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SpaceX Vehicles and Missions => SpaceX Reusability => Topic started by: LouScheffer on 06/11/2022 11:50 am

Title: Aviation week article on SpaceX reusability
Post by: LouScheffer on 06/11/2022 11:50 am
There is a most excellent article on Aviation Week, SpaceX Building Airline-Type Flight Ops For Launch (https://aviationweek.com/defense-space/space/spacex-building-airline-type-flight-ops-launch) that is chock full of information. It's behind a paywall, but here are a few points:

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.

They are aiming at a flight every 5 days with a 21 booster fleet.

The engine boots are water-cooled and get replaced proactively.

The oxidizer transfer tube has seals (thermal expansion, I'd guess) and is being looked at carefully.

SpaceX has an airline type inspection system.  'A' check after every flight, 'B' check every 6-7 flights, 'C' check for life leaders and crewed missions.

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.

SpaceX has had two recent-ish booster engine shutdowns (March 2020 and Feb 2021).  Both still made orbit.  The 2020 failure was cleaning fluid left in the oxygen section of the gas generator, the 2021 failure was hot gas penetrating the engine shield and eating a harness.  This was the center engine so no landing was possible.

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.

On Starlink launches they are experimenting with dropping the fairings earlier, allowing up to 10x the normal heating (which I think is one sun).

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.

Lots of other tidbits.  Overall a fascinating article in the best Aviation Week tradition.


Title: Re: Aviation week article on SpaceX reusability
Post by: ThatOldJanxSpirit on 06/11/2022 02:50 pm
Itís 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: NavierĖStokes on 06/11/2022 03:08 pm
Thanks for the summary. It should be noted that the full article is accessible with a free Aviation Week account.
Title: Re: Aviation week article on SpaceX reusability
Post by: Norm38 on 06/20/2022 02:39 am
Why would dropping the fairings earlier mean more heating? 
Isnít that a lower velocity and closer to shore?
Title: Re: Aviation week article on SpaceX reusability
Post by: gongora on 06/20/2022 02:57 am
Why would dropping the fairings earlier mean more heating? 
Isnít that a lower velocity and closer to shore?

More heating of the uncovered payload on Stage 2
Title: Re: Aviation week article on SpaceX reusability
Post by: rpapo on 06/20/2022 11:03 am
Why would dropping the fairings earlier mean more heating? 
Isnít that a lower velocity and closer to shore?
More heating of the uncovered payload on Stage 2
It's not just heating.  If you uncover the payload too soon, you also risk damage due to physical drag.
Title: Re: Aviation week article on SpaceX reusability
Post by: Jim on 07/19/2022 02:08 pm
Itís 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: meekGee on 07/20/2022 12:11 am
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.

He was the reason for the "NASA" way and was in position to affect it.
Yup and either he found it impossible to change, or more likely it was impossible for him to see how stagnant it is while looking from the inside.

If that was all he saw and knew, then that's what he thought the universe was like.  And after a bit of time somewhere else, he came around to realize maybe there is a better way, and he now gets frustrated at the very things he used to accept.

It just shows that he's capable of changing and growing.

Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/05/2022 07:48 pm
Quote from: LouScheffer
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.
This is a very interesting.

So 7 years after the start of reuse a booster can manage maybe 15 flights, compared to the previous 0 reuses of all previous systems. It's very impressive what can be achieved with a constant focus on improvement.

So linearly that's a smidgeon over 2 increases per year.

[Edit Just to put this in perspective the Space Shuttle Discovery made 39 flights during its opearting lifetime. I'm not sure if the structure was at its retirement limits at that point or if they could have continued flying if the programme continued. Stage and pad turnaround times are remarkable, but F9 is still far from breaking that number of reuses but with current rate of prgress should be there by 2033]

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

Obviously a clean-sheet design incorporating all the lessons learned from F9/FH ops will be considerably better

But how much better? On the current basis a 100 flights sound like a massive improvement.  Actual airliner relaibility is into the 10s of 1000s.


Quote from: LouScheffer
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.
There was a NASA project using these techniques connected to the SSME's. Seemed an excellent idea but I was never sure if they got it deployed before the programme ended.
Obviously the processors running the Merlins are much more powerful than the dual M68000's that ran the 2nd generation SSME controllers.

Quote from: LouScheffer
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.
TBH I always thought the claim that "Block 5" would be the end of F9 development was rather strange and always expected them to go on tweaking it, wheather it was announced as  new version or not.

Quote from: LouScheffer
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.
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: LouScheffer
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.
NASA Goddard have done a lot of work in this area. The application of AI ("Deep learning" to some, advanced pattern recognition to others) to space operations as a way to eliminate routine eyeballing of the data and automated management-by-exception

It's good to get an idea of how an SoA launch operations centre functions.

One key area that has proved very expensive in the past (IIRC about 30% of shuttle launch costs) were misison planning. IE trajectory design and things like coupled loads analysis IE making sure the payload didn't excite dangerous resonances in the LV, and vice versa. Historically this has been very time consuming, especially when the a dangerous mode can't be fixed by changing the engine burn, or the fuel loading and the payload needs to be rebuilt.
Title: Re: Aviation week article on SpaceX reusability
Post by: FutureSpaceTourist on 08/21/2022 12:40 pm
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 theyíre not sure where the weak links might be and at what point theyíll hit a limitation (at least without significant refurbishment). So theyíve 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 SpaceXís focus to Starship, I donít think heís particularly interested in finding out any more (for F9, Starship is a whole other issue).
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/21/2022 01:25 pm
100s of reuses requires 100s of flights. I think SpaceX have just been taking a cautious / methodical approach as theyíre not sure where the weak links might be and at what point theyíll hit a limitation (at least without significant refurbishment). So theyíve built up a reasonably sized fleet of boosters to support many flights even if 10 - 15 per booster proves a limit.
15 flights (IIRC the fleet leader has done 13) seems pretty low. They could do 2 more launches on it and find out what happens. That would still leave them with 20 boosters to cycle through
Quote from: FutureSpaceTourist
100s of flights may be possible but with Elon switching SpaceXís focus to Starship, I donít think heís particularly interested in finding out any more (for F9, Starship is a whole other issue).
Maybe, maybe not.

The question is wheather what causes failure is down to the materials or the launch mode itself.

If the former then (plausibly) switching to steel for Starship will radically raise the threshold as Aluminum just can't take it.

But if it's the launch mode itself that's the issue that's not really going to change.

Imagine you drove to work each day like this.
 You'd stand on the brakes, build up the revs then screech out your driveway.
At work you'd stop by coasting into your parking spot, starting up you engine in neutral, then engaging in reverse at the last possible moment so it stops just before it hits the kerb.


Sounds like it could be a bit tough on your engine?

Time will tell how much higher SX can get their stage limit.  Aircraft, any aircraft can handle 1000s of take offs and landings.  SX's launch manifesto should kick at least one stage up to its (current) life limit by the end of the year.

You can argue that this is not that important, with Starship taking over F9 launch duties but the question for that is when will it do so, given a) SS has not achieved orbit yet b)its last test flight was 3 months ago.

Maybe it's next flight be an "all-up-test" straight to orbit with full TPS, but we'll see.
Title: Re: Aviation week article on SpaceX reusability
Post by: Hobbes-22 on 08/21/2022 03:40 pm
Quote
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.

Coasting leads to an increase in gravity losses.
Title: Re: Aviation week article on SpaceX reusability
Post by: Hobbes-22 on 08/21/2022 03:41 pm
Why would dropping the fairings earlier mean more heating? 
Isnít 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: rpapo on 08/21/2022 10:32 pm
Why would dropping the fairings earlier mean more heating? 
Isnít 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.
Both of you are right, but talking about different things.  It looks like Norm38 is referring to the heating on the fairings, particularly upon reentry.  And that you (Hobbes-22) are talking about the heating on the payload. 
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/23/2022 07:03 am
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: M.E.T. on 08/23/2022 10:57 am
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 wonít build any more boosters beyond the current 21? Every additional booster gives them 15 more launches as may be needed.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/23/2022 01:51 pm
How do you know that they wonít build any more boosters beyond the current 21? Every additional booster gives them 15 more launches as may be needed.
It's the logical thing to do. Just as shutting down F1 production and the CFRP SS were the logical things to do after they outlived their usefulness. I don't think anyone has ever accused Musk of being a sentimentalist.

I agree it would be sensible for the time being, to continue low rate production of F9 boosters until an SS makes orbt and lands. But I'm not Elon Musk. It's the article we are discussing that says SX is retiring F9's after 15 flights because they want to be ready for SS.

For maximum financial benefit you shut down the booster mfg line, leaving the US line (are they still making new Dragons as well?) running, then build enough for the remaining agreed launches and shut that down as well.

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.

Of these two I think NASA is the bigger issue. I think SX would like to go with a fully reusable system to support the ISS IE phase out Dragons. I think that's a step too far for NASA, and they will want to continue with dragons. Docking SS to ISS is a very different beast to docking a crewed Dragon. :(  If they really decided to be awkward they could insist on them launching on F9's, but I think they will be reasonable (and I suspect the contract clauses cover this issue in some form).

Which leaves what happens if the have shut down the F9 boosterline, run out of F9 booster launches and (for whatever reason) SS has still not reached orbit.

Hence my interest in finding out what the state of the "clock" actually is. With the fleet leader at 13 that gives at least another 42 launches across the fleet, which sounds quite a lot (by the standards of other launch service companies) but for SX not so much.

So I guess the next question is which has the least number of launches on it so far?

Of course if it's just a business decision to retire after 15 flights (and F9 boosters have lots more flights left in them) then they just have to raise the "retirement age" and keep them flying and the problem goes away.
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 08/23/2022 09:01 pm
I agree itíd be smart to prepare a much bigger buffer of F9 capacity than Elon would probably prefer, butÖ

Docking Starship to ISS is not very different from docking Shuttle to ISS.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/24/2022 06:07 am
I agree itíd be smart to prepare a much bigger buffer of F9 capacity than Elon would probably prefer, butÖ
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.  :)
Title: Re: Aviation week article on SpaceX reusability
Post by: AmigaClone on 08/24/2022 10:11 am
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/24/2022 11:57 am
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.
Interesting.

Until Starlink a launcher that could deploy 60 satellites would be expected to be able to deploy most constellations in a single launch (excepting Iridium). A different world.
Title: Re: Aviation week article on SpaceX reusability
Post by: wannamoonbase on 08/24/2022 02:12 pm
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.

I agree that we will see F9/FH fly for sometime, a decade doesn't seem unreasonable.  The rate will taper after Starship is successful.  The out years will have some FH and F9's for NASA and DOD missions and F9's for human flights.  Maybe 4-6 per year in the later years.
Title: Re: Aviation week article on SpaceX reusability
Post by: sghill on 08/24/2022 02:20 pm
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.

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.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/24/2022 04:11 pm
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.

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.  :(
Title: Re: Aviation week article on SpaceX reusability
Post by: freddo411 on 08/24/2022 07:27 pm
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.

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.

Title: Re: Aviation week article on SpaceX reusability
Post by: Hog on 08/24/2022 10:56 pm
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.

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.
Everything you stated is true, and evidenced, although ignored(prior to STS-51L), during operations of the STS Solid Rocket Boosters.  Almost 4 decades ago in spaceflight history.  The SRMs were talking, but management wasn't listening.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/25/2022 07:01 am

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.
True, all of which discourages failures in the first place.
Title: Re: Aviation week article on SpaceX reusability
Post by: MP99 on 08/28/2022 09:07 pm

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.  :)

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.
Title: Re: Aviation week article on SpaceX reusability
Post by: DanClemmensen on 08/28/2022 09:12 pm


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.  :)

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.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/30/2022 06:58 am
As 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: MP99 on 08/30/2022 08:28 am
Sorry - I wasn't thinking of crewed Dragon inside Starship, only cargo.

If NASA wants a LAS for crewed flights (as I would expect), then it would need to sit in the nose. Starship would need a nose to reenter - not sure how that could work. Maybe a dummy nose inside the cargo space?



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Title: Re: Aviation week article on SpaceX reusability
Post by: DanClemmensen on 08/30/2022 02:04 pm
As 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 08/31/2022 06:45 am
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.
For cargo that's viable, although it adds complexity.

Quote from: DanClemmensen
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.
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 08/31/2022 02:00 pm
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: matthewkantar on 08/31/2022 03:27 pm
A 50 ton fairing is around 30K USD in scrap, probably not worth the effort.
Title: Re: Aviation week article on SpaceX reusability
Post by: DanClemmensen on 08/31/2022 04:29 pm
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.
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.
If it's better to leave the panels in space, then by all means do it. Send them up like any other long-term module. To the extent that this model matches Shuttle, that's fine with me. Shuttle flew 134 times and was by far the longest-running crewed US space program. It "failed" because it was too expensive, but if successful Starship will be less expensive by at least an order of magnitude. But SS for crew quarters and "short-term" lab space is very different than Shuttle, because this "lab" Starship is not also designed to deliver large modules.

Why is "leaving stuff in there" a bad choice? This stuff does not have to stay in space as it is being used for short-term experiments. By leaving it in the "lab" Starship you can bring it back to Earth and service it in relative comfort using specialized equipment and personnel rather than using astronauts in free fall with more limited equipment.

We are now drifting far off topic, so perhaps a different thread?
Title: Re: Aviation week article on SpaceX reusability
Post by: wannamoonbase on 08/31/2022 05:24 pm
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.

Although I love the idea of what hardware would require such a fairing, it's hard to imagine what is needed beyond the 9 meters, at this time anyway.

An expendable upper stage with a 9 meter fairing is a mental image in my mind.  I know the the Elon and SpaceX amazing peoples hate when I bring up an expendable upper stage.  But think of the volume and mass to LEO!

Frankly, if SS is as cheap to make as it appears to be, then an expendable US for 100+ MT to LEO would be a huge bargain.

And if you can reuse the fairing, then rinse repeat!
Title: Re: Aviation week article on SpaceX reusability
Post by: AC in NC on 08/31/2022 06:10 pm
An 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?
Title: Re: Aviation week article on SpaceX reusability
Post by: dglow on 08/31/2022 07:06 pm
An 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?

Hinged petals, a la Neutron, would be a simpler choice if full recovery was the objective IMO.
Title: Re: Aviation week article on SpaceX reusability
Post by: mandrewa on 08/31/2022 07:27 pm
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.

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(?).
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 08/31/2022 07:34 pm
An expendable upper stage with a 9 meter fairing is a mental image in my mind.
How much extra payload does jettisoning the fairing add? 

Ö
Probably about 20 tons. And that applies to every orbit Starship can launch to. So to GTO or to escape velocity missions, that is huge. Doubling payload or even more.

Plus allows much larger payloads to be launched. Think like something similar to LUVOIR but without folding. Or a massive Skylab-like station. Or a huge but bulky solar array optimized for mass instead of stowage volume. Or a huge depot with more capacity than an entire Super Heavy booster. Or an in-space transfer vehicle for hundreds of people. Or an expandable habitat for thousands.

If you want to make a mega-telescope capable of 20m diameter or something exceeding any terrestrial scope.
Title: Re: Aviation week article on SpaceX reusability
Post by: M.E.T. on 08/31/2022 11:26 pm
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.

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(?).

https://twitter.com/elonmusk/status/1564994769826172929?s=21&t=Qr6mxKFx-RCkc1morHYO0g

Title: Re: Aviation week article on SpaceX reusability
Post by: TomH on 09/01/2022 01:33 am
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.

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.
Title: Re: Aviation week article on SpaceX reusability
Post by: M.E.T. on 09/01/2022 02:10 am
Quote
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.

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 donít have complete coasting either. Or does the inefficiency outweigh the benefits of a couple of seconds of extra partial thrust?

Title: Re: Aviation week article on SpaceX reusability
Post by: jimothytones on 09/01/2022 04:56 am
You'd spend more time reorienting the S2/Fairing/spacecraft complex to a radial out-ish attitude using S2's very limited onboard gas RCS than you would just waiting to get some more distance from the booster. For a *very* marginal payload benefit, if any. TBH it would probably reduce your total available dV, at least on lighter payloads.

Heating and mechanical erosion from exhaust plume impingement decreases very rapidly with distance at the altitudes where F9 likes to stage. The performance advantage X is looking for when tweaking the timing of S2 ignition is measured in kilograms, not tons. It's worth fiddling with, but not really worth trying out any major operational changes.
Title: Re: Aviation week article on SpaceX reusability
Post by: OTV Booster on 09/01/2022 10:36 pm
I agree itíd be smart to prepare a much bigger buffer of F9 capacity than Elon would probably prefer, butÖ
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.  :)
I'm late to the party, but have to comment. The difficulties in docking the SS to the ISS may be more profound than you expect.


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.


The SS has no comparable strong point. One could be designed in but it would have to load into the hull structure and spread the load widely in an area not designed for loads of that type. The shuttle probably needed extra reinforcement too but it would have been loading into a relatively small structure already designed to be rigid and already designed to load into a strong box structure.


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.

Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/02/2022 11:44 am

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.
Exactly. IMHO any point you can reasonably put a docking port is still going to have a substantial portion of the vehicle mass a substantial way from it, giving the ability to excert serious torque on that docking port.

Quote from: OTV Booster
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.
True.  Those do look like the major options. And this is certainly nothing like the sort of bait-n-switch that Boeing did with XS-1

It's nearest parallel is ULA's wish to migrate all launches to Vulcan but still having contractual obligations DIVH.  :(

Economically (and let's not forget Musk has a degree in Economics as well as Physics) SX's best path is total shut down of the F9/FH operation, once SS shows it can get to and return from orbit.

The joker is of course wheather the 15 flight maximum is an economic or a physical limit imposed by the flight conditions and if it takes longer SS to prove out that SX expect. SX say it's the former, so if SS needs more testing then that's not a problem as they just raise the limit.

As always time will tell.
Title: Re: Aviation week article on SpaceX reusability
Post by: TomH on 09/03/2022 12:03 am

....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.

Add to this, Elon wants to retire F9 and Dragon ASAP. Also, if Russia does abandon ISS, it will require significant effort to keep it functioning. With that being the case, Elon may consider the whole thing not worth the risk. (A risk that is beyond engineering risk and more the risk of what the very unpredictable and unreliable Russians will do.)

It's like a really bad marriage, especially if one party is just playing mind games. Sometimes therapy is futile and divorce is the better option.
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 09/03/2022 03:57 am
SpaceX will STILL need a docking port for Dragon, Orion, and Gateway. I donít buy that shuttle was uniquely reinforced and Starship canít be.
Title: Re: Aviation week article on SpaceX reusability
Post by: su27k on 09/03/2022 04:27 am
Also even if Starship doesn't dock with ISS, it'll need to dock with commercial stations, so the ability to dock with space station is kind of a requirement. I think Nanorack already mentioned Starlab can be serviced using Starship.
Title: Re: Aviation week article on SpaceX reusability
Post by: OTV Booster on 09/03/2022 05:03 pm

New Dragon contract.

https://arstechnica.com/science/2022/09/nasa-will-pay-boeing-more-than-twice-as-much-as-spacex-for-crew-seats/ (https://arstechnica.com/science/2022/09/nasa-will-pay-boeing-more-than-twice-as-much-as-spacex-for-crew-seats/)

Main point: SX is now contracted for 14 more Dragon missions.

Another point in favor of keeping F9 in service is ground support. It's all there. It works. It's ready to go. It doesn't intrude on SS operations (yet).

SS has a lot on its development plate. EDL, refueling and Artemus, not to mention human rating. It looks like ISS is toast in 7+ years and NASA has all the missions contracted. There will most probably be private Dragon flights. Number unknown.

SS docking will have to be developed for Artemus, private stations and by reasonable extension SX internal use, but not for ISS.

Title: Re: Aviation week article on SpaceX reusability
Post by: MP99 on 09/03/2022 08:29 pm
Quote
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.

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 donít have complete coasting either. Or does the inefficiency outweigh the benefits of a couple of seconds of extra partial thrust?
I think Elon may have discussed something related.

Starlink is released by spinning the vehicle end over end, which moves the sats away gently via centri-whatever forces.

He said same for staging SS, which would leave the bottom of SS and top of Booster rotating away from each other.

Cheers, Martin

Sent from my Lenovo TB-X606X using Tapatalk

Title: Re: Aviation week article on SpaceX reusability
Post by: FutureSpaceTourist on 09/05/2022 05:49 am
Current booster reuse status, following Starlink launch few hours ago:

twitter.com/_rykllan/status/1566656119921147904

Quote
#SpaceX's #Falcon9 & #FalconHeavy flightworthy boosters as of Sep 5, 2022

https://twitter.com/_rykllan/status/1566656128402046976

Quote
Statistics of #SpaceX's #Falcon9 & #FalconHeavy booster missions as of Sep 5, 2022
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/05/2022 07:44 am
Current 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: AmigaClone on 09/05/2022 02:01 pm
Current 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.

From the article in the original post.

Quote
The decision to requalify the boosters for 15 flights was a natural outgrowth of the ongoing evolution of the Block 5. ďEvery flight, weíre 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,Ē says Kiko Dontchev, SpaceX vice president for launch.

Quote
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/06/2022 07:08 am

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.
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: DanClemmensen on 09/06/2022 01:51 pm

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.
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: wannamoonbase on 09/06/2022 02:37 pm

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.
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: AmigaClone on 09/06/2022 06:44 pm

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.
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
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/06/2022 07:22 pm
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.
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 09/06/2022 07:32 pm
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.
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.
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: DanClemmensen on 09/06/2022 07:33 pm

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.
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
In steady state, they would need to add five new boosters a year to maintain a launch cadence of 100/yr. I know that the analyses you guys are doing are for the wind-down, not steady state, but 5/yr is not a lot. As I understand it, SpaceX uses the same production line for boosters and second stages, so they would need to build one booster for every 20 second stages in steady state. This does not count FH, which basically throws all the computations off. You also need to consider that as F9 nears EOL, most or all of the remaining flights post-2028 will be CCP. CCP will probably not fly on boosters older than 5 flights, and they will need at least one reserve booster.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/06/2022 07:35 pm

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
Yes. Being able to flip an FH booster back to regular F9 booster is turning out to be quite handy.

I never really bought into the the idea that "Block 5" was going to be the end of F9 development and it would be completely frozen, although I don't expect we'll be seeing major obviously bigger/wider boosters like we did in earlier years.  I do expect ongoing operational tweaks, both on the launch and the refurb, and (when justified) build changes.

The thing is building/launching/recovering/refurbing a rocket stage is so complex that with every launch an alert team should find ways to make things run just a little bit better, or see ways it could have been built a bit better. Coupled with a management that wants to innovate (which seems to be SX's default style) that pretty much guarantees that what's launching at the end of a year is not-quite what was launching in January, whatever it's called.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/07/2022 06:58 am
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: Nomadd on 09/07/2022 07:54 am
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 09/07/2022 01:09 pm
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
falcon 9 had a lot of scrubs trying to get all 9 engines working at the same time. By the time they got to 27 engines on FH, they had done dozens of Falcon 9 launches so had gotten the bugs worked out.

With Super Heavy, they only have the experience of the suborbital Starship hops which used at most 3 engines, and they never achieved much of a flight rate.

So I expect a bunch of scrubs getting 33 going at once, and being full flow staged combustion probably doesnít make it easier.

Theyíll get it done, of course. But itís a lot of work.
Title: Re: Aviation week article on SpaceX reusability
Post by: ZachS09 on 09/07/2022 01:15 pm
So what's with the overestimating SpaceX guys on Twitter that question Starship/Super Heavy, believing that it's already ready to go?
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 09/07/2022 01:17 pm
So what's with the overestimating SpaceX amazing peoples 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: ZachS09 on 09/07/2022 01:22 pm
So 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: DanClemmensen on 09/07/2022 01:32 pm
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
I'm sure you are correct, but Raptors have started up hundreds of times on the test stands. Thus, you must be thinking about things that make it harder to start them when they are clustered. Can you describe those interactions and their effects for those of us who are not experts?
Title: Re: Aviation week article on SpaceX reusability
Post by: Hog on 09/07/2022 04:24 pm
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
bold mine
SSFC? 
Title: Re: Aviation week article on SpaceX reusability
Post by: AC in NC on 09/07/2022 05:15 pm
SSFC?
FFSC
Title: Re: Aviation week article on SpaceX reusability
Post by: Nomadd on 09/07/2022 05:42 pm
SSFC?
FFSC

OAMOE420 (Organic Acronym Memory Overflow Error)
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 09/07/2022 09:13 pm
So 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 wouldnít bet a launch attempt (ie clamps release) of Starship before the end of the year, but itís a significant possibility. I also wouldnít bet on an SLS launch attempt before November.
Title: Re: Aviation week article on SpaceX reusability
Post by: OTV Booster on 09/07/2022 10:18 pm
Current 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: wannamoonbase on 09/07/2022 10:30 pm
So 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 wouldnít bet a launch attempt (ie clamps release) of Starship before the end of the year, but itís a significant possibility. I also wouldnít 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: OTV Booster on 09/07/2022 10:30 pm
As of right now, itís just the nitty gritty of getting 33 powerful engines to work at the same time. Have to static fire until they get there.

Thatís the necessary (but not sufficient) step needed right now. If they can do that reliably, test Starship as well, then theyíll 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.
Merlin is a much more benign engine. And they had a lot of experience lighting off nine at a time before trying 27. I can get my head around Raptor steady state running but starting it makes my brain hurt.
Title: Re: Aviation week article on SpaceX reusability
Post by: Robotbeat on 09/07/2022 11:07 pm
So 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 wouldnít bet a launch attempt (ie clamps release) of Starship before the end of the year, but itís a significant possibility. I also wouldnít 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.
27 engine Falcon Heavy is pretty comparable, actually, just without the advantage of an intermediate Falcon 9.
Title: Re: Aviation week article on SpaceX reusability
Post by: AmigaClone on 09/08/2022 01:12 am
Current 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.

Non-Starlink launches appear to be fairly rare even between the 6th and 10 launch of a booster. There is potentially one booster which might launch a commercial satellite after it's 10th launch which happened nearly a year ago.

Two are planned for the future:
B1049 - 11th flight? (Potentially expended after launching a commercial satellite.)
B1052 - ?th flight (Viasat-3 Americas)

Half of the non-Starlink launches for boosters between their 6th and 10th launch were Transporter launches (dozens of cubesats), with only 4 major payloads assigned to boosters with that range of launches.

B1051 - 7th flight (SXM 7)
B1052 - 6th flight (Danuri (KPLO))
B1061 - 9th flight (Globalstar FM15)
B1062 - 7th flight (Nilesat-301)

B1058 - 10th flight (Transporter-3)
B1060 - 8th Flight (Transporter-2)
B1061 - 7th flight (Transporter-4)
B1061 - 8th flight (Transporter-5)

In comparison, boosters that have flown six or more times launched 35 groups of Starlink satellites as their primary payload.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/08/2022 07:50 am
27 engine Falcon Heavy is pretty comparable, actually, just without the advantage of an intermediate Falcon 9.
But with the knowledge gained from the process of learning how to make 27 engines start reliably.

However there is another issue with Raptor.

AFAIK when FH debuted the Merlin design was stable. No major plumbing changes, no major changes in mfg methods, and IIRC the boosters were pre-flown, so demonstrated they could get the job done.

But AIUI Raptor is now in it's second generation and is actually Raptor II. With continual development of both the components (IE mfg methods and materials) and the configuration (IE how the parts fit together) continuing to change you have a paradox. IIRC Musk said he expcted Raptor development to be done by SN50 but I think they are way past that and it's still evolving.

You have 100s of Raptor tests but how many of them are of exactly the same engine design?

On that basis I can see why Raptor development could be the long pole in the SS tent.
Title: Re: Aviation week article on SpaceX reusability
Post by: Nomadd on 09/08/2022 07:55 am
 A change of plans is not a "paradox".
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/08/2022 09:57 am
A change of plans is not a "paradox".
No, the paradox is that if you want a lot of something then you need to freeze the design and commit to making that design, but the design is not frozen.

So yes your N+1 iteration may be better than your current version, but you'll never stop updating long enough to make the 33 (or whatever they are currently needing) to load up a full SH booster.

The other alternative is to just sling the last X number of Raptors on the structure and see what happens. Hope their EMU's can keep them all in synch with regard to thrust and MR during the flight (is it my imagination or is Musk trying to go back to a no EMU design? I could have sworn I read something about this).

The usual solution to this dilemma is a)Freeze the design b)release to mfg c)Continue to refine a test unit(s) but  confine changes that will allow them to be dropped into the existing vehicle d)When you've got enough improvement (by whatever metric is relevant to you) release the new version to mfg.

IOW Block upgrades.

However WRT this threads title while increasing the Pch and the operating temp can make substantial improvements to Isp they are likely to make the whole design a bit more fragile.

 The only real way to quantify how much more fragile is to get them off the stand and put enough on a SH to put an actual SS on it, and repeat that till something breaks.  :(

It's a cliche but the only real test of reusability is to actually try reusing something.
Title: Re: Aviation week article on SpaceX reusability
Post by: FutureSpaceTourist on 09/11/2022 07:14 am
Notice that boosters going over 10 flights are doing only StarLinks.

Thatís mostly true and yet the new record 14th (and successful) flight of B1058 tonight was a rideshare with the BlueWalker3 customer satellite.

Elon also tweeted:

https://twitter.com/elonmusk/status/1568788727014752257

Quote
No obvious limit to rocket reflight so far

So I think SpaceX are definitely going to push past the 15 flights target.
Title: Re: Aviation week article on SpaceX reusability
Post by: M.E.T. on 09/11/2022 08:04 am
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.

Thatís for 16 tons to LEO. Remarkable.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/11/2022 09:40 am
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.

Thatís for 16 tons to LEO. Remarkable.
And at around a $63m launch price that's a 270% profit.

If the development process cost (as I think Musk stated) $1Bn then 21 paying customer launches (IE not starlink) would have recovered the costs and start making pure profit.

Of course to the customer the price is still the same.

A situation I don't expect will start to change until Neutron starts launches and customers have a real choice in semi-reusable launch systems. :(
Title: Re: Aviation week article on SpaceX reusability
Post by: FutureSpaceTourist on 09/12/2022 06:33 am
We already have a Neutron vs F9 & SS thread:

https://forum.nasaspaceflight.com/index.php?topic=55413.0

So the last page of discussion has magically moved there.

Back to the Aviation Week article Ö
Title: Re: Aviation week article on SpaceX reusability
Post by: AmigaClone on 09/12/2022 11:44 am
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.

https://twitter.com/elonmusk/status/1568788727014752257
Title: Re: Aviation week article on SpaceX reusability
Post by: AC in NC on 09/12/2022 03:55 pm
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.
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.
Title: Re: Aviation week article on SpaceX reusability
Post by: OTV Booster on 09/12/2022 05:36 pm
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.
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.
One purpose of the deep inspections is to determine the interval needed for deep inspections. My experience with mechanical life cycles is it starts with rapid wear, called break-in, followed by a long period of near steady state with a slow rate of wear. The last stage, where wear is unacceptable all too often shows wear accelerating rapidly. This has to be caught.


If post flight checks can monitor this without a tear down - cool. Think checking crank shaft thrust bearing play by yanking on the harmonic balancer instead of opening the engine. If it's more like valve guide play it can be checked by partial tear down but far less than pulling the head.


I'd expect to see some systems getting closer attention than others after 5*N flights. Maybe see swappable units to allow deeper inspection. Sort of like getting a refurb/reman alternator for your car.
Title: Re: Aviation week article on SpaceX reusability
Post by: sghill on 09/13/2022 11:10 am

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.

Thatís 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.
Title: Re: Aviation week article on SpaceX reusability
Post by: OTV Booster on 09/14/2022 01:00 am

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.

Thatís 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.
Uh, it doesn't work that way.
If a booster costs a nominal $30m a pop and it's not reusable it's a straight $30m deduction. Actually it's not one big deduction but ongoing deductions for everything that goes into building it.


If it's reusable, well I don't think the IRS has guidance for reusable rockets. Any way it has to be declared as a 3, 5, 10, 15, 20 or 30 year property. Let's ignore accelerated depreciation. Makes it too complicated. The labor and materials that goes into building the reusable booster is not deducted as it would be for a throwaway. It gets credited to an account that represents the 'basis' of that booster.


If it costs $30m to build (the basis) and it's declared to be a five year property, every year they can claim $6m depreciation, which essentially acts as a deduction from income before taxes are calculated. In other words, they deduct the cost of building the booster over its expected lifetime. There is an amazing amount of niggling and maneuvering associated with depreciation but this is it at its simplest.
Title: Re: Aviation week article on SpaceX reusability
Post by: john smith 19 on 09/14/2022 06:44 am

Thatís for 16 tons to LEO. Remarkable.
For SX profit margin yes it is.

As a customer, so what?
Title: Re: Aviation week article on SpaceX reusability
Post by: M.E.T. on 09/14/2022 08:44 am

Thatís for 16 tons to LEO. Remarkable.
For SX profit margin yes it is.

As a customer, so what?

It means if SpaceX wants a launch customer, they have room to drop to a price of $17M and still break even, while any competitor with a higher cost rocket does not have that luxury.

You stubbornly insist on viewing F9 as a $65M rocket when assessing the prospects of would-be competitors. That is wrong. You need to compare the cost of the respective rockets, to really understand what any new competitor is up against. F9 is a $17M rocket.

That is the true reflection of the exercisable market power that SpaceX has.
Title: Re: Aviation week article on SpaceX reusability
Post by: FutureSpaceTourist on 09/22/2022 09:20 pm
So this thread went completely off the rails Ö

Iíve pruned right back and restoring it locked (for reference). Iíll unlock if anyone has something on topic that theyíre keen to share (but will permanently lock if it goes off the rails again).