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#140
by
Alberto-Girardi
on 14 May, 2021 17:36
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twitter.com/teslaownerssv/status/1392989623169667073
Starship to do an orbital flight from Texas to Hawaii. 🤯🤯🤯 @elonmusk
https://twitter.com/elonmusk/status/1393064162335485952
3/4 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?
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#141
by
JohnM
on 14 May, 2021 17:39
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twitter.com/teslaownerssv/status/1392989623169667073
Starship to do an orbital flight from Texas to Hawaii. 🤯🤯🤯 @elonmusk
https://twitter.com/elonmusk/status/1393064162335485952
3/4 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.
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#142
by
philw1776
on 14 May, 2021 17:42
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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.
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.
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#143
by
racevedo88
on 14 May, 2021 17:42
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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
Edit/Lar: Preview exists for a reason. Fix your quotes. My patience is not inexhaustible.
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#144
by
Alberto-Girardi
on 14 May, 2021 17:44
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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
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.
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#145
by
RonM
on 14 May, 2021 17:51
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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.
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#146
by
Framryk
on 14 May, 2021 18:42
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Love the temerity of it. Absolutely love it.
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!
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#147
by
Lars-J
on 14 May, 2021 18:43
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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.
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#148
by
cscott
on 14 May, 2021 19:16
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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.
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#149
by
neoforce
on 14 May, 2021 19:35
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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.
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#150
by
eriblo
on 14 May, 2021 19:35
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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...
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#151
by
RedLineTrain
on 14 May, 2021 19:45
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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, it looks like most/all have been removed.
That said,
Perdido is some 140 miles downrange and could see quite a show.
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#152
by
Jim
on 14 May, 2021 19:53
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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.
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#153
by
Jim
on 14 May, 2021 20:05
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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.
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#154
by
meekGee
on 14 May, 2021 20:27
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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.
Agreed - there's certainly risk on ascent..
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.
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#155
by
ugordan
on 14 May, 2021 20:53
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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.
Agreed - there's certainly risk on ascent..
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.
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#156
by
meekGee
on 14 May, 2021 21:05
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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.
Agreed - there's certainly risk on ascent..
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...
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#157
by
oldAtlas_Eguy
on 14 May, 2021 21:15
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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.
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#158
by
philw1776
on 14 May, 2021 22:04
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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.
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#159
by
Lars-J
on 14 May, 2021 22:46
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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")