Why would dropping the fairings earlier mean more heating? Isn’t that a lower velocity and closer to shore?
Quote from: Norm38 on 06/20/2022 02:39 amWhy would dropping the fairings earlier mean more heating? Isn’t that a lower velocity and closer to shore?More heating of the uncovered payload on Stage 2
It’s so good to see how well Gerst appears to have adapted to SpaceX culture, and fascinating how frustrated he had become with the NASA way.
Quote from: ThatOldJanxSpirit on 06/11/2022 02:50 pmIt’s so good to see how well Gerst appears to have adapted to SpaceX culture, and fascinating how frustrated he had become with the NASA way.He was the reason for the "NASA" way and was in position to affect it.
They are now aiming at 15 flights per booster. They do this vibrating, heating, etc. each component to 4x the expected time of exposure at 15 flights.
Static fires used to be run after an engine was pulled or a turbine wheel changed. Now only if 3 engines are pulled; turbine wheels are now monitored by accelerometers during startup, and don't force a static fire.
Even Block 5 is still evolving; examples include better thermal shields and a way to drain the second stage tanks even if the QD pops off (which would otherwise be fatal). For most changes they identify the potential improvement, then test it on the bench, then on a StarLink launch, then it becomes general.
They keep tweaking the time interval between MECO and second stage start. The smaller the delay, the better the performance, but the more wear on the first stage.
They have two software systems tuned for re-use. One called Hyperion looks at the telemetry and points out areas that need a closer look. Warp, their production system, also has modifications for re-use such as pointing out similar problems that have occured on prior flights.
IOW into 10s of reuses of a first stage to M6, but nowhere near the 100's (1000s?) Musk thought was possible. That suggests the booster takes a hell of a beating
100s of reuses requires 100s of flights. I think SpaceX have just been taking a cautious / methodical approach as they’re not sure where the weak links might be and at what point they’ll hit a limitation (at least without significant refurbishment). So they’ve built up a reasonably sized fleet of boosters to support many flights even if 10 - 15 per booster proves a limit.
100s of flights may be possible but with Elon switching SpaceX’s focus to Starship, I don’t think he’s particularly interested in finding out any more (for F9, Starship is a whole other issue).
Now this is surprising. I'd have guessed a longer coast would have given them more altitude and be beneficial. OTOH more booster damage due to earlier sustainer ignition makes perfect sense due to greater exposure to engine plume.
Quote from: Norm38 on 06/20/2022 02:39 amWhy would dropping the fairings earlier mean more heating? Isn’t that a lower velocity and closer to shore?Lower velocity, but also a lower altitude so more atmospheric drag. The threshold for dropping the fairing is the amount of heat generated by drag.
In another description of the article it's stated that 15 is the limit as they want to phase out F9 launches and that in fact the real limit is higher. That may be true, but given that Starship hasn't reached orbit yet that is a very bold plan, never mind going to Mars (still 130 days to go to 2023).I wonder if someone who's been tracking number of launches across the 21 booster fleet can say how many of those 315 possible launches (15*21) the fleet has left in total? That's basically how long SX has to get SS orbit capable. Once that happens they can fix any outstanding issues with the design. Obviously SX could use the last flight of each as a "special" with maximum payload due to no landing gear (even for the fairings, as they are phasing out the whole vehicle). Really crank up the payload. Outer planets probe? I don't think Neptune or Uranus has had a visit since Voyager.
How do you know that they won’t build any more boosters beyond the current 21? Every additional booster gives them 15 more launches as may be needed.
I agree it’d be smart to prepare a much bigger buffer of F9 capacity than Elon would probably prefer, but…
Docking Starship to ISS is not very different from docking Shuttle to ISS.
Currently, SpaceX has 13 active boosters. Additionally, there are 10 more boosters that have been spotted in either testing or transit.It has been speculated that B1049 will be expended after it's next mission. Based on the available mission profile, it appears the 4 FH core boosters will be expended after their first launch as well.The true number of launches with just the current boosters likely is between 80 and 160 - without SpaceX deciding to certify some of the later ones to 20 flights.Based on the number of FH launches scheduled in the next 5 years, SpaceX will have to make up to 9 core boosters in that time frame, possibly more. I would not be surprised if SpaceX also makes several boosters in that time period.I personally don't see the F9/FH being retired prior to Starlink Gen2 being at least close to full deployment. That easily could take up to 9 years taking into account the shear number of launches needed.
The key items that can throw big spanners in the works are a)NASA contracts to supply ISS and b)SS is not orbit ready before the last F9 flies out.
Quote from: john smith 19 on 08/23/2022 01:51 pmThe key items that can throw big spanners in the works are a)NASA contracts to supply ISS and b)SS is not orbit ready before the last F9 flies out. The third big key item is an RUD of a reused booster well before the 15 launch expected lifetime. They'd have to alter all their key lifetime assumptions, and hence resulting fleet size.
Quote from: sghill on 08/24/2022 02:20 pmQuote from: john smith 19 on 08/23/2022 01:51 pmThe key items that can throw big spanners in the works are a)NASA contracts to supply ISS and b)SS is not orbit ready before the last F9 flies out. The third big key item is an RUD of a reused booster well before the 15 launch expected lifetime. They'd have to alter all their key lifetime assumptions, and hence resulting fleet size.True, unless it was caused by something that was obviously a one off event. I'm thinking something like FOD from something that was near/on the pad at launch?Otherwise if it happened once it could happen again, until whatever triggered is identified. As always in these situations the question is "Do you have very solid processes that have caught every error before it raises an issue, or have you just been lucky?" I think the high launch rate drives a virtuous circle that keeps their staff tight and well focussed but we'll find if such a mishap does occur. Unfortunately the reverse argument doesn't work. Absence-of-evidences cannot be taken as implying an evidence-of-absence.
Quote from: john smith 19 on 08/24/2022 04:11 pmQuote from: sghill on 08/24/2022 02:20 pmQuote from: john smith 19 on 08/23/2022 01:51 pmThe key items that can throw big spanners in the works are a)NASA contracts to supply ISS and b)SS is not orbit ready before the last F9 flies out. The third big key item is an RUD of a reused booster well before the 15 launch expected lifetime. They'd have to alter all their key lifetime assumptions, and hence resulting fleet size.True, unless it was caused by something that was obviously a one off event. I'm thinking something like FOD from something that was near/on the pad at launch?Otherwise if it happened once it could happen again, until whatever triggered is identified. As always in these situations the question is "Do you have very solid processes that have caught every error before it raises an issue, or have you just been lucky?" I think the high launch rate drives a virtuous circle that keeps their staff tight and well focussed but we'll find if such a mishap does occur. Unfortunately the reverse argument doesn't work. Absence-of-evidences cannot be taken as implying an evidence-of-absence. Reusability gives one a chance to see "almost failures", and to see the rate of decay of items that wear out. This goes a long way toward preventing random RUDs that need long investigations because all the evidence is burned and/or scattered into tiny bits.If there is a RUD, there are a dozen flown vehicles to examine, both for evidence of decay and for testing out possible failure theories.
Reusability gives one a chance to see "almost failures", and to see the rate of decay of items that wear out. This goes a long way toward preventing random RUDs that need long investigations because all the evidence is burned and/or scattered into tiny bits.If there is a RUD, there are a dozen flown vehicles to examine, both for evidence of decay and for testing out possible failure theories.
Quote from: Robotbeat Docking Starship to ISS is not very different from docking Shuttle to ISS.Given that it's about 13m longer than shuttle and designed to carry about 4x the mass of Shuttles payload bay (even if it came to orbit with only Shuttle's payload level) it's mass properties, such as 2nd moment of area, are going to be very different than Shuttles. That's important because of the loads put on the docking adapter. I think of it as a pool cue. The sharp end is at the adapter but the heavy end is at the other end of the cue, only the heavy end is now 13m further away, able to excert much more torque on that interface. Obviously with enough RCS control authority and fast enough acting control systems these issues can be overcome, if the will is there to do so. We'll find out when Starship makes orbit. Starship docked to ISS will be quite a sight.
Quote from: john smith 19 on 08/24/2022 06:07 amQuote from: Robotbeat Docking Starship to ISS is not very different from docking Shuttle to ISS.Given that it's about 13m longer than shuttle and designed to carry about 4x the mass of Shuttles payload bay (even if it came to orbit with only Shuttle's payload level) it's mass properties, such as 2nd moment of area, are going to be very different than Shuttles. That's important because of the loads put on the docking adapter. I think of it as a pool cue. The sharp end is at the adapter but the heavy end is at the other end of the cue, only the heavy end is now 13m further away, able to excert much more torque on that interface. Obviously with enough RCS control authority and fast enough acting control systems these issues can be overcome, if the will is there to do so. We'll find out when Starship makes orbit. Starship docked to ISS will be quite a sight. If push came to shove, I'd think that Dragon could be launched inside Starship.I'm sure it would require some modifications to Dragon, but possibly nothing drastic.
As we have discussed elsewhere, just leave a Dragon up there and use it to taxi crews back and forth between ISS and Starship.
Quote from: DanClemmensen on 08/28/2022 09:12 pmAs we have discussed elsewhere, just leave a Dragon up there and use it to taxi crews back and forth between ISS and Starship.Certainly possible, but then we get into the question of what that extended period on orbit does to Dragon. IIRC it's design target was something like 200+ days on orbit then back to earth (or re-entry) but this could leave it years in space. The alternative is to bring a Dragon with them on each launch but one of the key selling points is it's esape system. AFAIK that can't work inside SS payload bay.
A taxi does not need to be a full-up Dragon, but you do need a Dragon up there as a lifeboat. I think the Dragon is also used for living space? In any event, you can swap out the taxi/Dragon/whatever by carrying it as uncrewed cargo on an uncrewed Starship as often as you need to. No need for LAS since no crew. Cargo Starship flights are supposed to be cheap. This decouples the whole LAS-for-crewed-Starship from the Dragon/taxi completely. Once there are enough reliable crewed Starships, the taxi/lifeboat no longer needs to be EDL-capable, because a Starship can rescue the lifeboat crew.
If I were designing a space station, I would have the short-term experiments and the crew quarters in the Starship, so each crew comes up with its own quarters and experiments. Starships can stay on-station for as long as needed, from a week to six months or more. Only the long-term experiments stay on the much smaller long-term portion of the station. Among other things, It would be a lot easier to keep the place clean.
Quote from: DanClemmensen on 08/30/2022 02:04 pmIf I were designing a space station, I would have the short-term experiments and the crew quarters in the Starship, so each crew comes up with its own quarters and experiments. Starships can stay on-station for as long as needed, from a week to six months or more. Only the long-term experiments stay on the much smaller long-term portion of the station. Among other things, It would be a lot easier to keep the place clean.You do realize you're essentially repeating the design of Shuttle, right? It's like turning an 18 wheeler into an RV. Using SS's payload bay to set the size of modules greatly raises the module size and mass limits, but leaving stuff in there is not a good choice. Likewise the power needs for such a module are likely to need substantial arrays which are better as left permanently on orbit.
I think it may be a good idea to develop a jettisonable fairing for Starship. A big, highly-hammerheaded fairing, say 13m in diameter and 50m long. The fairing may be pretty massive, maybe 50t, but made of stainless steel so relatively inexpensive. Could even be recoverable, although likely used too rarely to justify that. Recover the stainless to recycle it I suppose.Whether the upper stage portion is reusable or not, I think this would be a useful capability to have.
An expendable upper stage with a 9 meter fairing is a mental image in my mind.
Quote from: wannamoonbase on 08/31/2022 05:24 pmAn expendable upper stage with a 9 meter fairing is a mental image in my mind.How much extra payload does jettisoning the fairing add? My mental counter-image is precisely what we have today except that the top of SS detaches at the top of the tanks, SS with Payload backs out of it, deploys Payload, reattaches, and comes only with full reusability. Same volume at the expense of the mass bump and the incremental complexity of a reattaching "nosecone". Craxy?
Currently, SpaceX has 13 active boosters. Additionally, there are 10 more boosters that have been spotted in either testing or transit.It has been speculated that B1049 will be expended after it's next mission. Based on the available mission profile, it appears the 4 FH core boosters will be expended after their first launch as well.The true number of launches with just the current boosters likely is between 80 and 160 - without SpaceX deciding to certify some of the later ones to 20 flights.
Quote from: wannamoonbase on 08/31/2022 05:24 pmAn expendable upper stage with a 9 meter fairing is a mental image in my mind.How much extra payload does jettisoning the fairing add? …
Quote from: AmigaClone on 08/24/2022 10:11 amCurrently, SpaceX has 13 active boosters. Additionally, there are 10 more boosters that have been spotted in either testing or transit.It has been speculated that B1049 will be expended after it's next mission. Based on the available mission profile, it appears the 4 FH core boosters will be expended after their first launch as well.The true number of launches with just the current boosters likely is between 80 and 160 - without SpaceX deciding to certify some of the later ones to 20 flights.So counting it up, there are ninety-six flights left in the current thirteen active boosters. That is if we assume an average of fifteen flights per booster. And that doesn't include the new boosters that are in the pipeline or the side boosters which after supporting Falcon Heavy flights could be converted to regular Falcon 9 boosters.Ninety-six flights will probably take SpaceX halfway through 2024. And it will be a whole lot more flights if we count the boosters that are in the production pipeline.SpaceX is prepared to do a lot more flights on the Falcon 9. I would say that they have definitely not assumed in the Falcon 9 production pipeline that the Starship will work.And it's really eleven active boosters that have been responsible for the flights so far this year. Booster 1949 last flew in September 2021. It's supposed to be expended on its next flight this November. And Booster 1069 just returned to flight a few days ago after an accident from a flight from last December(?).
Quote from: john smith 19 on 08/05/2022 07:48 pmNow this is surprising. I'd have guessed a longer coast would have given them more altitude and be beneficial. OTOH more booster damage due to earlier sustainer ignition makes perfect sense due to greater exposure to engine plume.Coasting leads to an increase in gravity losses.
Quote from: Hobbes-22 on 08/21/2022 03:40 pmQuoteNow this is surprising. I'd have guessed a longer coast would have given them more altitude and be beneficial. OTOH more booster damage due to earlier sustainer ignition makes perfect sense due to greater exposure to engine plume.Coasting leads to an increase in gravity losses.Correct. During the coast phase, the vehicle would be gaining altitude but also losing velocity that must be regained via the next stage. Think about throwing a rock straight up. Two things are happening as it approaches apex. It keeps getting higher and higher, but also is traveling slower and slower as gravity cancels out the energy your arm muscles put into it. Kinetic energy is changing into potential energy of elevation (which is then changed back to kinetic energy during descent.) The total acceleration a vehicle is undergoing at any point in time equals the positive acceleration coming from the engines minus the negative acceleration from gravity (known as gravity losses). During coast phase, there is no positive acceleration from engines, but you still have the cosine of one G decelerating the vehicle. From a performance perspective, you want coast to be as brief as possible. Since you want to recover and reuse the booster, you need enough coast time that the upper stage engine does not roast the booster. I am not sure how much thrust there is from ullage on both stages.
QuoteNow this is surprising. I'd have guessed a longer coast would have given them more altitude and be beneficial. OTOH more booster damage due to earlier sustainer ignition makes perfect sense due to greater exposure to engine plume.Coasting leads to an increase in gravity losses.
Quote from: Robotbeat on 08/23/2022 09:01 pmI agree it’d be smart to prepare a much bigger buffer of F9 capacity than Elon would probably prefer, but…Keep in mind 42 is a minimum figure for available launches. I'm not sure how evenly the launches have been spread throughout the fleet. I think some of them are quite a bit lower, but it's not something I've tracked in detail, hence my question. [EDIT Checked the F9 launch list on Wiki. It reckons they are at about 178 launches so far, so between 6-7 launches per booster left on average. Given some are within 2 launches of their 15 launch limit that confirms my feeling that the launches have been quite unevenly allocated, for whatever reasons]As I noted for other launch companies having 42 launches available would be good for years of launches but SX's cadence is much higher than most (all?) others.Quote from: Robotbeat Docking Starship to ISS is not very different from docking Shuttle to ISS.Given that it's about 13m longer than shuttle and designed to carry about 4x the mass of Shuttles payload bay (even if it came to orbit with only Shuttle's payload level) it's mass properties, such as 2nd moment of area, are going to be very different than Shuttles. That's important because of the loads put on the docking adapter. I think of it as a pool cue. The sharp end is at the adapter but the heavy end is at the other end of the cue, only the heavy end is now 13m further away, able to excert much more torque on that interface. Obviously with enough RCS control authority and fast enough acting control systems these issues can be overcome, if the will is there to do so. We'll find out when Starship makes orbit. Starship docked to ISS will be quite a sight.
The Shuttle aft bulkhead, between the cargo bay and the engine bay was a massive slab of titanium, hogged out leaving reinforcing ribs and attachment bosses. The stringers and beams leading forward from it attached to the bulkhead between the cargo bay and the crew cabin. This box assembly had to be strong enough to resist buckling and twisting from wing loading during EDL. In other words, that front bulkhead had to be pretty strong too.This front bulkhead is where the air lock and docking port lived. If the Shuttle had a bit of torque to feed into the connection, this very strong bulkhead is what would be loaded. Probably the second strongest point on the shuttle. Maybe the third after the wing spar attachments.
I see only two solutions. 1) Reinforce some or all ships. 2) Drop the idea and stay with Dragon.There's a lot to be said for staying with dragon and F9. It's known to be reliable, NASA is comfortable with it and I think I saw something about NASA contracting for more dragon flights, or planning on it. When the next contract is up, if SX has started phasing out the F9, is the time to renegotiate on the basis of NASA either paying enough to make a legacy system worth SX's time or paying enough to justify special mods to SS. It's not bait and switch. It's a new set of conditions.
....I see only two solutions. 1) Reinforce some or all ships. 2) Drop the idea and stay with Dragon.There's a lot to be said for staying with dragon and F9. It's known to be reliable, NASA is comfortable with it and I think I saw something about NASA contracting for more dragon flights, or planning on it. When the next contract is up, if SX has started phasing out the F9, is the time to renegotiate on the basis of NASA either paying enough to make a legacy system worth SX's time or paying enough to justify special mods to SS. It's not bait and switch. It's a new set of conditions.
Quote from: TomH on 09/01/2022 01:33 amQuote from: Hobbes-22 on 08/21/2022 03:40 pmQuoteNow this is surprising. I'd have guessed a longer coast would have given them more altitude and be beneficial. OTOH more booster damage due to earlier sustainer ignition makes perfect sense due to greater exposure to engine plume.Coasting leads to an increase in gravity losses.Correct. During the coast phase, the vehicle would be gaining altitude but also losing velocity that must be regained via the next stage. Think about throwing a rock straight up. Two things are happening as it approaches apex. It keeps getting higher and higher, but also is traveling slower and slower as gravity cancels out the energy your arm muscles put into it. Kinetic energy is changing into potential energy of elevation (which is then changed back to kinetic energy during descent.) The total acceleration a vehicle is undergoing at any point in time equals the positive acceleration coming from the engines minus the negative acceleration from gravity (known as gravity losses). During coast phase, there is no positive acceleration from engines, but you still have the cosine of one G decelerating the vehicle. From a performance perspective, you want coast to be as brief as possible. Since you want to recover and reuse the booster, you need enough coast time that the upper stage engine does not roast the booster. I am not sure how much thrust there is from ullage on both stages.Probably absurd idea, for any number of reasons, but is there no benefit in briefly flipping the tail of the 2nd stage downwards by say 30 degrees to allow for immediate ignition upon separation, with the plume then directed mostly away from the separating booster? For those few seconds the thrust will not be exactly in the intended direction, but you don’t have complete coasting either. Or does the inefficiency outweigh the benefits of a couple of seconds of extra partial thrust?
#SpaceX's #Falcon9 & #FalconHeavy flightworthy boosters as of Sep 5, 2022
Statistics of #SpaceX's #Falcon9 & #FalconHeavy booster missions as of Sep 5, 2022
Current booster reuse status, following Starlink launch few hours ago:
Quote from: FutureSpaceTourist on 09/05/2022 05:49 amCurrent booster reuse status, following Starlink launch few hours ago:Interesting.So B1051,1058 and 1060 are the flight leaders. It'll be interesting to see what happens when they reach 15 flights.
The decision to requalify the boosters for 15 flights was a natural outgrowth of the ongoing evolution of the Block 5. “Every flight, we’re continuously inspecting, learning and then reapplying those lessons to either changing the design, a manufacturing process or our inspection methods across the fleet and into the next flights,” says Kiko Dontchev, SpaceX vice president for launch.
SpaceX has three classes of inspections: A class is performed for every mission; B class involves periodic maintenance, which is now performed every sixth or seventh flight; and C class, the most thorough maintenance process, is used for the fleet life-leaders and for all crewed missions.
I suspect that SpaceX might do a more intensive inspection on at least B1058 and B1060 in view of potentially requalifing those boosters and the ones that follow to 20 flights. I'm not certain if B1051 would also undergo that inspection or not.
Quote from: AmigaClone on 09/05/2022 02:01 pmI suspect that SpaceX might do a more intensive inspection on at least B1058 and B1060 in view of potentially requalifing those boosters and the ones that follow to 20 flights. I'm not certain if B1051 would also undergo that inspection or not.Well Musk is saying 100 launches next year so that number of flights is not nealy as much leeway as it appeared. Looking to get the fleet up to 20 each would be a sensible precaution. We'll see.
Quote from: john smith 19 on 09/06/2022 07:08 amQuote from: AmigaClone on 09/05/2022 02:01 pmI suspect that SpaceX might do a more intensive inspection on at least B1058 and B1060 in view of potentially requalifing those boosters and the ones that follow to 20 flights. I'm not certain if B1051 would also undergo that inspection or not.Well Musk is saying 100 launches next year so that number of flights is not nealy as much leeway as it appeared. Looking to get the fleet up to 20 each would be a sensible precaution. We'll see.This also depends on how many of Elon's launches are Starship. If he magically hits 30 Starship launches, he only has 70(!) F9/FH to worry about.
It's been 6 years to get to a SS/SH on the OLM. I would love to be wrong, but I think SS will be in the single digits in 2023 and maybe even 2024.F9/FH are going to be carrying the mail in 2023.
Quote from: wannamoonbase on 09/06/2022 02:37 pmIt's been 6 years to get to a SS/SH on the OLM. I would love to be wrong, but I think SS will be in the single digits in 2023 and maybe even 2024.F9/FH are going to be carrying the mail in 2023.That's my view as well. The simple fact is it's 116 days to 2023 and SS has not reached orbit yet. Obviously it could launch tomorrow, and the era of Starship will have finally dawned, but it could just as easily stay on the ground till next year. I'm not really clear what the delay is at this point. The economics from SX's PoV are get SS to orbit and start winding down the whole expendable infrastructure.
Quote from: john smith 19 on 09/06/2022 07:08 amQuote from: AmigaClone on 09/05/2022 02:01 pmI suspect that SpaceX might do a more intensive inspection on at least B1058 and B1060 in view of potentially requalifing those boosters and the ones that follow to 20 flights. I'm not certain if B1051 would also undergo that inspection or not.Well Musk is saying 100 launches next year so that number of flights is not nealy as much leeway as it appeared. Looking to get the fleet up to 20 each would be a sensible precaution. We'll see.I suspect it will take a combination of certifying at least some of the boosters to 20 flights and converting some FH side boosters to F9 to reach that goal of 100 Falcon 9 launches. Note that booster B1052 flew twice as a FH side booster and this year has flown 5 times as a Falcon 9, so it's something that's been done with a Block 5
I suspect it will take a combination of certifying at least some of the boosters to 20 flights and converting some FH side boosters to F9 to reach that goal of 100 Falcon 9 launches. Note that booster B1052 flew twice as a FH side booster and this year has flown 5 times as a Falcon 9, so it's something that's been done with a Block 5
As of right now, it’s just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.That’s the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then they’ll be well-positioned for an FAA launch license. Although there are a bunch of other things needed as well.Could come by the end of the year if all goes well.
Quote from: Robotbeat on 09/06/2022 07:32 pmAs of right now, it’s just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.That’s the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then they’ll be well-positioned for an FAA launch license. Although there are a bunch of other things needed as well.Could come by the end of the year if all goes well.Except FH manages to start up 27 Merlins in a few seconds, with each group of 9 under control of a different processor. Multiple times so far. Compared to the troubles of working out the SSME start sequence (LH2 is the only compressible liquid at these pressures, everything else should behave more like water) the issues should be relatively straightforward. I'd have bet more on TPS issues, or the Cp/Cg shift through re-entry.
So what's with the overestimating SpaceX amazing peoples on Twitter that question Starship/Super Heavy, believing that it's already ready to go?
Quote from: ZachS09 on 09/07/2022 01:15 pmSo what's with the overestimating SpaceX guys on Twitter that question Starship/Super Heavy, believing that it's already ready to go?They may be able to get ready for launch within a month or two.
So what's with the overestimating SpaceX guys on Twitter that question Starship/Super Heavy, believing that it's already ready to go?
Quote from: john smith 19 on 09/07/2022 06:58 amQuote from: Robotbeat on 09/06/2022 07:32 pmAs of right now, it’s just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.That’s the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then they’ll be well-positioned for an FAA launch license. Although there are a bunch of other things needed as well.Could come by the end of the year if all goes well.Except FH manages to start up 27 Merlins in a few seconds, with each group of 9 under control of a different processor. Multiple times so far. Compared to the troubles of working out the SSME start sequence (LH2 is the only compressible liquid at these pressures, everything else should behave more like water) the issues should be relatively straightforward. I'd have bet more on TPS issues, or the Cp/Cg shift through re-entry. There's a reason everybody doesn't use ssfc engines. They're much harder to start up exactly the way you want than Merlin type engines. FH isn't really proof that the Raptor booster is easily doable.
SSFC?
Quote from: Hog on 09/07/2022 04:24 pmSSFC? FFSC
Quote from: Robotbeat on 09/07/2022 01:17 pmQuote from: ZachS09 on 09/07/2022 01:15 pmSo what's with the overestimating SpaceX guys on Twitter that question Starship/Super Heavy, believing that it's already ready to go?They may be able to get ready for launch within a month or two.We'll see.
Quote from: ZachS09 on 09/07/2022 01:22 pmQuote from: Robotbeat on 09/07/2022 01:17 pmQuote from: ZachS09 on 09/07/2022 01:15 pmSo what's with the overestimating SpaceX guys on Twitter that question Starship/Super Heavy, believing that it's already ready to go?They may be able to get ready for launch within a month or two.We'll see.I wouldn’t bet a launch attempt (ie clamps release) of Starship before the end of the year, but it’s a significant possibility. I also wouldn’t bet on an SLS launch attempt before November.
Quote from: Robotbeat on 09/07/2022 09:13 pmQuote from: ZachS09 on 09/07/2022 01:22 pmQuote from: Robotbeat on 09/07/2022 01:17 pmQuote from: ZachS09 on 09/07/2022 01:15 pmSo what's with the overestimating SpaceX guys on Twitter that question Starship/Super Heavy, believing that it's already ready to go?They may be able to get ready for launch within a month or two.We'll see.I wouldn’t bet a launch attempt (ie clamps release) of Starship before the end of the year, but it’s a significant possibility. I also wouldn’t bet on an SLS launch attempt before November.No one has flown anything like or as large as Starship before. So who knows how many things SpaceX will learn before they to clamp release.I think we all know they will get there, and so will SLS.I've been 6 years working to get to this point from the first presentation for the ITS that became SLS, a few more months on booster on stand testing is pretty exciting itself.
Quote from: john smith 19 on 09/05/2022 07:44 amQuote from: FutureSpaceTourist on 09/05/2022 05:49 amCurrent booster reuse status, following Starlink launch few hours ago:Interesting.So B1051,1058 and 1060 are the flight leaders. It'll be interesting to see what happens when they reach 15 flights.Notice that boosters going over 10 flights are doing only StarLinks. My guess is it'll stay this way up to 15 flights. Then do a deep dive on one or two and decide if 20 would work. If it's a go, from 16 to 20 will be starlinks only but they might decide paying customers can go up to 15. Repeat every increase of five. Just guessing.
27 engine Falcon Heavy is pretty comparable, actually, just without the advantage of an intermediate Falcon 9.
A change of plans is not a "paradox".
Notice that boosters going over 10 flights are doing only StarLinks.
No obvious limit to rocket reflight so far
Back of the envelope - if an F9 booster costs $30M to build, 15 uses gets that cost down to $2M per flight. Add $1M for refurbishment and we are now as low as $3M booster cost per flight, all inclusive.Add $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.That’s for 16 tons to LEO. Remarkable.
It appears that Elon is suggesting that soon at least some of the F9 Block 5 boosters might receive intensive checks to support certifying them to twenty flights, an increase of five compared to the fifteen flights mentioned in the article.
Quote from: AmigaClone on 09/12/2022 11:44 amIt appears that Elon is suggesting that soon at least some of the F9 Block 5 boosters might receive intensive checks to support certifying them to twenty flights, an increase of five compared to the fifteen flights mentioned in the article.While I wouldn't be surprised if they follow through on the previously-suggested plan to pull one for checks at 15, I'm interpreting that quote as they might keep pressing forward and wait for standard refurbishment inspections to suggest the need for intensive check-out/certification.
Add $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.That’s for 16 tons to LEO. Remarkable.
Quote from: M.E.T. on 09/11/2022 08:04 amAdd $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.That’s for 16 tons to LEO. Remarkable.It's less than that. They can start depreciating the $10 booster cost now that it isn't being thrown away.
That’s for 16 tons to LEO. Remarkable.
Quote from: M.E.T. on 09/11/2022 08:04 amThat’s for 16 tons to LEO. Remarkable.For SX profit margin yes it is. As a customer, so what?