Stratolaunch: General Company and Development Updates and Discussions

[JohnFornaro]

And speaking of Denver:  The December 27th issue of NYT had a feature "Frequent Flyer".  They interviewed a guy, Dave Alberga, chief of Active Network.

Q.  What's your least favorite airport?"

A. Denver.  Everything is too spread out.

I know.  Everybody's a critic.  But the Stratolaunch announcement is marketing hype, and speculation on Denver is subject to a lot of spin either way.

[hop]

A successor to the current stratospheric observatory (SOFIA) would be an interesting application for stratolaunch (when it isn't busy)!

http://en.wikipedia.org/wiki/Stratospheric_Observatory_for_Infrared_Astronomy

Why do you think there will be a successor to SOFIA ?
Who is going to fund it ?
How is the Stratolaunch carrier going to be better ?

SOFIA ended up costing as much as a pretty decent space telescope (and is close to the expected costs of 30 meter class ground based scopes), I don't think anyone is going to be in a hurry to repeat that particular debacle. It's a cool telescope with some unique capabilities, and will undoubtedly produce some interesting results, but I don't see a SOFIA 2 any time soon.

[go4mars]

Why do you think there will be a successor to SOFIA?

There may not be but if there is, it could be a lot larger, and less constrained in its design if clipped onto stratolaunch instead of jammed in a 747. 

Who is going to fund it ?

No Idea.  DLR/NASA again?

How is the Stratolaunch carrier going to be better? 

2 main reasons stratolaunch would be a better carrier:
SOFIA = 2.5 meter reflecting telescope (sized based on 747 constraints).   Statolaunch could have a much larger "light-bucket" (likely 4-30 times the light gathering power depending whether its done simply or fancy) and the aircraft could 'moonlight' as a rocket launcher and other things during daylight hours.   

SOFIA ended up costing as much as a pretty decent space telescope (and is close to the expected costs of 30 meter class ground based scopes)

Truly, I would much rather see funding go toward http://www.langorigami.com/science/technology/eyeglass/eyeglass.php
or a 100+m "Overwhelmingly Large Telescope". 
But usually prototypes and predecessors cost more per unit utility.  If the makers of SOFIA think they can bring the cost down significantly then it may be worth doing.   

It's a cool telescope with some unique capabilities

Agreed.

[Jim]

Wrong, there is nothing than says Stratolauncher is going to have a larger diameter fuselage than a 747

[Jason1701]

Stratolauncher actually looks to be much narrower than a 747.

[go4mars]

Wrong, there is nothing than says Stratolauncher is going to have a larger diameter fuselage than a 747

I don't believe that it will. 

Stratolauncher actually looks to be much narrower than a 747.

The twin fuselages?  Agreed. 

The 747 couldn't open a large, unobstructed door straight up (without prohibitive modification).  So it was stuck with a 2.5 meter mirror even though a 747 fuselage is much bigger than that. 

In the simple case, I am assuming that stratolauncher can do a 5 meter mirror (4 times the light gathering compared to SOFIA) that faces straight up (or can be angled as needed), near the back of a telescope that is clipped on to the F5 attachment points.  One of the renderings (main page of their website) shows the F5 with what I assume is a 5 meter PLF.  I think it's reasonable to assume that is possible as a baseline (which would be the lowest cost option). 

In the fancy case, there are extra possibilities:  One is a very wide clip-on telescope that fills a lot of the space between the fuselages, with the mirror oriented to it's zenith but with less ability to tilt.  The whole thing would be shaped kind of like a boogie-board hanging down instead of a cylinder (so that it isn't too tall).  This could allow for a very large mirror and associated optics, but would require the "boogie board" to be almost as long as stratolaunch.  A counterweight out the front side would be required and it might as well be an additional mirror oriented in reverse to the rear one. 

Depending on how you wanted to do the telescope geometry, you could even have aerodynamic dobsonian extenders going up from it. 

A rocket can't have a kink in it, but a telescope can.  Even if the maximum diameter rocket possible on stratolaunch is 5 meters or less for take-off and landing clearance, a telescope can bend upward from the attachment points.  So a still fairly simple single mirror, perhaps 8 meters diameter should be possible.  Three of these, placed side by side hanging from the usual attachment points would be an impressive improvement over SOFIA. 

If you wanted to get really fancy with it, you could have mirrors and parts that unpack ala James Webb but in a complex aerodynamic configuration...

There are lots of possibilities when you have an attachment point that can hold half a million pounds and have about 75 feet between the fuselages.   

Stratolaunch could stargaze all night, pull in to the hanger, unclip its telescope, then clip on a rocket for its morning excursion.   

[Jim]

No, on the last line

[Patchouli]

A rocket can't have a kink in it, but a telescope can.  Even if the maximum diameter rocket possible on stratolaunch is 5 meters or less for take-off and landing clearance, a telescope can bend upward from the attachment points.  So a still fairly simple single mirror, perhaps 8 meters diameter should be possible.  Three of these, placed side by side hanging from the usual attachment points would be an impressive improvement over SOFIA.     

You might have just pointed out one of the reasons why they went with a kerolox rocket vs hydrogen as a hydrogen core that fully utilizes the payload of the aircraft may be too wide.

[HMXHMX]

A rocket can't have a kink in it, but a telescope can.  Even if the maximum diameter rocket possible on stratolaunch is 5 meters or less for take-off and landing clearance, a telescope can bend upward from the attachment points.  So a still fairly simple single mirror, perhaps 8 meters diameter should be possible.  Three of these, placed side by side hanging from the usual attachment points would be an impressive improvement over SOFIA.     

You might have just pointed out one of the reasons why they went with a kerolox rocket vs hydrogen as a hydrogen core that fully utilizes the payload of the aircraft may be too wide.

LOX-hydrogen at the full payload capability of the aircraft will fit fine; there is an S-IVB worth of diameter available so the overall length for the stage is only about 60-80 feet.  It was one of the early options for which I did a design for a previous version of the a/c about five years ago.  I wanted to go with a one-stage expendable SSTO approach but that turned out to be a bit radical for my colleagues so we punted to 2 stage LOX-hydrocarbon.  By the time you finish a real design, they both end up about the same length, since the interstage and second stage engine takes up a lot of length.

I'm certain the reason they ended up with the configuration they did was simply availability of an in-production propulsion option and the perception that it is easy enough to adapt an "existing" design to air-launch.  That's not true, but if you haven't delved into the details, it makes a good story to investors and customers.

[go4mars]

First off, SUPER COOL!  Thanks for sharing.

LOX-hydrogen at the full payload capability of the aircraft will fit fine; there is an S-IVB worth of diameter available so the overall length for the stage is only about 60-80 feet. 

  So a 6.6 meter diameter rocket would fit no sweat?  That's fascinating! 

I wanted to go with a one-stage expendable SSTO approach but that turned out to be a bit radical for my colleagues ... I'm certain the reason they ended up with the configuration they did was simply availability of an in-production propulsion option and ...perception

Any sense that selecting 2-stage might have also been for excess margin for stage recovery systems?

[Patchouli]

A rocket can't have a kink in it, but a telescope can.  Even if the maximum diameter rocket possible on stratolaunch is 5 meters or less for take-off and landing clearance, a telescope can bend upward from the attachment points.  So a still fairly simple single mirror, perhaps 8 meters diameter should be possible.  Three of these, placed side by side hanging from the usual attachment points would be an impressive improvement over SOFIA.     

You might have just pointed out one of the reasons why they went with a kerolox rocket vs hydrogen as a hydrogen core that fully utilizes the payload of the aircraft may be too wide.

LOX-hydrogen at the full payload capability of the aircraft will fit fine; there is an S-IVB worth of diameter available so the overall length for the stage is only about 60-80 feet.  It was one of the early options for which I did a design for a previous version of the a/c about five years ago.  I wanted to go with a one-stage expendable SSTO approach but that turned out to be a bit radical for my colleagues so we punted to 2 stage LOX-hydrocarbon.  By the time you finish a real design, they both end up about the same length, since the interstage and second stage engine takes up a lot of length.

I'm certain the reason they ended up with the configuration they did was simply availability of an in-production propulsion option and the perception that it is easy enough to adapt an "existing" design to air-launch.  That's not true, but if you haven't delved into the details, it makes a good story to investors and customers.

I wonder if they looked at hydrogen options?

The only hydrogen engine options I know that could deliver the performance needed for their payload range are the J-2X,Vulcain 2,SSME,and RD-0120.


The J-2X seems to be a good match if they did go hydrogen and actually could carry a S-IVB sized stage.

[as58]

There may not be but if there is, it could be a lot larger, and less constrained in its design if clipped onto stratolaunch instead of jammed in a 747. 

Do you honestly believe that SOFIA's delays and overruns were due to the lack of a large enough plane? Or that a (lot) larger telescope could be easily designed for Stratolauncher?

Who is going to fund it ?

No Idea.  DLR/NASA again?

SOFIA development has been a disaster much like JWST (and considering the science return, IMO much worse). I really doubt NASA is willing to go for it again.

It's a cool telescope with some unique capabilities

Agreed.

I agree, although it has come with a huge price.

[baldusi]

A rocket can't have a kink in it, but a telescope can.  Even if the maximum diameter rocket possible on stratolaunch is 5 meters or less for take-off and landing clearance, a telescope can bend upward from the attachment points.  So a still fairly simple single mirror, perhaps 8 meters diameter should be possible.  Three of these, placed side by side hanging from the usual attachment points would be an impressive improvement over SOFIA.     

You might have just pointed out one of the reasons why they went with a kerolox rocket vs hydrogen as a hydrogen core that fully utilizes the payload of the aircraft may be too wide.

Their renders did showed a SpaceX's standard fairing of 5.2m. If they can lengthen proportionally, a 5.2m core has 3 times the volume of a 3.65m, one. In other words, the volume difference of an hydrolox stage to a kerolox one. And you are already having a 5.2m drag, so nothing is lost there either. Hydrolox shouldn't be a problem for the Stratolauncher.
BTW, a Delta IV Medium is 550klb. And it's 5m wide. Or they could have gone the Liberty way, and studied a EPC+ECB. All sort of "simple" fits. I think they went with SpaceX both for price and the possibility of converting to a RLV in the near future.

[JohnFornaro]

Why do you think there will be a successor to SOFIA?

There may not be but if there is, it could be a lot larger, and less constrained in its design if clipped onto stratolaunch instead of jammed in a 747.

You do realize that you didn't answer his question, don't you?  Further, the 140 ton SLS, with perhaps a 10m fairing, will be even less of a mirror constraint.  Why wouldn't SLS be better?

Their renders did showed a SpaceX's standard fairing of 5.2m. If they can lengthen proportionally, a 5.2m core has 3 times the volume of a 3.65m, one.

Now you suggest making the rocket even longer than it is currently rendered.  I continue to struggle with acceptance of the idea of hanging a long, skinny rocket from its middle, without seeing what the hanging structure looks like.  The additional mass needed is ameliorated somehwhat by the prospect of launching it from such an altitude, but the only information there is to go on is an illustration on a website.

I didn't have this problem with WK2 and SS2 and all.  That LV is a stubby one, shaped for horizontal aerodynamics.   Stratolaunch should abandon the disposable rocket paradigm and focus on ther reusability of a winged craft, scaled along the lines of their large mass projections.

[go4mars]

Stratolaunch could stargaze all night, pull in to the hanger, unclip its telescope, then clip on a rocket for its morning excursion.

No, on the last line

If "roll-out to launch in <60 minutes" is a possibility for F9, then I don't see why this isn't. 

[go4mars]

I wonder if they looked at hydrogen options?

He just said they did. 

LOX-hydrogen at the full payload capability of the aircraft will fit fine; ...  It was one of the early options for which I did a design for a previous version of the a/c about five years ago. 

Or do you mean whether they were considering developing a new engine (raptor stage?) instead of buying something already made.  He addressed that too: 

I'm certain the reason they ended up with the configuration they did was simply availability of an in-production propulsion option...perception

[go4mars]

Do you honestly believe that SOFIA's delays and overruns were due to the lack of a large enough plane?

Mainly no.  But the configuration of the plane impacted its utility. 

Or that a (lot) larger telescope could be easily designed for Stratolauncher?

Yes.  Much more easily.  A lot of the issues were worked out during the birthing pains of SOFIA.  The next one would be easier to make, using a lot of the systems developed for SOFIA, and better (much more light gathering area).  The next one wouldn't involve a lot of technology development.

SOFIA development has been a disaster much like JWST (and considering the science return, IMO much worse)...it has come with a huge price.

No arguments from me there.  It was expensive.  It would be a shame if the stabilization, aircraft control systems, and lessons learned were only ever used on the one project.   

Once again, Ben Franklin after seeing the first hot air balloon flight was asked:  "What good is it?"  He replied, "What good is a newborn baby?"

[go4mars]

You do realize that you didn't answer his question, don't you?

You caught me. 

Further, the 140 ton SLS, with perhaps a 10m fairing, will be even less of a mirror constraint.  Why wouldn't SLS be better?

Did you read the "fancy options" part?  "Boogie-board shape"?  Triple-binary 8m kinkers?  No need to pay for an SLS launch?  Designing the optics for the space environment?

I suspect that's a leading question to get me to spell out answers that you already know, but I'll comply.  Here's a comparison assuming monolithic mirrors and no folding parts (unlike JWST):

SLS telescope                         Stratolaunch telescope
launch cost (billion bucks?)      cost (nocturnal lease agreement)
140 ton max                           500 ton max         (irrelevant in both cases)
8 m mirror                              24mx2 mirrors (boogie) or 6 x 8m mirrors (three double-ended kinkers)
50 square meters                   900 square meters or 300 square meters 
repair cost (billion bucks?)        Access is free and easy
design everything for space       Don't design everything for space environment

Don't get me wrong, I like space telescopes.  Particularly km-wide fresnel lens ideas like this:  http://www.langorigami.com/science/technology/eyeglass/eyeglass.php

SOFIA (bless her little heart) is <5 square meters.

Now you suggest making the rocket even longer than it is currently rendered.  I continue to struggle with acceptance of the idea of hanging a long, skinny rocket from its middle, without seeing what the hanging structure looks like.

Your coat hanger keeps the shoulders of your coat supported...I suspect that the hangar will be more of a truss with multiple points of attachment along it than a big hook.  But you probably do too.

[HMXHMX]

I wonder if they looked at hydrogen options?

He just said they did. 

LOX-hydrogen at the full payload capability of the aircraft will fit fine; ...  It was one of the early options for which I did a design for a previous version of the a/c about five years ago. 

Or do you mean whether they were considering developing a new engine (raptor stage?) instead of buying something already made.  He addressed that too: 

I'm certain the reason they ended up with the configuration they did was simply availability of an in-production propulsion option...perception

They didn't look at alternatives to my knowledge, I did.  Different effort, but same a/c.

[Jim]

Stratolaunch could stargaze all night, pull in to the hanger, unclip its telescope, then clip on a rocket for its morning excursion.

No, on the last line

If "roll-out to launch in <60 minutes" is a possibility for F9, then I don't see why this isn't. 

It isn't attaching the rocket to launch in <60 minutes