Conference 7.286::space

    	I would like to just HOW the "space plane" could "penetrate"
    SDI measures.
    
    	The truth is finally coming out - Reagan tried to make the space
    plane look like a futuristic means of very fast transportation for
    civilian airlines, but it is obviously a much more practical military
    transport than a commercial one (How many civilians would pay thousands
    of dollars more than on regular jets just to get to their destination
    a few hours sooner?).
    
    	Reagan has to fool - I mean sell - the space plane to the public
    in order to get funding approved for the military. 
    	I'm surprised they're even bothering with this tactic - why
    don't they just go ahead and spend millions on the project with
    or without public approval?
    
    	The space plane is a nice idea - but not in Reagan's short-sided
    plans.
    
    	Larry
    

Newsgroups: net.space
Path: decwrl!ucbvax!DFVLROP1.BITNET!ESG7
Subject: The oxygen condenserin the HOTOL propulsion system
Posted: 22 Sep 86 09:41:15 GMT
Organization: The ARPA Internet
 
I received the following question from Paul Dietz:
=======================================================================
  You said HOTOL works by condensing liquid oxygen from air and burning
it in an SSME clone.  I'm really confused about how this could work.
Wouldn't atmospheric water ice up the system, and how do you separate
oxygen and nitrogen?  Moreover, wouldn't one get more thrust (and, due
to the lower exhaust temperature, more complete combustion) if the
nitrogen was not excluded?
=======================================================================
     It should be emphasized that the details of the HOTOL are still
classified.  Rolls Royce won't release the info until their prototype
is working, they've a bullet proof patent, and there is an established
market.  The liquid oxygen condenser is the key technology that will
make or break the HOTOL.  The best sources of info on the HOTOL are the
British Interplanetary Society publications.  My sources are these B.I.S
publications plus inside gossip that I've heard at the DFVLR in
Goettingen.  I **suspect** that the condenser is based on a conventional
supersonic inlet, followed by a diverging section, leading to a liquid
hydrogen heat exchanger followed by a converging section to dump the
nitrogen gas to atmosphere.  The boiling point for nitrogen is -195.8
deg. Celsius.  The boiling point for oxygen is -182.962 deg. Celsius.
The trick is to have the condensor at about -190.0 deg. Celsius so you
get liquid oxygen but the nitrogen just passes through as gas.  Ice
is an obvious problem.  However the upper atmosphere is very dry.  Plus
if you can get the air below zero in the diverging section, then the
crystals would form in midair rather than on the heat exchanger.  The
heat exchanger could be placed in a region where the flow is separated
so the crystals wouldn't impact the exchanger and the oxygen could
puddle.  Hydrogen has an enormous heat capacity, and has the best
specific impulse of all rocket fuels.  Burning air in the rocket
wouldn't work because too much energy would go into heating the nitrogen
and forming useless NOx molecules.  The specific impulse would be to
small to make the propulsions system viable against a pure oxygen
system.  I emphasize that this design is based on my interpolations
of rumors that I've heard and read.  ***Believe at your own risk***
                        Gary Allen

Newsgroups: sci.space
Path: decwrl!ucbvax!slb-test.CSNET!DIETZ
Subject: NASP: Rockets just as cheap?
Posted: 13 Jan 87 21:59:00 GMT
Organization: The ARPA Internet
 
The January 1987 issue of Technology Review has a scathing article on
the national aerospace plane.  Some points it makes: 
 
  -- The vehicle or spinoffs have no chance of being effective passenger
    transports, and would have no plausible military utility beyond
    being a shuttle replacement.
 
  -- Many of the technologies critical to NASP will work just as well
    in reusable rocket powered vertical takeoff vehicles.  For example,
    a space shuttle redesigned to use modern composite materials (instead
    of aluminum, for example) would save over 15,000 pounds.  Some NASA
    people think an advanced shuttle with dual-fuel rockets would
    be as economical as a scramjet powered launch vehicle.  Crucial
    common technologies are low maintenance subsystems, highly
    simplified & automated checkout and launch, and advanced
    materials.
 
  -- Development costs have been grossly understated.  The author of
    the article estimates NASP will cost $17 billion, not the $3 billion
    DOD says.
 
  -- According to the author, a vehicle the size and weight of
    a conventional aircraft could get to orbit using scramjets only
    if the scramjets can operate up to about Mach 17.

    This past weekend I heard a wild rumor from some friends who go to
    Maine. They said that the space plane has been flying for about a year!
    Supposedly, it goes to Australia in less than an hour. No body was
    supposed to know, but.....
    
    john

    
    re: -1
    
    It's not a wild rumor. I know one of the people who worked on
    the engine.
    
    /prc

    	There have been "rumors" circulating about a DoD black program for
    a sort of lifting body unmanned hypersonic aircraft. I've heard of a
    couple of sightings in Maine but most of them have been out West. The
    program is HIGHLY classified and the DoD won't even acknowledge its
    existance but there have been enough sightings to indicate it (or maybe
    of family of "its") exists and has been tested for a few years.
    
    				Drew
    

Avleak claim that the unmanned DoD hypersonic vehicle is code named Aurora.
Or was, as it is DoD policy to change code names once an existing one becomes
known. It gets mentioned from time to time, notably in their 'Aerospace Vista'
issues at the end of the year.

gary

    Re: last few

    Note that Aviation Week believes that there is also a manned hypersonic
    aircraft program (ref. Oct. 1, 1990 issue), as well as at least one
    other subsonic craft.  

    The "hypothetical" unmanned hypersonic bomber described in the Vista
    issue (Dec. 24, 1990) has 121 ports for weapons on its underside and
    uses an external burning concept in which fuel is sprayed into the area
    between the detached shock wave and the aft surface of the vehicle,
    which forms a virtual nozzle at cruise speed. The hypersonic vehicle
    sightings in southern California described in the 10/1/90 issue speak
    of an extremely loud vehicle with a pulsing sound.  Whether this
    behavior is consistent with an external burning mechanism is not clear
    from the literature (all unclassified) that I've seen.  Note that such
    a craft would probably be a high-mach cruise vehicle and not be 
    capable of attaining orbit unless it had some type of conventional
    rocket (a la X-30) for the final kick into orbit.

    Speed of the unmanned vehicle described in the 12/24/90 issue is Mach
    6-8, which is consistent with the Aurora "figures" given by Sweetman,
    Richardson, and the NY Times January 1988 article.  AW&ST claims the
    Lockheed Aurora concept was for a Mach 7-8 TAV for recon and tactical
    duties, and was canceled (10/1/90).  Whether Aurora became something
    else or begat another vehicle is unclear.  Its utility to the civil
    space program is also unclear, although that was not a consideration in
    its development.

    Finally, the history of black programs is always being rewritten as new
    information (or disinformation) comes to light.  The D-21 drone was
    rock-solid secret until the mid-80s, 20 years after its development. 
    No one is really sure if there was (or is) an F-19 fighter, as distinct
    from the F-117 that is now semi-white.  Whether the US has an
    operational X-30 like craft, or something close to it, is purely
    speculation until the thing lands at JFK.

    The 8/26/91 issue of AW&ST has a story on the McDonnell Douglas DC-X
    single stage to orbit vehicle funded by SDIO.  McD-D has a contract to
    develop a VTOL technology demonstrator for tests in 1994-95, powered by
    modified Pratt & Whitney RL-10s.  Dimensions of the demonstrator are 12
    ft. diameter and 39 ft. length.  The full size vehicle will weigh
    1-1.2M lbs. and deliver 20K lbs to LEO.  The artwork is kind of
    comical, looking like a sketch from "Destination Moon".  Hard to
    suppress the image of the nose cone opening on a hinge and a helicopter
    dumping a load of carrots down to Bugs Bunny inside.

    Actually, the artwork looks a lot like MDD's old SSTO designs from the
    early 70s.
    
    gary

    Actually, the artwork looks like a sketch of the Douglas Intrepid from
    1963, which was a single stage ballistic suborbital transport that
    could carry 1500 troops, powered by four F-1 engines.  

    I should clarify that I don't think the vehicle looks silly, just the
    way in which the facilities and pre-launch activities are depicted in
    the artwork.  The DC-X as shown is kind of interesting aerodynamically. 
    I'm curious about what serves as low-speed control surfaces.  It's much
    different that the competing General Dynamics design, which owed a lot
    to the Chrysler design for the ASSC study.  (Imagine a real big Apollo
    CM).

    FWIW, the ballistic troop carrier was the justification for USAF
    funding the F-1 in the days before the Saturn/Nova programs.
    
    gary

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VNS TECHNOLOGY WATCH:                           [Mike Taylor, VNS Correspondent]
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                              Microwave Shuttles

    Traveling halfway around the globe in 45 minutes is the vision of Leik
    Myrabo, an associate professor of aerospace engineering at Rensselaer
    Polytechnic Institute.  Over the past eight years, the US Air Force,
    NASA, and the SDI office have awarded him more than $600,000 to develop
    the idea of travel on pulsing beams of focused microwave or laser
    energy.  The biggest obstacle has been finding energy sources powerful
    enough.  But with the development of high-powered microwave energy
    beams, which can produce up to 1 gigawatt, Myrabo says the idea looks
    more credible.  In the lower atmosphere, a microwave beam could explode
    volumes of air beneath the craft, forcing it upward in small blasts
    thousands of times a second.  Ground based microwave beams would also
    slow the craft's descent.  Passengers would be sealed inside, protected
    from the energy.  This year, Myrabo will work at the Space Studies
    Institute in Princeton, NJ, to develop his idea.

    {Business Week Feb 22, 1993}

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