SANGER-another Concorde/Shuttle flop?

From:         MLINDROOS@FINABO.ABO.FI (Marcus Lindroos INF)
Organization: ABO AKADEMI UNIVERSITY, FINLAND
Date:         20 Nov 94 01:59:01 
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Right now, it looks as if the European Space Agency's next major project
is going to be Sanger - a two-stage hybrid hypersonic aircraft/small
rocket plane. The first stage will be about the size of a Jumbo Jet and
capable of mach 7 flight using "ordinary" turboramjets rather than 
scramjets. The second stage (HORUS) will be carried piggyback on Sanger
and separate at an altitude of 45km, it will then fire its engines to
achieve Earth orbit. The max.payload is just 3-4t and HORUS will land
like a glider, much like the US Space Shuttle.
---
There are other contenders for ESA's $15 billion FESTIP project too, but
Sanger is "politically correct" since Germany's Messerschmitt-Bolkow-Blohm
would be the main contractor. The main competitors (British Aerospace and
Reaction Engines Ltd.) will probably be out of the race as long as the
British government refuses to contribute money to Europe's aerospace plane
program.
---
Would Sanger be good? Prominent sci.space.* readers doubt a two-stage-to-orbit
spaceplane would bring down launch costs as much as would ballistic 
single-stage-to-orbit reusable rockets. Sanger could be become just another
expensive economic disaster like the Space Shuttle and Concorde before it.
But the technical risks (apart from those associated with 1st/2nd stage 
separation at hypersonic velocities) generally appear to be smaller since
propulsion/materials requirements will be less severe than for SSTOs. But
there are two crucial questions:

-Could Sanger act as a hypersonic airliner?! It could cruise at mach 4-5
 and if HORUS was replaced with a passenger compartment pod, Sanger could
 transport 200-300 people across the Atlantic twice as fast as Concorde.
 However, new airport support facilities would be required since Sanger's
 jet engines burn liquid hydrogen, which is difficult to store for long
 periods of time. Does anyone know the maximum range with full tanks (=100t
 of LH2)...?

-Would it be possible to modify Sanger to serve as a "flying launch pad"
 for other, more capable but heavier space planes as well...? For weight
 reasons, most horizontal takeoff-&-landing SSTO spaceplanes have to use a 
 detachable landing gear system (launch trolleys or piggyback launches on 
 aircraft) since lightweight gear cannot support the weight of a fully fueled 
 vehicle. Ukraine's giant Mriya cargo carrier (max payload=275t at
 mach 0.8) has been proposed, but only two planes have been built so far.
 Maybe Sanger could be modified to launch heavier, air-breathing spaceplanes
 like Britain's HOTOL/SKYLON as well? In this case, the craft would separate
 at subsonic speeds and much lower altitude. The big question mark is how much
 weight Sanger could support...HORUS has a mass of 95t and the maximum amount
 of fuel is 100t for a total of ~200t. HOTOL & SKYLON both weight in the 270t
 range.

If Sanger works out well, we will have an affordable hypersonic *AND* space
transportation system so the project could be more versatile and economical 
than other systems... 


MARCU$