USAF Reusable Booster System (RBS)

[brianc]

I'm gonna have to try this one!

http://www.theregister.co.uk/2009/05/13/usaf_rbs_ploy/print.html

The US Air Force has announced that it is interested in a "Reusable Booster System" (RBS) - a combination of rocket and aeroplane which could replace the first stage of existing orbital launch stacks. After the upper stages separated and carried on into space, the winged RBS would glide down to a winged landing for refuelling and subsequent re-use.

[wilsotr]

Interesting concept. Sounds a lot like a thing called "The Space Shuttle."

[AstronMike]

Hmm, interesting, but wheres a good pic of it in full stack mode and one of a top view as well?

Its another delta derivative, so its very similar to stuff I have done before, such as the delta based glide booster from over 15yrs ago. IOW, it was a fully functional glider serving as a booster stage with a large flexie RG atop it as a sustainer. Worked well until one of the D motors in it catoed, burning the booster to a crisp and not igniting the flexie sustainer.

Might have to revisit this thing again, preferably upscaled.

Let us know what you are going to be doing with this, Brian!

[Nuke Rocketeer]

I'm gonna have to try this one!

http://www.theregister.co.uk/2009/05/13/usaf_rbs_ploy/print.html

It will get porkulated by the congresscritters if DoD tries to follow through with it. Just like the shuttle did when Congress found out NASA was going to use fewer people to run operations.

[GregGleason]

Hmm, interesting, but wheres a good pic of it in full stack mode and one of a top view as well?



There was a link to a PPT in the news link. Not great dimensional information but it is interesting.

In the 2nd pic, the lower right vehicle looks similar the Centuri Space Shuttle. :)

Greg

[tbzep]

It will get porkulated by the congresscritters if DoD tries to follow through with it. Just like the shuttle did when Congress found out NASA was going to use fewer people to run operations.

I thought it was the DoD that got NASA to pork it up so it would be big enough to haul spy sat payloads. Or are you speaking of the program as a whole, not the specs on the shuttle? :confused:

[wilsotr]

I thought it was the DoD that got NASA to pork it up so it would be big enough to haul spy sat payloads.

Yep .... that's pretty much the way it worked. Much of Shuttle's capability was driven by DoD - not NASA - requirements. There was a "partnership" there that made the program palatable to Congress.

[wilsotr]

In the 2nd pic, the lower right vehicle looks similar the Centuri Space Shuttle.

Which itself came from early NASA Space Shuttle proposals ... or at least appears to have come from them. History repeats. :)

[Nuke Rocketeer]

I thought it was the DoD that got NASA to pork it up so it would be big enough to haul spy sat payloads. Or are you speaking of the program as a whole, not the specs on the shuttle? :confused:

The program as a whole. I found about the porking of the shuttle for employment from Jerry Pournelle's website. It was not widely publicized, but it was there. Certain powerful congresscritters wanted no shuttle caused drops in employment in their districts. Even with the DoD specs increasing the size/cross-range capability/etc, NASA projected that it would take far fewer people to run operations.

[luke strawwalker]

This is a flyback BOOSTER... lofting either an expendable upper stage or a spaceplane. This has been proposed before but the cost always seems to get in the way.

There were proposals for a bimese or even trimese shuttles using either one or two 'flyback boosters' to propel lift an orbiter to act as a first and second stage where the orbiter would finish it's own ascent to orbit while the boosters returned to their own runway landing. Cost ultimately killed the idea which then led to the expendable tank solution, but which required huge SRB's to lift the thing off the ground for the first 2 minutes of flight. Hence the shuttle we have.

It's a VERY interesting read, if you're really interested in how the shuttle as we have it came to be, since it is SO different from the original proposals were. I highly recommend "The Space Shuttle Decision" by T. A. Heppenheimer. It details all the twists and turns and political machinations that can turn a technically challenging but feasible 'next step' engineering problem/solution into an overbudget, underperforming, compromised by compromises politically-derived vehicle that doesn't really satisfy ANYBODY'S requirements. We're seeing much the same from NASA all over again, only this time they can't blame the DoD/Air Force. Constellation is NASA's own perfect screwup...

Shuttle had to switch from the Faget short straight wing/conventional tailplane orbiter design to the delta wing configuration to get enough cross-range for AF/DOD requirements when returning from polar orbits. The orbiter got HUGE in response to AF/DOD requirements for payload bay sizing and lift capabilities for national defense payloads. The expendable tank came about after it was figured out that a shuttle would be TOO BIG to ever lift off carrying it's own fuel internally, and would not be able to carry a payload because of the internal tankage. The SRB's came about after the orbiter size had grown to the point that the amount of fuel required to propel it to orbit was SO heavy it would never lift off without booster rockets, and the money wasn't there to develop flyback boosters or a 'mother ship' to carry it to altitude where it COULD fly to orbit on it's own power with an external tank. All those decisions compromised the shuttle design, all for requirements that NEVER were utilized. The AF/DOD shuttle launch pads at Vandenberg were converted for Delta IV and NEVER used to launch a shuttle into the planned military polar orbits, which had to launch from Vandenberg to allow the SRB's the parachute into the Gulf of California or the Pacific off the Mexico coast... polar shuttle missions couldn't be launched from Florida without risking dropping the SRB's on Cuba or South America. Because of phasing of polar orbits (as the earth rotates underneath the orbiting vehicle) the large cross-range was required, which compromised MANY of the shuttle designs.

What's sad is that had the resources POURED into shuttle been diverted to upgrades and streamlining production and cost reductions on Saturn vehicles, we would have gotten FAR more return on investment... The Saturn S-IC stage could have been redesigned into the S-ID stage, with the four outer F-1 engines jettisoning halfway to orbit like the ATLAS missile did, with the remaining F-1 propelling the stage and it's cargo to orbit. Such a 1.5 stage to orbit vehicle could have given the same lift capability to orbit as shuttle for the same price or less, despite being an expendable vehicle. Plans were also in the works for using an S-IVB stage and a modified S-IC stage as a replacement for Saturn IB, or developing liquid booster rockets for the Saturn V, each of which would have had two F-1 engines, which could have been used as a first stage for a Saturn IB replacement. Sadly such plans all came to naught in the rush to trash the Saturns.

Now here we are 40 years later rushing BACK to the expendable capsule paradigm and expendable boosters, because shuttle has proven SO horrifically expensive, unsafe, and ill suited to exploration beyond LEO.

Interesting how history works sometimes.... OL JR :)

[FlyBack]

.... I highly recommend "The Space Shuttle Decision" by T. A. Heppenheimer. It details all the twists and turns and political machinations that can turn a technically challenging but feasible 'next step' engineering problem/solution into an overbudget, underperforming, compromised by compromises politically-derived vehicle that doesn't really satisfy ANYBODY'S requirements.

Yes, it is interesting how history repeats. Toward the end of my senior year in high school I was awarded a NASA internship at AMES in Sunnyvale, California. I spent most of my time working in the model shop and got to see many of the shuttle configurations being tested at the time (1969 Jan-Jun). Max Faget's straight wing design was my favorite. It seemed like every week they brought in a new model for the craftsmen there to put the finishing touches on. It was fascinating to watch it evolve over a very short period from a TSTO flyback booster/orbiter to something like what we have now.

Anyway... found the link to T.A. Heppenheimer's report online (http://history.nasa.gov/SP-4221/contents.htm). Excellent read. Enjoy.

Regards,

FlyBack

[Jeff Walther]

The program as a whole. I found about the porking of the shuttle for employment from Jerry Pournelle's website. It was not widely publicized, but it was there. Certain powerful congresscritters wanted no shuttle caused drops in employment in their districts. Even with the DoD specs increasing the size/cross-range capability/etc, NASA projected that it would take far fewer people to run operations.

That would explain a few things. In May of 1984 I went to work at NASA JSC with my shiny new Aerospace Engineering B.S.. I was working in Attached Payload Integration in Space Shuttle Operations. After about six months I had figured out that we wrote documents describing payloads, and that the documents weren't actually read by anybody outside our group.

Our only other function seemed to be to supply a Payload Officer to Mission Control (in the big room on TV) and two or three Payload Systems guys (in a back room no-one ever saw). The attached payload would have its own...darn, can't remember what they were called. But basically, there was a control room for "guests" who were monitoring/operating the actual payload. Really, the only thing the Payload Officer did was to be in between the leader of the payload-operating guests and the Flight Control Officer. I could never see any reason our entire area couldn't be shut down and shot into the sun.

Fortunately, McDonnell Douglas lost it's part of that contract to Rockwell, and I was able to jump to Orbital Dynamics, until that contract also went to Rockwell, at which point I jumped to Structures, but by that time Challenger had exploded and we had even less meaningful work to do. Sigh. Not-so-good-times.

NASA JSC Shuttle Operations--what a great place for a spirited new engineer. (NOT.)

[Jeff Walther]

One of the cooler concepts in TSTO (two stage to orbit) is the large air-breathing booster carrying the rocket or hybrid sustainer.

Oxidizer is a huge percentage of the mass of rocket fuel. If you can arrange to pick up your oxygen out of the atmosphere during ascent, you can vastly reduce your lift-off weight.

So, if you could somehow build your booster stage as a recoverable Ramjet/SCRAMjet powered aircraft you might garner some benefits.

Of course, one of the first obstacles is getting the thing up to Ramjet speeds without a set of turbine engines, but if you add the conventional turbine jet engines, then you've got extra weight you don't need.

Some kind of rocket assisted take off might work there. The initial velocity will be a little low for ramjets, but it will still be down where the air is pretty thick any way. One problem is that for any sizable vehicle, the take-off gear (the wheels) become massive. A sort of drop-away go-cart which never leaves the ground starts looking attractive for the take-off gear.

[Jerry Irvine]

One of the cooler concepts in TSTO (two stage to orbit) is the large air-breathing booster carrying the rocket or hybrid sustainer.


What tools do you use to model the boost to orbit phase of various candidate designs?

Jerry

[Jeff Walther]

What tools do you use to model the boost to orbit phase of various candidate designs?

When we did this as a senior design project (1st Runner up, 1984 Bendix Design Competition) we wrote our own flight/trajectory simulator in Fortran on the dual CDC6700 at UTexas.

I wrote the propulsion subroutine which calculated thrust and fuel consumption, based, in part, on atmospheric conditions during ascent. My first run generated nonsense. I checked and checked the code and couldn't find any errors. It turns out one of my team mates had converted the atmosphere modeling subroutine from english units to metric units so whenever my routine asked, "How's the air at this altitude?" it got figures which made no sense.

Ten or so years later, JPL crashed a probe into Mars by making the same mistake...

[Jeff Walther]

There was a link to a PPT in the news link. Not great dimensional information but it is interesting.

In the 2nd pic, the lower right vehicle looks similar the Centuri Space Shuttle. :)

That "Heavy" version would never make it through a safety evaluation. With two boosters separating at similar times, there are too many ways to have a collision after separation.

[Doug Sams]

With two boosters separating at similar times, there are too many ways to have a collision after separation.Jeff,

What am I missing? That is, how is that event any different than the current shuttle with two boosters separating at the same time? Or for that matter, don't the Deltas and Atlases also shed boosters?

Doug

.

[Jeff Walther]

Jeff,

What am I missing? That is, how is that event any different than the current shuttle with two boosters separating at the same time? Or for that matter, don't the Deltas and Atlases also shed boosters?.

Well, I could be wrong, of course. :-) Shooting off my keyboard and all that.

The difference in this case is that the two boosters are also either gliders or airplanes. So instead of just following a ballistic path, which is pretty predictable, they have the opportunity to use their aero surfaces to fly into each other. A little pitch in the nose down direction and the two will hit each other. Two much pitch in the nose up postion and they'll loop around and hit each other. Odd winds or effects from the vehicles passage, and perhaps those big wings will drag them into each other.

I guess with a careful gentle nose up pitch they could predictably fall away from each other... It would definitely get a lot of scrutiny, I think.

[FlyBack]

It would definitely get a lot of scrutiny, I think.

... it has, and you are abslolutely correct. It is a very difficult problem to solve. A quick literature search on the separation dynamics of hypersonic vehicles yielded the following:

UNSTEADY AERODYNAMICS OF A HYPERSONIC VEHICLE DURING A SEPARATION PHASE (http://docs.google.com/gview?a=v&q=cache:NRvRz4KrjesJ:www.iscfdj.net/cfdj_list/absV10N4/v10n4a06.pdf+HYPERSONIC+SEPARATION+DYNAMICS&hl=en&gl=us)

exerpt - "At high altitude and
high Mach number the orbital stage is released and
the ”Separation Phase” starts. The separation phase
is mainly dominated by aerodynamic interference ef-
fects, hence safety considerations in order to achieve a
certain distance between both vehicles as fast as pos-
sible are of great interest."

Also, found at aiaa.org:

Wind tunnel tests for separation dynamics modeling of a two-stage hypersonic vehicle (http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=20600)

Lateral Separation Dynamics and Stability of a Two-Stage Hypersonic Vehicle (http://www.aiaa.org/content.cfm?pageid=406&gTable=Paper&gID=14028)


For those of you who like a little light reading before bed.. enjoy.


Regards,

FlyBack