ST401385@BROWNVM.BITNET (02/28/86)
Several people have been asking questions about the "Aerospace
Plane". I recently read in Physics Today an interview with George
Keyworth II, the outgoing director of OSTP and Reagan's science
advisor, that discussed a lot of this material.
I am posting relevant exerpts herewith.
Note "Scramjet" means "Supersonic Combustion RAMJET".
The reason Scramjets are a research topic of the 80's, while ramjets
were a topic of the 40's, is that it is much harder to make a ramjet
work without slowing the incoming air down.
---Geoffrey A. Landis, Brown University
Reply to: ST401385%BROWNVM.BITNET@WISCVM.ARPA
<Exerpts from an interview with George Keyworth II>
--from Physics Today, Feb. 1986
"Even my concerns, which I think were well known early on,
about whether the space station was being represented in
a candid fashion, are completely withdrawn when I now
see the prospects of reducing the cost of launching
material into space by a factor of 100 or so with an
aerospace plane. I think such a vehicle suggests a new set of
dimensions for space travel.
Q: Do you think there's much of a chance of funding such a plane?
In my years here I haven't seen anything that has received as high
a level of support in such a short period as the aerospace plane. I
think we'll doubttless proceed with it, flying a prototype in the early
1990's. The Air Force, DARPA, NASA have all been committed to this
project for several years. It's not a brand new program.
Q: Philosophically, though, isn't it the sort of thing this
Administration has opposed--a civilian project funded by Federal
dollars?
It began in DARPA because it was pertinent to defense. But it also
has applications for a full spectrum of space capabilities as well as
major importance in commercial air transport. The commercial aspects
will see large involvement by the private sector. In a classical sense,
it is a defense spinoff to the civilian community...
...We're talking about an airplane that files at possibly Mach 15 at
altitudes of up to 150,000 feet or more. We're talking about a plane
with a range virtually unlimited, because it is capable of reaching
space orbit. It would climb at a high rate, so that the significant
shock distrubance--noise--would be drastically reduced. Most of all,
there is the possibility--still premature in our thinking--of being cost
effective because it could carry large payloads.
Q: Are the Soviets working on something like this?
Not to the best of our knowledge. I would say that it's fairly
unlikely because of the range of technologies that have come
together--materials, propulsion, design--giving us a rare exponential
opportunity. There is no single advance or invention involved, like the
transistor, say, but an array of new ideas and technologies... an hour
to Europe from Washington, an hour and a half to Japan. Incredible!
Q: What sort of support do you seek from industry?
Defense and NASA will need to spend $3 billion to $4 billion to
build and fly a prototype in 1991 or so. By doin that, we will gain a
lot of experience with ultrahigh speeds and the companies in this domain
can then proceed to build commercial aircraft. Virtually every
aerospace firm in this country, including engine manufacturers, has been
involved in the project for the last three years. They are all very
excited about it. Everyone in defense and space sees applications and
opportunities with the aerospace plane. The only hitch is that there
may be a tug of war over who pays for what...
...the aerospace plane, or as some call it, the TAV, the Trans
Atomopheric Vehicle, is critical if we're to maintain preeminence in
technology, broadly, and aerospace in particular.
Q: can you discuss the President's feelings about ... HST
<nb: HST=Hypersonic transport. --GL>
A president's job is to make policy. ...the president has
not been briefed on it yet. What I'm saying is that Ronald REagan
does not spend a lot of time poring over each item in the federal
budget.... the TAV is only a small part of DARPA, which is in turn a
very small part of Defense. Neither item is a Presidential priority.
<note by GL: I think that part is slightly dated.>
<the interview goes on to discuss Gramm-Rudman-Hollings, SDI, and other
things.>
My apologies for any typos. --GL
Other comments:
(1) If Gallileo passes close over the south pole of the sun, and
is in an elliptical orbit crossing Jupiter's orbit, it will be
VERY FAR from the sun when it passes over the north pole (nb. The facts
given are enough to calculate how far, if you assume that Jupiter's orbit
is normal to the polar axis of the sun, but I'm too lazy to do it).
(2) There are four solutions to the Olber's problem. (a) The
Universe is finite in space (b) The universe is finite in time
(c) Some mechanism removes energy from light coming from the farther
stars (eg., redshift) (d) The universe is hierarchically clumped,
so that the average density of luminous matter approaches zero on
large enough scales
Geoffrey A. Landis, Brown University
Reply to: ST401385%BROWNVM.BITNET@WISCVM.ARPA