In article ,
Andi Kleen writes:
(Derek Lyons) writes:

Just done in a small fraction of the cost of the X15 and able
to carry more people.

ROTFL. I *love* how everytime someone points out the low performance
of the SS1 as compared to the X-15, or how it only spends a couple of
minutes in 'space' as compared to the Russian 'tourist' flights....
Someone else always parrots the 'its cheaper though! and privately
built! and carries people!" as though that changes things.

It depends on your metrics. If your main metric is how many people the
craft is able to carry then the SS1 is at least three times better
than the X-15.

That's not necessarily so. Part of teh original specification for the
X-15 proposals was that there be a 2-seat version. (Pilot & FTE) In
the event, it wasn't deemed necesssary, but...
The X-15 also carried 1200 lbs (550+ Kg) of test instrumentation in a
pressurized, air conditioned bay behind the cockpit. If playing
"X-15/X-Prize) games are what you're ecter, there was certainly enough
payload margin and volume available to make X-Prize legal provisions.
(The view wouldn't be much, but nobody said anything about windows.)

And price/performance is an important metric too, even if people
used to the industrial military complex are not always aware of that.

My bet is that the price/performance of the SS1 is significantly
better than that of the X-15.

Price for altitude performance, most likely yes. But the X-15 wasn't
built to a limited specification - it was a research vehicle, intended
to put itself into unexplored, and extremely hazardous flight regimes,
collect data, and return. The information collected did much to
enhance not merely the Upper Left Corner of the Envelope stuff, but
also provided very real advances in aerodynamics, structures, control
systems, and aeromedical data. The triple-adaptive flight control
system was the foundation on which today's FBW control systems was
built.

SpaceShip 1 is an impressive project. Make no mistake about that.
But it's a very limited system, for a very limited purpose. While I'd
be more than happy to bet that they'll win the X-Prize, it's not going
to advance the State of the Art. White Knight, on the other hand, may
end up with a useful post X-Prize career hauling payloads to high
altitudes, for purposes such as Atmospheric Sampling or UV Astronomy.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster