Stratolaunch: General Company and Development Updates and Discussions

[HMXHMX]

Wow, that's quite a change. Why buy 747s if you are going to change everything? Even the wings (presumably the primary reason for buying 747s) don't look like 747 wings anymore.

This gets better and better (pass the popcorn).  I think Dwayne Day nailed it with Egolauncher.

That Space review article had obvious flaws.  I leave discovery of each them as an exercise for the student.

[simonbp]

As for the LV - can anyone tell me why air launched rockets need to have such massive wings/fins?

It's not that they need to, just that it is advantageous for certain air launch profiles, especially those which Orbital is familiar with...

Total speculation here, but looking again at the render, it looks more like a liquid first stage with separate bulkheads and a smaller second stage. That would make sense, and the combination of structural rigidity from split bulkheads and those relatively large control surfaces could mean a flyback first stage. Given that their potential competitors are SpaceX and Blue Origin, both with reusable first stages, that would make sense. But it would also mean a much longer development cycle...

[Comga]

Wow, that's quite a change. Why buy 747s if you are going to change everything? Even the wings (presumably the primary reason for buying 747s) don't look like 747 wings anymore.

This gets better and better (pass the popcorn).  I think Dwayne Day nailed it with Egolauncher.

I really like Mr. Day's writing, but this article is an exception.  I find it totally unpersuasive.  Paul Allen is building a useless behemoth airplane and rocket so he can tell who that his is bigger?  Bezos and Musk?  And the bit about going backwards? "an inherent flaw: after being dropped from its carrier aircraft and falling toward the Earth, the rocket engines had to cancel the backwards velocity before they could start providing forward velocity."  Air launched rockets, even the eponymous AirLaunch, don't actually go backwards, although they do go downwards.  And how does he know that there is nothing launched secretly he doesn't know about, especially if it doesn't stay in orbit long enough for amateur observers to find it?  The X-37 sometimes stayed lost for quite a while after changing orbits.  And DoD wouldn't allow a switch from an untenable concept, and SpaceX wouldn't walk away from a customer who wants them to be an engineering services supplier for five years? 

Sorry. IMHO, this article doesn't pass the sniff test anymore than the original Stratolaunch announcement.  There has to be a better explanation.  But I do agree with Lars_J on one thing: Pass the popcorn!

OT PS  This week Lockheed announced that a UK subsidiary is developing technology to mine the deep ocean beds for nodules of copper, rare earths, and...... manganese!  Just in case you forgot about the Glomar Explorer.

[HMXHMX]

As for the LV - can anyone tell me why air launched rockets need to have such massive wings/fins?

It's not that they need to, just that it is advantageous for certain air launch profiles, especially those which Orbital is familiar with...

Total speculation here, but looking again at the render, it looks more like a liquid first stage with separate bulkheads and a smaller second stage. That would make sense, and the combination of structural rigidity from split bulkheads and those relatively large control surfaces could mean a flyback first stage. Given that their potential competitors are SpaceX and Blue Origin, both with reusable first stages, that would make sense. But it would also mean a much longer development cycle...

My speculation is, too, that this might be a fly-back (or perhaps a fly-forward booster like Jon Goff has proposed for air-launch CONOPS).  This conclusion comes from observing the aft position of the wing.  It is ill-suited to act like the Pegasus wing to turn the flight path angle since it is not at the Cg of the launch vehicle.  If I was Stratolaunch I'd be considering the surplus NK-43 engines, also, since they aren't usable in the Orbital Antares program.  If they derate them, the life goes up.

I emphasize this is speculation as I have no insight into the stage design.

[antonioe]

the wing [ ... ] is ill-suited to act like the Pegasus wing to turn the flight path angle since it is not at the Cg of the launch vehicle.

Oh?  How do you know that?

[HMXHMX]

the wing [ ... ] is ill-suited to act like the Pegasus wing to turn the flight path angle since it is not at the Cg of the launch vehicle.

Oh?  How do you know that?

My conclusion is based on the fact that one would generally attach the LV to the aircraft pylon at the Cg, no?  And the Cp of the wing looks to be aft of that line – at least that is how it appears from looking at the small illustration that was posted on thread page 69. It would be nice to see a side view.

Edit: clarification of "source"

[JohnFornaro]

This week Lockheed announced that a UK subsidiary is developing technology to mine the deep ocean beds for nodules of copper, rare earths, and...... manganese!

I gotta deal for them.

[RanulfC]

the wing [ ... ] is ill-suited to act like the Pegasus wing to turn the flight path angle since it is not at the Cg of the launch vehicle.

Oh?  How do you know that?

"Know" is a loaded word in this case no?

What we KNOW is only what we see and the picture posted previously show a very aft mounted wing. I'll note meanwhile that the second picture on the main webpage (http://www.stratolaunch.com/) showing a view from forward/below towards the aft end also shows the wings are mounted very far aft and on the bottom of the LV. While I'm "at-it" I might as well do some speculation/questioning of the "fairing" structure that mounts the wings to the booster since it seems external to the overall LV making it look perfect for some landing gear wells to be mounted in there

So you going to enlighten us a bit sir or just tell us it's an "artists-conception" with nothing to do with reality? yet?

Randy

[antonioe]

Well, my choice of the word "know" was rather inappropriate ... I meant a very Vulcan "how do you reach that conclusion, Captain" and HMX^2's answer is very logical.  Some suggestions, though:

a) Review location of delta (or near-delta) - planform wing's cp location w.r.t., say, the apex of the triangle
b) Imagine where the WHOLE VEHICLE Cp (including the fairing) would be
c) compare with expected location of the aircraft wing's cp (quarter-chord?)
d) take cold beer out of fridge (Shelter Pale, please)
e) lay back on hammock in the back yard under the trees
f) ponder where the center of MASS of the rocket would be ... which depends, of course on the assumed propellant density for each stage ...
g) finish beer - get up and get a second one (120 minute IPA this time)
h) lay back on hammock and review in your mind the G/P (gross over payload) ratio of famous launch vehicles and what made them high or low (differentiate between "advertised" and "actual" performance)

I wish I could get into details - but somebody is paying for that design and they own it - in this project we're just lowly designers for hire...

[DavidH]

...
I wish I could get into details - but somebody is paying for that design and they own it - in this project we're just lowly designers for hire...

Really nice having you around here sir.

[HMXHMX]

Well, my choice of the word "know" was rather inappropriate ... I meant a very Vulcan "how do you reach that conclusion, Captain" and HMX^2's answer is very logical.  Some suggestions, though:

a) Review location of delta (or near-delta) - planform wing's cp location w.r.t., say, the apex of the triangle
b) Imagine where the WHOLE VEHICLE Cp (including the fairing) would be
c) compare with expected location of the aircraft wing's cp (quarter-chord?)
d) take cold beer out of fridge (Shelter Pale, please)
e) lay back on hammock in the back yard under the trees
f) ponder where the center of MASS of the rocket would be ... which depends, of course on the assumed propellant density for each stage ...
g) finish beer - get up and get a second one (120 minute IPA this time)
h) lay back on hammock and review in your mind the G/P (gross over payload) ratio of famous launch vehicles and what made them high or low (differentiate between "advertised" and "actual" performance)

I wish I could get into details - but somebody is paying for that design and they own it - in this project we're just lowly designers for hire...

As was my choice of the word "ill-suited"... ... so while sipping a metaphorical glass of wine (in place of beer, another fine choice):

I've now had a chance to look at the updated Stratolaunch web site which has a few other new images.  Part of my original problem was the way shadows fall on the image that was posted here; it is hard to see the delta wing apex.  I also concur that the fairing is going to significantly influence overall vehicle Cp.  (Which brings up that nagging issue of why the fairing is so large for so small a payload mass?  But I digress.) So bottom line, Antonio is right.  Not that one would have expected it to be otherwise, it was just puzzling.

I still think a recoverable Stage One would be a nice move.

Edit: spelling (darn autocorrect)

[Elmar Moelzer]

I still think a recoverable Stage One would be a nice move.

Edit: spelling (darn autocorrect)

Yeah, I am a bit confused by that. They spend all that money on developing a huge carrier plane and then they launch an expendable rocket from it. I do understand the advantages of airlaunch, but still this just feels "wrong".

[RocketmanUS]

I still think a recoverable Stage One would be a nice move.

Edit: spelling (darn autocorrect)

Yeah, I am a bit confused by that. They spend all that money on developing a huge carrier plane and then they launch an expendable rocket from it. I do understand the advantages of airlaunch, but still this just feels "wrong".

Air launch advantages.
Launch above the weather.
Not fixed to a launch pad location.

[antonioe]

I still think a recoverable Stage One would be a nice move.

Yeah, I am a bit confused by that. They spend all that money on developing a huge carrier plane and then they launch an expendable rocket from it. I do understand the advantages of airlaunch, but still this just feels "wrong".

Well, wiser men than me concluded in 1975 that a reusable launch vehicle becomes more economical than an expendable one at the rate of 50 to 60 launches/year (reason: added development and recurring cost of the reusable, which has a much worse G/P than an expendable and more expensive components, which must be amortized through the life of the program at a time-discounetd rate).  That justified the Shuttle, which was planned to fly once a week (*cough*, *cough*...)

Even wiser men concluded in 2000 that the "crossover" annual rate between expendable and reusables, given the technology in 2000 was ... can you guess?... 50 to 60 launches per year!

No coincidence: specific impulse and structural mass fraction, the two key figures of merit that determine the expendable vs. reusable G/P (the main contributor to the "crossover" rate,) really haven't changed much since 1975.

BTW this result is to first order independent of the launch mode (ground or air.)

OK - since I'm atop the soap box, I'm going to pontificate and you guys can't stop me: 

Yesterday I gave a lecture to the docents at the Udvar-Hazy on Pegasus, since they have one on display (the "artifact", as museum curators say.)  I started the lecture trying to convince them how fundamentally different aircraft and rockets really are, a difference that many, many things try to blur (e.g. "Air and Space Museum", "NASA" and my degree in "Aeronautics and Astronautics".)  So I started the pitch with a picture of the Bruce Nuclear Generating Station (BNGS) in Bruce County, Ontario, the world's largest (operating) nuclear power plant.  BNGS's EIGHT reactors produce 14,000 MW of THERMAL power in order to generate 4,000 MW of electricity (about 30% efficiency.)

The two SRB's on the Shuttle consume 1,000,000 Kg of solid propellant (at 4 MJ/kg) in 120 seconds, thus generating 33,000 MW of thermal power during their burn - more than twice that of BNGS... and Saturn V's stage 1 numbers are even more impressive: 185,000 MW, the equivalent of 14 times the world's largest nuclear power plant!!!!!!!!

Anytime you are handling this amount of power it's going to be a) very dangerous and b) very expensive, especially if it has to be lightweight enough to fly!

Aircraft and rockets - they just aren't the same thing.

[Robotbeat]

Go ahead and keep pontificating!

[Nomadd]

 Antonioe is channeling Kelly Johnson. (Use the Ale Luke)

[Elmar Moelzer]

Well, wiser men than me concluded in 1975 that a reusable launch vehicle becomes more economical than an expendable one at the rate of 50 to 60 launches/year (reason: added development and recurring cost of the reusable, which has a much worse G/P than an expendable and more expensive components, which must be amortized through the life of the program at a time-discounetd rate).  That justified the Shuttle, which was planned to fly once a week (*cough*, *cough*...)

of course those "wise men" were assuming a reusable launch vehicle with the development and recurring cost of the STS, an RLV built to keep the NASA centers occupied. They were not talking about any conceivable RLV. And since that is OT for this thread, I will leave it at that.

[Jim]

of course those "wise men" were assuming a reusable launch vehicle with the development and recurring cost of the STS, an RLV built to keep the NASA centers occupied. They were not talking about any conceivable RLV. And since that is OT for this thread, I will leave it at that.

Wrong on all accounts, again.   Know who you are talking to. 

[Elmar Moelzer]

of course those "wise men" were assuming a reusable launch vehicle with the development and recurring cost of the STS, an RLV built to keep the NASA centers occupied. They were not talking about any conceivable RLV. And since that is OT for this thread, I will leave it at that.

Wrong on all accounts, again.   Know who you are talking to. 

Well, I am sure that they did not assume a more expensive one, because then the 60 launches would not have covered the cost. With a cheaper vehicle with lower running cost, they would not need that many launches to make it cost effective. No?

[baldusi]

of course those "wise men" were assuming a reusable launch vehicle with the development and recurring cost of the STS, an RLV built to keep the NASA centers occupied. They were not talking about any conceivable RLV. And since that is OT for this thread, I will leave it at that.

Wrong on all accounts, again.   Know who you are talking to. 

Well, I am sure that they did not assume a more expensive one, because then the 60 launches would not have covered the cost. With a cheaper vehicle with lower running cost, they would not need that many launches to make it cost effective. No?

STS was supposed to be cheaper than commercial. I would love to read the papers, though. I'm wondering how do they define launch. Does multicore LV change the equation?
In any case there's not a single country, that needs 50 to 60 launches per year. I keep saying that the secret to reusable LV are order of magnitude cheaper payloads.
Regrettably, the only ones that can think realistically of (humans) require something like three orders of magnitude cheaper launcher AND spacecraft. But I digress.

Antonio, I'm wondering what were the lessons learned about the Pegasus. I understand that technically (and financially) it was a reasonable success. But I've noticed OSC haven't pressed on with the air launch strategy. As a secondary question, were you surprised by the advances the SC did in aircraft technology to make a bigger LV viable? I guess you can't say much because of NDA.