Author Topic: Rockets that return home - SpaceX pushing the boundaries  (Read 204683 times)

Offline groundbound

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #40 on: 04/23/2014 01:31 am »
Yes and I think that Chris does a good job of emphasizing that in his article.

I didn't mean to imply otherwise.. but some people seem to think that SpaceX are just a few years away from flying daily, or something.

Remember that even for relatively low flight rates they want to have a fairly short checklist of things to do before re-using a core. If that is not true, then they might have to add a lot of workforce near the pad. My economics is somewhat poor but "more workforce" + "low flight rate" seems like a poor way to get to lower cost.

So a one day turnaround for relatively low flight rates may make sense: service the core quickly and then everyone goes back to the stuff they have to do now.

Offline GregA

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #41 on: 04/23/2014 01:34 am »
300,000 feet altitude - how close is that to being in space?
The Karman line is 100 km, or 328,083.99 feet.
Sorry if this is obvious - but at what altitude did the first stage separate on the CRS-3 mission?

Offline QuantumG

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #42 on: 04/23/2014 01:35 am »
Remember that even for relatively low flight rates they want to have a fairly short checklist of things to do before re-using a core.

Yes, but aspirational goals take time to achieve. There's a learning curve.

Human spaceflight is basically just LARPing now.

Offline oiorionsbelt

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #43 on: 04/23/2014 01:38 am »
Yeah flying daily is far off, in the mean time...
F9R flights from Texas and New Mexico, abort tests, and orbital launches, trying to get the 1st stage back, building a human rated spacecraft that lands vertically, getting ready to debut F9H, working on a new Methane engine, planing to go to Mars and I probably left somethings out.

Offline QuantumG

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #44 on: 04/23/2014 01:49 am »
Sorry if this is obvious - but at what altitude did the first stage separate on the CRS-3 mission?

T plus 2 minutes, 30 seconds, vehicle 63 km altitude, 1.8 km/s, downrange distance 55 km.

Stage separation happened about 10 seconds later.


Human spaceflight is basically just LARPing now.

Offline GregA

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #45 on: 04/23/2014 03:05 am »
T plus 2 minutes, 30 seconds, vehicle 63 km altitude, 1.8 km/s, downrange distance 55 km.

Stage separation happened about 10 seconds later.
Thanks. So a bit below the altitude limit for the dev rocket. Good stuff.

Offline NotOnImpact

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #46 on: 04/23/2014 03:18 am »
Yeah flying daily is far off, in the mean time...
F9R flights from Texas and New Mexico, abort tests, and orbital launches, trying to get the 1st stage back, building a human rated spacecraft that lands vertically, getting ready to debut F9H, working on a new Methane engine, planing to go to Mars and I probably left somethings out.

Refurbishing the old Shuttle launchpad.
Second Stage recovery (probably last on the priority list, but still part of the master plan)

Offline Lars_J

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #47 on: 04/23/2014 03:23 am »
T plus 2 minutes, 30 seconds, vehicle 63 km altitude, 1.8 km/s, downrange distance 55 km.

Stage separation happened about 10 seconds later.
Thanks. So a bit below the altitude limit for the dev rocket. Good stuff.

Keep in mind that 63km is not the top of the trajectory - it's trajectory at MECO1 will take it much higher at apogee. (close to 300k ft?)

Offline Llian Rhydderch

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #48 on: 04/23/2014 04:22 am »
If it's no miracle then why have they had so many range problems to-date?  I think there's learning curve to building a rapid launch range that is just as steep as learning to fly the vehicle rapidly. This thing they do where they fly half the team from California to Florida every launch has gotta stop, for a start.

I think it is possible that you are confusing real "business process" range problems that any commercial company might have at any range facing commercial incentives with the inertia of government processes that tend to get locked in by path dependence on historical antecedents, and even if the history was not deep and baked-in, any government-run range is facing the inevitable public choice logic from generally risk-averse public workers.  The center of the delay distribution will not be equally distributed around some ostensibly "correct" outcome; it will rather tend to be quite disproportionately on the delay, or no-can-do-soon, side of the continuum.

I'm not saying that there are no real range issues that would exist in a commercial range.  There are, and there will be.  But I am saying that 1) that path dependent history does have a set of costs it brings with it, along with the purported benefits, and 2) the incentives the various actors face are critically important to what sort of process at a range gets baked in.

There is a rather large difference between the sort of "pit stop" processes that private actors have developed for refueling and adjusting Indy Car Racers and what "the government" developed to "refurbish" (refuel and adjust) the "reusable" launch vehicle that the government designed.  Only a part of those process differences are related to the differences in the technology; many are related to the different incentives each party faces.

So I think the work SpaceX will do to decrease the "pit stop" time in New Mexico will be critically important to deconstructing which part of the launch delays are technological in the SpaceX Falcon 9 launch vehicle and launch vehicle ground support equipment, and which fall in some other category (weather, range rulz, government policy on launch sites, etc.)

Only when that is better understood, will SpaceX be able to turn the crank and improve the process, step by step, to get faster turnaround, whether at the new SpaceX private launch site, or at any of their three existing facilities leased from the government.
Re arguments from authority on NSF:  "no one is exempt from error, and errors of authority are usually the worst kind.  Taking your word for things without question is no different than a bracket design not being tested because the designer was an old hand."
"You would actually save yourself time and effort if you were to use evidence and logic to make your points instead of wrapping yourself in the royal mantle of authority.  The approach only works on sheep, not inquisitive, intelligent people."

Offline Llian Rhydderch

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #49 on: 04/23/2014 04:28 am »
My question is how the range authorities and the FAA are going to handle a rocket coming back to the pad or near the pad.  We have almost 60 years of regulations and experience launching expendable rockets.   How are they going to handle reusable rockets?

With great difficulty.

The folks that matter on the range side of things are government workers who face a very different set of incentives than workers in typical private companies, especially in the tech sector.  No one in government gets fired for being slow and methodical about changing the seemingly hard-coded logic of "that's how we do it here."  The reverse is not true. 

Given that set of incentives, the modfications will be challenging.
« Last Edit: 04/23/2014 04:29 am by Llian Rhydderch »
Re arguments from authority on NSF:  "no one is exempt from error, and errors of authority are usually the worst kind.  Taking your word for things without question is no different than a bracket design not being tested because the designer was an old hand."
"You would actually save yourself time and effort if you were to use evidence and logic to make your points instead of wrapping yourself in the royal mantle of authority.  The approach only works on sheep, not inquisitive, intelligent people."

Offline QuantumG

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #50 on: 04/23/2014 04:40 am »
I think it is possible that you are confusing real "business process" range problems that any commercial company might have at any range facing commercial incentives with the inertia of government processes that tend to get locked in by path dependence on historical antecedents, and even if the history was not deep and baked-in, any government-run range is facing the inevitable public choice logic from generally risk-averse public workers.

I really don't think you need to look much further than me to find someone who thinks SpaceX can run a launch range better than the government, especially if they're only running it for their own use. The key point I was making is that it won't happen right away.

Only when that is better understood, will SpaceX be able to turn the crank and improve the process, step by step, to get faster turnaround, whether at the new SpaceX private launch site, or at any of their three existing facilities leased from the government.

Yes, which will take a long time. The idea that SpaceX is going to revolutionize the launch industry next year, which is a commonly held expectation these days it seems, just isn't gunna happen.
Human spaceflight is basically just LARPing now.

Offline sdsds

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #51 on: 04/23/2014 04:43 am »
My question is how the range authorities and the FAA are going to handle a rocket coming back to the pad or near the pad.

Right! That's the big question, and getting that process in place is probably the "rate determining step" in their overall attempts at a soft touchdown on land.

It seems pretty clear the FAA and range will not allow a flying, thrusting stage to get anywhere near occupied land without active flight termination control. What I think this means is that even after they "safe" the flight termination system on the upper stage they will leave the FTS on the first stage active. (Would it stay active once the instantaneous impact point of the returning stage is on land? Dunno.)

I speculate that SpaceX will do something else never done before: implement a system to send control commands to the stage. I expect that the stage will autonomously target a return to a spot just off-shore, and then if all goes well and only on command it will divert to touch down on land.
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Offline TomH

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #52 on: 04/23/2014 05:43 am »
I speculate that SpaceX will do something else never done before: implement a system to send control commands to the stage. I expect that the stage will autonomously target a return to a spot just off-shore, and then if all goes well and only on command it will divert to touch down on land.

My guess would be that is exactly what they will do for the first several hard landing attempts. OTOH, I could see a clean track record allowing that to be relaxed in the future. After all, aircraft of all types, including the unpowered shuttle, land(ed) on the runway right by the VAB, and contrary to launch, the stage will be virtually empty of propellants upon landing.

Offline mme

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #53 on: 04/23/2014 08:01 am »
My question is how the range authorities and the FAA are going to handle a rocket coming back to the pad or near the pad.  We have almost 60 years of regulations and experience launching expendable rockets.   How are they going to handle reusable rockets?

With great difficulty.

The folks that matter on the range side of things are government workers who face a very different set of incentives than workers in typical private companies, especially in the tech sector.  No one in government gets fired for being slow and methodical about changing the seemingly hard-coded logic of "that's how we do it here."  The reverse is not true. 

Given that set of incentives, the modfications will be challenging.
Must we make these assumptions about the FAA, the people that work there and their motivations? Do we have any evidence that the FAA will be an issue, or even relevant for boost back to KSC?
Space is not Highlander.  There can, and will, be more than one.

Offline InfraNut2

One burning question for me though:  how close did it come to the intended touchdown point?

They said the 1st stage was on the expected trajectory until they lost live telemetry to the cape. (IIRC it was said in the post-launch press conf).

So unless it veered off in the last few kilometers, it landed right where they expected.

edit: typos
« Last Edit: 04/23/2014 09:02 am by InfraNut2 »

Offline MP99

Quote
“We’re going to keep doing tests at McGregor with the F9-R Dev 1 and F9-R Dev 2 will be at Spaceport America. Anything we can test at a relatively low altitude – below around 10,000 feet – will continue to be tested at McGregor,” noted Mr. Musk.

Z11“The high altitude stuff – where it’s going atmospheric, 300,000 feet plus – will be tested in New Mexico as we need a much bigger clear area.”


Quote
“This year we’ll be able to recover a rocket booster, but I’m not sure we’ll be able to refly it this year,” Mr. Musk continued.

“That is likely next year. That’ll complete the picture as far as the booster stage is concerned.”


With their production holdups now apparently resolved, I wonder if it makes more sense for them to re-task the first recovered stage as Dev-2 or build it fresh?

I'd be surprised if they want to wait until next year to start flying Dev-2, but it's hard to see how they could refly a launch stage this year, even without Elon's confirmation.

OTOH, 10 flights this year is a big step up in production capacity, without having to build Dev-2, too.

Nothing really new here, except trying to apply recent statements to the question.

Cheers, Martin

Offline MP99

That is an excellent article, Chris.  Really covers the SpaceX reusability waterfront, with both the Grasshopper and F9R prototype vehicle tests, and also the controlled-descent high-altitude tests that are occurring after some of the F9v1.1 operational missions.  The historical background was useful context as well.

Thanks! A lot of work involved with this one, so that comment really made it worthwhile! :)

Just got round to reading it (I add to the "read later pile" until I have time to digest properly).

Excellent summary of where we're at and got here, and the forward looking statements of where we're going.

Cheers, Martin

Offline Jim

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #57 on: 04/23/2014 11:05 am »
Launch ops or vehicle production are not the only bottle necks
« Last Edit: 04/23/2014 08:49 pm by Lar »

Offline clongton

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #58 on: 04/23/2014 11:48 am »
Just saw this article as I've been on the road most of yesterday and last night. Trying to catch up now. Excellent roundup of where SpaceX stands with their reusability goals. Thanks for doing this. So much information is scattered thru many threads it's really useful to see it all neatly bundled into one place. "That Look" photo on Elon's face is epic. He is a true believer. Yes, he needs to run a profitable company in order to do the things he wants to do, but I caught the phrase he used "prove them wrong" when speaking of reusability. He really is driven by things other than profit. That, btw, is where so many posters go off the rails when they analyze what he does in terms of "the market" when they say there is no market for this or for that. Markets are secondary to him. So long as he's making enough to pay all the bills he is happy with that. He has other things on his mind. He is driven by his dreams and is a man on a mission. He is out to prove the naysayers wrong and go do what other, more timid souls, say can't be done. Good for him, and qudos to you for this article.
« Last Edit: 04/23/2014 11:48 am by clongton »
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Offline Llian Rhydderch

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Re: Rockets that return home - SpaceX pushing the boundaries
« Reply #59 on: 04/23/2014 01:01 pm »
My question is how the range authorities and the FAA are going to handle a rocket coming back to the pad or near the pad.  We have almost 60 years of regulations and experience launching expendable rockets.   How are they going to handle reusable rockets?

With great difficulty.

The folks that matter on the range side of things are government workers who face a very different set of incentives than workers in typical private companies, especially in the tech sector.  No one in government gets fired for being slow and methodical about changing the seemingly hard-coded logic of "that's how we do it here."  The reverse is not true. 

Given that set of incentives, the modfications will be challenging.
Must we make these assumptions about the FAA, the people that work there and their motivations? Do we have any evidence that the FAA will be an issue, or even relevant for boost back to KSC?

I made no assumptions whatsoever about the motivations of those who work at the FAA, nor at any government bureau.

I made the empirically verifiable observation that government workers in general face a significantly different set of incentives, and that those incentives taken in aggregate will oftentimes result in rather different outcomes.
Re arguments from authority on NSF:  "no one is exempt from error, and errors of authority are usually the worst kind.  Taking your word for things without question is no different than a bracket design not being tested because the designer was an old hand."
"You would actually save yourself time and effort if you were to use evidence and logic to make your points instead of wrapping yourself in the royal mantle of authority.  The approach only works on sheep, not inquisitive, intelligent people."

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