Stratolaunch: General Company and Development Updates and Discussions

[SoCalEric]

Curious.... polite parting of ways (Strat/SpaceX) notwithstanding, do economics more or less dictate that Strato will eventually launch with (a) whichever, and (b) only those rockets that can reusably land themselves? (I.e., certainly NOT Delta)?

Also, was there ultimate consensus re how small a fraction launched rockets would likely be in the first place of total Strato payloads? (Considering how versatile the design is).

Thanks

[Lar]

Image of the Hangar:
https://twitter.com/PaulGAllen/status/317696319512801281
https://pbs.twimg.com/media/BGivHo-CcAAbjc_.jpg:large

Update:
http://www.flightglobal.com/news/articles/stratolaunch-marches-forward-383992/

As others have commented, how can they be designing the craft (and bending metal for wingspars) if they don't know what they are launching yet??? The whole thing seems screwy to me. I wish them all the best but ... ?

[JohnFornaro]

Doubtful. The wing is supposed to be balanced for the entire LV when it is released, to assist in the pull-up maneuver - see here: http://forum.nasaspaceflight.com/index.php?topic=27520.msg1028020#msg1028020

I don't think it will be able be balanced to act as a fly-back first stage with the payload and top two stages removed. It seems implausible.

But I have been wrong before.

Well, I was wrong once back in 1977, so I know how that feels.

Consider that a rocket with tailfins is conceivable.  I would say with the unusual horizontal launching configuration, that they would be necessary.  In any case, the delta wing illustrated would have elevators:

http://en.wikipedia.org/wiki/Elevator_(aircraft)

As best as I can tell from the illustration, there are three stages total, and the delta wing is not attached to stage 3.  If they anticipate flyback, then I'd imagine there to be a nose cone on stage 1. Hard to imagine atmospsheric flight with the blunt end of a cylinder.

Even so, it's an illustration, and they can change it every day if they want to.

[pippin]

The topic was not the shuttle, but what assumptions the "50 to 60 flights" were based on. I assumed that they thought that every RLV would need as many replacement parts as the shuttle did after every flight (and service time between flights). In this case, "many" is relative.

Read some of the studies being done and then you know the assumptions. It's not like this stuff wasn't publicly available. If you want to argue, do your homework.

And your argument about Shuttle's excessive refurbishment cost is bogus because the original study was made BEFORE Shuttle was developed and didn't even factor that in, they only learned about these excessive costs after the fact. The 50-60 were for a paper shuttle looking ever as optimistic as you can design one.
The Shuttle that actually flew would have been superior to an expendable at no launch rate in the world simply because the refurbishment costs alone were probably more expensive than a whole expendable launch (of an unmanned vehicle, that is. Not counting in the re-use of the spacecraft itself. That _might_ actually have been economical, counting the Shuttle's capabilities, I don't know. But we are talking launches here, not spacecraft)

The one thing that is right, though, is that the 50-60 are for an all-up LV, not just the first stage.

[Lar]

Read some of the studies being done and then you know the assumptions. It's not like this stuff wasn't publicly available. If you want to argue, do your homework.

Do you have links you can share to some of the studies for those that DO want to do homework but are unsure where to start? Thanks.

[pippin]

No, but I am sure your Google-Foo is as good as mine plus L2 is often a pretty good resource.
I don't keep directories of links of stuff I've read, especially since I wouldn't find anything there any better than using Google but I know I have seen at least two of these studies here somewhere.

Oh, and another hint: I'm not sure Antonio is right about 1975, I thought that study was older, like from '72 or so.

[Lar]

No, but I am sure your Google-Foo is as good as mine plus L2 is often a pretty good resource.
I don't keep directories of links of stuff I've read, especially since I wouldn't find anything there any better than using Google but I know I have seen at least two of these studies here somewhere.

If you remember any titles, or portions, that might help with searching... thanks.

[Jim]

ET, tiles, and one could argue that the booster engines were basically rebuilt after every flight.

Rebuilt does not mean parts were replaced.  The engines were stripped down and inspected and reassemble.

Anyways, the ET is only one part then.

[Elmar Moelzer]

ET, tiles, and one could argue that the booster engines were basically rebuilt after every flight.

wrong again.  Rebuilt does not mean parts were replaced.  The engines were stripped down and inspected and reassemble.

Anyways, the ET is only one part then.

I meant the SRBs, when I said boosters. Refueling an SRB is not like refueling a liquid.
Also the ET consists of many parts... But lets not split hairs.
Anyway, I was simply asking for more information on how the math was done that came to the conclusion that you need 50 to 60 flights for an RLV (any type of RLV?) versus an expendable that is usually already economic with a couple of flights a year. Oh and please spare me your ad hominem attacks.

[Elmar Moelzer]

Read some of the studies being done and then you know the assumptions. It's not like this stuff wasn't publicly available. If you want to argue, do your homework.

I did not know the older study, sorry.
I read a study from 2000 that based a lot of its assumptions on numbers derived from the shuttle. While the author was trying to correct for this, it still resulted in very unfavorable baselines to the RLV.
I think that in example of SpaceX the numbers that are usually unfavorable for an RLV (refurbishment cost, recovery cost, debelopment cost, insurance) can be assumed to be much lower than in that paper.
I actually think that insurance will go down as experience goes up. For an expendable there is no way you can do a test flight. Every launch is a new vehicle that has never been tested. For an RLV this is different. Because of this, I think that relyability will go up and insurance will ultimately go down. The study also assumed an enormous increase in complexity between the RLV and the ELV. As in SpaceX case, at least for the first stage, the differences are much more subtle. For the second stage things are different. The Dragon capsule would have to be recovered either way. So e.g. there the cost for reocovery is identical.
And so on and so forth. Anyway, because of this, I was asking for the assumed costs that were the basis for this calculation.

[Elmar Moelzer]

Tiles is a myth. When Discovery went to the Smithsonian, most of the original tiles were still on her. There were replaced tiles on every flight, but not as many as people think, and the same ones tended to be replaced over and over.

Of course most tiles were still on her, but they have to inspect all of them and replace the damaged ones and there are MANY tiles on the shuttle.
From what I understand much of the turnarround time for the much smaller Dreamchaser will also be because of the TPS tiles.

[Elmar Moelzer]

Still not as many replaced as you think.

And how many do I think needed replaced? Just curious...

[Elmar Moelzer]

Enough to make it a significant factor in shuttle costs and turnaround time.

So you are saying that they were not a significant factor in the cost and turnaround time?
IIRC, they are for the DC.
And I mean the labour for the inspection and replacement there as well as the cost of the tiles themselves. Correct me if I am wrong, but I remember up to 150 tiles needing replacement after every shuttle flight and that takes some 25 manhours per tile just for the replacement.
Now you may not consider that much, I do. I may be wrong, but I dont see how a reusable first stage would need that, since it will most likely not meet these extreme conditions (and that may be different for some designs than for others, but for most two stage designs this should be true).
And this is just one example. I am not set on the tiles. There is also the tank. There are the SRBs which are rather expensive to refurbish and so on. Anyway, I get it, the study did not use the shuttle as a reference. So I will try to dig it up somewhere...

[Lar]

Enough to make it a significant factor in shuttle costs and turnaround time.

So you are saying that they were not a significant factor in the cost and turnaround time?
IIRC, they are for the DC.
And I mean the labour for the inspection and replacement there as well as the cost of the tiles themselves. Correct me if I am wrong, but I remember up to 150 tiles needing replacement after every shuttle flight and that takes some 25 manhours per tile just for the replacement.
Now you may not consider that much, I do. I may be wrong, but I dont see how a reusable first stage would need that, since it will most likely not meet these extreme conditions (and that may be different for some designs than for others, but for most two stage designs this should be true).
And this is just one example. I am not set on the tiles. There is also the tank. There are the SRBs which are rather expensive to refurbish and so on. Anyway, I get it, the study did not use the shuttle as a reference. So I will try to dig it up somewhere...

Perhaps today, inspection could be automated but back in the day... there were a lot of tiles. Even if each one only got 15 seconds of inspection (seems low to me) that's many thousands of seconds.

This is way off topic for this thread though. Start a new thread or find somewhere to anchor it...

[pippin]

As in SpaceX case, at least for the first stage, the differences are much more subtle.

We don't know that, yet. They still have to recover their first one so nobody knows in which condition they will come back and how many design iterations they will have to go through until this works.
The first iterations clearly did not at all work as SpaceX expected, all the first stages broke up and could not be recovered so far and attempts to fix this failed.

I am not so sure the added cost is so low. In the flyback case they need the legs, more fuel, an additional flight computer (which needs to be integrated and tested with the one on the second stage; this is a completely different control profile: you need to handover, make sure everything works out fine etc. without adding risk to the mission,...) and let's not forget that all the fixed cost that you amortize over a number of vehicles for an expendable don't go away just because you now start to re-use. You can't calculate as "An expendable stage costs 10 million bucks and if I reuse it 10 times I'm down to 1". As of my experience with aerospace manufacturing chances are at least 5 of these 10 million are fixed costs (engineering, tooling, testing, verification, paperwork,...) and don't go away so all of a sudden you are not saving 9 million per launch but only 4.5 and your added effort eats into that. Plus you add more overhead (recovery infrastructure, landing sites, vessels, personnel...).
Reusing a first stage may be cheaper than a full-up vehicle but then BUILDING a first stage is cheaper, too.

Compared to the aggressive costs SpaceX quotes for their expendable operation it will be quite a challenge to have really low costs for the refurbishment. It's not like they are quiting Titan prices or whatever was the basis for an expendable launcher in 2000

[Elmar Moelzer]

We don't know that, yet. They still have to recover their first one so nobody knows in which condition they will come back and how many design iterations they will have to go through until this works.
The first iterations clearly did not at all work as SpaceX expected, all the first stages broke up and could not be recovered so far and attempts to fix this failed.

I am not so sure the added cost is so low. In the flyback case they need the legs, more fuel, an additional flight computer (which needs to be integrated and tested with the one on the second stage; this is a completely different control profile: you need to handover, make sure everything works out fine etc. without adding risk to the mission,...) and let's not forget that all the fixed cost that you amortize over a number of vehicles for an expendable don't go away just because you now start to re-use. You can't calculate as "An expendable stage costs 10 million bucks and if I reuse it 10 times I'm down to 1". As of my experience with aerospace manufacturing chances are at least 5 of these 10 million are fixed costs (engineering, tooling, testing, verification, paperwork,...) and don't go away so all of a sudden you are not saving 9 million per launch but only 4.5 and your added effort eats into that. Plus you add more overhead (recovery infrastructure, landing sites, vessels, personnel...).
Reusing a first stage may be cheaper than a full-up vehicle but then BUILDING a first stage is cheaper, too.

Compared to the aggressive costs SpaceX quotes for their expendable operation it will be quite a challenge to have really low costs for the refurbishment. It's not like they are quiting Titan prices or whatever was the basis for an expendable launcher in 2000

You are right. We dont know yet exactly how much difference there will really be, but from the current information that we have, we can make a guess. It seems to me like the differences will be subtle and mostly in the software and the landing legs. From what I understand, they wont have more fuel in them, but simply that the payload will be slightly reduced.

[RanulfC]

One crazy idea, add a couple of spaceshipone/two-like feathers to the air launched first stage being designed by Orbital and bring it back as a reusuble first stage. I'm not an engineer so don't know the technical feasibility of such an aproach. I'd like to know your views on this idea. Also I don't know if there are any intelectual property issues that would prevent them from using this aproach, if it was feasible.

I'd really like your feedback on this.

IIRC Burt Rutan actually noted that the "feather" feature doesn't work well above a certain "sub-orbital" reentry speed. He wasn't very specific but I believe Mach-10 would be to high. The "big" feature of the feather-entry is simply allowing for a very "high-drag" but stable reentry when in use but it also has a rather high landing speed because the wings are not optimized for that regime.

Pretty much this entire thread is "based" on various ideas of how one could recover and reuse the 'first" rocket stage of an air-launched spacecraft, so welcome to the discussion

I note that no one has actually pointed this out for those who might not actually KNOW the full story, so I'll let all the "new" folks know that "antonioe" (http://forum.nasaspaceflight.com/index.php?action=profile;u=2965) is actually one of the folks DESIGNING StratoLaunch's rocket so while the REST of us might "suggest" designs his posts will probably be the ones you want to keep an eye on
(Not, mind you that I'm going to let a piddly little "fact" like that stop me from "suggesting" the heck out of things!

Randy

[yg1968]

Stratolaunch To Award Booster Contract to Orbital in May:
http://www.spacenews.com/article/financial-report/34789stratolaunch-to-award-booster-contract-to-orbital-in-may#.UWcyW7WG32s

[Blackstar]

Have not seen it here, but OSC revealed details of their launch vehicle last week at the Space Symposium. They had a model on display.

[FutureSpaceTourist]

Have not seen it here, but OSC revealed details of their launch vehicle last week at the Space Symposium. They had a model on display.

Thanks for the update. Nothing yet I can see on either the Orbital or Stratolaunch websites, but I guess Orbital's focus is somewhere else right now! Hopefully they'll publish something soon.