Stratolaunch: General Company and Development Updates and Discussions

[Patchouli]

The slight benefits of extra height and speed at deployment are probably not worth developing a new vehicle/plane for.

The biggest benefit from air launch is having a choice of launch locations, not being locked to a latitude or longitude.

True and they may be on to something here as launch windows and range availability could become a constraining factor for higher flight rates.

Of course you need a lot of capital to develop both an aircraft and a LV at a the same time but Paul Allen has enough money it's not a big issue for him.

[Rocket Science]

Maybe the military wants a carrier aircraft for some “super-size MOAB”... Who really knows...?

[Patchouli]

Maybe the military wants a carrier aircraft for some “super-size MOAB”... Who really knows...?

More likely launch on demand satellites or even a space plane.

A small space plane that could be launched on demand could fulfill the many of the observation missions the airforce originally envisioned for the Shuttle.

[Kabloona]

I think I have posted either in this thread or elsewhere my notes from a talk that he gave early this year. He discussed their early assumptions for Pegasus, almost all of which proved wrong, and concluded that air launch makes little sense.

You're proving my point that if Paul Allen had just picked up the phone and called Antonio Elias he would have been told by the expert what a bad idea Stratolaunch was/is, as I mused earlier that he could/should have done.

Antonio admitted many of his assumptions about Pegasus were wrong, but Pegasus still worked well enough to survive 25 years and do 40+ launches. But he would have known that scaling up makes all air-launch problems worse, and Stratolaunch would have no chance of being viable.

[QuantumG]

You're proving my point that if Paul Allen had just picked up the phone and called Antonio Elias he would have been told by the expert what a bad idea Stratolaunch was/is, as I mused earlier that he could/should have done.

I'm pretty sure Paul Allen has forgotten more about due diligence that you ever knew. Try to show just a smidge of humility, okay?

[Kabloona]

You're proving my point that if Paul Allen had just picked up the phone and called Antonio Elias he would have been told by the expert what a bad idea Stratolaunch was/is, as I mused earlier that he could/should have done.

I'm pretty sure Paul Allens has forgotten more about due diligence that you ever knew. Try to show just a smidge of humility, okay?

I'm not the expert and not claiming to be. I am claiming that Antonio Elias is the expert, and Antonio himself has said that Pegasus was marginal. Did Paul Allen discuss Stratolaunch with Antonio? If he did discuss it with Antonio, I can't imagine Antonio told him he thought it was a good idea. If he didn't discuss it with Antonio, that seems rather a big and unfortunate missed opportunity.

[HMXHMX]

Air launch has always seemed like a terrible idea. The first issue is that while you get a bit of starting height, you are working with a negative vertical velocity that you have to overcome right from the get go after being dropped.

I was told by a person who was involved on the Air Force side that this was the problem with AirLaunch several years ago--that was supposed to be dropped out of the back of a C-17 cargo plane. One problem was that the downward velocity of the vehicle pretty much erased the benefits of the air launch. If I remember correctly, I think he said that it was the equivalent of launching it from a hole in the ground. (There were other drawbacks as well, such as the fact that no pilot in the Air Force would agree to fly with a huge tank of heated propane in his cargo hold.)

That's not correct; our trajectory models showed definite performance gains vs. ground launch and even vs. winged air-launch.  We wouldn't have won a two full and open competitions if that were true.  (The first one was against 24 competitors including Orbital, the second against 14, the third against the final two – LM and Microcosm.)  There are several open-source papers on the project, which I'd be happy to point you to off-line if you PM me. 

As for safety, the propane pressure was the same as normal commercial propane tanks (~200 psia), and we passed all the safety reviews we were faced with.  The LOX under that same pressure was a far greater source of concern, but since we showed that the C-17 routinely flies with LOX under pressure (and even has specific vents for cryo gas venting from those tanks), it was shown not to be a hazard.  Most enlightening was the fact that the aircraft emergency oxygen system is in fact located directly under the crew seats and is pressurized too...

I don't want to hijack this thread but I did want to correct the errors of fact.  The primary reason the project didn't go forward was we threatened the hypersonics programs of the USAF – and safety was one of the shibboleths that opponents used in their whisper campaign to kill us.

[Blackstar]

Maybe the military wants a carrier aircraft for some “super-size MOAB”... Who really knows...?

That's not a combat-capable aircraft. It's not being built to military specs.

This is no different than the claim years ago that although the commercial justification for Stratolaunch made no sense, so there must be some hidden military justification for it. But nobody can point to any stated military requirement. There's nothing that exists, only civilian amateurs inventing reasons.

[Rocket Science]

Maybe the military wants a carrier aircraft for some “super-size MOAB”... Who really knows...?

That's not a combat-capable aircraft. It's not being built to military specs.

This is no different than the claim years ago that although the commercial justification for Stratolaunch made no sense, so there must be some hidden military justification for it. But nobody can point to any stated military requirement. There's nothing that exists, only civilian amateurs inventing reasons.

The military has an interest in the project. Like I said "who really knows...?" and that includes you...

[Star One]

Maybe the military wants a carrier aircraft for some “super-size MOAB”... Who really knows...?

That's not a combat-capable aircraft. It's not being built to military specs.

This is no different than the claim years ago that although the commercial justification for Stratolaunch made no sense, so there must be some hidden military justification for it. But nobody can point to any stated military requirement. There's nothing that exists, only civilian amateurs inventing reasons.

The military has an interest in the project. Like I said "who really knows...?" and that includes you...

Maybe they want to launch their proposed boost glide Mach 9 hypersonic global strike weapon off it.

[R7]

The military has an interest in the project.

Obviously military has interest in anybody advertizing responsive space launches but are there citations for any interests beyond that?

[Rocket Science]

The military has an interest in the project.

Obviously military has interest in anybody advertizing responsive space launches but are there citations for any interests beyond that?

There was an article recently (I forget where, it could be on here as well) where for security-sensitive reasons not to photograph a part of the aircraft...

[Robotbeat]

The military has an interest in the project.

Obviously military has interest in anybody advertizing responsive space launches but are there citations for any interests beyond that?

There was an article recently (I forget where, it could be on here as well) where for security-sensitive reasons not to photograph a part of the aircraft...

ITAR is just like that. It has nothing to do with any further military applications.

[Rocket Science]

The military has an interest in the project.

Obviously military has interest in anybody advertizing responsive space launches but are there citations for any interests beyond that?

There was an article recently (I forget where, it could be on here as well) where for security-sensitive reasons not to photograph a part of the aircraft...

ITAR is just like that. It has nothing to do with any further military applications.

True Chris, but our good friend Mary-Lynn suspects otherwise and I respect her opinion.(no dis to you)

[robert_d]

So -
1) Redesign carrier aircraft to make it unmanned; it could be remotely piloted from 737 class command plane. Saves weight, complexity. Aircraft could be LNG powered (re below)
2) Use BE-4 class LNG powered vehicle but with 2 to 4 smaller outboard engines. Same vacuum optimized smaller LNG engine would power 2nd stage.
3) Because plane is unmanned smaller engines could be started while still attached to carrier aircraft.
    Stress applied to wing by drag of vehicle would actually be reduced - allowing plane to assume ascent profile.
4) Aircraft would be in positive angle, accelerating upwards. Release. Main engine start would be almost at release, close enough so that the vehicle would never be descending, no wing necessary.
5) Key - Make first stage of vehicle reusable - it would use smaller engines to return for land landings in California or barge landing (rent from SpaceX?).

Given a reusable first stage and relativly rapid turn-around, costs may be contained enough. But you still need to assume a robust small - to midsize payload launch market.

Edit to clarify effect of early small engine start.

[Jim]

So -
1) Redesign carrier aircraft to make it unmanned;

Non starter.  FAA is not going to allow that

3) Because plane is unmanned smaller engines could be started while still attached to carrier aircraft.
    Stress applied to wing would actually reduce the drag - allowing plane to assume ascent profile.

Totally not possible.  Stress on a wing has no bearing on drag. 

5) Key - Make first stage of vehicle reusable - it would use smaller engines to return for land landings in California or barge landing (rent from SpaceX?).

Makes no sense to have a reusable stage for a air carry.  The weight of  legs offsets any benefits. It still wouldn't launch towards land so California is out. 

Also, Spacex is not going to rent a barge to a competitor.

[robert_d]

So -
1) Redesign carrier aircraft to make it unmanned;

Non starter.  FAA is not going to allow that

3) Because plane is unmanned smaller engines could be started while still attached to carrier aircraft.
    Stress applied to wing would actually reduce the drag - allowing plane to assume ascent profile.

Totally not possible.  Stress on a wing has no bearing on drag. 

5) Key - Make first stage of vehicle reusable - it would use smaller engines to return for land landings in California or barge landing (rent from SpaceX?).

Makes no sense to have a reusable stage for a air carry.  The weight of  legs offsets any benefits. It still wouldn't launch towards land so California is out. 

Also, Spacex is not going to rent a barge to a competitor.

1) There is NO reason a remotely guided aircraft would be more dangerous than a crewed one. There might even be oppurtunities to replace some weight of crew support equipment with more robust avionics/redundent flight systems that would make it inherently safer. It's not like it would be flying over populated areas anyway. This is 2015, afterall.
3) Bad wording on my part, thanks. I tried to reword it in the original post. Point being central carrier wing is already strong to support the weight and drag of a rather substantial vehicle. While the transient might be an issue, the drag should be reduced by the thrust of the smaller engines. Reason for early ignition is to allow release at pitch-up.
5) So their own barge then, let's not be so pendantic this early. And a net/airbag system could "catch" the thing anyway. Legs have not even yet been proven to work - SpaceX may need to add a vertical net to stop the slide-off/tipping they have encountered. We don't yet know what the final system will include. 
(Morning, Jim!)

[Jim]

1) There is NO reason a remotely guided aircraft would be more dangerous than a crewed one.

Yes, there are many valid reasons.  That is why there are no remote guided planes now.  Also, this one would have more fuel onboard/

[edkyle99]

Biggest benefit of air launch is probably higher ISP allowed by initial ignition at altitude, in theory.  This only works if the first stage engine is designed to extract the higher ISP, of course, compared to a ground launch.   

 - Ed Kyle

[matthewkantar]

  There are many precedents for large unpiloted aircraft. You Tube has numerous videos of unmanned airliners crashed in US and Mexican deserts for research purposes. The military remotely flies all sorts of outdated aircraft for test and target purposes. A certain unmanned aircraft is currently practicing takeoffs and landings on an aircraft carrier. There are some regulatory hurdles for sure, but the take off and landing of the carrier is relatively straight forward. Dropping the huge already-firing-rocket from the plane bit could be done safely far off shore over any convenient ocean.

  The whole Stratolaunch design makes little sense to me, especially the fact that they may complete the carrier before they figure out what it is going carry. I would love to be proved wrong though. The scale and ambition of the whole thing should produce some memorable video in any event.

Matthew