Author Topic: Refurbishment of Used Stages/Vehicles  (Read 162426 times)

Offline meekGee

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Re: Refurbishment of Used Stages/Vehicles
« Reply #600 on: 03/25/2017 03:58 PM »
The reliability record of reused rockets is still TBD, but that was not the issue.

Time required to recycle a stage is now established as 6-8 weeks, after a first article at 16 weeks.

It is reasonable to expect it to drop down to 1-2 weeks, and maybe less.

We know the goal is 1 day, but as people pointed out, even if it's a week, you can fly 2/week from each of 2 pads with an active fleet of four boosters, with a much slower production rate of S1, and a fast rate of S2.
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Offline drunyan8315

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Re: Refurbishment of Used Stages/Vehicles
« Reply #601 on: 03/25/2017 04:14 PM »
From the "last second" deployment before touchdown,I assume that the landing legs deploy and lock mostly passively, under the Gs generated by the landing deceleration, perhaps aided by an internal spring or compressed gas cylinder. There also seems to be some form of actuator on the hull near to top of the folded leg, which I would guess kicks off the process, but pics of them post-landing appear to show a stroke length only a fraction of what would be required for those actuators to fully extend the leg, and show that they are no longer attached to the leg, only to the hull.

This may be a very simple and lightweight design for deploying the legs, but would seem to preclude the legs being deployed against the slipstream at altitude. Of course  this method, elegant as it appears to be, has failed to fully lock a leg at least once, with resultant loss of the vehicle.

Offline guckyfan

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Re: Refurbishment of Used Stages/Vehicles
« Reply #602 on: 03/25/2017 05:13 PM »
Of course  this method, elegant as it appears to be, has failed to fully lock a leg at least once, with resultant loss of the vehicle.

Yes, but that was a known bug, already fixed for the next flight, when it happened. They were still early in the experimental stage.

Offline tdperk

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Re: Refurbishment of Used Stages/Vehicles
« Reply #603 on: 03/27/2017 11:36 AM »
From the "last second" deployment before touchdown,I assume that the landing legs deploy and lock mostly passively, under the Gs generated by the landing deceleration, perhaps aided by an internal spring or compressed gas cylinder. There also seems to be some form of actuator on the hull near to top of the folded leg, which I would guess kicks off the process, but pics of them post-landing appear to show a stroke length only a fraction of what would be required for those actuators to fully extend the leg, and show that they are no longer attached to the leg, only to the hull.

This may be a very simple and lightweight design for deploying the legs, but would seem to preclude the legs being deployed against the slipstream at altitude. Of course  this method, elegant as it appears to be, has failed to fully lock a leg at least once, with resultant loss of the vehicle.

It failed owing to the unexpected presence of ice, and has been altered to prevent such a failure in the future.

Offline Brian45

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Re: Refurbishment of Used Stages/Vehicles
« Reply #604 on: 03/27/2017 06:06 PM »
Anyone have any idea if there has been discussions here about the stress testing of the fuselage of the reused F9?

Online vanoord

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Re: Refurbishment of Used Stages/Vehicles
« Reply #605 on: 03/27/2017 06:30 PM »
SpaceX have recovered 8 boosters, so it's difficult to imagine that they've not been inspected thoroughly to check that they have not suffered damage from the launch / re-entry cycle.

One (B1022 / JCSAT-14) has apparently had 8 (?) full-duration engine tests since it was recovered, which would hopefully deal with the tanking cycle question.

Whether one will be / has been dismantled to assess how it has dealt with stress loadings is probably unknown, but there are arguments that (i) it may well be possible to assess that through non-destructive testing/examination; and (ii) that dismantling may be undertaken on a stage that has flown 2/3/more times in order to see what the effects of several cycles are.

In any instance, the SES-10 core (B1021) will have been through a long set of tests and refurbishment ahead of this flight. Added to that, the booster stages are designed to be re-used, so you'd imagine that SpaceX has probably made sure that they can stand the stresses of a few flights.

Yes, the SES-10 launch is a big, big step for SpaceX, but they've been working on this for many years and and know what to expect.

Offline old_sellsword

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Re: Refurbishment of Used Stages/Vehicles
« Reply #606 on: 03/27/2017 06:41 PM »
Anyone have any idea if there has been discussions here about the stress testing of the fuselage of the reused F9?

Not sure about discussions here, but SpaceX did mention they've been doing exactly that:

https://www.youtube.com/watch?v=tTmbSur4fcs?t=14m10s

However which booster they used for this is still a mystery.
« Last Edit: 03/27/2017 06:42 PM by old_sellsword »

Offline Lar

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Re: Refurbishment of Used Stages/Vehicles
« Reply #607 on: 03/27/2017 07:01 PM »
doesn't mean they were successful ... None of what they've done has proved the concept ... we'll find out if refurb can be done ... I hope they don't have to have 3 failures to figure out if it works!

nitpicking

I believe the colloquial term is "concern trolling."

it is. And it's not really a good thing to do. Please dial back the concern a bit Brian45...
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Offline Herb Schaltegger

Re: Refurbishment of Used Stages/Vehicles
« Reply #608 on: 03/27/2017 10:32 PM »
doesn't mean they were successful ... None of what they've done has proved the concept ... we'll find out if refurb can be done ... I hope they don't have to have 3 failures to figure out if it works!

nitpicking

I believe the colloquial term is "concern trolling."

it is. And it's not really a good thing to do. Please dial back the concern a bit Brian45...

So now anyone who points out that "unknown unknowns" are a real danger in aerospace is now "concern trolling" and essentially told to pipe down? I'm disappointed, frankly.

Fueling a rocket on a pad was pretty well-known until someone tried something outside the experience base and things went pear-shaped. For every commercially-manufactured aircraft that flies, there are thousands of flight-hours logged in rigorous test-flights to prove out the structures, the systems and the operating procedures, and these things STILL fall out of the air or fly into the dirt with depressing regularity.

SpaceX has launched a few dozen rockets and recovered a small-ish percentage of those. There are plenty of unknown unknowns out there, especially if reuse become a real thing. If NSF isn't the place to discuss what SpaceX may have done to narrow those down, and what they might or might not have done for whatever reason, in a sober, rational and thoughtful way without being labeled or attacked for raising the discussion, where is?
« Last Edit: 03/27/2017 10:32 PM by Herb Schaltegger »
Ad astra per aspirin ...

Offline envy887

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Re: Refurbishment of Used Stages/Vehicles
« Reply #609 on: 03/27/2017 11:16 PM »
In reading about re-use of a first stage, all I've seen are concerns about the engines, pumps, tanks, etc. ie the "guts" of the rocket. Was there any discussion about the actual structure of the metal tube that holds everything together?

The tanks ARE "the actual structure of the metal tube that holds everything together".

There's some discussion of tank fatigue stresses here:
http://forum.nasaspaceflight.com/index.php?topic=27748.1235;wap2

And here:
http://forum.nasaspaceflight.com/index.php?topic=27748.1240;wap2

And there's a lot of interesting info in the discussions of the AMOS failure, like this: http://forum.nasaspaceflight.com/index.php?topic=41252.msg1596202#msg1596202

Perusing those threads would be of interest, if you haven't already. Google if your friend.

https://www.google.com/search?safe=active&espv=2&q=site%3Anasaspaceflight.com+falcon+9+tank+fatigue

Offline Lar

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Re: Refurbishment of Used Stages/Vehicles
« Reply #610 on: 03/28/2017 01:18 AM »
doesn't mean they were successful ... None of what they've done has proved the concept ... we'll find out if refurb can be done ... I hope they don't have to have 3 failures to figure out if it works!

nitpicking

I believe the colloquial term is "concern trolling."

it is. And it's not really a good thing to do. Please dial back the concern a bit Brian45...

So now anyone who points out that "unknown unknowns" are a real danger in aerospace is now "concern trolling" and essentially told to pipe down? I'm disappointed, frankly.

Fueling a rocket on a pad was pretty well-known until someone tried something outside the experience base and things went pear-shaped. For every commercially-manufactured aircraft that flies, there are thousands of flight-hours logged in rigorous test-flights to prove out the structures, the systems and the operating procedures, and these things STILL fall out of the air or fly into the dirt with depressing regularity.

SpaceX has launched a few dozen rockets and recovered a small-ish percentage of those. There are plenty of unknown unknowns out there, especially if reuse become a real thing. If NSF isn't the place to discuss what SpaceX may have done to narrow those down, and what they might or might not have done for whatever reason, in a sober, rational and thoughtful way without being labeled or attacked for raising the discussion, where is?

No.

Herb, you know better.

We talk about all sorts of things and dig deeply into lots and lots of different topics, it's what we do here and we're good at it. We ferret out stuff others missed, and draw conclusions on very limited data that are often shockingly accurate. Further, people who come here to learn with an open mind... never leave unsatisfied. And questions are part of the process. Even questions that question decisions SpaceX or ULA or whoever made.

Nothing wrong with raising that unknown unknowns exist, if it's not repetitive. Nothing wrong with speculating on things that might go wrong, if it's not repetitive. Nothing wrong with finding the right topic area and then digging into the topic. We all learn from that. Sometimes we have to decode Jim's cryptic hints and that's part of the fun.

But concern trolling, narrowly defined, isn't helpful or welcome. If the post comes off as "I think I'm smarter than SpaceX" or "I can't believe they didn't think of thing Y", that's not good. It's a perception thing. If someone says you might be concern trolling (and sometimes I think maybe you do post in that style, a little, and sometimes I'm pretty sure my own posts do come off that way) you might want to try to refactor how you word things a bit. For the good of all.

If you really felt strongly about this, you should take it up with Chris. He may tell me I'm over thinking this and that's fine. But this is a meta discussion. Report to mod if you want to go further. No more meta.

PS: removed a post AFTER this one arguing about the definition of concern trolling. Didn't save it, didn't send it back to the poster, didn't move it to dead threads, just removed it. It's gone. Forever. What part of "no more meta" was unclear?
« Last Edit: 03/28/2017 10:21 AM by Lar »
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Brian45

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Re: Refurbishment of Used Stages/Vehicles
« Reply #611 on: 03/28/2017 03:07 AM »
Thanks people for answering my question and explaining where I went off track with the structure of my inquiry.

Offline Negan

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Re: Refurbishment of Used Stages/Vehicles
« Reply #612 on: 03/28/2017 04:45 PM »
Bolded mine

Quote
Our CTO Martin Halliwell talks about #SES10 and the launch on #flightproven rocket!

https://twitter.com/ses_satellites/status/846742078310690818

https://www.periscope.tv/w/a6kjoTFETEtCeURWT2FEUUp8MWpNSmdZd3JPYXlLTOkPzfjLKb6zX572-CwWcPxK89_4GMQLEeCpVDy3-Oo7

Here are some notes:

* Mass is 5281.7 kg, insertion orbit will be 35410 km x 218 km at 26.2, so barely subsynchronous GTO. Orbit raising will be done with chemical engines.

* SES block bought SES-10, SES-11, SES-14, SES-16. Then last August they were approached with the opportunity to use a pre-flown booster.

* Essentially no change in the insurance premium, 100th of a percent.


* First stage booster is contractually obligated to make certain altitude, velocity, downrange, etc. SpaceX works with the leftovers for landing. This will be a very hot landing, but if it comes back, SES gets "bits" for their boardroom.

* Satellite requires 13 hours of checkouts once the full stack is vertical on the pad.

Offline WmThomas

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Re: Refurbishment of Used Stages/Vehicles
« Reply #613 on: 03/28/2017 06:00 PM »
The NASA information for CRS-11 describes the planned Dragon one that has previously flown.

Is there information somewhere about how much of the Dragon is being reused? Is it just the pressure vessel?


Offline john smith 19

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Re: Refurbishment of Used Stages/Vehicles
« Reply #614 on: 03/28/2017 07:22 PM »
Let's see if we can all agree on a few points.

Despite lots of people talking about refurbishment and reuse this is in fact the first ever time a first stage will be relaunched.

Ever.

Essentially the whole history of first stage reuse started with the first Grasshopper landing. Everything prior to this for the reuse or reflight of high aspect ratio TSTO VTO LV's was theoretical.

This represents tremendous progress in a comparatively short period of time.

Reflight is a never previously attempted process. It is likely to be a very complex.

The odds on bet must be that SX will get some things wrong. The worst case being they are unable to recover the stage. Such a scenario is unlikely but AMOS 6 should have reminded everyone that there is a big difference between "unlikely" and impossible.

This will not matter.

In the worst case as long as they get enough telemetry and recover enough of the pieces they can identify the cause and (in principle) design out the root cause.  Note it would delay the next flight of a reused stage. That does not mean it should ground use of the first stage as a normal first use first stage.

Anything less drastic will likely be added to the upgrade list for the next generation.

A second (successful) launch of an F9 first stage will be a technical triumph for SX. It will absolutely move the baseline of how far a conventional TSTO architecture can be pushed, without requiring the re mating of a specific engine module IE the ULA and Arianspace (suggested) approach.

Reuse is not a goal. It is a means to lowering the cost per unit mass to orbit by a significant amount.

This is the ultimate goal.

True success will be delivering this goal.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Mader Levap

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Re: Refurbishment of Used Stages/Vehicles
« Reply #615 on: 03/28/2017 11:30 PM »
The odds on bet must be that SX will get some things wrong. The worst case being they are unable to recover the stage.
Wrong. Worst case is that there will be launch faliure.
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Offline john smith 19

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Re: Refurbishment of Used Stages/Vehicles
« Reply #616 on: 03/29/2017 06:30 AM »
The odds on bet must be that SX will get some things wrong. The worst case being they are unable to recover the stage.
Wrong. Worst case is that there will be launch faliure.
Literally true, although SX have a history of finding new ways to have a launch failure it does seem a little early for another one, and we know the first stage has functioned flawlessly already, which raises confidence in 50% of the vehicle stages (or 90% of the engines) already.

My focus is always on the customer. From their PoV it doesn't matter if the first stage explodes into a million fragments, provided it happens after stage separation and none of the fragments does any damages to the second stage (even if some of them hit it).
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline JamesH65

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Re: Refurbishment of Used Stages/Vehicles
« Reply #617 on: 03/29/2017 12:39 PM »
Essentially the whole history of first stage reuse started with the first Grasshopper landing. Everything prior to this for the reuse or reflight of high aspect ratio TSTO VTO LV's was theoretical.

I think Armadillo Aerospace and Masten might disagree with this statement. They both demonstrated Grasshopper levels of control, albeit on a smaller scale.

Offline mme

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Re: Refurbishment of Used Stages/Vehicles
« Reply #618 on: 03/29/2017 03:35 PM »
Essentially the whole history of first stage reuse started with the first Grasshopper landing. Everything prior to this for the reuse or reflight of high aspect ratio TSTO VTO LV's was theoretical.

I think Armadillo Aerospace and Masten might disagree with this statement. They both demonstrated Grasshopper levels of control, albeit on a smaller scale.
Neither have put a payload into orbit and brought a booster back from hypersonic velocities nor did they use boosters capable of that.  Hence the explicit mention of doing it with a "high aspect ratio TSTO VTO LV."

We (the forum) always get into a Simpsons did it first arguments. I know people sometimes make outrageous claims about SpaceX firstyness/bestyness, but this one seemed fairly explicitly constrained.
Space is not Highlander.  There can, and will, be more than one.

Offline JamesH65

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Re: Refurbishment of Used Stages/Vehicles
« Reply #619 on: 03/29/2017 04:12 PM »
Essentially the whole history of first stage reuse started with the first Grasshopper landing. Everything prior to this for the reuse or reflight of high aspect ratio TSTO VTO LV's was theoretical.

I think Armadillo Aerospace and Masten might disagree with this statement. They both demonstrated Grasshopper levels of control, albeit on a smaller scale.
Neither have put a payload into orbit and brought a booster back from hypersonic velocities nor did they use boosters capable of that.  Hence the explicit mention of doing it with a "high aspect ratio TSTO VTO LV."

We (the forum) always get into a Simpsons did it first arguments. I know people sometimes make outrageous claims about SpaceX firstyness/bestyness, but this one seemed fairly explicitly constrained.

Clearly there are further hurdles to overcome when coming in from orbit, but vertical take off and landing was done well before grasshopper, which, clearly was not an orbital booster, and was the referenced craft. Please refer back to the original quote.

Actually, I have done a disservice to the DC-X which was I believe the first to do it.

I have no problem with people 'firsting', but when the statement is clearly false, it should not be left to stand. Grasshopper was not the start of the history of first stage reuse.

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