Stratolaunch: General Company and Development Updates and Discussions

[baldusi]

Help me here. The ISS has a period of 90 minutes, right? This means that the earth moves 1/16th or about 22.5degrees between orbits, right?
1300nm from the KSC going straight to the East are 25degrees. Would that mean that they could do daily first orbit rendezvous?

[MP99]

Help me here. The ISS has a period of 90 minutes, right? This means that the earth moves 1/16th or about 22.5degrees between orbits, right?
1300nm from the KSC going straight to the East are 25degrees. Would that mean that they could do daily first orbit rendezvous?

Supplementary question - if the answer to above is yes.

If you restricted ground-launch F9 to the same payload as Stratolaunch (cut by nearly half), could you fly a dogleg from either KSC or Vandenburg to achieve the same thing as above?

cheers, Martin

[Robotbeat]

Help me here. The ISS has a period of 90 minutes, right? This means that the earth moves 1/16th or about 22.5degrees between orbits, right?
1300nm from the KSC going straight to the East are 25degrees. Would that mean that they could do daily first orbit rendezvous?

Should be able to. It's one of the greatest advantages in this approach. Join the ARocket mailing list and read what Henry Spencer wrote about Stratolaunch.

[baldusi]

Should be able to. It's one of the greatest advantages in this approach. Join the ARocket mailing list and read what Henry Spencer wrote about Stratolaunch.

Could you point me out the list? Google is sort of inconsistent.

[krytek]

What would folding wings accomplish?

[Rocket Science]

What would folding wings accomplish?

Make it cost more?

[HMXHMX]

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.

Thanks. Out of curiosity have you folks reviewed the paper I cited earlier?
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002822_2007001607.pdf

The more I'm reading the more I am seeing confirmationo of many of the background themes you/TSpace/AirLaunch have espoused over the years.

If it doesn't impinge on any of the above "issues" is the fact that this project is moving forward going to have a postivie outcome for your efforts?

Randy

I've read that paper, and know Joe, and we have discussed that work and other air-launch matters while he was on sabbatical at the Naval Postgraduate School. He makes some very good points.

In response to your other question, in general, any announced project from a credible source will tend to help similar projects, even if they are competitive.  So yes, it would help if I was doing something related. 

As is said: "A rising tide lifts all boats."

Paul Allen has a bigger boat than I, however.

And since we are being a bit nautical here, perhaps it is time for another related turn of phrase:

Brutus:
There is a tide in the affairs of men.
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves,
Or lose our ventures.
Julius Caesar Act 4, scene 3

[Robotbeat]

Should be able to. It's one of the greatest advantages in this approach. Join the ARocket mailing list and read what Henry Spencer wrote about Stratolaunch.

Could you point me out the list? Google is sort of inconsistent.

http://exrocketry.net/mailman/listinfo/arocket You have to subscribe.

[docmordrid]

Rutan was just on Fox via phone and said they need to buy a 3rd 747 for its landing gear & other bits.

[Lee Jay]

I had a discussion a while back with Antonio Elias here on NSF about using what I called a "zoom launch".  The idea is to place the carrier aircraft into a shallow dive to pick up speed, and then pull up hard and release the rocket at the proper angle, thus avoiding most or all of the turning losses that the wing on Pegasus is supposed to also help to mitigate.  I've simulated this a little (don't ask) and I still don't see exactly why this wouldn't work, but I could imagine some implementation details that could be a problem.

I just got around to watching their video, and it shows them doing this maneuver without the pre-maneuver dive.

[RobLynn]

Wonder if strut braced wings would make sense for the Stratolaunch carrier?
http://www.dept.aoe.vt.edu/~mason/Mason_f/AIAA2000-0420.pdf

Basically aerofoil struts from bottom of fuselage to a long way out on wing and also to low down on the centre rocket mounting pod.

For such a massively long wing it would reduce structural weight a lot, and might allow the wings to be thinned down to increase speed or to increase the aspect ratio even further for improved L/D.  Any of these improvements would potentially increase the payload capacity of the plane or reduce the field length requirement.

[mrmandias]

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.

One both accounts, I agree... They'll pay a greater premium for lower first-stage Isp than a lot of other launch concepts, since they'll be optimizing for greatest payload for a given "lift-off" mass, not allowing them to parametrize the lift-off mass. Increases in lift-off thrust for the rocket engine have less potential for performance increase than for a ground-launched rocket.

I think that once this thing is operational and if it is a big success but they're finding they need to launch larger payloads to higher energy orbits, they will probably be looking for higher Isp options, including hydrogen (though fluid transfer would be more difficult). The carrier aircraft is the biggest technical problem, not the rocket itself... It makes sense they didn't try to push the rocket's performance too much initially. They have a saying in this sort of business... Try for at most one miracle at a time.

I do wonder what Rutan would think of Jon's gamma-maneuver (or whatever you call it), which should allow a sizable increase in payload without increasing the size or mass of the rocket itself. Sounds a little scary, to be honest. Scary in a good way.

I recognize the utility of "one miracle at a time," but I think that if you want to do Jon Goff's near-vertical launch maneuver, you have to design your aircraft and connection systems for it from the beginning.  I think retrofitting would be extremely expensive.  You can probably get incremental performance increases with a redesigned rocket, but if you want to gamma, you have to gamma from the get-go.

[RanulfC]

I recognize the utility of "one miracle at a time," but I think that if you want to do Jon Goff's near-vertical launch maneuver, you have to design your aircraft and connection systems for it from the beginning.  I think retrofitting would be extremely expensive.  You can probably get incremental performance increases with a redesigned rocket, but if you want to gamma, you have to gamma from the get-go.

And Gamma is "important" in this concept, the various loses without it seem to be a deal killer for economics on the concept.

Given the "pull-up" shown in the video I don't see how else they could pull it off without using the rockets unless they are going to invest some big bucks in advanced duct-burning turbo-fans.

Randy

[RanulfC]

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.

Thanks. Out of curiosity have you folks reviewed the paper I cited earlier?
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002822_2007001607.pdf

The more I'm reading the more I am seeing confirmationo of many of the background themes you/TSpace/AirLaunch have espoused over the years.

If it doesn't impinge on any of the above "issues" is the fact that this project is moving forward going to have a postivie outcome for your efforts?

Randy

I've read that paper, and know Joe, and we have discussed that work and other air-launch matters while he was on sabbatical at the Naval Postgraduate School. He makes some very good points.

In response to your other question, in general, any announced project from a credible source will tend to help similar projects, even if they are competitive.  So yes, it would help if I was doing something related. 

As is said: "A rising tide lifts all boats."

Paul Allen has a bigger boat than I, however.

And since we are being a bit nautical here, perhaps it is time for another related turn of phrase:

Brutus:
There is a tide in the affairs of men.
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves,
Or lose our ventures.
Julius Caesar Act 4, scene 3

Cryptic as (almost) always but interesting, as always also

Randy

[Magnus_Redin]

And Gamma is "important" in this concept, the various loses without it seem to be a deal killer for economics on the concept.

Given the "pull-up" shown in the video I don't see how else they could pull it off without using the rockets unless they are going to invest some big bucks in advanced duct-burning turbo-fans.

Randy

Finding the optimal engine or adding an advanced afterburner are ill suited ideas for a specialized low milege aeroplane with second hand engines. The obvious low cost way to increase performace is to add more engines, go from six to eight or even ten engines.

[Robotbeat]

I thought this Systems Engineering talk by our excellent antonioe (a member here) was pertinent:
He goes on to talk about the advantages of airlaunch, etc.

[RanulfC]

And Gamma is "important" in this concept, the various loses without it seem to be a deal killer for economics on the concept.

Given the "pull-up" shown in the video I don't see how else they could pull it off without using the rockets unless they are going to invest some big bucks in advanced duct-burning turbo-fans.

Randy

Finding the optimal engine or adding an advanced afterburner are ill suited ideas for a specialized low milege aeroplane with second hand engines. The obvious low cost way to increase performace is to add more engines, go from six to eight or even ten engines.

The "problem" is that you're just not going to get the thrust out of a turbo-fan at altitude, the thrust-to-weight isn't there and adding more engines won't help.

Randy

[RanulfC]

I posted this over in Advanced Concepts but for "completeness" figured I might as well post it here too:
Crossbow=Cargo ROcket Space System, BOx Wing
http://eddy.nps.edu/IDDR/techMatrixPages/3d/crossbow/crossbow.html

Randy

[Robotbeat]

I thought this Systems Engineering talk by our excellent antonioe (a member here) was pertinent:
He goes on to talk about the advantages of airlaunch, etc.

In parts of the video, Antonio talks about larger, medium-lift airlaunched rockets. The first time is cut from the video soon after he mentions it, the second time when talking about trading flight path angle and flight velocity he starts talking about what Burt Rutan was doing right before he retired, then he stops himself (and the audience laughs). It sounds like Antonio was well aware that something like Stratolaunch was in the works (not that that's surprising).

Even I heard rumblings of this coming, with hints dropped by people who had talked to Rutan at space conferences and such. Of course, they didn't recognize it as such at the time, but I can see the hints in hindsight.

[starsilk]

And Gamma is "important" in this concept, the various loses without it seem to be a deal killer for economics on the concept.

Given the "pull-up" shown in the video I don't see how else they could pull it off without using the rockets unless they are going to invest some big bucks in advanced duct-burning turbo-fans.

Randy

Finding the optimal engine or adding an advanced afterburner are ill suited ideas for a specialized low milege aeroplane with second hand engines. The obvious low cost way to increase performace is to add more engines, go from six to eight or even ten engines.

JATO bottles?