> As you're no doubt thinking, there's quite the jump between
> hovering and orbit, and in the final analysis, no chemical rocket
> system is ever likely to give us Flash Gordon or Star Wars style
> flight into/out of orbit.  The numbers on SSTO (Single-Stage to
> Orbit) vehicles are absolutely brutal.

True.
SSTO if you stay in orbit and don't mind a low payload is entirely 
doable right now and has been for decades.

But, if by SSTO you mean "there and back again in one piece", and 
that's what the term is usually taken to mean, then it's very very 
very hard and the question which is much debated is 'is SSTO the best 
way to do it'. ie if you had an eg TSTO (two stage to orbit) system 
and the first stage could fly home again after use (as is being 
proposed by a number of people) then why use SSTO. The Jury is still 
out and will be for a long time.

The Titan 2 missile first stage could do SSTO (one way) all by itself 
with modest payload.

The 1958 vintage Atlas 1 could do 1.5 stages to orbit, and did, just 
under 50 years ago. The 0.5 stage consisted of dropping off the two 
external motors after use. These were not a true whole stage as they 
were fuelled from the rocket proper (just as the Shuttle Main Engines 
are fuelled from the External Tank) BUT at the stage they were dropped 
they constituted a major fraction of the remaining mass so helped 
boost the Mr greatly and thus made all the difference. The remaining 
central "sustainer" motor on the rocket then completed whatever task 
it was doing.

On 18 December 1958 the US, lagging in the "space race" and needing to 
make a visible demonstration of capability to put really large and 
really heavy things into orbit, launched a Christmas message from the 
President in the form of an Atlas missile with onboard tape recorder. 
The whole Atlas missile went to orbit (less of course the drop off 
motors) . This then broadcast a Christmas message to all mankind. The 
general "peace on earth goodwill to all men" nature of the message did 
not and was not meant to hide another message. The name of the mission 
was "Signal Communication by Orbiting Relay Equipment".   The name 
spelled out by the capital letters in that name was not, needless to 
say, a mistake :-).



            Russell


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