Please take this geopolitical stuff to the Policy Forum, not this thread. It's messy enough with all the pissing at each other regarding the definitions of "orbital" and "suborbital."
I still vote for EIO though. Exactly descriptive.
Oh and this subtopic won't die until they start fueling the beast...
(Which is when?)
I'm Pacific Time and will have a launch viewing party over an early breakfast
Post by: oiorionsbelt on 04/16/2023 06:17 pm
Anyone know why the ships fuel/methane load starts before the LOX load?
The boosters LOX loading and methane loading start at the same time.
Post by: meekGee on 04/16/2023 06:38 pm
Looking at the SpaceX test flight timeline.Just went to the SpaceX website to look at the timing. (Fueling is about 1 hour, if you want to watch the excitement build)
Anyone know why the ships fuel/methane load starts before the LOX load?
The boosters LOX loading and methane loading start at the same time.
Why is the flight diagram so god awful?
Booster flies back, and only then performs the flip and then boost-back burn?
Then it flies back, changes its mind, flies forward again (so why not just fly forward to begin with?)
What's happening?
Post by: jimvela on 04/16/2023 06:52 pm
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
I've amplified the noise by believing an early and it turns out very unreliable source that it was elevator-related.
Apologies.
I'm still somewhat amazed that something can fall into or at least down the elevator shaft without grinding work to a halt, and am incredulous about the processing with man lifts and stair access.
There's a lot about this processing flow and the determination and pressure to proceed that makes an old dog like me see it as reckless.
I'll be watching the remaining processing and launch attempt with interest and an open mind.
I do hope that the launch attempt succeeds wildly, and if nothing else I hope that it clears the pad and at least gets down range far enough that the next attempt can be relatively quickly.
Post by: sdfasdfasd on 04/16/2023 06:57 pm
spacex.com states that the broadcast will begin at 6:15am for a 6:15 + "45 minutes before" = 7am launch, which squares with the 7am "test window" text.
spacex.com also states that there is a Propellant Load Go poll at T-2:00
So we should start looking for the results of that poll at 5am ?
spacex.com also states that the test window will be open until 7:00 + 150 minutes = 9:30am.
So the Starship splashdown will occur at 7am + 1:30 = 8:30am at the earliest and 9:30am + 1:30 = 11am at the latest ?
All times CDT.
Post by: clongton on 04/16/2023 07:12 pm
re. The timing.
spacex.com states that the broadcast will begin at 6:15am for a 6:15 + "45 minutes before" = 7am launch, which squares with the 7am "test window" text.
It's important to note that all the posted times are local to Boca Chica - Central Time.
Plan you personal schedules accordingly.
Post by: alugobi on 04/16/2023 07:18 pm
If you had an open mind about it, you wouldn't be characterizing the launch attempt as "reckless".It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
I've amplified the noise by believing an early and it turns out very unreliable source that it was elevator-related.
Apologies.
I'm still somewhat amazed that something can fall into or at least down the elevator shaft without grinding work to a halt, and am incredulous about the processing with man lifts and stair access.
There's a lot about this processing flow and the determination and pressure to proceed that makes an old dog like me see it as reckless.
I'll be watching the remaining processing and launch attempt with interest and an open mind.
I do hope that the launch attempt succeeds wildly, and if nothing else I hope that it clears the pad and at least gets down range far enough that the next attempt can be relatively quickly.
Post by: baking on 04/16/2023 07:25 pm
What time tomorrow morning will the official NSF webcast for the Starship IFT begin?Midnight central time for your roadblocks and venting viewing pleasure.
Post by: KGyST on 04/16/2023 07:32 pm
Any chance from seeing it flying above Euorpe? (Obviously not too much)
Post by: baking on 04/16/2023 07:35 pm
Is there a ground track available for the Starship? What will be its inclination?It will pass over southern Africa.
Any chance from seeing it flying above Europe? (Obviously not too much)
Post by: Perchlorate on 04/16/2023 07:37 pm
It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
I've amplified the noise by believing an early and it turns out very unreliable source that it was elevator-related. Apologies.
I'm still somewhat amazed that something can fall into or at least down the elevator shaft without grinding work to a halt, and am incredulous about the processing with man lifts and stair access.
There's a lot about this processing flow and the determination and pressure to proceed that makes an old dog like me see it as reckless.
I'll be watching the remaining processing and launch attempt with interest and an open mind.
I do hope that the launch attempt succeeds wildly, and if nothing else I hope that it clears the pad and at least gets down range far enough that the next attempt can be relatively quickly.
It's heartening to see an "old dog" from "old space" cheering on this historic attempt...even if the "interest" and "open mind" comes with skepticism about what he sees as a "reckless" flow and launch attempt.
I don't so much begrudge him the "reckless" characterization. The opposite of "reckless" are words like "careful," "deliberate" and even "reckoned." Literally, to be "reckless" is not to "reckon," or consider, carefully the consequences. It's not quite accurate to consider SpaceX' high-speed rapid-iteration process as "reckless." They just "reckon" very quickly, iterate, then charge ahead. It's different from--and not necessarily better or worse than--old space's approach.
I'm 75, and an ardent follower of all things space since my childhood. I've followed SpaceX since Falcon 1, Flight 1 and the corroded B-nut; I don't consider myself a "fanboi," but an occasionally skeptical, mostly admiring, follower.
So when I see an old dog like jimvela pull back a bit from a harsh initial position, and even apologize, then cheer the mission on, I'm inclined to offer some grace and not bust him on the use of "reckless."
Just my ramblings as we await the making of some history....
Post by: alugobi on 04/16/2023 07:56 pm
Have a nice trip!Is there a ground track available for the Starship? What will be its inclination?I will pass over southern Africa.
Any chance from seeing it flying above Europe? (Obviously not too much)
Post by: kdhilliard on 04/16/2023 07:58 pm
Is there a ground track available for the Starship? What will be its inclination?
Any chance from seeing it flying above Euorpe? (Obviously not too much)
https://twitter.com/Marco_Langbroek/status/1647593329268252675
Quote from: Dr Marco Langbroek · @Marco_Langbroek · 13:30 UTC · Apr 16, 2023
Tomorrow's #Starship trajectory.
Numbers next to positions are minutes after launch.
No visibility after launch (passes over land are either in daylight or earth shadow).
But the reentry fireball will be visible from Hawaii.
Post by: ChrisC on 04/16/2023 08:58 pm
Is there a ground track available for the Starship? What will be its inclination?
Please review the updates thread before posting questions like this.
Post by: Alberto-Girardi on 04/16/2023 09:14 pm
Is the village cleared at the same time the road is closed?
At what time will we see noticeable tank farm activity? NSF live says it will be hours before propellant loading. Do we have anything more precise or does it vary every time?
Post by: Lee Jay on 04/16/2023 09:39 pm
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
Post by: Dante2121 on 04/16/2023 09:40 pm
Post by: FutureSpaceTourist on 04/16/2023 09:40 pm
Quote
Starship Test Flight sound-activated camera setup. I’ll quote tweet this tomorrow with the results😃🚀
Post by: Jake-ZA on 04/16/2023 09:41 pm
Is there a ground track available for the Starship? What will be its inclination?I will pass over southern Africa.
Any chance from seeing it flying above Europe? (Obviously not too much)
But - sadly - in daylight. It'll be over quite far to the north of my location early afternoon local time. 15h30 GMT?
Post by: FutureSpaceTourist on 04/16/2023 09:43 pm
Quote
The world’s biggest and most powerful rocket ever built… and just me, some goofball who’s going to ride that thing some day 🤯 can’t wait to finally see this thing fly tomorrow!!! 🙌
I can’t imagine the feeling of watching this live at all, let alone and knowing that you’ll be on it one day.
Post by: FutureSpaceTourist on 04/16/2023 10:03 pm
Quote
I've interviewed about 100 SpaceXers on their final hours before the first Falcon 1, Falcon 9, and Falcon Heavy launches. It was pure madness and adrenaline in all three cases. The engineers and technicians who've gone nonstop on Starship have my respect and best wishes tonight.
Post by: testguy on 04/16/2023 10:04 pm
I’m right with you brother with the same history and just a little older.It wasn't the elevator that dropped.
Neither was it a counter weight.
My source says that you can take that to the bank.
And I say that the concern trolls can go home and cry about it. End of story.
I've amplified the noise by believing an early and it turns out very unreliable source that it was elevator-related. Apologies.
I'm still somewhat amazed that something can fall into or at least down the elevator shaft without grinding work to a halt, and am incredulous about the processing with man lifts and stair access.
There's a lot about this processing flow and the determination and pressure to proceed that makes an old dog like me see it as reckless.
I'll be watching the remaining processing and launch attempt with interest and an open mind.
I do hope that the launch attempt succeeds wildly, and if nothing else I hope that it clears the pad and at least gets down range far enough that the next attempt can be relatively quickly.
It's heartening to see an "old dog" from "old space" cheering on this historic attempt...even if the "interest" and "open mind" comes with skepticism about what he sees as a "reckless" flow and launch attempt.
I don't so much begrudge him the "reckless" characterization. The opposite of "reckless" are words like "careful," "deliberate" and even "reckoned." Literally, to be "reckless" is not to "reckon," or consider, carefully the consequences. It's not quite accurate to consider SpaceX' high-speed rapid-iteration process as "reckless." They just "reckon" very quickly, iterate, then charge ahead. It's different from--and not necessarily better or worse than--old space's approach.
I'm 75, and an ardent follower of all things space since my childhood. I've followed SpaceX since Falcon 1, Flight 1 and the corroded B-nut; I don't consider myself a "fanboi," but an occasionally skeptical, mostly admiring, follower.
So when I see an old dog like jimvela pull back a bit from a harsh initial position, and even apologize, then cheer the mission on, I'm inclined to offer some grace and not bust him on the use of "reckless."
Just my ramblings as we await the making of some history....
Post by: CMac on 04/16/2023 10:12 pm
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
Maybe he is flying on a reconnaissance flight?
Post by: KilroySmith on 04/16/2023 10:14 pm
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
If it’s cooler than the first Super Heavy launch, it better involve space aliens
Post by: DigitalMan on 04/16/2023 10:16 pm
What are the chances any of this will be visible on the gulf side of Florida as the rocket gets higher up?
Family in Tampa regularly watch launches from the cape. I think the deciding factor will be clear skies, or not.
Post by: Lee Jay on 04/16/2023 10:22 pm
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
If it’s cooler than the first Super Heavy launch, it better involve space aliens
Or warp drive.
Post by: GmP on 04/16/2023 10:25 pm
I'm an avid NSF content consumer. But I don't think any other content provider will deliver what Ellie delivered in this video; an interview with the Brownsville mayor involved in the entire journey of SpaceX in Boca Chica. And the mayor has a heartfelt recognition of what Starship means to her community and to the world (and to her son :-) Very much worth a view.
https://www.youtube.com/watch?v=4TKJUJy7LhU
Just watched it. Very impressed with the whole interview.
Post by: alastairmayer on 04/16/2023 10:32 pm
Looking at the SpaceX test flight timeline.Just went to the SpaceX website to look at the timing. (Fueling is about 1 hour, if you want to watch the excitement build)
Anyone know why the ships fuel/methane load starts before the LOX load?
The boosters LOX loading and methane loading start at the same time.
Why is the flight diagram so god awful?
Booster flies back, and only then performs the flip and then boost-back burn?
Then it flies back, changes its mind, flies forward again (so why not just fly forward to begin with?)
What's happening?
It's Booster's first flight. Expect it to be a little hesitant and confused. ;)
Post by: david1971 on 04/16/2023 10:54 pm
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
Clearly the Blue Origin factory tour.
Post by: wannamoonbase on 04/16/2023 10:59 pm
However, I have a growing feeling that it’s actually going to fly tomorrow.
I think stage 1 will do its job, after that, no idea, could be anything.
I am shocked there hasn’t been more coverage about this but maybe that is by design with a late Friday approval and announcement. Keep it quiet in case of RUD.
Post by: Steve G on 04/16/2023 11:01 pm
Post by: alphacentauri on 04/16/2023 11:09 pm
I am shocked there hasn’t been more coverage about this but maybe that is by design with a late Friday approval and announcement. Keep it quiet in case of RUD.I've seen brief articles about it on some of the mainstream news media websites. Despite all the hoopla among us spaceflight enthusiasts who think this is the most important event of the past few years, most people won't care about it unless it makes a huge fireball.
Post by: Surfdaddy on 04/16/2023 11:19 pm
Is there an ability to recycle during the window, or is it a one attempt and done situation? They certainly don't need the extra performance on this flight.
Post by: clongton on 04/16/2023 11:21 pm
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
Perhaps the 38th Colorado Space Symposium? It runs April 17-20th.
He may have already purchased admission to the event.
https://www.spacesymposium.org/
Post by: alugobi on 04/16/2023 11:30 pm
I know it’s the first launch attempt and many things could happen to prevent liftoff.Look for a local yokel in a boat that scrubs the launch.
Post by: meekGee on 04/17/2023 12:09 am
The only way to guarantee that it goes on the first try is if I somehow oversleep.I know it’s the first launch attempt and many things could happen to prevent liftoff.Look for a local yokel in a boat that scrubs the launch.
Post by: meekGee on 04/17/2023 12:22 am
Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Nope. You are totally wrong.
To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Wrong. As I wrote, this applies to everything behaving like a rocket. In fact, it'd be more doable with a space gun (realistically it must be either some type of EM gun or nuclear) than with a rocket: guns always have perigee below ground level, you must raise it later. And no rocket burns for tens of minutes. The longest ascent burns approaches 20m and it takes less than 1/10 of the full circle to ascent. Way too little to cut the exoatmospheric part of the flight below half circle which would be required to play games with lowering perigee without raising apogee.
And yes, you can insert into an apogee of an orbit, that's not a problem at all (and rockets without upper stage restart capability did this in the past). The thing is, you can't then have the perigee not only under ground but even in the significant atmosphere (i.e. below 90km) and do a 270° around the Earth. If you wanted to go for less than half circle, then you're free to do so. But with 270° flight you're limited by the reality that perigee is necessarily 180° from the apogee. If you insert to an overhead apogee, your perigee will be at the antipode of your launch site, 180° away. Obviously, you're not doing 270° if your perigee is only 180° away and underground. It must be above the ground, and significantly at that.
The way to have the lowest perigee (if this is your particular goal; it's not even Starship goal to begin with) while keeping apogee below the set level (235km here) is to have it roughly half-way between your splashdown/landing site and your launch site (give or take 5°). Apogee then must be about half way of your flight.
Too many mental gymnastics going on in this thread. It is a suborbital ballistic trajectory, period.
Saying "period" doesn't make you more authoritative or your reasoning less flimsy.
This orbit is the same as if a spacecraft was in orbit and then lowered its perigee slightly to intersect the atmosphere, since it's going more than halfway around, and it's only burning once during launch.
Post by: ChrisC on 04/17/2023 12:29 am
Post by: Lee Jay on 04/17/2023 12:32 am
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
Perhaps the 38th Colorado Space Symposium? It runs April 17-20th.
He may have already purchased admission to the event.
https://www.spacesymposium.org/
I think, "I can't tell you what it is" should eliminate that possibility.
Post by: wannamoonbase on 04/17/2023 12:55 am
The Scott Manley video on this has a really interesting tidbit.
"...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."
WTH?
Clearly the Blue Origin factory tour.
“See this vast completely empty building? One day we will have machines that can make rocket parts, not the rocket itself mind you, let’s not go too fast.”
Blue Origin needs to show some results.
But back to the pre launch insanity for 11 hours from now.
Post by: alugobi on 04/17/2023 12:57 am
Post by: BillB on 04/17/2023 01:02 am
I know it’s the first launch attempt and many things could happen to prevent liftoff.Look for a local yokel in a boat that scrubs the launch.
There has been some speculation that some environmental group would like to stop SpaceX from using Boca Chica. I would not be surprised that since there was not time to file a lawsuit to stop this launch that such a group would put a boat out in the prohibited area.
Post by: kdhilliard on 04/17/2023 01:03 am
Oh god NOOOO it's baaaaack, and with untrimmed quotes :)Hahahaha!
Not to flog that semantic dead horse, but as far as I've seen, no one here has offered a calculation showing a possible post-SECO trajectory which intersects Earth's surface when calculated without taking atmosphere drag into account (given the expected SECO altitude, approximate apogee, and reentry location).
In lieu of that, I'm trusting Jonathan McDowell:
https://twitter.com/planet4589/status/1647321808658395136
https://twitter.com/planet4589/status/1647324115819278337
Quote from: Rand Simberg · @Simberg_Space & Jonathan McDowell · @planet4589 · 19:29 UTC · Apr 15, 2023
Rand Simberg: Has SpaceX provided a planned trajectory?
Jonathan McDowell: No, but there are enough clues in the NOTAMs, the timelines, and some FAA statements to infer one.
Simberg: To what degree of precision? (And accuracy)?
McDowell: perigee is between 40 and 60 km with fairly high confidence.
apogee is between 200 and 245 km. inclination is 26.3 +- 0.1 deg.
OK, edited to prod the dead horse *only slightly* by reporting without comment McDowell's choice of terminology:
https://twitter.com/planet4589/status/1647649762722603008
Quote from: Jonathan McDowell · @planet4589 · 1:14 PM · Apr 16, 2023
No, I would say it will be "marginally orbital". For true orbital, I require perigee > 80 km.
Post by: DecoLV on 04/17/2023 02:37 am
I'm an avid NSF content consumer. But I don't think any other content provider will deliver what Ellie delivered in this video; an interview with the Brownsville mayor involved in the entire journey of SpaceX in Boca Chica. And the mayor has a heartfelt recognition of what Starship means to her community and to the world (and to her son :-) Very much worth a view.
https://www.youtube.com/watch?v=4TKJUJy7LhU
Well, I don't think she is the mayor just yet. Ellie described her as a mayoral candidate. The point is she has been there from the beginning, and the Brownsville folks are happy to see this day finally arrive. Good video of that perspective.
Post by: oiorionsbelt on 04/17/2023 02:50 am
https://twitter.com/TrevorMahlmann/status/1647785292730884096
Post by: Slothman on 04/17/2023 02:59 am
I thought that gimbaling shot in the tweet from 44 minutes ago was current for a second but no. Pretty sure that's on a sub orbital mount.
https://twitter.com/TrevorMahlmann/status/1647785292730884096
It is clearly the OLM. Note the pillar in the back and the piping up top
Post by: FutureSpaceTourist on 04/17/2023 03:22 am
Quote
Made my @NBCNightlyNews debut live from the Starship pad, to talk about one of the most significant rocket launches of the 21st century so far: https://www.nbcnews.com/nightly-news/video/spacex-s-starship-to-make-its-first-orbital-test-flight-170442821902
https://youtu.be/ewm5xkPv57U
Post by: FutureSpaceTourist on 04/17/2023 03:23 am
Quote
It today the final day of the Before Starship Era? Because when this begins to work, it changes humanity’s relationship to the sky forever. Mass, volume, and cost have been ruthless adversaries to spaceflight. What happens when we start to beat them back? 🚀
https://twitter.com/rookisaacman/status/1647802583317381123
Quote
We go to Mars
Post by: FutureSpaceTourist on 04/17/2023 03:25 am
https://twitter.com/roughridersshow/status/1647777617745985540
Post by: FutureSpaceTourist on 04/17/2023 03:29 am
Quote
Flights into Brownsville recently as Starship is posed to launch tomorrow. Elon Musk, Antonio Gracias (Fmr. Director of Tesla), and Yusaku Mazawa. Flying in from Tokyo, ~11 hour trip.
Post by: FutureSpaceTourist on 04/17/2023 03:35 am
https://twitter.com/nasaspaceflight/status/1647805527378784256
Quote
When the laser display folks like that we're enjoying their show, pop into chat, say "watch this,"- and put NSF on the Megabay for a few seconds..... 😎
nsf.live/starbase
Post by: FutureSpaceTourist on 04/17/2023 05:04 am
Quote
Good luck @SpaceX and @elonmusk 🍀🚀
Post by: sdfasdfasd on 04/17/2023 07:08 am
Launch is now 8am at the earliest.
I guess Prop Load Go Poll is now 6am
Spacex video will begin at 7:15am
Starship splashdown is now 9:30am earliest
But is the launch window still 150 minutes or has it reduced to 90 minutes?
P.S. Can the orbit posts not simply be deleted by the mods when they appear?
Post by: sanman on 04/17/2023 07:24 am
https://www.youtube.com/watch?v=Xs91n0DNZTQ
Post by: FutureSpaceTourist on 04/17/2023 07:38 am
Quote
Here's a nice bit of info for you to mark the OFT of Starship today...Cryo Delivery numbers!
Total number of cryo deliveries since B7 Cryo (3rd Apr)
98 x LN2
32 x LOX
12 x CH4
Post by: FutureSpaceTourist on 04/17/2023 08:17 am
Quote
Huge line of vehicles at Isla Blanca Beach Park gate at 3am. Gate opens at 4am, Starship launch at 8am 🚀
Post by: sanman on 04/17/2023 08:37 am
Post by: sdfasdfasd on 04/17/2023 09:18 am
He mentioned the hundreds of changes from Booster 7 to Booster 9 including electric thrust vectoring, new heat shield, etc.
It occurred to me that that magnitude of change, to a rocket system that has already been designed and built, would take an Old Space company literally YEARS to plan, build, component test, integrate, integration test, etc etc. Really highlights the Move Fast And Break Things advantage.
Post by: allio on 04/17/2023 09:44 am
there has been no mention of an entry burn.... Is there not a risk of damage to the engines coming in hot without reducing speed. Falcon regulary knocks off 2000-3000 kph at entry burn.
any thoughts?
Post by: CMac on 04/17/2023 09:59 am
Post by: allio on 04/17/2023 10:07 am
I understand that staging happens earlier, at lower speed. Also the steel can handle heat better
It wasn't the steel i was worried about, rather the engines which take the brunt of it with the booster coming at the atmosphere ass first... If seperation is at a slower speed then apogee must be lower after boostback, thence reentry interface speed must be lower.
Any Numbers?
Post by: Alvian@IDN on 04/17/2023 10:09 am
Regarding the booster return...Electron recovery shows it's possible to survive what's Peter called "The Wall"
there has been no mention of an entry burn.... Is there not a risk of damage to the engines coming in hot without reducing speed. Falcon regulary knocks off 2000-3000 kph at entry burn.
any thoughts?
Post by: CMac on 04/17/2023 10:25 am
Post by: FutureSpaceTourist on 04/17/2023 10:36 am
Quote
Final look at what raptors we know on S24 and B7 ahead of their Orbital Launch Attempt!
(Now with new list-like descriptions)
Post by: FutureSpaceTourist on 04/17/2023 11:20 am
Quote
It’s a beautiful morning here on South Padre Island awaiting the launch of SpaceX’s Starship. A touch of the Milky Way over the rocket by @washpostnewton
Post by: FutureSpaceTourist on 04/17/2023 11:34 am
Quote
SpaceX cameras ready for launch
Post by: FutureSpaceTourist on 04/17/2023 11:40 am
Quote
The dawn of a new era
Post by: litton4 on 04/17/2023 12:06 pm
Nearly 150,000 viewers last time I checked
Post by: Orbiter on 04/17/2023 12:07 pm
NSF Youtube stream keeps pausing for me.....just a heads-up
I'm also having a similar problem, page keeps crashing for me. Just FYI for any of the NSF team who might be looking at the forums today.
Post by: clongton on 04/17/2023 12:13 pm
I hope that they do a Mission Control audio for this one.
https://www.youtube.com/watch?v=Ln8hXptcA90&ab_channel=SpaceX
Post by: Herb Schaltegger on 04/17/2023 12:15 pm
Must be your network/ISP or some associated issue. I’ve had the stream up for 25 minutes without issue.NSF Youtube stream keeps pausing for me.....just a heads-up
I'm also having a similar problem, page keeps crashing for me. Just FYI for any of the NSF team who might be looking at the forums today.
Post by: Slothman on 04/17/2023 12:19 pm
Must be your network/ISP or some associated issue. I’ve had the stream up for 25 minutes without issue.NSF Youtube stream keeps pausing for me.....just a heads-up
I'm also having a similar problem, page keeps crashing for me. Just FYI for any of the NSF team who might be looking at the forums today.
I have the same, "Out of Memory" crash of the tab, happens maybe every hour or so
Post by: gsa on 04/17/2023 12:25 pm
I have the same, "Out of Memory" crash of the tab, happens maybe every hour or soTry to turn off the chat. Worked for me.
Post by: Herb Schaltegger on 04/17/2023 12:27 pm
Must be your network/ISP or some associated issue. I’ve had the stream up for 25 minutes without issue.NSF Youtube stream keeps pausing for me.....just a heads-up
I'm also having a similar problem, page keeps crashing for me. Just FYI for any of the NSF team who might be looking at the forums today.
I have the same, "Out of Memory" crash of the tab, happens maybe every hour or so
That’s a browser error. Turn off the chat, try a different browser, whatever.
Post by: Framryk on 04/17/2023 12:33 pm
I'm on a 12 hour work shift bringing 1.2 gigawatts of nuclear power back on the grid, no access to live YouTube, Twitter, etc, but can get the forum updates and it's helping me through the day watching this exciting event unfold :)
Really big thank you!
Post by: bulkmail on 04/17/2023 12:48 pm
The official mission patch looks very... Electron. But that's not a bad thing.
What are the 10 "star/lines" symbolizing?
Patch is at: https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=47352.0;attach=2175152;sess=1219
Post by: Herb Schaltegger on 04/17/2023 12:51 pm
Second stage engine view.
Ship 24’s engine bay looks a lot neater/cleaner than the prior suborbital test flight Ships. Nice to see a good view of the more or less “finished” installation complete with shields and everything buttoned up out of harm’s way.
Post by: sanman on 04/17/2023 01:12 pm
Post by: WisRich on 04/17/2023 01:12 pm
Post by: PM3 on 04/17/2023 01:20 pm
Post by: Herb Schaltegger on 04/17/2023 01:22 pm
"Recycle in minium 48 hours" enables a launch on 4/20. :D
A 48 hour recycle is 4/19. A 72 hour recycle would be 4/20. As a non-stoner, I am annoyed by the juvenile fascination with the weed jokes.
Post by: frogamazog on 04/17/2023 01:27 pm
Post by: Orbiter on 04/17/2023 01:28 pm
Post by: rdale on 04/17/2023 01:29 pm
A minimum 48 hour recycle to 7 am CST is 4/20.
So the 48-hr requirement is a scrub to the start of the original window or 48 hours from when it was scrubbed?
Also please avoid confusion - Houston Texas is on Daylight Saving Time so use CDT (or just CT year round :) ) to reduce that.
Post by: kanno41 on 04/17/2023 01:29 pm
Post by: Herb Schaltegger on 04/17/2023 01:30 pm
"Recycle in minium 48 hours" enables a launch on 4/20. :D
A 48 hour recycle is 4/19. A 72 hour recycle would be 4/20. As a non-stoner, I am annoyed by the juvenile fascination with the weed jokes.
A minimum 48 hour recycle to 7 am CST is 4/20.
What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
Post by: ChrisC on 04/17/2023 01:39 pm
Mission control audio feed https://youtube.com/watch?v=Ln8hXptcA90
Did anyone actually hear anything on that loop? I scrubbed to a few random points during the countdown and never heard anything. I was going to listen all the way through later today, but they've now taken that video private.
(LOL you amateurs with "CST". See my sig. And good to see rdale here :) )
Post by: TomH on 04/17/2023 01:44 pm
This is where doing that other WDR the week before likely would have discovered the issue. But hey, this is why we test things -- to learn. SpaceX isn't viewing this is a failure.
And if they had done that WDR with no issues, it would have been a lost opportunity to launch. They would not have been able to launch due to not having the license. Doing the WDR does cost money. Using today as an opportunity to launch, but to turn it into WDR if unable to launch was far more prudent and cost effective from a probabilities POV. Besides, this vehicle has been through WDR before and this issue did not happen. Had a WDR have been done a week ago, there is no guarantee the valve would have frozen. Playing armchair quarterback from the outside is not helpful.
Post by: jpo234 on 04/17/2023 01:44 pm
During the Stream they said "Wednesday".A minimum 48 hour recycle to 7 am CST is 4/20.What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
Post by: litton4 on 04/17/2023 01:47 pm
Mission control audio feed https://youtube.com/watch?v=Ln8hXptcA90
Did anyone actually hear anything on that loop? I scrubbed to a few random points during the countdown and never heard anything. I was going to listen all the way through later today, but they've now taken that video private.
(LOL you amateurs with "CST". See my sig. And good to see rdale here :) )
Silence here, too......would have been nice to hear about the scrub reasons
Post by: Indygreg on 04/17/2023 01:47 pm
Post by: rdale on 04/17/2023 01:48 pm
A minimum 48 hour recycle to 7 am CST is 4/20.
What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
I may be too juvenile to understand - is the new attempt 4/19 or 4/20?
Post by: edzieba on 04/17/2023 01:50 pm
Starship uses supercooled propellants, correct?SpaceX stream commentary now clarify: 48h minimum recycle time.
Is there an ability to recycle during the window, or is it a one attempt and done situation? They certainly don't need the extra performance on this flight.
That's likely not a hard limit for any Starship stack recycle, but probably for the specific bodged-together setup at BC, where if they run out of N2 for the chillers it needs to be trucked in from the air liquefaction plant at the build site (along with any makeup for boiloff losses).
Post by: jpo234 on 04/17/2023 01:51 pm
NET 4/19. But that's only 46 hours and not 48, which is where the joke comes from.A minimum 48 hour recycle to 7 am CST is 4/20.
What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
I may be too juvenile to understand - is the new attempt 4/19 or 4/20?
Post by: abaddon on 04/17/2023 01:51 pm
Coming from a guy named "Herb" the irony is thick. (Not a stoner either... but c'mon, it was sitting right there)Because someone missed the same point as Herb. :)During the Stream they said "Wednesday".A minimum 48 hour recycle to 7 am CST is 4/20.What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
More on topic, I'd have given 90% chances of a scrub today for a variety of reasons. Hopefully the pressurization issue is easy to fix and they can make a proper go and at least light off some engines on the next shot!
[EDIT] Fixed to quote the right post!
Post by: Indygreg on 04/17/2023 01:54 pm
I am really curious how big the crowds are in south padre? I would think the little rv park there would be booked for years.Coming from a guy named "Herb" the irony is thick. (Not a stoner either... but c'mon, it was sitting right there)
More on topic, I'd have given 90% chances of a scrub today for a variety of reasons. Hopefully the pressurization issue is easy to fix and they can make a proper go and at least light off some engines on the next shot!
I don’t know who herb is. I was just curious how big the crowds are down there.
Post by: sanman on 04/17/2023 01:56 pm
"Recycle in minium 48 hours" enables a launch on 4/20. :D
A 48 hour recycle is 4/19. A 72 hour recycle would be 4/20. As a non-stoner, I am annoyed by the juvenile fascination with the weed jokes.
A minimum 48 hour recycle to 7 am CST is 4/20.
What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
Anything sacred about 7 am, as opposed to 9 am ?
Post by: Slothman on 04/17/2023 01:58 pm
Mission control audio feed https://youtube.com/watch?v=Ln8hXptcA90
Did anyone actually hear anything on that loop? I scrubbed to a few random points during the countdown and never heard anything. I was going to listen all the way through later today, but they've now taken that video private.
(LOL you amateurs with "CST". See my sig. And good to see rdale here :) )
Silence here, too......would have been nice to hear about the scrub reasons
I think at some point I heard "Ship lox load concluded" or something similar. But nothing else. Unfortunately the video is gone now.
Post by: Herb Schaltegger on 04/17/2023 01:58 pm
Coming from a guy named "Herb" the irony is thick. (Not a stoner either... but c'mon, it was sitting right there)Because someone missed the same point as Herb. :)During the Stream they said "Wednesday".A minimum 48 hour recycle to 7 am CST is 4/20.What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
More on topic, I'd have given 90% chances of a scrub today for a variety of reasons. Hopefully the pressurization issue is easy to fix and they can make a proper go and at least light off some engines on the next shot!
[EDIT] Fixed to quote the right post!
Seriously? Like I never heard THAT joke before in the last 5+ decades but admittedly middle school was a long way away.
That said, when a launch is recycled for 24/48/72 hours or whatever, it’s NOT that the count restarts 48 hours after the scrub or T-0 time, it’s that the new target T-0 time after the scrub is however many hours later.
Not sure why there is so much stubborn confusion about this from PM3 and anyone else.
Post by: clongton on 04/17/2023 02:02 pm
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19.
Why? Do you understand why scheduled launches slip the next launch time from previous scrubs? It's because they need to meet up with other objects or slots - in orbit - that have phased since the scrub. This is a test flight - emphasis on flight. It doesn't have to meet anything in orbit. It can be launched any time day or night that suits them.
Post by: matthewota on 04/17/2023 02:05 pm
Post by: Danrar on 04/17/2023 02:10 pm
It's unlikely the "minimum 48 hours" is actually 48 hours but instead a statement that it should take ~<2 days to get enough new propellent delivered to fill the tank farm. I take that as meaning a 4/19 run is possible.NET 4/19. But that's only 46 hours and not 48, which is where the joke comes from.A minimum 48 hour recycle to 7 am CST is 4/20.
What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
I may be too juvenile to understand - is the new attempt 4/19 or 4/20?
Grabbed the Pez animation:
https://youtu.be/zQr2ihbKs1o
Post by: geza on 04/17/2023 02:14 pm
Launch control box in foreground.
What is this?
Post by: dnavas on 04/17/2023 02:17 pm
This is a test flight - emphasis on flight. It doesn't have to meet anything in orbit. It can be launched any time day or night that suits them.
One thought is that it might be better for re-entry to be in the dark for thermal monitoring. I think that's still plenty of schedule room, but there's debugging to be done, probably more than just a stuck valve (likely plenty of minor things to review as well). We'll know a date when it's released -- I'm not sure I'd trust anything specific prior to successful detank and a few hours of workers in the area.
Post by: Stan-1967 on 04/17/2023 02:19 pm
Launch control box in foreground.
What is this?
It belongs in the party thread or a Wiley Coyote cartoon.
Post by: whitelancer64 on 04/17/2023 02:31 pm
Launch control box in foreground.
What is this?
A joke.
Post by: chopsticks on 04/17/2023 02:34 pm
Sorry if reality triggered you. No way anybody is just going to crack a beer and give a thumbs up for Monday after something like that.Please stop with your conspiracy theories.Doesn’t sound or look great:Wonderful. Now OSHA will shut it down for three weeks for an "investigation".
Just coming back here to remind you of "reality".
Post by: Jimmy_C on 04/17/2023 02:44 pm
Post by: envy887 on 04/17/2023 02:46 pm
What could be used to mitigate the stuck valve? Replace and retest in this case? Cycling the valve? Insulation or a heater on the valve for future Starships?
Do we even know whether it's a vehicle or GSE valve?
Post by: Nomadd on 04/17/2023 02:52 pm
Post by: EspenU on 04/17/2023 03:06 pm
As in how long can the ship remain stacked before they have to bring it down again to swap them?
Post by: MP99 on 04/17/2023 03:06 pm
It's not "marginally orbital", it's "the most massive test hop, ever".Oh god NOOOO it's baaaaack, and with untrimmed quotes :)Hahahaha!
Not to flog that semantic dead horse, but as far as I've seen, no one here has offered a calculation showing a possible post-SECO trajectory which intersects Earth's surface when calculated without taking atmosphere drag into account (given the expected SECO altitude, approximate apogee, and reentry location).
In lieu of that, I'm trusting Jonathan McDowell:
https://twitter.com/planet4589/status/1647321808658395136
https://twitter.com/planet4589/status/1647324115819278337Quote from: Rand Simberg · @Simberg_Space & Jonathan McDowell · @planet4589 · 19:29 UTC · Apr 15, 2023Rand Simberg: Has SpaceX provided a planned trajectory?
Jonathan McDowell: No, but there are enough clues in the NOTAMs, the timelines, and some FAA statements to infer one.
Simberg: To what degree of precision? (And accuracy)?
McDowell: perigee is between 40 and 60 km with fairly high confidence.
apogee is between 200 and 245 km. inclination is 26.3 +- 0.1 deg.
OK, edited to prod the dead horse *only slightly* by reporting without comment McDowell's choice of terminology:
https://twitter.com/planet4589/status/1647649762722603008Quote from: Jonathan McDowell · @planet4589 · 1:14 PM · Apr 16, 2023No, I would say it will be "marginally orbital". For true orbital, I require perigee > 80 km.
Cheers, Martin
Post by: MP99 on 04/17/2023 03:13 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.They loaded prop at the coldest time of the day.
My speculation: maybe the extra heat would have stopped it from freezing up.
Have they ever done a WDR/similar before dawn?
Cheers, Martin
Post by: oldAtlas_Eguy on 04/17/2023 03:24 pm
Post by: chopsticks on 04/17/2023 03:28 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.They loaded prop at the coldest time of the day.
My speculation: maybe the extra heat would have stopped it from freezing up.
Have they ever done a WDR/similar before dawn?
Cheers, Martin
The temperature differential between the hottest time of day vs the coldest would hardly have an impact on this IMO due to the far greater temperature differential between ambient and cryogenic.
For LOX, it's what, -200C or so? So if it was 15C this morning (probably wasn't that cold) and it gets up to 30C during the day, that's only 15 degrees of difference. To me, whether the LOX is -215 or -230 from ambient seems like it wouldn't make a difference on whether a valve freezes or not, but maybe they are that picky.. IDK
Post by: sanman on 04/17/2023 03:30 pm
Post by: Garrett on 04/17/2023 03:37 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.They loaded prop at the coldest time of the day.
My speculation: maybe the extra heat would have stopped it from freezing up.
Have they ever done a WDR/similar before dawn?
Cheers, Martin
I think there have been multiple Starship tests on cold days/close to dawn. SN11 for example.
I don't think we know where the valve is nor what type of valve it is. Wherever it is, I suspect it will always be relatively cold because of the cold air around the rocket, regardless of the time of day.
Presumably it was a GSE valve, as the rocket would have at least single, if not double redundancy, which could have been an option (albeit risky one) to take advantage of and continue with the launch.
Post by: sanman on 04/17/2023 03:42 pm
I think there have been multiple Starship tests on cold days/close to dawn. SN11 for example.
I don't think we know where the valve is nor what type of valve it is. Wherever it is, I suspect it will always be relatively cold because of the cold air around the rocket, regardless of the time of day.
Presumably it was a GSE valve, as the rocket would have at least single, if not double redundancy, which could have been an option (albeit risky one) to take advantage of and continue with the launch.
Maybe they need to cycle these cryo valves on & off even during the filling process, just to keep them moving and "limber" -- just have them on a rotational schedule. Or do they already do that?
Post by: MP99 on 04/17/2023 03:43 pm
Starting at 20:40
https://www.youtube.com/live/L5QXreqOrTA?feature=share
It felt to me that they went into some depth on Polaris, Dear Moon, and Dennis Tito. Then they followed it with a brief mention of Artemis III and the preceeding test mission, and didn't even mention Artemis IV.
Am I just being over-sensitive, or should there have been more acknowledgement of NASA's faith in them, and their collaboration on the HLS programme?
Cheers, Martin
Post by: whitelancer64 on 04/17/2023 03:50 pm
What were people's thoughts on the section of today's SpaceX broadcast that talked about the Starship missions they're working on:
Starting at 20:40
https://www.youtube.com/live/L5QXreqOrTA?feature=share
It felt to me that they went into some depth on Polaris, Dear Moon, and Dennis Tito. Then they followed it with a brief mention of Artemis III and the preceeding test mission, and didn't even mention Artemis IV.
Am I just being over-sensitive, or should there have been more acknowledgement of NASA's faith in them, and their collaboration on the HLS programme?
Cheers, Martin
Artemis IV is ~2028. That's a long ways out, and they were talking about the near-term flights with humans on board. I got the impression they were emphasizing that these flights will ensure success on Artemis III.
Post by: wannamoonbase on 04/17/2023 03:50 pm
What were people's thoughts on the section of today's SpaceX broadcast that talked about the Starship missions they're working on:
Starting at 20:40
https://www.youtube.com/live/L5QXreqOrTA?feature=share
It felt to me that they went into some depth on Polaris, Dear Moon, and Dennis Tito. Then they followed it with a brief mention of Artemis III and the preceeding test mission, and didn't even mention Artemis IV.
Am I just being over-sensitive, or should there have been more acknowledgement of NASA's faith in them, and their collaboration on the HLS programme?
Cheers, Martin
Maybe you don’t want to tell the world this is going to land people on the moon if there are concerns that it could air burst on a global video feed
Post by: Slothman on 04/17/2023 03:53 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.They loaded prop at the coldest time of the day.
My speculation: maybe the extra heat would have stopped it from freezing up.
Have they ever done a WDR/similar before dawn?
Cheers, Martin
I think there have been multiple Starship tests on cold days/close to dawn. SN11 for example.
I don't think we know where the valve is nor what type of valve it is. Wherever it is, I suspect it will always be relatively cold because of the cold air around the rocket, regardless of the time of day.
Presumably it was a GSE valve, as the rocket would have at least single, if not double redundancy, which could have been an option (albeit risky one) to take advantage of and continue with the launch.
If it was a pressurization issue, does it make sense that it would be a GSE valve? I would think that in this case there would be a valve on the vehicle at the end of the propellant line. They wouldn't want to pressurize the tanks with the vehicle valve open.
I'm assuming here that the issue was a frozen-open valve. If it was frozen closed, the redundant valves on the vehicle would be able to take over. On the other hand, maybe even with redundancy, they wouldn't want to fly it. However, they absolutely couldn't fly it if it was frozen-open.
Post by: cplchanb on 04/17/2023 04:07 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.
quite the irony that this scrub was due to faulty valves as well ;D People were chirping SLS for it left right and center lol
Post by: meekGee on 04/17/2023 04:10 pm
And I didn't see it!Coming from a guy named "Herb" the irony is thick. (Not a stoner either... but c'mon, it was sitting right there)Because someone missed the same point as Herb. :)During the Stream they said "Wednesday".A minimum 48 hour recycle to 7 am CST is 4/20.What? Today is 4/17. Forty eight hours is two days. That’s 4/19.
T-0 today was 8:20. Next T-0 will likely be 7:00. That would be a 46 hours and 40 minutes recycle on 4/19. Not juvenile enough to understand this?
More on topic, I'd have given 90% chances of a scrub today for a variety of reasons. Hopefully the pressurization issue is easy to fix and they can make a proper go and at least light off some engines on the next shot!
[EDIT] Fixed to quote the right post!
Even if they launch on 4/19, if they cross the international date line, will they land on 4/20?
Post by: jedijeff123 on 04/17/2023 04:15 pm
Post by: meekGee on 04/17/2023 04:17 pm
No, because they will be crossing back into Hawaii, which is the same day as the rest of the US. If they were splashing it down in the lagoon on Kwaj, it would have worked out though!Foiled by geoTemporalPolitics!
Post by: alugobi on 04/17/2023 04:22 pm
If it was a pressurization issue, does it make sense that it would be a GSE valve?Could be. They have to close and isolate all the fill lines back to the tank farm in order to prevent a burn back from a 'splody rocket.
Post by: woods170 on 04/17/2023 05:02 pm
Does SpaceX make their own valves in-house, or do they procure them from somebody else?
Vehicle side valves are all built in-house. Non-industry standard GSE-side valves are also built in-house or by their favourite contractor to specs provided by SpaceX. But stuff like ground valves at the tank farm are all industry-standard stuff and procured commercially.
Post by: woods170 on 04/17/2023 05:05 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.
quite the irony that this scrub was due to faulty valves as well ;D People were chirping SLS for it left right and center lol
Wasn't a faulty valve. It was a perfectly normally working valve that got frozen. One of the SLS scrubs however involved a valve on the ICPS that was actually kaput (as in broken, defective, etc), and had to be replaced by a non-kaput one.
Post by: chopsticks on 04/17/2023 05:20 pm
Yusaku Maezawa (of DearMoon) gave more information about the valve issue:Quote燃料タンクにヘリウムガスを装填するバルブが冷却によって凍ってしまい、ガスの装填が上手くいかなかったとのこと。Quote from: TranslatedThe valve that charges the helium gas to the fuel tank was frozen due to cooling, and gas charging did not go well.
https://twitter.com/yousuck2020/status/1647983047676153858
Does this mean that the methane tank is pressed with helium instead using autogenous pressurization?
Or maybe there are helium COPVs inside the methane tank that are used for Raptor spinup?
Post by: Fireworking on 04/17/2023 05:21 pm
It does seem strange that it froze this time, even though they have done fillups on the booster multiple times. It's possible they treated this more like a WDR from the start, and if everything went well they would launch. I'm just speculating here.
It's definitely encouraging that nothing went wrong aside from the valve, and that we were able to make it all the way to T-40s.
Post by: sanman on 04/17/2023 05:26 pm
Post by: Slothman on 04/17/2023 06:00 pm
But is the helium being used cryogenic? Why would the valve be vulnerable to cooling? Or is it somehow in contact with the other cryo-propellants?
I suppose the valve connects to the propellant tank(s), which were more or less full at the time and frosty to the top (minus some of the domes) and full of cryo liquids.
Post by: Prettz on 04/17/2023 06:21 pm
Post by: Comga on 04/17/2023 06:31 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.They loaded prop at the coldest time of the day.
My speculation: maybe the extra heat would have stopped it from freezing up.
Have they ever done a WDR/similar before dawn?
Cheers, Martin
The temperature differential between the hottest time of day vs the coldest would hardly have an impact on this IMO due to the far greater temperature differential between ambient and cryogenic.
For LOX, it's what, -200C or so? So if it was 15C this morning (probably wasn't that cold) and it gets up to 30C during the day, that's only 15 degrees of difference. To me, whether the LOX is -215 or -230 from ambient seems like it wouldn't make a difference on whether a valve freezes or not, but maybe they are that picky.. IDK
Agreed WDK (We don’t know)
But there could be a counterintuitive link.
The difference in temperature differences would be small, as said.
But warmer air will carry more moisture.
15 C of difference means 2.8X in water carrying capacity. (2^(dT/10K) )
Ice buildup could be faster.
We can only hope that SpaceX gives us some additional information.
And now they have courtesy of Maezawa.
Post by: envy887 on 04/17/2023 06:38 pm
I thought it was established that SH/SS used no helium.
They may not have any stored on board, but that doesn't preclude using ground-supplied helium to pressurize the tanks while on the pad.
Helium is really nice for this because it doesn't condense into subcooled liquid propellants. And the onboard autogenous system does not supply any hot pressurants before engine ignition.
Post by: Prettz on 04/17/2023 06:52 pm
They may not have any stored on board, but that doesn't preclude using ground-supplied helium to pressurize the tanks while on the pad.Hopefully very little, otherwise that's gonna add up.
Helium is really nice for this because it doesn't condense into subcooled liquid propellants. And the onboard autogenous system does not supply any hot pressurants before engine ignition.Sure, but the ground could supply anything needed. I thought they'd figured something out already.
Post by: Alberto-Girardi on 04/17/2023 06:54 pm
I don't think that the issue we saw today could have happened during that WDR, because we saw them doing a booster test (maybe a WDR) a few days ago. If any issue was known they would probably have been able to test for it.
My completely speculative take: this is a kind of failure that has some probability to happen, maybe low, it doesn't seem to be a inherent issue with the vehicle design.
Post by: Alberto-Girardi on 04/17/2023 06:56 pm
They have a line supplying the booster with gas oxygen and CH4, the so called "prepress", but idk if they are to be used during the propellant loading to fill some internal storage COPV.
...Helium is really nice for this because it doesn't condense into subcooled liquid propellants. And the onboard autogenous system does not supply any hot pressurants before engine ignition.Sure, but the ground could supply anything needed. I thought they'd figured something out already.
Post by: Michel Van on 04/17/2023 07:20 pm
Post by: SpunkyEnigma on 04/17/2023 07:22 pm
Lotsa people walking the beach down from the hotels
Post by: Alberto-Girardi on 04/17/2023 07:26 pm
For reference Falcon Heavy test flight was watched by 2.3 M live (now youtube lists 33M because of the replays).
Counting the biggest "unofficial streams" we have 240k watching NSF and ~100k with Everyday Astronaut ( I am being triple counted here).
This is strange given the growth of the space community in this 5 years.
edit: this is about the web coverage, I am not contradicting what SpunkyEnigma said, I don't know about that.
Post by: cplchanb on 04/17/2023 07:27 pm
Well, I thought they should do a WDR before proceeding to launch ... but I actually DON'T feel vindicated by this. But for the valve issue, everything went flawlessly and they nearly were ready to go. Was probably a low probability of going all the way to hold-down release, but prepping everything for liftoff seems reasonable. They did the truest possible rehearsal and will be more likely to be ready to go next time.
quite the irony that this scrub was due to faulty valves as well ;D People were chirping SLS for it left right and center lol
Wasn't a faulty valve. It was a perfectly normally working valve that got frozen. One of the SLS scrubs however involved a valve on the ICPS that was actually kaput (as in broken, defective, etc), and had to be replaced by a non-kaput one.
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
then again we shall see in the next 48hrs what they will do to address this. will they also replace the valve?? who knows...
Post by: ugordan on 04/17/2023 07:29 pm
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
So let me get this straight: you bring the valve outside its designed operating environment (by freezing it by an outside factor) and that makes it faulty?
Okay.
If a water pipe bursts because ice formed inside it, was the pipe at fault or was it whatever let the water get frozen inside it?
Post by: Herb Schaltegger on 04/17/2023 07:39 pm
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
Post by: RDMM2081 on 04/17/2023 07:46 pm
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
What description would an aerospace engineer use to describe such a situation? I'm genuinely curious, and nothing is coming directly to my mind, but then again, I am not an aerospace engineer. Disabled? Inoperative? Malfunctioning? These all seem to have their own subtle connotation as well which I think rules them out just as well as 'faulty'.
Post by: DecoLV on 04/17/2023 07:54 pm
I haven't seen the village this quiet in a while.
Ain't the same without you, Nomadd ;D
Post by: Coastal Ron on 04/17/2023 08:05 pm
What description would an aerospace engineer use to describe such a situation?well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
I'm not an engineer, but we have to remember that the valve is controlling the flow of something, so whatever that liquid or gas is could be affecting the actuation of the valve. For instance, if the line has contamination in it, or it froze up, then even if the valve opened the line may still be blocked.
I'm sure we'll hear what they found, and while there are design issues that you hope are caught during ground tests, sometimes there are operational issues that happen since you're doing something new. Personally I'm surprised that was the only issue with the vehicle...
Post by: whitelancer64 on 04/17/2023 08:17 pm
Also, what can we say about this flight being somewhat ignored? AFAIR the spaceX stream peaked at ~0.5 M viewers. The launch was scrubbed only at T- 9 minutes, well close to launch.
For reference Falcon Heavy test flight was watched by 2.3 M live (now youtube lists 33M because of the replays).
Counting the biggest "unofficial streams" we have 240k watching NSF and ~100k with Everyday Astronaut ( I am being triple counted here).
This is strange given the growth of the space community in this 5 years.
edit: this is about the web coverage, I am not contradicting what SpunkyEnigma said, I don't know about that.
The time may have had something to do with it - early on a Monday morning when a lot of people (especially on the west coast) are still asleep or just going to work.
Also, there were a ton of other live streams as well. Mainstream media like CNN, CNBC, and many other space-related youtubers had live streams.
Post by: mn on 04/17/2023 08:18 pm
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
If it was designed and expected to work in a given operating environment and instead it froze it's fair to call it faulty/failed. (If on the other hand things got colder than intended, (or for more time than intended, etc) that would be different).
Post by: kevindbaker2863 on 04/17/2023 08:27 pm
Post by: Lijazos on 04/17/2023 08:33 pm
In this tweet, Zack Golden mentions that this many LN2/LOX/CH4 tankers are needed to replenish the Tank Farm after this kind of WDR.
https://twitter.com/CSI_Starbase/status/1647953241001345025
Is it accurate in any way? One would think they wouldn't need as much CH4.
Post by: alugobi on 04/17/2023 08:42 pm
Fix that, please, SX.
Post by: Herb Schaltegger on 04/17/2023 08:57 pm
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
What description would an aerospace engineer use to describe such a situation? I'm genuinely curious, and nothing is coming directly to my mind, but then again, I am not an aerospace engineer. Disabled? Inoperative? Malfunctioning? These all seem to have their own subtle connotation as well which I think rules them out just as well as 'faulty'.
Typically it would be initially described simply as "failed." That's an functionality or operability statement regarding status alone, without distinction between a hardware failure, a design failure, a materials flaw, a manufacturing error or anything else. If and only if the unit is found to be physically broken or to suffer from an inherent design defect relevant to its suitability for the intended role in the system might someone reasonably consider using the term "faulty" but that term is imprecise, with no regard to the root cause of the failure.
That's why initially it's better simply to say the valve status is "failed," then proceed with a root cause analysis.
Post by: GmP on 04/17/2023 09:00 pm
Hey. I'm finding it hard to get accurate answers about this.
In this tweet, Zack Golden mentions that this many LN2/LOX/CH4 tankers are needed to replenish the Tank Farm after this kind of WDR.
https://twitter.com/CSI_Starbase/status/1647953241001345025
Is it accurate in any way? One would think they wouldn't need as much CH4.
I have the same question. Where did the propellant go that was in the Starship and Booster tanks at the time of the scrub? Some (most I would expect) gets recycled into the tanks? Or not? My assumption is it would, so they only need to replenish what was lost due to venting, right?
Or did they really vent the whole content in Starship and Booster?
Post by: Chris Bergin on 04/17/2023 09:11 pm
Post by: CMac on 04/17/2023 09:15 pm
Post by: SpaceFinnOriginal on 04/17/2023 09:15 pm
Window is 150 minutes long:QuoteSpaceX is targeting as soon as Monday, April 17 for the first flight test of a fully integrated Starship and Super Heavy rocket from Starbase in Texas. The 150-minute test window will open at 7:00 a.m. CT.
Official SpaceX Mission patch:
Thank you for posting.
Question. What is this patch then?
Post by: cuddihy on 04/17/2023 09:30 pm
Post by: joek on 04/17/2023 09:31 pm
I feel an "orbital/suborbital" deja vue. Just substitute frozen/failed.Awww... c'mon, you want to start another umpteen page debate over proper use of deja vu?
Post by: CMac on 04/17/2023 09:41 pm
Post by: WannaWalnetto on 04/17/2023 09:53 pm
The wind shear info in Updates. There is a brand new high tech wind shear radar system at Starbase. It can give give high accuracy up to the "minute" detailed wind shear data. ….
I’ve looked a couple of times, but I can’t find anything more than a passing reference to wind shear. Maybe I’m looking in the wrong update thread (looking in topic=58568)?
Post by: WannaWalnetto on 04/17/2023 10:10 pm
They reported that the “SpaceX Launch has been SCRAPPED” shortly after the launch was converted into a WDR. That gives a totally different picture of events in my mind.
Post by: Chris Bergin on 04/17/2023 10:30 pm
Window is 150 minutes long:QuoteSpaceX is targeting as soon as Monday, April 17 for the first flight test of a fully integrated Starship and Super Heavy rocket from Starbase in Texas. The 150-minute test window will open at 7:00 a.m. CT.
Official SpaceX Mission patch:
Thank you for posting.
Question. What is this patch then?
Our patch! :)
https://shop.nasaspaceflight.com/collections/starship-orbital-flight-test?utm_source=forum
NSF Patch by the amazing Pauline.
Post by: alugobi on 04/17/2023 10:32 pm
That's what makes them money: making it about Musk.
Post by: rdale on 04/17/2023 11:19 pm
That's what makes them money: making it about Musk.
Well - let’s look at Twitter. Musk made it about Musk and destroyed a pretty good product while doing so.
But I’d like to go down the media path - how do they make money by making a “Musk” connection that wouldn’t be made if they didn’t mention Elon?
Post by: alugobi on 04/17/2023 11:21 pm
Post by: Hog on 04/17/2023 11:24 pm
Can someone just clarify -- does the vehicle on the pad use helium pressurization only on the ground for initial filling or is it on the vehicle overall?There's gotta be at least one COPV of gHe in that big assed prototype SS/SH stack. Obviously attempting to exclude on vehicle stored He during operations.
Post by: DigitalMan on 04/18/2023 12:27 am
I think more Kate and John would have been good. The other dude, well, for example when he talked about Super Heavy, he goes on to say its "Super" and its "Heavy". Well, why not explain what is the scale that people use, such as medium, heavy, super heavy, etc.
I think that is enough to get an idea how to improve things.
Post by: alugobi on 04/18/2023 12:31 am
Because they have time to fill, it's going to become repetitive, and from that it gets boring.
Fix whatever was wrong with the Mission Control audio stream so we can listen to launch info, and skip the elementary primer on the program.
Post by: russianhalo117 on 04/18/2023 12:42 am
It is known as a transatmospheric orbit.It's not "marginally orbital", it's "the most massive test hop, ever".Oh god NOOOO it's baaaaack, and with untrimmed quotes :)Hahahaha!
Not to flog that semantic dead horse, but as far as I've seen, no one here has offered a calculation showing a possible post-SECO trajectory which intersects Earth's surface when calculated without taking atmosphere drag into account (given the expected SECO altitude, approximate apogee, and reentry location).
In lieu of that, I'm trusting Jonathan McDowell:
https://twitter.com/planet4589/status/1647321808658395136
https://twitter.com/planet4589/status/1647324115819278337Quote from: Rand Simberg · @Simberg_Space & Jonathan McDowell · @planet4589 · 19:29 UTC · Apr 15, 2023Rand Simberg: Has SpaceX provided a planned trajectory?
Jonathan McDowell: No, but there are enough clues in the NOTAMs, the timelines, and some FAA statements to infer one.
Simberg: To what degree of precision? (And accuracy)?
McDowell: perigee is between 40 and 60 km with fairly high confidence.
apogee is between 200 and 245 km. inclination is 26.3 +- 0.1 deg.
OK, edited to prod the dead horse *only slightly* by reporting without comment McDowell's choice of terminology:
https://twitter.com/planet4589/status/1647649762722603008Quote from: Jonathan McDowell · @planet4589 · 1:14 PM · Apr 16, 2023No, I would say it will be "marginally orbital". For true orbital, I require perigee > 80 km.
Cheers, Martin
Post by: ChrisC on 04/18/2023 01:18 am
Mission control audio feed https://youtube.com/watch?v=Ln8hXptcA90
Did anyone actually hear anything on that loop? I scrubbed to a few random points during the countdown and never heard anything. I was going to listen all the way through later today, but they've now taken that video private.
Thanks StevenO for the pointer to the SpaceX video engineer fishing for criticism (https://forum.nasaspaceflight.com/index.php?topic=58568.msg2476601#msg2476601). This comment is applicable here:
Commenter: ... the sound level on the net only stream was way too quiet.
SpaceX video engineer: Concur and copy. I’ll hVe them boost BCD1 volume and compression gain.
Post by: InterestedEngineer on 04/18/2023 02:10 am
Hey. I'm finding it hard to get accurate answers about this.
In this tweet, Zack Golden mentions that this many LN2/LOX/CH4 tankers are needed to replenish the Tank Farm after this kind of WDR.
https://twitter.com/CSI_Starbase/status/1647953241001345025
Is it accurate in any way? One would think they wouldn't need as much CH4.
I have the same question. Where did the propellant go that was in the Starship and Booster tanks at the time of the scrub? Some (most I would expect) gets recycled into the tanks? Or not? My assumption is it would, so they only need to replenish what was lost due to venting, right?
Or did they really vent the whole content in Starship and Booster?
Reviving this question, haven't seen a good answer.
Why would it require more than a handful of trucks to replenish after a WDR?
Post by: Herb Schaltegger on 04/18/2023 02:20 am
Hey. I'm finding it hard to get accurate answers about this.
In this tweet, Zack Golden mentions that this many LN2/LOX/CH4 tankers are needed to replenish the Tank Farm after this kind of WDR.
https://twitter.com/CSI_Starbase/status/1647953241001345025
Is it accurate in any way? One would think they wouldn't need as much CH4.
I have the same question. Where did the propellant go that was in the Starship and Booster tanks at the time of the scrub? Some (most I would expect) gets recycled into the tanks? Or not? My assumption is it would, so they only need to replenish what was lost due to venting, right?
Or did they really vent the whole content in Starship and Booster?
Reviving this question, haven't seen a good answer.
Why would it require more than a handful of trucks to replenish after a WDR?
Most of the consumables are probably LN2 to replenish the stocks used in sub-cooling during tanking and recondensing post-scrub. The rest will be to top off the LOX and methane lost during that same process.
Post by: meekGee on 04/18/2023 02:32 am
Faulty is not such a bad adjective.well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
What description would an aerospace engineer use to describe such a situation? I'm genuinely curious, and nothing is coming directly to my mind, but then again, I am not an aerospace engineer. Disabled? Inoperative? Malfunctioning? These all seem to have their own subtle connotation as well which I think rules them out just as well as 'faulty'.
It was the valve that didn't work.
The reason may have been transient, the fault may have been intermittent, the design itself (valve, enclosure procedure) is lacking or deficient since it allowed a fault to develop under normal operating conditions.
Contrast that with a valve that failed because a forklift drove over it. In that case, it wouldn't be faulty.
Post by: Herb Schaltegger on 04/18/2023 02:46 am
Faulty is not such a bad adjective.well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
No engineer in the world, especially an aerospace engineer, would describe a frozen valve as “faulty” absent a physical fault preventing actuation (a condition for which we have zero evidence).
What description would an aerospace engineer use to describe such a situation? I'm genuinely curious, and nothing is coming directly to my mind, but then again, I am not an aerospace engineer. Disabled? Inoperative? Malfunctioning? These all seem to have their own subtle connotation as well which I think rules them out just as well as 'faulty'.
It was the valve that didn't work.
The reason may have been transient, the fault may have been intermittent, the design itself (valve, enclosure procedure) is lacking or deficient since it allowed a fault to develop under normal operating conditions.
Contrast that with a valve that failed because a forklift drove over it. In that case, it wouldn't be faulty.
But it still would be accurately described - in the absence of data as to root cause - as “failed.”
Similarly, a cryogenic fluid valve is not “faulty” if it is exposed to fluids other than those with which it is expected to operate; if it is supplied with an over-current of the electrical power with which is it is actuated or alternately, an over-pressure of the pneumatic fluid which operates it. The valve is not faulty if there are contaminants in the fluid causing it to bind, freeze up or actuate sluggishly and out of specification … et cetera.
But if commanded and it fails to actuate, is is still “failed” even though not “faulty.”
Post by: TomH on 04/18/2023 02:57 am
well regardless of whether its actually broken or frozen shut, the fact is that it failed to operate when commanded which means theres a fault to it, hence a faulty valve.
Sorry, but it is the above conclusion which is faulty. The problem could be procedural, as in sequence of events, or timing. Such an adjustment could eliminate the problem, just as was the case with the Amos-6 mission. A change of sequence and timing in loading the supercooled prop solved the problem. In other cases, additional insulation and/or heaters have solved similar problems.
The valve itself is not faulty. An adjustment to the physical and temporal conditions related to and surrounding the valve need to be adjusted. The valve itself requires no change.
Post by: TomH on 04/18/2023 03:16 am
Anything sacred about 7 am, as opposed to 9 am?
I would note that (in general) weather is calmer in the early morning. As the sun rises, its angle moves closer to vertical, it has less atmosphere through which to travel (less and less coming through sideways). The increasing thermal solar gain heats the surface of the ground and water, thus inducing more air currents. In simple terms, it tends to be calmer at 7 than at 9.
Post by: matthewkantar on 04/18/2023 03:44 am
Post by: FutureSpaceTourist on 04/18/2023 03:50 am
Quote
Today’s #satellite image (April 17, 2023) of the @SpaceX Boca Chica launch facilities in Texas with a view of the #Starship and Super Heavy rocket on the launch pad. Today’s scheduled launch of the most powerful rocket ever constructed was scrubbed. Stay tuned! 🚀
Post by: chopsticks on 04/18/2023 03:52 am
Is it me or has bickering about semantics become a trend here? With what "faulty" means, how long 48 hours is, what "orbital" means, and others, going on for pages and pages, it feels like being trolled.Not just you. It seems like people are often arguing about the definitions of words when it's pretty clear that people do in fact understand each other. It's tiresome, like kids bragging about how much smarter they are than the next kid.
Post by: sdfasdfasd on 04/18/2023 07:21 am
Is it me or has bickering about semantics become a trend here? With what "faulty" means, how long 48 hours is, what "orbital" means, and others, going on for pages and pages, it feels like being trolled.
It is solved on other sites by threading comments, so those who enjoy it can go down their silly rabbitholes but normal people can just skip over those threads. It also makes quoting much less necessary.
Unfortunately this site seems to use technology from the 90s that cannot do comment threads.
Post by: catdlr on 04/18/2023 07:34 am
According to CSI Starbase, the booster can not launch with these lines connected (see clip below)
https://youtube.com/clip/UgkxG_I_eJnWZqaPOx4ZD0NByythzo6_wtk0
Post by: woods170 on 04/18/2023 07:42 am
In the attached screengrab from engineering cameras under the booster in the OLM I see what appears to be frosted tubing extending from the launch mount to each engine. They are put in after the explosion in December and are not part of the LN2 stage zero connectors for engine spin-up. What are these for? Are they directly connected to each engine and how are they disconnected at launch or do they just tear off at launch?
Those are flex lines and are torn off at launch. Temporary thing. Only applies to B7. On B9 et al. a different solution is applied.
Post by: catdlr on 04/18/2023 07:46 am
In the attached screengrab from engineering cameras under the booster in the OLM I see what appears to be frosted tubing extending from the launch mount to each engine. They are put in after the explosion in December and are not part of the LN2 stage zero connectors for engine spin-up. What are these for? Are they directly connected to each engine and how are they disconnected at launch or do they just tear off at launch?
Those are flex lines and are torn off at launch. Temporary thing. This only applies to B7. On B9 et al. a different solution is applied.
Thanks, I added a clip from CSI Starbase that mentions that the booster can't launch like that. But if they are designed to tear away, then I'm good
Post by: woods170 on 04/18/2023 07:51 am
Hey. I'm finding it hard to get accurate answers about this.
In this tweet, Zack Golden mentions that this many LN2/LOX/CH4 tankers are needed to replenish the Tank Farm after this kind of WDR.
<snip>
Is it accurate in any way? One would think they wouldn't need as much CH4.
Zack's numbers are way off. As in way too high, particularly for LN2.
And no, SpaceX doesn't vent all of the propellants when they detank the vehicle. It is just that during tanking, stable replenishment and detanking, a LOT of the cryogenics warm up to the point that they change phase from fluid to gas. To prevent over pressure in the vehicle tanks, storage tanks and all of the plumbing in-between, the gaseous oxygen, nitrogen and methane need to be vented.
SpaceX does employ recondensors to turn some of the gaseous stuff back to fluids, but those are far from 100% effective.
Given the massive amounts of LOX and liquid methane involved, it is inevitable that many truckloads worth of LN2, LOX and liquid methane are required to top off the tank farm.
Post by: eeergo on 04/18/2023 07:59 am
https://www.nasaspaceflight.com/2022/04/sls-wet-dress-rehearsal/
Of course, LH2 shall always be more "lossy" than warmer, bigger-molecule propellants such as LOX or LNG. On the other hand, KSC infrastructure may be more leak-tight than Boca Chica's, both because of the amounts involved as well as the speed of operations and such factors. Maybe a 30% overall loss rate is the ballpark of what they're experiencing, with a 10-15% load loss as per the slide's breakdown?
Post by: CrazySpace on 04/18/2023 08:30 am
??
Post by: clongton on 04/18/2023 10:23 am
Launch control box in foreground.
What is this?
Some immature person's sick idea of a stupid joke
Post by: ThatOldJanxSpirit on 04/18/2023 11:25 am
They tried to launch on the 17th. They are recycling to the 20th for good technical reasons. Are people really suggesting that they should rush or delay the recycle to avoid a meme.
Post by: ugordan on 04/18/2023 11:36 am
It is so sad to see this forum declining to the abject level of Reddit or the Ars Technica comments section.
They tried to launch on the 17th. They are recycling to the 20th for good technical reasons. Are people really suggesting that they should rush or delay the recycle to avoid a meme.
And it's not like there's a high chance of it launching on that date, either, let's be realistic here.
Post by: edzieba on 04/18/2023 12:04 pm
CSI Starbase is not an authoritative source. Much pure speculation is presented as fact.In the attached screengrab from engineering cameras under the booster in the OLM I see what appears to be frosted tubing extending from the launch mount to each engine. They are put in after the explosion in December and are not part of the LN2 stage zero connectors for engine spin-up. What are these for? Are they directly connected to each engine and how are they disconnected at launch or do they just tear off at launch?
Those are flex lines and are torn off at launch. Temporary thing. This only applies to B7. On B9 et al. a different solution is applied.
Thanks, I added a clip from CSI Starbase that mentions that the booster can't launch like that. But if they are designed to tear away, then I'm good
Post by: Chris Bergin on 04/18/2023 12:13 pm
It is so sad to see this forum declining to the abject level of Reddit or the Ars Technica comments section.
They tried to launch on the 17th. They are recycling to the 20th for good technical reasons. Are people really suggesting that they should rush or delay the recycle to avoid a meme.
Not to pick you out, but the point made.....I'm not sure what posts like this do to solve that. Yes, there were a fair amount of absolutely pointless posts, but thankfully some members here don't quote bad posts and says "bad post" creating two bad posts. They report to mod and we can clean up the crap.
That's this thread, not "this forum". A thread that is a discussion, not update, thread, on a subject that is about the most talked about thing in this subject matter, on the internet, full of people with different opinions and styles of getting their point across.
And on that note, everything think before posting, because some certainly didn't. 1000s of people are reading your posts, so try not to embarrass yourself when hitting post, because some of the three word doozies I removed we very much in the style Janx complained about. Any repeat offenders will find they'll be in read only for a month.
Carry on (plus I'll start a new thread for Attempt 2).
Post by: Chris Bergin on 04/18/2023 12:19 pm
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
Post by: saturnsky on 04/18/2023 01:37 pm
Post by: rdale on 04/18/2023 02:00 pm
Post by: Tomness on 04/18/2023 02:02 pm
By the way, I saw people quoting numbers for yesterday, and totally wrong. It was a lot more.
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
That's crazy, almost 1:1 sub/view ratio
Post by: wannamoonbase on 04/18/2023 02:13 pm
By the way, I saw people quoting numbers for yesterday, and totally wrong. It was a lot more.
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
I joined on April 10, 2006 and have seen the growth and interest. To have that many views with a such a historic rocket, could not have been imagined 17 years ago.
Chris, it's epic what you have built here.
Post by: Slothman on 04/18/2023 02:15 pm
By the way, I saw people quoting numbers for yesterday, and totally wrong. It was a lot more.
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
That's crazy, almost 1:1 sub/view ratio
I was also curious about the concurrent viewers since the chat just lagged my browser tab (with 32 GB system RAM) and the most viewers I saw were about 250.000 on the NSF stream. Mind you, that's concurrent viewers at the same time. Not individual viewers over the whole stream. And I was seriously impressed by that number. More than Tim Dodd's stream when I checked.
Post by: cuddihy on 04/18/2023 02:20 pm
I don't think there is a 37th Space Wing? They have their own meteorologists.There are no US Space Force "Wings", only Deltas. Space Launch Delta 45 supports launches at the Eastern Range out of Patrick Space Force Base, FL. The 45th Weather Squadron (45WS) supports the Eastern Range, but far as I know no USSF supports the Texas launch site, they rely on National Weather Service
Post by: Alberto-Girardi on 04/18/2023 02:37 pm
Indeed in my post I meant the most viewers at a given instant. Not the total, but I'm not sure about how youtube calculates that.By the way, I saw people quoting numbers for yesterday, and totally wrong. It was a lot more.
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
That's crazy, almost 1:1 sub/view ratio
I was also curious about the concurrent viewers since the chat just lagged my browser tab (with 32 GB system RAM) and the most viewers I saw were about 250.000 on the NSF stream. Mind you, that's concurrent viewers at the same time. Not individual viewers over the whole stream. And I was seriously impressed by that number. More than Tim Dodd's stream when I checked.
Post by: whitelancer64 on 04/18/2023 02:49 pm
By the way, I saw people quoting numbers for yesterday, and totally wrong. It was a lot more.
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
The numbers quoted yesterday were for view counts at the time. Obviously as time passes the view count goes up as more people watch it.
Post by: FutureSpaceTourist on 04/18/2023 02:50 pm
Quote
To me the most exciting thing of yesterday was finally putting together all the times for certain key events on Starship's countdown. When SpaceX had published their timeline, there had been certain events that were not in there and we finally got to know some of them
Quote
I put together the script for this video we did last week at NSF analyzing the times from SpaceX's timeline and correlating it to things we could see. Some stuff I got very close, a few others... not so much. But hey it was worth a shot:
https://www.youtube.com/watch?v=tHa-37Bcg_Q
https://twitter.com/alexphysics13/status/1648327665051480070
Quote
Based on all the stuff we've learned and seen so far, I've put together an updated timeline with more information and posted it on NSF's discord on the Starship channel so if you're in there pop in and search for it for Thursday's event.
And maybe... we'll use it next time 🤔
Post by: cuddihy on 04/18/2023 02:53 pm
-Autogenous pressurization is used to maintain pressure in the tanks once the engines are running for Super Heavy
-Autogenous pressurization is used to maintain pressure in the tanks once Starship deploys from the SH.
-there are no helium tanks on either vehicle.
WHAT I THOUGHT:
-self pressurization (evaporation) maintains pressure on the pad when both SS & SH are loaded, but clearly that is not the case
So trying to puzzle out:
1. Is helium only used during loading ops or through the launch up to engine start?
2. Is it just on SS, just on SH, or on both?
Any pointers would be appreciated.
Post by: kdhilliard on 04/18/2023 03:04 pm
Perhaps he misspoke.
Post by: frogamazog on 04/18/2023 03:14 pm
Post by: frogamazog on 04/18/2023 03:15 pm
Post by: lrk on 04/18/2023 03:53 pm
Post by: rsdavis9 on 04/18/2023 03:59 pm
Quick Disconnect for both ship and booster.
SQD and BQD respectively.
Post by: envy887 on 04/18/2023 04:01 pm
One of the objectives for the long-duration Booster static fire they did a month or two ago was testing autogenous pressurization. It may be that they use autogenous in flight, but pressurize with helium on the ground before launch. That would simplify the GSE needs for this initial test by avoiding the need to supply high-pressure gaseous CH4 and O2. Probably something they would like to eliminate long-term.
It will be difficult to eliminate He pressurization on the upper stage during boost, because the subcooled props will really tend to condense out the gaseous autogenous pressurants, especially when agitated during flight.
They could get around that issue by using the booster to supply hot gaseous pressurants to the upper stage in flight, or by running a heater or APU on the upper stage.
Post by: Alberto-Girardi on 04/18/2023 04:38 pm
One of the objectives for the long-duration Booster static fire they did a month or two ago was testing autogenous pressurization. It may be that they use autogenous in flight, but pressurize with helium on the ground before launch. That would simplify the GSE needs for this initial test by avoiding the need to supply high-pressure gaseous CH4 and O2. Probably something they would like to eliminate long-term.
It will be difficult to eliminate He pressurization on the upper stage during boost, because the subcooled props will really tend to condense out the gaseous autogenous pressurants, especially when agitated during flight.
They could get around that issue by using the booster to supply hot gaseous pressurants to the upper stage in flight, or by running a heater or APU on the upper stage.
Great point. We know that there is no connection (not even eletrical, only a wireless data one, IIRC) between the two stages, so this might be true.
Post by: envy887 on 04/18/2023 04:47 pm
I don't know which stage had the issue yesterday, or whether it was even a issue on the vehicle or GSE.One of the objectives for the long-duration Booster static fire they did a month or two ago was testing autogenous pressurization. It may be that they use autogenous in flight, but pressurize with helium on the ground before launch. That would simplify the GSE needs for this initial test by avoiding the need to supply high-pressure gaseous CH4 and O2. Probably something they would like to eliminate long-term.
It will be difficult to eliminate He pressurization on the upper stage during boost, because the subcooled props will really tend to condense out the gaseous autogenous pressurants, especially when agitated during flight.
They could get around that issue by using the booster to supply hot gaseous pressurants to the upper stage in flight, or by running a heater or APU on the upper stage.
Great point. We know that there is no connection (not even eletrical, only a wireless data one, IIRC) between the two stages, so this might be true.
But wasn't the problem on the booster?
But the consumables cost for the He to press only the ullage space before liftoff is very small, probably only a few thousand dollars. If it saves any complexity, that's a good trade until flight rates are quite high.
Post by: rdale on 04/18/2023 04:51 pm
they rely on National Weather Service entirely.
That's a new one for me - that would be highly unethical for the NWS to be their sole weather provider, plus that would mean their weather criteria are available for public viewing and we know that's not the case :)
Where have you seen that publicized?
Post by: kraisee on 04/18/2023 04:51 pm
He may also be used for purging lines, though N2 is probably sufficient for most instances.
I'm not sure; is He used to initially spin any of the Raptor 2 turbopumps too?
Ross.
Post by: joek on 04/18/2023 04:52 pm
...Do not think that was stated-confirmed? Do we have a reference?
But wasn't the problem on the booster?
In any case, need to be careful speculating about what we are see now vs. what is likely in the future. SpaceX appears to be taking some short term tactical steps in order to buy down (or gain more knowledge of) longer term strategic risks. Not unusual given their MO.
Post by: xvel on 04/18/2023 04:58 pm
Post by: joek on 04/18/2023 05:22 pm
they rely on National Weather Service entirely.That's a new one for me - that would be highly unethical for the NWS to be their sole weather provider, plus that would mean their weather criteria are available for public viewing and we know that's not the case :)
Where have you seen that publicized?
They do not rely on NWS exclusively for local launch conditions, as clearly stated in the PEA/WR (https://www.faa.gov/media/27271):
Quote
Prior to launch, SpaceX will deploy weather balloons to measure weather data. ...Not sure about reentry conditions; PEA is vague on that, but implies USCG data (which presumably is better than NWS public data?):
Quote
Weather and ocean current data would be used to further characterize the debris field as the operation is conducted. During the operation, SpaceX would coordinate findings and action items directly with the USCG Sector 14 to ensure all of the requirements of the Letter of Intent are met.
Post by: cuddihy on 04/18/2023 05:28 pm
Post by: Jcc on 04/18/2023 05:49 pm
Given that the propellant liquids are super chilled, using GOX or GCH4 in the ullage space would cause much of the gas to condense into liquid. He won't condense at these temps, so it is used to keep the pressure stable initially. Once the engines start, the autogenous system takes over.
He may also be used for purging lines, though N2 is probably sufficient for most instances.
I'm not sure; is He used to initially spin any of the Raptor 2 turbopumps too?
Ross.
I think N2 is supplied from GSE to spin the outer 20 engines, and the externally mounted copvs (covered up) contain N2 to spin the inner engines and for restart. I think N2 is also used to pressurize empty stages for transport. To pressurize full tanks before engine start maybe they do need a heater for the propellant and do that outside the tank.
Post by: clongton on 04/18/2023 05:53 pm
I don't think there is a 37th Space Wing? They have their own meteorologists.
Can you provide an update on the potential for shear at high altitude? AIUI, that is/was the main concern for a Thursday launch.
Post by: Jim on 04/18/2023 05:55 pm
Prior to launch, SpaceX will deploy weather balloons to measure weather data. ...
That is for winds aloft and not local conditions.
Post by: Jim on 04/18/2023 05:56 pm
Weather and ocean current data would be used to further characterize the debris field as the operation is conducted. During the operation, SpaceX would coordinate findings and action items directly with the USCG Sector 14 to ensure all of the requirements of the Letter of Intent are met.
That would be for the sea conditions and not weather.
Post by: Jim on 04/18/2023 05:58 pm
they rely on National Weather Service entirely.
That's a new one for me - that would be highly unethical for the NWS to be their sole weather provider, plus that would mean their weather criteria are available for public viewing and we know that's not the case :)
Where have you seen that publicized?
How so? NWS can supply the data. It is up to SpaceX to determine the criteria and it doesn't have to share it.
Post by: joek on 04/18/2023 06:05 pm
That is for winds aloft and not local conditions.
They have other sensors for that. Did not think it was worth mentioning, but, from the previous PEA (https://www.faa.gov/sites/faa.gov/files/2022-06/PEA_for_SpaceX_Starship_Super_Heavy_at_Boca_Chica_FINAL.pdf):
Quote
SpaceX plans to use a portable sound detection and ranging (SODAR) device to collect weather data needed for launch and landing. The SODAR sends out a short sonic pulse every 15 minutes that can reach 92 decibels (dB) at the source and dissipates to 60 dB within 100 feet. The SODAR would be located on a SpaceX private parcel in the production and manufacturing area, north of the solar farm.
Post by: clongton on 04/18/2023 06:06 pm
Post by: rdale on 04/18/2023 06:08 pm
they rely on National Weather Service entirely.
That's a new one for me - that would be highly unethical for the NWS to be their sole weather provider, plus that would mean their weather criteria are available for public viewing and we know that's not the case :)
Where have you seen that publicized?
How so? NWS can supply the data. It is up to SpaceX to determine the criteria and it doesn't have to share it.
NWS cannot provide specific forecasts for private sector organizations. They only way around is if they are supporting something with a large public safety threat - such as an outdoor concert, large sporting event, etc.
But they don't have a hotline to SpaceX mission control :) Those decisions are made by SpaceX meteorologists.
Post by: joek on 04/18/2023 06:10 pm
All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
Speculation: They'll use He for Earth launch until they figure out how to make it work in situations where He is not an option. Again, they are buying down risk. One step at a time.
Post by: alastairmayer on 04/18/2023 06:16 pm
Is it me or has bickering about semantics become a trend here? With what "faulty" means, how long 48 hours is, what "orbital" means, and others, going on for pages and pages, it feels like being trolled.
It is solved on other sites by threading comments, so those who enjoy it can go down their silly rabbitholes but normal people can just skip over those threads. It also makes quoting much less necessary.
Unfortunately this site seems to use technology from the 90s that cannot do comment threads.
The 90s? Heck, the software I wrote back in the early 80s (CoSy, used for BIX among others) could do threads. Mind, it was purely text based, so there's that. ;)
Post by: rdale on 04/18/2023 06:17 pm
Can you provide an update on the potential for shear at high altitude? AIUI, that is/was the main concern for a Thursday launch.
Not bad - after the low level directional change they look fairly benign through upper levels. Not "quiet" but not much different than what Monday looked like.
Post by: envy887 on 04/18/2023 06:51 pm
All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
I imagine they will forgo subcooling on Mars. Without subcooling, LOX and LCH4 will self-pressurize while just sitting there, and then once the engines are running add in autogenous.
Post by: Hog on 04/18/2023 07:11 pm
that sounds sporty for the Raptors.All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
I imagine they will forgo subcooling on Mars. Without subcooling, LOX and LCH4 will self-pressurize while just sitting there, and then once the engines are running add in autogenous.
Post by: wannamoonbase on 04/18/2023 07:13 pm
that sounds sporty for the Raptors.All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
I imagine they will forgo subcooling on Mars. Without subcooling, LOX and LCH4 will self-pressurize while just sitting there, and then once the engines are running add in autogenous.
If they are qualified for fuels at a range of temperatures it should only be a difference in performance, which should not be a problem for Mars gravity.
However, I'd be much more concerned with an unprepared launch pad.
Post by: whitelancer64 on 04/18/2023 07:18 pm
that sounds sporty for the Raptors.All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
I imagine they will forgo subcooling on Mars. Without subcooling, LOX and LCH4 will self-pressurize while just sitting there, and then once the engines are running add in autogenous.
If they are qualified for fuels at a range of temperatures it should only be a difference in performance, which should not be a problem for Mars gravity.
However, I'd be much more concerned with an unprepared launch pad.
Soon after people are on Mars, there will be prepared launch / landing pads.
Post by: Chris Bergin on 04/18/2023 07:23 pm
By the way, I saw people quoting numbers for yesterday, and totally wrong. It was a lot more.
SpaceX got 5.2m views.
NSF got 3.3m (on a longer stream of course).
That's crazy, almost 1:1 sub/view ratio
I was also curious about the concurrent viewers since the chat just lagged my browser tab (with 32 GB system RAM) and the most viewers I saw were about 250.000 on the NSF stream. Mind you, that's concurrent viewers at the same time. Not individual viewers over the whole stream. And I was seriously impressed by that number. More than Tim Dodd's stream when I checked.
This was attempt one:
Post by: rsdavis9 on 04/18/2023 07:33 pm
All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
I imagine they will forgo subcooling on Mars. Without subcooling, LOX and LCH4 will self-pressurize while just sitting there, and then once the engines are running add in autogenous.
At mars pressure lox and lch4 are subcooled.
Post by: kdhilliard on 04/18/2023 08:00 pm
On spacex stream was clearly stated multiple times that it was "first stage issue"Yep. From T-17m15s (https://youtube.com/watch?v=L5QXreqOrTA&t=27m45s):
Quote from: John Insprucker
The clock is coming up on T-17 minutes from liftoff. We're continuing to click towards zero, however right now we've just begun listening in, the first stage team is working a pressurization issue. They're troubleshooting that right now. Now we do have the option if need be, if we can't solve this, then we would hold the count and probably treat today as a Wet Dress and not be able to launch. However we are continuing to do propellant loading on both the Superheavy and the Ship stages. ... But as a reminder, T-15m10s and counting, we are working an issue on the first stage and will bring an update as we get more insight into that issue.
Post by: alugobi on 04/18/2023 08:09 pm
Post by: ChrisC on 04/18/2023 08:42 pm
QuoteThe TFR for a Starship launch attempt on Thursday has been removed. Awaiting an update from SpaceX.QuoteRight now the next TFR is for a possible launch attempt on April 21.
Poor Elon, he must be soooo disappointed. But I'm impressed that he listened to the team and let it slip past his juvenile joke date.
EDIT: I may have spoken too soon :(
Post by: Oersted on 04/18/2023 08:44 pm
I response to the post in updates asking for feedback regarding the SpaceX webcast:
I think more Kate and John would have been good. The other dude, well, for example when he talked about Super Heavy, he goes on to say its "Super" and its "Heavy". Well, why not explain what is the scale that people use, such as medium, heavy, super heavy, etc.
I think that is enough to get an idea how to improve things.
As someone working in the voice business, I think they should give a bit more thought to which voices they use. Insprucker has a fantastic "1960s rocket engineer" voice. Content-wise he is good and getting better. Most of the others... not great. A California valley girl voice (plus intonation), as well as a high-pitched adolescent boy voice just won´t keep audiences happy. They will get annoyed after a while and turn off the feed.
It is harsh, I know, but it has been the reality in broadcasting for decades. Lots of excellent journalists are tested for their screen personality and no matter how good they are content-wise, by far the majority of them just don´t have the necessary on-screen charisma, of which the voice and intonation play a huge part. Think Walter Cronkite for somebody who had the voice and the personality.
We can´t demand the same level from youtube feed presenters but broadcast quality voices are what they are being judged against by the viewers.
Post by: chopsticks on 04/18/2023 09:00 pm
I response to the post in updates asking for feedback regarding the SpaceX webcast:
I think more Kate and John would have been good. The other dude, well, for example when he talked about Super Heavy, he goes on to say its "Super" and its "Heavy". Well, why not explain what is the scale that people use, such as medium, heavy, super heavy, etc.
I think that is enough to get an idea how to improve things.
As someone working in the voice business, I think they should give a bit more thought to which voices they use. Insprucker has a fantastic "1960s rocket engineer" voice. Content-wise he is good and getting better. Most of the others... not great. A California valley girl voice (plus intonation), as well as a high-pitched adolescent boy voice just won´t keep audiences happy. They will get annoyed after a while and turn off the feed.
It is harsh, I know, but it has been the reality in broadcasting for decades. Lots of excellent journalists are tested for their screen personality and no matter how good they are content-wise, by far the majority of them just don´t have the necessary on-screen charisma, of which the voice and intonation play a huge part. Think Walter Cronkite for somebody who had the voice and the personality.
We can´t demand the same level from youtube feed presenters but broadcast quality voices are what they are being judged against by the viewers.
Disagree. My favourite presenters are John Innsbrucker, Jesse Anderson, and Kate Tice. They are all great. That's my opinion and you are entitled to yours.
(BTW, I wonder when Chris G. will popup on screen ha.)
Post by: Echo_Jex on 04/18/2023 09:04 pm
Snip...
We can´t demand the same level from youtube feed presenters but broadcast quality voices are what they are being judged against by the viewers.
With enough celebrity youtubers now, i think there is enough data to show that cable "Broadcast Quality" patterns dont perfectly parallel internet livestreamer quality expectations. With a wider target age range for livestream platforms i think different resonators are chosen. So a 20's year old might not resonate with a strong voiced sharply dressed charismatic guy, but instead with someone that would fit in within their own friend group, what some would call a flawed voice others might call relatable. Is there an NSF thread we can take this to for discussing how well NSF adapted to on screen presence?
Post by: Alberto-Girardi on 04/18/2023 09:10 pm
Now on the NSF livestream the commentator said the problem was on the booster....Do not think that was stated-confirmed? Do we have a reference?
But wasn't the problem on the booster?
In any case, need to be careful speculating about what we are see now vs. what is likely in the future. SpaceX appears to be taking some short term tactical steps in order to buy down (or gain more knowledge of) longer term strategic risks. Not unusual given their MO.
Post by: sdfasdfasd on 04/18/2023 09:17 pm
As someone working in the voice business, I think they should give a bit more thought to which voices they use. Insprucker has a fantastic "1960s rocket engineer" voice. Content-wise he is good and getting better. Most of the others... not great. A California valley girl voice (plus intonation), as well as a high-pitched adolescent boy voice just won´t keep audiences happy. They will get annoyed after a while and turn off the feed.
That was me for one!
I could not continually watch the Spacex broadcast because of those two's voices.
The "boy"'s voice was particularly nasal and jarring, I thought.
NSF have a couple of guys with great voices, surely Spacex can find a couple more!
Edit: What's Ted Williams doing these days :-)
Post by: Hog on 04/18/2023 09:51 pm
Agreed, voice makes all the difference. Grating when it's wrong.I response to the post in updates asking for feedback regarding the SpaceX webcast:
I think more Kate and John would have been good. The other dude, well, for example when he talked about Super Heavy, he goes on to say its "Super" and its "Heavy". Well, why not explain what is the scale that people use, such as medium, heavy, super heavy, etc.
I think that is enough to get an idea how to improve things.
As someone working in the voice business, I think they should give a bit more thought to which voices they use. Insprucker has a fantastic "1960s rocket engineer" voice. Content-wise he is good and getting better. Most of the others... not great. A California valley girl voice (plus intonation), as well as a high-pitched adolescent boy voice just won´t keep audiences happy. They will get annoyed after a while and turn off the feed.
It is harsh, I know, but it has been the reality in broadcasting for decades. Lots of excellent journalists are tested for their screen personality and no matter how good they are content-wise, by far the majority of them just don´t have the necessary on-screen charisma, of which the voice and intonation play a huge part. Think Walter Cronkite for somebody who had the voice and the personality.
We can´t demand the same level from youtube feed presenters but broadcast quality voices are what they are being judged against by the viewers.
Post by: RDMM2081 on 04/18/2023 10:37 pm
Post by: TheRadicalModerate on 04/18/2023 11:02 pm
that sounds sporty for the Raptors.All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
I imagine they will forgo subcooling on Mars. Without subcooling, LOX and LCH4 will self-pressurize while just sitting there, and then once the engines are running add in autogenous.
I think the sportiness is required, unless you're planning on putting big cryocoolers in place from the git-go, along with the heat rejection needed to make them work. Raptors have to be able to restart over a wide range of idle intervals, some of which are too short for active cooling but too long for the prop to remain subcooled on-orbit. (I think most GTO profiles fit this constraint.)
And things are even worse on the lunar and martian surfaces, where you can't play attitude tricks, the sun moves, and you have a quasi-lambertian surface radiating at you from all directions.
At mars pressure lox and lch4 are subcooled.
Dropping pressure lowers the boiling point. If you drop the pressure on a boiling liquid, it just boils faster. You can raise the pressure and make it subcooled, though.
Post by: kdhilliard on 04/18/2023 11:08 pm
I think N2 is supplied from GSE to spin the outer 20 engines, ...Oh, is that what we're seeing in this 2-second shot during the SpaceX Starship livestream intro?
See 3:54 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m54s).
[The full 80-second into starts at 3:15 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m15s).]
Post by: TheRadicalModerate on 04/18/2023 11:14 pm
All this discussion about He vs. autogenous begs the question - how are the propellants going to be pressurized for engine restart on the surface of the moon or Mars?
Pump liquid (LCH4 or LOX) into a COPV, seal the COPV, and superheat it.
There are a lot of things that need high-pressure gas over the operating regime of a fully functional Starship:
1) Bringing main and header tanks up to flight pressure (~6bar).
2) Providing spin-start gases (>100bar?).
3) Driving cold-to-warm-gas thrusters (6-20bar).
4) Driving combusting thrusters (6-10bar).
My guess is that the current test articles can't do all of these things yet, and the COPVs and heaters are either rudimentary or non-existent. Note that this may be yet another explanation for what Starship is going to belly-flop all the way into the sea: there simply aren't enough COPVs to handle more than the Starship spin-start at stage separation.
Post by: alugobi on 04/18/2023 11:20 pm
Now on the NSF livestream the commentator said the problem was on the booster.Their source?
Post by: kdhilliard on 04/18/2023 11:51 pm
John Insprucker.Now on the NSF livestream the commentator said the problem was on the booster.Their source?
See my post (https://forum.nasaspaceflight.com/index.php?topic=53846.msg2476898#msg2476898) 13 above.
Post by: sferrin on 04/19/2023 12:02 am
A shame some people have NO sense of humor.QuoteThe TFR for a Starship launch attempt on Thursday has been removed. Awaiting an update from SpaceX.QuoteRight now the next TFR is for a possible launch attempt on April 21.
Poor Elon, he must be soooo disappointed. But I'm impressed that he listened to the team and let it slip past his juvenile joke date.
Post by: kdhilliard on 04/19/2023 12:28 am
...I think you and rs are using the term differently.At mars pressure lox and lch4 are subcooled.
Dropping pressure lowers the boiling point. If you drop the pressure on a boiling liquid, it just boils faster. You can raise the pressure and make it subcooled, though.
Yes, a liquid is subcooled when it is below its boiling temperature for its given pressure, but by that standard the LOX in a Falcon 1 tank was subcooled once the tanks were pressurized for flight. SpaceX, when speaking of subcooled propellants, is of course saying that they are densified by being brought below their boiling point at Earth atmospheric pressure (since they are usually stored in bulk near atmospheric pressure, with their temperature maintained through boil-off).
Subcooling methane with respect to Mars atmospheric pressure will be difficult to do given its triple point of 90.69K/0.117bar, well above Mars's atmospheric pressure of 6mbar! Instead, what I believe rs is saying is simply that the densified propellant temperatures that SpaceX calls subcooled on Earth will be that of boiling propellants in an only partially pressurized tank on Mars.
Post by: TomH on 04/19/2023 12:51 am
Is it me or has bickering about semantics become a trend here? With what "faulty" means, how long 48 hours is, what "orbital" means, and others, going on for pages and pages, it feels like being trolled.Not just you. It seems like people are often arguing about the definitions of words when it's pretty clear that people do in fact understand each other. It's tiresome, like kids bragging about how much smarter they are than the next kid.
Words and their definitions do matter. If the valve itself is faulty, then it needs to be replaced or redesigned. If the valve froze due to a procedural error, then the procedure is faulty, not the valve.
Chronological measurement matters. While I can see your point regarding the 48 hours, timing is of great importance in such spaceflight.
Unit measurement is also vital. The Mars Climate Orbiter, a $125M craft, was lost due to an error in Imperial/metric conversion.
If one finds intellectual discourse tiresome, the possibility exists that the issue lies with the reader, not the writers.
Is it me or has bickering about semantics become a trend here? With what "faulty" means, how long 48 hours is, what "orbital" means, and others, going on for pages and pages, it feels like being trolled.
It is solved on other sites by threading comments, so those who enjoy it can go down their silly rabbitholes but normal people can just skip over those threads. It also makes quoting much less necessary.
Unfortunately this site seems to use technology from the 90s that cannot do comment threads.
As someone working in the voice business, I think they should give a bit more thought to which voices they use. Insprucker has a fantastic "1960s rocket engineer" voice. Content-wise he is good and getting better. Most of the others... not great. A California valley girl voice (plus intonation), as well as a high-pitched adolescent boy voice just won´t keep audiences happy. They will get annoyed after a while and turn off the feed.
That was me for one!
I could not continually watch the Spacex broadcast because of those two's voices.
The "boy"'s voice was particularly nasal and jarring, I thought.
Respectfully, I'm going to ask that you reflect on this a little bit. Agreeing with those who think discussion of word meaning is pedantic, then turning around and being critical of someone's voice (and referring to him as a boy) is, at best ironic, and at worst hypocritical. Please think with more discretion before clicking save.
Post by: AS_501 on 04/19/2023 05:01 am
Post by: chopsticks on 04/19/2023 05:04 am
https://twitter.com/elonmusk/status/1648550090330480640I wonder what these many issues are. Did the WDR do a number on the booster somehow?QuoteThe team is working around the clock on many issues. Maybe 4/20, maybe not.
Edit: oops, I posted to the launch attempt thread, didn't realize it was updates only
Post by: Danrar on 04/19/2023 05:54 am
That's the FireX. Which also uses LN2. I believe the outer engines spin up the same way the inner ones do they just have simpler drain plumbing being closer to the mount.I think N2 is supplied from GSE to spin the outer 20 engines, ...Oh, is that what we're seeing in this 2-second shot during the SpaceX Starship livestream intro?
See 3:54 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m54s).
[The full 80-second into starts at 3:15 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m15s).]
Post by: alastairmayer on 04/19/2023 06:10 am
[...]I wonder what these many issues are. Did the WDR do a number on the booster somehow?QuoteThe team is working around the clock on many issues. Maybe 4/20, maybe not.
Edit: oops, I posted to the launch attempt thread, didn't realize it was updates only
Curious about that too, and made the same mistake.
Post by: Danrar on 04/19/2023 06:18 am
It's possible they had other issues they were able to work around. Remember they were aiming at 8:00am and it slipped to a slightly later time.Curious about that too, and made the same mistake.[...]I wonder what these many issues are. Did the WDR do a number on the booster somehow?QuoteThe team is working around the clock on many issues. Maybe 4/20, maybe not.
Edit: oops, I posted to the launch attempt thread, didn't realize it was updates only
It would be prudent to fix anything they had to work during the previous countdown while handling the blocking issue.
Post by: edzieba on 04/19/2023 08:20 am
No, it's not the detonation suppression system. Note the jets are of gas rather than water, and originating from the retractable QD couplings for the outer engines and not the suppression system nozzles (which hare fixed and further out on the underside of the OLM ring).That's the FireX. Which also uses LN2. I believe the outer engines spin up the same way the inner ones do they just have simpler drain plumbing being closer to the mount.I think N2 is supplied from GSE to spin the outer 20 engines, ...Oh, is that what we're seeing in this 2-second shot during the SpaceX Starship livestream intro?
See 3:54 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m54s).
[The full 80-second into starts at 3:15 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m15s).]
Post by: RamsesBic on 04/19/2023 08:54 am
No, it's not the detonation suppression system. Note the jets are of gas rather than water, and originating from the retractable QD couplings for the outer engines and not the suppression system nozzles (which hare fixed and further out on the underside of the OLM ring).That's the FireX. Which also uses LN2. I believe the outer engines spin up the same way the inner ones do they just have simpler drain plumbing being closer to the mount.I think N2 is supplied from GSE to spin the outer 20 engines, ...Oh, is that what we're seeing in this 2-second shot during the SpaceX Starship livestream intro?
See 3:54 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m54s).
[The full 80-second into starts at 3:15 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m15s).]
The FireX system uses nitrogen to atomize the water. The nitrogen nozzle is pointing at the water nipple. So we get a mixture of both.
Post by: edzieba on 04/19/2023 09:47 am
Look at the photo. The spray is from the engine QDs, not the detonation suppression system nozzles. Both are visible in the photo.No, it's not the detonation suppression system. Note the jets are of gas rather than water, and originating from the retractable QD couplings for the outer engines and not the suppression system nozzles (which hare fixed and further out on the underside of the OLM ring).That's the FireX. Which also uses LN2. I believe the outer engines spin up the same way the inner ones do they just have simpler drain plumbing being closer to the mount.I think N2 is supplied from GSE to spin the outer 20 engines, ...Oh, is that what we're seeing in this 2-second shot during the SpaceX Starship livestream intro?
See 3:54 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m54s).
[The full 80-second into starts at 3:15 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m15s).]
The FireX system uses nitrogen to atomize the water. The nitrogen nozzle is pointing at the water nipple. So we get a mixture of both.
Post by: RamsesBic on 04/19/2023 11:24 am
I see. I thought you were talking about the FireX.Look at the photo. The spray is from the engine QDs, not the detonation suppression system nozzles. Both are visible in the photo.No, it's not the detonation suppression system. Note the jets are of gas rather than water, and originating from the retractable QD couplings for the outer engines and not the suppression system nozzles (which hare fixed and further out on the underside of the OLM ring).That's the FireX. Which also uses LN2. I believe the outer engines spin up the same way the inner ones do they just have simpler drain plumbing being closer to the mount.I think N2 is supplied from GSE to spin the outer 20 engines, ...Oh, is that what we're seeing in this 2-second shot during the SpaceX Starship livestream intro?
See 3:54 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m54s).
[The full 80-second into starts at 3:15 (https://youtube.com/watch?v=L5QXreqOrTA&t=3m15s).]
The FireX system uses nitrogen to atomize the water. The nitrogen nozzle is pointing at the water nipple. So we get a mixture of both.
Post by: sferrin on 04/19/2023 12:05 pm
Some of these critiques are starting to sound a little like personal insults. I appreciate the various hosts for their differences, their passion, and the connection they have with SpaceX in addition to just being some "hired newscast blob" but that's all just my opinion and I'll leave it at that.
I'd be surprised if anybody means them as insults. Some people have a "face for radio" and others have a "voice for print". It's just a harsh reality.
Post by: kdhilliard on 04/19/2023 12:08 pm
It will be interesting to see (i.e. "hear") how many decibels this bird generates at liftoff. I think Saturn V was around 120-125, while SLS-1 was 135-140.Is there a standard distance these are measured at?
Post by: Orbiter on 04/19/2023 01:12 pm
It will be interesting to see (i.e. "hear") how many decibels this bird generates at liftoff. I think Saturn V was around 120-125, while SLS-1 was 135-140.Is there a standard distance these are measured at?
This article quotes Saturn V as 120 dB from 1.5 km away. The same distance for SLS was recorded at 136 dB.
https://www.bbc.com/future/article/20230306-just-how-loud-is-a-rocket-launch
Post by: kdhilliard on 04/19/2023 02:05 pm
That would make sense, but instead the article cites measurements at 1.5 mi for Saturn V and 1.5 km for SLS.This article quotes Saturn V as 120 dB from 1.5 km away. The same distance for SLS was recorded at 136 dB.It will be interesting to see (i.e. "hear") how many decibels this bird generates at liftoff. I think Saturn V was around 120-125, while SLS-1 was 135-140.Is there a standard distance these are measured at?
https://www.bbc.com/future/article/20230306-just-how-loud-is-a-rocket-launch
Quote
Even 1.5 miles (2.4km) away, the noise from a Saturn V launch was recorded as being 120 decibels – as loud as a rock concert, or a car horn at very close quarters.
...
A study by scientists at Brigham Young University and Rollins College in Florida studied recordings from the SLS during the Artemis 1 launch in November 2022 found it made more noise than pre-launch models had predicted. They found at 0.9 miles (1.5km) from the launchpad, the maximum noise level reached 136 decibels while at 3.2 miles (5.2km) it was 129 decibels.
(There's a pun in there somewhere about comparing Apollos and Orange rockets.)
Post by: litton4 on 04/19/2023 02:12 pm
That would make sense, but instead the article cites measurements at 1.5 mi for Saturn V and 1.5 km for SLS.This article quotes Saturn V as 120 dB from 1.5 km away. The same distance for SLS was recorded at 136 dB.It will be interesting to see (i.e. "hear") how many decibels this bird generates at liftoff. I think Saturn V was around 120-125, while SLS-1 was 135-140.Is there a standard distance these are measured at?
https://www.bbc.com/future/article/20230306-just-how-loud-is-a-rocket-launchQuoteEven 1.5 miles (2.4km) away, the noise from a Saturn V launch was recorded as being 120 decibels – as loud as a rock concert, or a car horn at very close quarters.
...
A study by scientists at Brigham Young University and Rollins College in Florida studied recordings from the SLS during the Artemis 1 launch in November 2022 found it made more noise than pre-launch models had predicted. They found at 0.9 miles (1.5km) from the launchpad, the maximum noise level reached 136 decibels while at 3.2 miles (5.2km) it was 129 decibels.
(There's a pun in there somewhere about comparing Apollos and Orange rockets.)
When I take my car on a track day, the static measurement has to be (typically) 95-105dB at 1.5m, measured at 45 degrees to the exhaust.
I suspect SS will be a bit higher....
Post by: AllenB on 04/19/2023 03:10 pm
This article quotes Saturn V as 120 dB from 1.5 km away. The same distance for SLS was recorded at 136 dB.
https://www.bbc.com/future/article/20230306-just-how-loud-is-a-rocket-launch
That is a huge difference, given the logarithmic nature of decibels, for two rockets of fairly comparable power. The one obvious difference would seem to be solid vs. liquid. Do we know if solids are significantly louder by nature? If so, perhaps Starship won't be so bad.
Post by: Jake-ZA on 04/19/2023 03:32 pm
I'd be surprised if anybody means them as insults. Some people have a "face for radio" and others have a "voice for print". It's just a harsh reality.
As regards SpaceX live commentary during a flight, including Falcon 9s, I can recall listening on short wave radio, way back, to broadcasts of launches where anything originating from mission control was preceded by a very short sort of cueing break in "beep" which gave the commentators a clue as to when to shut up. There's probably a technical term for the mechanism, which presumably has gone extinct because of modern technology. It'd be quite useful if this could be reinvented and make it easier for inexperienced commentators to add a bit of structure to their words of wisdom.
The other thing I find annoying is having things repeatedly explained to me as if I were a five year old incapable of remembering what MECO or MAXQ is. Clearly I'm not the target audience, but it's irritating.
Post by: matthewkantar on 04/19/2023 03:47 pm
Post by: ZachS09 on 04/19/2023 03:49 pm
I believe the term you are looking for is “Quindar tones.”
I thought the Quindar tones were used when astronauts communicate with Mission Control.
Post by: jboone on 04/19/2023 03:50 pm
As regards SpaceX live commentary during a flight, including Falcon 9s, I can recall listening on short wave radio, way back, to broadcasts of launches where anything originating from mission control was preceded by a very short sort of cueing break in "beep" which gave the commentators a clue as to when to shut up. There's probably a technical term for the mechanism, which presumably has gone extinct because of modern technology. It'd be quite useful if this could be reinvented and make it easier for inexperienced commentators to add a bit of structure to their words of wisdom.
Quindar tones: https://en.wikipedia.org/wiki/Quindar_tones (https://en.wikipedia.org/wiki/Quindar_tones).
SpaceX still uses them on Crew Dragon missions.
Post by: psionedge on 04/19/2023 04:01 pm
Do you live in a strange world where something has to be false for it to be an insult? (Nevermind that these are opinions anyways)Some of these critiques are starting to sound a little like personal insults. I appreciate the various hosts for their differences, their passion, and the connection they have with SpaceX in addition to just being some "hired newscast blob" but that's all just my opinion and I'll leave it at that.
I'd be surprised if anybody means them as insults. Some people have a "face for radio" and others have a "voice for print". It's just a harsh reality.
Post by: Tcasper on 04/19/2023 04:07 pm
Would anybody be able to provide GPS coords or a Google Maps pin of the best place to watch the launch? Would be much appreciated!
Post by: Oersted on 04/19/2023 04:09 pm
Post by: rsdavis9 on 04/19/2023 04:11 pm
Looking forward to watching tomorrow’s Starship launch! Drove quite a ways to get to TX!
Would anybody be able to provide GPS coords or a Google Maps pin of the best place to watch the launch? Would be much appreciated!
https://goo.gl/maps/14B1Hfb3ap1xdAt87
Post by: abaddon on 04/19/2023 05:33 pm
People who work in broadcasting should not be too precious, or it will be excessively stressful for them. And criticism is not the same as insults, even though it is becoming fashionable in some circles to think so.That's cool; personally I think the broadcasts are fine and all of this pathetic whining about it is really sad and is a waste of time when we could be discussing actually interesting stuff.
I'm just being honest! /s
Post by: AS_501 on 04/19/2023 06:05 pm
This article quotes Saturn V as 120 dB from 1.5 km away. The same distance for SLS was recorded at 136 dB.
https://www.bbc.com/future/article/20230306-just-how-loud-is-a-rocket-launch
That is a huge difference, given the logarithmic nature of decibels, for two rockets of fairly comparable power. The one obvious difference would seem to be solid vs. liquid. Do we know if solids are significantly louder by nature? If so, perhaps Starship won't be so bad.
Jay Apt once told me that big liquid-fuel rockets produce a more basso-profundo roar than big solid-fuel rockets. Don't ask me to explain the underlying physics. :) It will also be interesting how far away SS/SH will be heard (depending on weather conditions). Corpus Christi? Brownsville? San Antonio? Houston? Hopefully the launch won't trigger 911 calls from those who have no idea what's going on. :)
Post by: wannamoonbase on 04/19/2023 06:35 pm
I like Kate, I like Jesse, I like John. The rest are fine too.
And I can pretty much guarantee that few people if anyone at SpaceX give's two rats' asses what anyone on this forum thinks about their webcast hosts. We are not their target demographic whatsoever, nor should we be. Sorry to be the bearer of bad news, my Fellow Olds, but that's reality. Instead of poking inane criticism at hosts for a free service we have no right to expect at all, why not go yell at some clouds instead?
I think SpaceX's hosts do a fine job. I think the launch coverage that SpaceX provides is an important component of their image and appeal to potential employees and attract Starlink Customers.
Post by: alugobi on 04/19/2023 07:15 pm
Post by: ZachS09 on 04/19/2023 08:57 pm
Post by: sdfasdfasd on 04/19/2023 09:02 pm
The 62 minute launch window opens tomorrow, April 20th, at 8:28 a.m. and closes at 9:30 a.m.
So ( for any others who are also planning their day around this ) Starship will have splashed down by 9:58 at the earliest or 11:00 at the latest.
All times CDT.
Edit2: ZachSog beat me to it. Thanks!
Edit3: And at Daedalus1:
Leave it mate, your argument is pointless and jut(sic) fills the thread with irrelevant comments.
I want to know what Starship is doing and want to enjoy watching the official stream, which is not helped by your puerile remarks about remarks about the presenters' qualities as presenters.
Post by: ZachS09 on 04/19/2023 09:22 pm
You're on:
Do we know what time the launch window will open tomorrow and how long it will be?
IIRC, the window opens at 13:28 UTC (8:28 AM Central) and lasts 62 minutes until 14:30 UTC (9:30 AM Central).
Post by: Steve G on 04/19/2023 10:00 pm
Post by: jon.amos on 04/19/2023 10:27 pm
Post by: SpeakertoAnimals on 04/19/2023 10:44 pm
Please don’t overlook that the SpaceX presenters are engineers who design/build the product for day jobs. The presenter gig is part time/for fun. They are not professional media personalities, they are enthusiastic amateur presenters but professional rocket builders first.I prefer the engineers, the media people frequently demonstrate that they have no idea what they are talking about.
Post by: oiorionsbelt on 04/19/2023 10:53 pm
In June 2010 when F9 launched for the first time and did so successfully, Jim commented something along the lines of, "Now NASA has a replacement for the Delta II" (Wish I could find the exact quote.)
F9 went on to become so much more than Delta ll
How will Starship be viewed after it's first successful launch? Now NASA has a replacement for Saturn V ?
It's likely to become so much more than Saturn V.
Post by: TheRadicalModerate on 04/19/2023 11:05 pm
...I think you and rs are using the term differently.At mars pressure lox and lch4 are subcooled.
Dropping pressure lowers the boiling point. If you drop the pressure on a boiling liquid, it just boils faster. You can raise the pressure and make it subcooled, though.
Yes, a liquid is subcooled when it is below its boiling temperature for its given pressure, but by that standard the LOX in a Falcon 1 tank was subcooled once the tanks were pressurized for flight. SpaceX, when speaking of subcooled propellants, is of course saying that they are densified by being brought below their boiling point at Earth atmospheric pressure (since they are usually stored in bulk near atmospheric pressure, with their temperature maintained through boil-off).
Subcooling methane with respect to Mars atmospheric pressure will be difficult to do given its triple point of 90.69K/0.117bar, well above Mars's atmospheric pressure of 6mbar! Instead, what I believe rs is saying is simply that the densified propellant temperatures that SpaceX calls subcooled on Earth will be that of boiling propellants in an only partially pressurized tank on Mars.
FYI, I posted a question over on the Raptor engineering thread (https://forum.nasaspaceflight.com/index.php?topic=53555.msg2477275#msg2477275) about this. Somebody over there is going to know the answer and save us from wandering off into the thermodynamic weeds.
Post by: DigitalMan on 04/19/2023 11:08 pm
Please don’t overlook that the SpaceX presenters are engineers who design/build the product for day jobs. The presenter gig is part time/for fun. They are not professional media personalities, they are enthusiastic amateur presenters but professional rocket builders first.
When StevenOBrien posted about SpaceXer PhotonEmpress wanting feedback, I tried to make a positive contribution. (point was don't just joke about something, explain the detail).
Obviously, feedback is feedback, I tried to limit mine to things those individuals could do to improve.
Post by: alugobi on 04/19/2023 11:49 pm
Post by: clongton on 04/19/2023 11:54 pm
Jay Apt once told me that big liquid-fuel rockets produce a more basso-profundo roar than big solid-fuel rockets. Don't ask me to explain the underlying physics. :)
Pretty good explanation here:
https://www.youtube.com/watch?v=BdCizNwLaHA&ab_channel=ScottManley
Post by: Echo_Jex on 04/20/2023 12:09 am
Considering the bodies they threw at the booster and qd since the scrub, seems as though there was a lot more than a HE valve they were having to fix.I really don't know if I'm adding anything here. I was startled on the fleet size sent out too. when airplanes are trying to take off, the pilot can have a priority 1 grounding problem, and then there can be 2 pages of priority 2 non mission critical discrepancies that can get worked while waiting for parts and labor to wrap up.
Post by: Glorin on 04/20/2023 12:20 am
Post by: intrepidpursuit on 04/20/2023 12:48 am
I need help. I need a ride from Valley International Airport at midnight tonight to South Padre Island.
I'm flying back into Valley International Airport at midnight tonight and my Turo rental car just cancelled. Turo has no more cars, the rental car companies will be closed, Uber and Lyft show that they are unavailable, the taxis are booked.
I have an incredible condo rental on South Padre Island that can see the launch mount. It had parking passes and an extra bed. I was actually hoping to post an invite to join me anyway, so company would be welcome.
Please message me if you are willing to save my trip. I would be in your debt.
Post by: Chris Bergin on 04/20/2023 02:23 am
DO not post here unless you have something useful to add.
In fact, I'll start a new thread and I'm just going to stop a bunch of people (I don't care if you're L2 or not) from posting if I have to come back here again to a set of report to mod alerts that even the mods are throwing their hands up at (and having read them, I see exactly why). It's only a handful of people, but I'm seeing the same names, and sadly they are long-time members. They will not be allowed to lower the tone of this forum into some Reddit food fight.
Thread 2:
https://forum.nasaspaceflight.com/index.php?topic=58671.0