Author Topic: Air Launch LLC (Read 16406 times)

guidanceisgo · « **on:** 05/07/2007 03:57 am »

Does anyone know the status of Air Launch LLC? Have they received the next phase of the FALCON contract or have they been turned down?

CentEur · « **Reply #1 on:** 05/08/2007 08:35 am »

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guidanceisgo - 7/5/2007 5:57 AM

Does anyone know the status of Air Launch LLC? Have they received the next phase of the FALCON contract or have they been turned down?

Their last effort seems to fall short. They planned to do "a full duration burn of approximately 230 seconds" but managed to do 191 seconds.

aero313 · « **Reply #2 on:** 05/08/2007 05:35 pm »

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CentEur - 8/5/2007 4:35 AM

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guidanceisgo - 7/5/2007 5:57 AM

Does anyone know the status of Air Launch LLC? Have they received the next phase of the FALCON contract or have they been turned down?

Their last effort seems to fall short. They planned to do "a full duration burn of approximately 230 seconds" but managed to do 191 seconds.

The other way to look at it is that except for a mixture ratio that was slightly off (and thus led to premature depletion of one propellant) the integrated stage firing was a complete success.

pippin · « **Reply #3 on:** 05/08/2007 06:55 pm »

That's a kind of "SpaceX"-way to see it ;-)

nacnud · « **Reply #4 on:** 05/08/2007 09:04 pm »

191 seconds is better than anyone else has managed with their type of set up. Pracitce makes perfect

CentEur · « **Reply #5 on:** 05/09/2007 07:40 am »

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nacnud - 8/5/2007 11:04 PM

191 seconds is better than anyone else has managed with their type of set up. Pracitce makes perfect

Nobody denies their achievement. I'm merely pointing that their last performance shortfall matches perfectly their reputation of what AW described as "people with a track record of overly optimistic estimates, as exemplified by Rotary Rocket". The question remains - what level of confidence have they built with DARPA guys.

aero313 · « **Reply #6 on:** 05/09/2007 02:44 pm »

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pippin - 8/5/2007 2:55 PM

That's a kind of "SpaceX"-way to see it ;-)

Maybe. The difference is that this was the first-ever attemp at a full duration firing of a fully integrated stage. Not a launch, not even a qualification test (that comes later). Just a technology demonstration. How many stage level tests did Space X conduct in Texas without telling anyone? How many blew up?

jongoff · « **Reply #7 on:** 05/09/2007 02:55 pm »

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CentEur - 9/5/2007 12:40 AM
Nobody denies their achievement. I'm merely pointing that their last performance shortfall matches perfectly their reputation of what AW described as "people with a track record of overly optimistic estimates, as exemplified by Rotary Rocket". The question remains - what level of confidence have they built with DARPA guys.

CentEur,
From what I know of their system, it's entirely likely that the performance shortfall was something that could've been fixed over another several firings. It's not that they grossly overestimated their engine Isp or their stage propellant volume or something like that. It's probably that they didn't have the engine or pressurization tuned quite right, so they depleted one propellant faster than planned. That's the sort of thing that can often happen in development, and just needs several iterations to work out.

At least as far as I understand things, this is a fundamentally different sort of issue from their issues with Roton. Roton's design was fundamentally flawed in several ways, and had no chance of meeting the performance subscribed. The Quickreach upper stage hasn't yet reached its performance targets after only like 3 hold down firings. I'd give the AirLaunch pretty good odds for being able to tune the system and get it working up to spec within 4-6 months if their contract were continued.

Alas, all the rumors I've heard say they won't be given the chance. That'll be a pity if that's the case, because they've been wonderful neighbors out here in Mojave, and have done some very interesting work. I'm sure there are plenty of examples aerospace companies that have hit closer to their performance goals by their 2nd or 3rd full-stage firing. But I'm also sure there's plenty of examples of companies that didn't that still were able to deliver a good product, but just took a bit longer than planned.

~Jon

Antares · « **Reply #8 on:** 05/13/2007 11:42 pm »

Any idea if they hit their Isp target? By hit, I mean within 10sec. Vapak is dubious to me.

yinzer · « **Reply #9 on:** 05/14/2007 12:48 am »

Dubious? Didn't they use it on SpaceShip One? Granted, characterizing the heat transfer from the propellants to the ullage and vice versa is a bit fiddly, but there doesn't seem like any reason it shouldn't be able to be made to work.

aero313 · « **Reply #10 on:** 05/14/2007 01:57 am »

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Antares - 13/5/2007 7:42 PM

Any idea if they hit their Isp target? By hit, I mean within 10sec.

They've been firing engines for about a year now. Isp is nearly right on prediction, so by your definition, yes, they "hit" it.

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Vapak is dubious to me.

That seems to be the opinion of everyone who can't be bothered to find out the facts.

jongoff · « **Reply #11 on:** 05/14/2007 02:31 pm »

Aero313,

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They've been firing engines for about a year now. Isp is nearly right on prediction, so by your definition, yes, they "hit" it.

Yeah, I think a lot of people have been confused about why they missed their time target with their latest full-stage hold-down test. I'm pretty sure it wasn't because their Isp just happened to be 25% low. It was more likely because something about the VaPak system wasn't quite dialed in right yet, so they had their mixture ratio change during the firing and burned out one propellant first. I wasn't there for that test (though I had been invited), so I can't say for sure, but based on what I know of their system, that'd be reasonable.

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Vapak is dubious to me.
That seems to be the opinion of everyone who can't be bothered to find out the facts.

It's an interesting techinque, and has some unique challenges and benefits. One thing though was I remember people ripping on it as a "chugmaster 2000" or some crap like that. Their test site is about 4-5minutes *walking distance* from ours, so I've seen a few of their firings. They were quite stable, with no obvious signs of chugging. And I've seen chugging before a few times, so I think I'd know what it looks like. :-)

~Jon

Antares · « **Reply #12 on:** 05/14/2007 05:03 pm »

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aero313 - 13/5/2007 9:57 PM
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Antares - 13/5/2007 7:42 PM
Any idea if they hit their Isp target? By hit, I mean within 10sec.
They've been firing engines for about a year now. Isp is nearly right on prediction, so by your definition, yes, they "hit" it.

Source?....

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Vapak is dubious to me.
That seems to be the opinion of everyone who can't be bothered to find out the facts.

[/quote]Is contacting them and being told they hadn't measured it yet sufficiently bothered?

For Vapak to work repeatably, propellant temperature has to be controlled very precisely and accurately. 1degR is ~5psi variation for saturated LOX around 220R. That's not ready for prime time until it performs repeatably and predictably for several thousand seconds, which should be easy if it's such a simple system.

aero313 · « **Reply #13 on:** 05/14/2007 08:18 pm »

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Antares - 14/5/2007 1:03 PM

Is contacting them and being told they hadn't measured it yet sufficiently bothered?

There has been some interaction but I can't say that I've been in the middle of it. Also keep in mind that they have been struggling to satisfy their final DARPA billing milestone on the current contract and have frankly not been able to respond to questions that have not come from the current paying customer's representatives. If you've been on one of the DARPA/Air Force propulsion review teams, I don't know what to tell you. I've seen Isp data.

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For Vapak to work repeatably, propellant temperature has to be controlled very precisely and accurately. 1degR is ~5psi variation for saturated LOX around 220R. That's not ready for prime time until it performs repeatably and predictably for several thousand seconds, which should be easy if it's such a simple system.

No argument, but this is a system tuning issue, not a fundamental physics issue. Investing a lot of time and money in the GSE makes sense if it reduces the cost of the expendable hardware. Are there insulation issues? Sure, but these are design detail issues, not "does it work" issues.

Danderman · « **Reply #14 on:** 05/14/2007 08:32 pm »

GSE is a kind of strange term here, considering that most of it would be utilized inside an aircraft.

Jim · « **Reply #15 on:** 05/14/2007 11:59 pm »

Propforce · « **Reply #16 on:** 05/15/2007 06:01 am »

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aero313 - 14/5/2007 1:18 PM

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Antares - 14/5/2007 1:03 PM

Is contacting them and being told they hadn't measured it yet sufficiently bothered?

There has been some interaction but I can't say that I've been in the middle of it. Also keep in mind that they have been struggling to satisfy their final DARPA billing milestone on the current contract and have frankly not been able to respond to questions that have not come from the current paying customer's representatives. If you've been on one of the DARPA/Air Force propulsion review teams, I don't know what to tell you. I've seen Isp data.

I have no involvement in this project but I agree with aero's response. Frankly why would they tell you anything if you're not their current paying customer? Afterall, they are involved in a competitive environment against SpaceX with their current contract as well as future potential contracts.

My personal experience of dealing with Gary Hudson has found him to be a sincere, open & honest guy. But hie's not going to tell you his competitive advantages especially if you don't believe in his concept.

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For Vapak to work repeatably, propellant temperature has to be controlled very precisely and accurately. 1degR is ~5psi variation for saturated LOX around 220R. That's not ready for prime time until it performs repeatably and predictably for several thousand seconds, which should be easy if it's such a simple system.

No argument, but this is a system tuning issue, not a fundamental physics issue. Investing a lot of time and money in the GSE makes sense if it reduces the cost of the expendable hardware. Are there insulation issues? Sure, but these are design detail issues, not "does it work" issues.

I certainly would not propose this concept for the ARES 1 booster propulsion system :laugh: At least not at the current TRL.

But this is WHY darpa is involved, e.g., high risk/ high payoff technologies. I may go as cynical as to say that nasa is almost exactly opposite to what darpa is these days, e.g., no-risk/ no-payoff tech programs.

Propforce · « **Reply #17 on:** 05/15/2007 06:03 am »

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Jim - 14/5/2007 4:59 PM

ASE

a simple SE will suffice

ps-
Just keep your acronym list upto date :laugh:

aero313 · « **Reply #18 on:** 05/15/2007 03:10 pm »

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Danderman - 14/5/2007 4:32 PM

GSE is a kind of strange term here, considering that most of it would be utilized inside an aircraft.

Not necessarily. Yes, you'd need some equipment to maintain propellant condition on the aircraft (and yes, ASE is the appropriate term for that) but you most likely would condition and load the propellant on the ground, hence the "G"SE.

Dan Moser · « **Reply #19 on:** 05/18/2007 03:38 am »

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Antares - 13/5/2007 6:42 PM

Any idea if they hit their Isp target? By hit, I mean within 10sec. Vapak is dubious to me.

Isp is important.. but you totally miss the real point. Achieving your COST target is of far greater importance. NASA missed the cost target on the Shuttle by a factor of 50 (!) ... now would you be OK with that because they "hit" their Isp target? Sheesh!

And your arbitrary "within 10 sec" target and "dubious" assessment.. sound like something an uninformed detractor might say. The Vapak system has been shown to be a viable concept with outstanding potential for enabling substantial launch cost reductions, whether air or ground launched. A growing body of test data continues to demonstrate this.

Now consider the SSME... very impressive Isp numbers, granted !... yet it is going extinct in less than 3 years in spite of the tens of billions of American taxpayers dollars that have been poured into its development.. . It's too expensive even for non-cost conscious NASA to deal with. .. talk about dubious!!