Re: Soyuz TMA-11 Comes Home, More or Less...



spazhoward wrote:
Somewhere, I still have a copy of "My Weekly Reader" from around 1971
or '72. The cover story was about the design competition for the
future space shuttle, and featured illustrations of 3 different
concepts; all of them huge, and all of them needlessly complex. All
these years later, and I still have the same question that I had in
the 6th grade...

"What happened to project Dyna-Soar?"

Small, reusable lifting bodies mounted on top of Titan-variant
boosters fueled by hypergolic propellants. Get in the truck, push the
START button and "Blast Off!" (well, no, not quite, but a lot closer
than anything we've got now). Leave all of the heavy lifting to the
big, dumb, disposable boosters, that's what they were designed for.

Small spaceplanes are hard to design, as they always end up being heavier than you thought they would be.
That means they suffer higher G loads and heating during reentry...which means more heat-shielding...which means more weight... which means higher reentry temperatures...which means more heat-shielding...
I wrote a posting about this a few years back:

...."here is the basic problem- any manned
aerodynamic vehicle needs certain systems; for on orbit work it needs: Life
support for it's crew, a means to maneuver itself, a means of radiating the
heat created by it's crew and electronics, and sufficient space to carry a
worthwhile mission payload (cargo, passengers, recon gear, death ray, etc.)
Add to this, for landing: landing gear of some sort, heat shielding,
aerodynamic control surfaces, fuel to decelerate from orbit, and avionics
capable of both orbital and atmospheric control.
Right from square one, it's obvious that is quite a bit to pack into a small
vehicle- but it gets worse- the avionics for a thirty foot long shuttle will
be about the same weight as a 130 foot long one...same with life support,
control panel, seats, suits, and crew. Propellant storage tanks will be
about the same thickness. Reaction control systems may be smaller, but will
need all of the valves and pumping systems associated with a large system,
and plumbing of equal tubing thickness to a large system. The amount of
insulation to protect it during re-entry stays the same thickness and weight
per square foot- and you have a lot fewer square feet to give you lift, so
the mass of it goes up proportionately to that of the vehicle-the same
applies to the skinning, and structural members of the machine. Then you hit
the next thorny problem- heat dissipation- the material that keeps the heat
out during re-entry tends to keep it in on-orbit; you need big radiators of
some sort to make this work. We (the U.S.) thought this wouldn't be too
difficult when we designed Dyna-Soar, and watched the weight steadily climb
to where a Gemini capable on-orbit vehicle with a single man crew was going
to need a Titan III or Saturn I to make orbit, all for the sake of greater
cross-range on landing, and gliding in horizontally, the way that God, and
the U.S. Air Force intended spacemen to land!
With true Gallic pride, the French tried the same idea twenty-odd years
later with "Hermes"- and hit the same weight snag, as the vehicle got more
and more complex, to the point where the payload had to be put into a
jettisonable mission module on the back end along with the retrorocket and
other vehicle systems- as it's original payload bay had to be given over to
radiators. The Soviets took a crack at the problem with "Spiral"... and ran
into the same weight-to-mission capability problem.
We tried it again with the HL-20... this time it was going to take a Titan
IV to get it into orbit! And all for some increased cross range on landing-
you will notice that the semi-canceled ISS escape vehicle looks like a
lifting body, re-enters like a lifting body, but floats down to earth under
a parachute- which might make one ask... why not a ballistic capsule? The
argument is "Greater Cross Range For Landing"- but a ballistic capsule could
simply stay in orbit for a turn or two, until a suitable emergency landing
site fell under it's orbital track."
But in order to procure funding, everything was promised to everybody
and we wound up with the beautiful, exquisite mess that is the STS;
not quite the right machine for any mission. And although it sounds
harsh, from an operational standpoint perhaps the worst part is that
no one involved with the STS project seemed to have ever watched any
'50's TV Sci-Fi. If the Space Rangers lost a ship, it was certainly a
tragedy; but there were still 20 (or 50, or 100) more ships in the
fleet. By designing a shuttle large enough to carry IUS boosters into
orbit (oh, and a few passengers, too), we wound up with only a handful
of extremely expensive vehicles, the loss of one of which constituted
1/4 OF THE FLEET in addition to the loss of the crew.

When the X-38 project came along, I thought perhaps some degree of
sanity had prevailed. No such luck. That project apparently made too
much sense, so obviously it had to be cancelled (after all of the
development money was spent, of course). I think maybe you're right,
Pat, the real purpose is just to spend money. After all, they managed
to "downsize" the space station until the redesigns cost more than
building the original concept would have, right?

Yeah, that's how it all ended up.
I've only seen one small spaceplane idea that really impressed me - and that's the Soviet "Spiral", which is one of the most extraordinary packaging jobs I've ever laid eyes on...including a escape capsule for the pilot that separate and do a reentry all on its own. Sort of like a Dyna-Soar with a Mercury capsule on the front:
http://www.buran.ru/htm/str126.htm
http://www.buran.ru/htm/spiral_5.htm#war
(love the video of it nuking the carrier task force.)
BTW - if Spiral looks a bit familiar: http://www.cloudster.com/Sets&Vehicles/Doppleganger/DoveTop.htm
It would be fun to know what exactly SAINT II was supposed to have inside it: http://www.astronautix.com/craft/saintii.htm

Pat
.