Author Topic: Stratolaunch: General Company and Development Updates and Discussions  (Read 1021006 times)

Offline hop

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For booster recovery in general, a lofted trajectory (climbing fast to orbital altitude and then burning out) is best, and is generally similar to the tourist suborbital trajectories.
For *very* loose values of similar. Any useful first stage will be re-entering a lot faster than SS2.

Offline jongoff

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Just an observation. I've seen about half a dozen statements like "people behind this project aren't stupid" - of course they are not, but such statements can also be seen as argumentum ad verecundiam.

The problem is that a lot of us who have studied air launch for years see some of the hand-wavy concerns on here, and don't have time to go dig up the references to quote chapter and verse on why people are blowing things out of proportion.  Personally, from having looked at liquid-fueled air-launch for as long as I have, I think a lot of the nay-saying is based on simplistic logic, ignoring key details, and ignoring the work that's been done in the field.  The approach Allen at least presented yesterday is totally technically feasible.  The bigger concern is that while they may make a system that can operate in a cashflow positive manner, he's taking an approach that I think misses some of the potential of air-launch.

~Jon

Offline RocketmanUS

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I like the t/Space concept with the Airlaunch LLC Quick Reach II rocket with the trapez release. Only one engine one the first stage, simple pressure feed design, same with the second stage. Crew enters capsule after plan is in the air for added safety.

With the Falcon
Could it be for the first stage 5 Merlin vacuum engines around 90,000lb+ each with one engine out from engines start?

Could the Falcon 9 second stage be the same size as for the air launch version?

Cost wise how could this compare to a possible future Falcon 9 RLV?

The advantage to air launch is
 The ability to go above bad weather.
 Multiple launches in one day not waiting for the launch pad to be ready.
 Multiple launch areas do to plane takes the rocket to launch area in the sky.

Offline docmordrid

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An SSTO spaceplane with large internal tanks akin to Venture Star? 
DM

Offline Namechange User

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P.S. On the 747 you could mount the Falcon above the center wing section and have it slide back off a rack at launch.

Oh my.  Something goes wrong with the rack, it gets hung up on one roller, wind gust at just the right moment.  Risk is part of this game, unnecessary risk is another thing entirely. 
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Offline Zed_Noir

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If all else fails, maybe you could use it to carry submarines  :D

Suppose you don't want to send your sub thru the Panama Canal, or thru the Suez Canal, or around the Cape of Good Hope, or around Tiera Del Fuego. Just hook it up to Stratolaunch, and fly it wherever you want.

Gee, come to think of it, wouldn't Stratolaunch be better as a giant seaplane, like Spruce Goose? Could eliminate landing-gear weight.

Even if you off-loaded all of the Trident missles at one coast, and re-loaded them at the other coast, do you really think you can get permission to fly that nuclear reactor (or perhaps Subs have multiple reactors ??) over land ? How does that reactor get cooled during flight ?


But small conventional Diesel-electric subs is doable. As well as Deep sea Submersibles with their support equipment.


Offline Rocket Science

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Try to figrure this...

Despite the caption, that is actually an F-82 Twin Mustang, not two P-51s bolted together. The F-82 was an all new aircraft that started from the P-51H design, but diverted from it radically. It was not two P-51s.

No, I guess I did not make my point clear as to the big "why"?

I'm afraid you still haven't. You quoted my whole post, but it discussed several different topics.

Were you asking why the twin fuselage on the F-82 but not on a passenger jet?

They needed a second engine and bigger wings to lift the extra fuel for longer range, and they wanted a second pilot to reduce fatigue on long overwater flights. Basing it on the P-51 saved development cost, and the separate cockpits avoided disadvantaging one crewman with a backseat view, as he was not a systems operator, but a full co-pilot.

In some ways it was similar to the twin-boom P-38, but that plane had a central fuselage and was single-seated.

If you're carrying passengers, you need a large pressurized volume, something neither the F-82 nor the Stratolauncher aircraft require. Two fuselages is not a structurally efficient way to provide that volume.

If you were asking why I think modifying two 747's to this configuration is more difficult than building the F-82, you'll have to point out which part of what I said in my previous post you disagree with.
I guess it’s not that I disagree with you at all. If an aircraft constructor is adamant that a certain concept is in their opinion “the best” and is well funded, then why not? It’s their money… I have total faith in Burt Rutan going right back to his early days. If he believes in this a/c, it will fly…  That doesn’t mean that there have not been alternatives throughout the years. My gut tells me that Burt really wants another record breaking aircraft and that is cool too…  8)

Regards
Robert
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator

Offline Zed_Noir

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P.S. On the 747 you could mount the Falcon above the center wing section and have it slide back off a rack at launch.

Oh my.  Something goes wrong with the rack, it gets hung up on one roller, wind gust at just the right moment.  Risk is part of this game, unnecessary risk is another thing entirely. 

IIRC the D-21 drone was deploy in such a manner off the SR71, not very successfully.

Offline simonbp

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Did you guys actually watch the press conference? Like the part where Burt Rutan himself says quite specifically that a twined 747 was just plain "stupid", and that you really have to build a purpose-designed aircraft?

Also, he's apparently had this design in his back pocket since at least 1991 (!), and jumped when he heard Allen was looking for something similar. All the internal systems (electrical, actuators, landing gear, flight deck) are from the cannibalized 747s, but the structure is all new, because it has to be.

Offline Dalon

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P.S. On the 747 you could mount the Falcon above the center wing section and have it slide back off a rack at launch.

Oh my.  Something goes wrong with the rack, it gets hung up on one roller, wind gust at just the right moment.  Risk is part of this game, unnecessary risk is another thing entirely. 

There is definite risk, even with this underwing design.

They could put explosive bolts within the strongback to effect a secondary separation in the event of a faulty separation.
« Last Edit: 12/14/2011 06:55 pm by Dalon »

Offline Dalon

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I won't be surprised if the carrier aircraft is designed to mid-flight refuel.

While I'm not aware of any civilian use of mid-flight refueling, the technology behind it is very mature.   Mid-flight refueling would drastically increase the available payload. 

I cannot imagine the military raising any objections against a group with these credentials.

Offline RanulfC

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I won't be surprised if the carrier aircraft is designed to mid-flight refuel.

While I'm not aware of any civilian use of mid-flight refueling, the technology behind it is very mature.   Mid-flight refueling would drastically increase the available payload. 
Actually there are a couple of companies that operate "civilian" mid-air refueling business. They usualy augment military operations or for governments that don't have "in-house" long-range refuelers.

Quote
I cannot imagine the military raising any objections against a group with these credentials.
"Objections" as in not allowing them to use military assets? Currently that's not "legal" for the military to do so while they won't "object" the truth is that they would have to go to the aforementioned companies as they would not be allowed access to military equipment.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline rdale

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Did you guys actually watch the press conference? Like the part where Burt Rutan himself says quite specifically that a twined 747 was just plain "stupid", and that you really have to build a purpose-designed aircraft?

That's not how the Internet rolls ;) You read bits and pieces of a press release, don't bother to look for info yourself, and post hair brained ideas with the purpose of starting a fight with those who actually know what is going on.

Offline Namechange User

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P.S. On the 747 you could mount the Falcon above the center wing section and have it slide back off a rack at launch.

Oh my.  Something goes wrong with the rack, it gets hung up on one roller, wind gust at just the right moment.  Risk is part of this game, unnecessary risk is another thing entirely. 

There is definite risk, even with this underwing design.

They could put explosive bolts within the strongback to effect a secondary separation in the event of a faulty separation.

Of course there is risk.  "Risk" in its own right should not be something that strikes fear in the hearts of everyone and keeps that job from happening.  What one does is design to minimize the risk within practical terms that have the least impact on technical, cost and schedule.

As for redundancy, what you suggested is a possibility, and is a function of the overall risk strategy, their design and ConOps. 
Enjoying viewing the forum a little better now by filtering certain users.

Offline Dalon

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Of course there is risk.  "Risk" in its own right should not be something that strikes fear in the hearts of everyone and keeps that job from happening.  What one does is design to minimize the risk within practical terms that have the least impact on technical, cost and schedule.

As for redundancy, what you suggested is a possibility, and is a function of the overall risk strategy, their design and ConOps. 

I've nothing against risk.  I think this is an enthralling design and I'm very happy to see more private investment attempting to lower costs to space.

I do have concerns about the tremendous complexity involved with this system.  Fueling will be complicated.  The tight timing from release to engine start could be hairy.  Safely mitigating abort scenarios could be the biggest undertaking of all.

There seem to be significant risks to the carrier aircraft.  I wouldn't want to be flying in that aircraft during the first few launches.  I even wonder if it will be remotely piloted.

Offline Namechange User

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Of course there is risk.  "Risk" in its own right should not be something that strikes fear in the hearts of everyone and keeps that job from happening.  What one does is design to minimize the risk within practical terms that have the least impact on technical, cost and schedule.

As for redundancy, what you suggested is a possibility, and is a function of the overall risk strategy, their design and ConOps. 

I've nothing against risk.  I think this is an enthralling design and I'm very happy to see more private investment attempting to lower costs to space.

I do have concerns about the tremendous complexity involved with this system.  Fueling will be complicated.  The tight timing from release to engine start could be hairy.  Safely mitigating abort scenarios could be the biggest undertaking of all.

There seem to be significant risks to the carrier aircraft.  I wouldn't want to be flying in that aircraft during the first few launches.  I even wonder if it will be remotely piloted.

Your concerns are noted.  None of them are insurmountable nor do they have to be overly complicated.  Given the freedom the carrier aircraft has and it's ability to not be fixed to one location at "T-0", abort scenarios (if and when even required) may be the easiest thing of all to mitigate.

As for the carrier aircraft risks, I suggest you do not apply for the job. 
« Last Edit: 12/14/2011 07:48 pm by OV-106 »
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Offline Robotbeat

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By the way, this hasn't been touched on here very much, but one thing people on the ARocket list are pointing out is that airlaunch would make first-orbit rendezvous a lot easier, meaning that if you are sending people/supplies or propellant to a space station or depot, you could launch any day (probably with multiple opportunities per day) without having to wait a couple days in a phasing orbit. This means you can make the cabin much more cramped than you otherwise would be able to get away with (think elevator versus sleeper car), and boil-off for cryogens on a tanker is a lot less of a design problem. Also, you can get time-critical supplies up there a lot faster.

This means you can offload more of the spacecraft mass to the station, getting more bang for your buck.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline baldusi

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One problem I have is wondering if 1300mn are enough. From KSC they can't reach betten than 8degrees latitude without launching ove Venezuelan air space. If they can launch form Puerto Rico (the longest runway is 11.500 feet, and I don't know how are they going to replenish the LOX), then they can get close to Kourou altitude. But still would be a problem to hit the Brazilian air space.
Kwajalein doesn't have a runway long enough. So they can't hit the equator from there.
The other thing that I've been wondering, is that once you build the aircraft, the only way to increase the payload would be to go with more efficient rocket per unit of weight (like staged combustion hydrogen). So they might eventually be interested in more "efficient" designs from SpaceX (like their proposed staged combustion light hydrocarbon engine) or somebody else.
At last, I'm still wondering if that aircraft isn't the perfect case for the GE90-94B. Two of those would have the same thrust of three of the 747-400 (around 820kN). nd I doubt GE would be worried of it competing with the Boeing 777. Or they could go with the GE90-115B monsters and get 20% more payload.

Offline HMXHMX

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Some people have asked if I'm involved, or AirLaunch or t/Space.  The answer is no to all three.

Perhaps someday I can comment, but not today.  NDAs and confidences are involved.  Sorry.

Offline rjholling

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As far as T-0 abort scenarios are concerned, isn't that automatically LOV whereas if you were launching from a pad you could still halt the launch and fix the problem?

 

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