X-37B with a ET?

I was thinking over the upcoming X-37B test on the Atlas V, and that
seems like a pretty expensive way to get one into orbit if it ever
became operational.
However, way back in the 1980's the Air Force started releasing artwork
of a ET equipped mini-shuttle that would ride to high altitude on a
stock or SSME equipped 747, and launch a minishuttle with a big drop
tank under it off of its back:
http://media.popularmechanics.com/im...ers/198212.jpg
(that, like the X-37B was a Boeing design, BTW.)
Although the single main engine of the X-37B doesn't seem to have enough
thrust to make this work, a version with multiple engines might be able
to do this.
The choice of hydrogen peroxide and JP-8 as propellants may be telling
in this regard also; the H2O2 makes for compact oxidizer storage, as
well as avoiding the icing problem associated with LOX without needing
foam insulation on the ET.
That would make the ET fairly cheap and compact, a good feature for the
expendable part of this launch technique.
It would also explain with they haven't released photos of the underside
of the X-37B, as those would show the attachment points to the ET, as
well as where the the JP-8 and H2O2 plumbing from the ET goes into the
orbiter.
If this is the intended operational launch technique, then suddenly the
whole thing makes a lot more sense, as it could either carry small
payloads into orbit and return in fairly short order to Earth or spend
time in orbit doing experiments in its cargo bay over a period of months
at the cost of a expendable drop tank for each flight, which would make
it very economical to operate...at that low cost, even the "Hot Eagle"
manned military troop transport become doable, and the spaceplanes and
their ETs could be kept ready-to-go on short notice atop their 747's,
needing only propellant loading and payload or troop insertion prior to
launch.
That could explain the giant new building down at Area 51, as it would
be where the X-37B and its ET are lowered into place onto the carrier
aircraft: http://www.lazygranch.com/a51pan.htm#newhangar
Or maybe it would get hoisted up in the old Hanger 18:
http://www.fas.org/irp/overhead/ikon...nger_18_01.htm

Pat

On Dec 4, 1:21*pm, Pat Flannery wrote:

1. The choice of hydrogen peroxide and JP-8 as propellants may be
telling
in this regard also;

2. It would also explain with they haven't released photos of the
underside
of the X-37B, as those would show the attachment points to the ET, as
well as where the the JP-8 and H2O2 plumbing from the ET goes into the
orbiter.

1. The propellants were changed to N2O4 and MMH

2. The engines don't have the thrust

It was never intended for this. It is a spacecraft that can return
from space and not a launch vehicle. It was already designed and
built when NASA managed the program.

Me wrote:
1. The propellants were changed to N2O4 and MMH


That needs adding to the Wikipedia article then, as it doesn't mention
it, although some other websites do.
That would also avoid the frost problem, and probably give better isp to
boot.


2. The engines don't have the thrust


In the early Boeing concept shown in the PM cover, the engines (RL10s)
were to run off of LOX/LH2, which made for a large ET due to the low
density of the LH2.
As I pointed out, to do this launch concept you would have to add more
engines to it, although the X-37B could serve as a aerodynamic test
vehicle for such a derivative.


It was never intended for this. It is a spacecraft that can return
from space and not a launch vehicle. It was already designed and
built when NASA managed the program.


Well, the Air Force has it now, and if it takes a Atlas V to boost it
into orbit, its whole purpose seems baffling.
http://www.foxnews.com/story/0,2933,569143,00.html
(That gets us back to the Boeing artwork of one with RVs riding on the
wings:http://www.msnbc.msn.com/id/3077821/
But sooner or later the thing has to land, and what's it supposed to do
with the RVs then?)
It's supposed to check out advanced technologies, but those technologies
are supposed to be used on what exactly?
Back when it was part of the Future-X program, that program also
included reusable launch vehicle studies:
http://www.designation-systems.net/dusrm/app4/x-37.html

Pat

In sci.space.history Pat Flannery wrote:

Well, the Air Force has it now, and if it takes a Atlas V to boost it
into orbit, its whole purpose seems baffling.

If not Atlas V, or Delta IV (?) then what is there for a U.S. military
lift? Is it as "reliable" as Atlas V? Perhaps Atlas V is overkill,
but if you don't have funding for too many tries, perhaps the more
reliable, but more costly overspec'ed, launcher is apropriate at this
stage?

rick jones
--
I don't interest myself in "why". I think more often in terms of
"when", sometimes "where"; always "how much." - Joubert
these opinions are mine, all mine; HP might not want them anyway...
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