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Nov17-09, 06:37 PM
Sci Advisor
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P: 8,953
I was thinking about a aircraft launched rocket - not the crazy balloon idea.

I think the real problem is just that rockets capable of reaching orbit with an appreciable payload are BIG, and can't really be carried by an aircraft (especially not in a horizontal orientation).
You can carry an (empty) space shuttle on the back of an airliner.

The pegasus is a pretty successful system - I was at the launch of an Infrared observatory by it 10years ago.
According to their site they can put 450kg into LEO, only about 1/10 of the capacity of a Delta or Ariane but a lot cheaper!
You probably aren't going to use it for a GSO communcations sat but great for GPS, sat-phone etc in LEO, especially because you are so flexible in the orbit window.

They claim the biggest cost advantage is that they don't need a steerable rocket motor.
To control a rocket's attitude at launch you need a lot of torque to overcome any wind or imbalance, that means a seriously complex vectorable rocket motor.
The pegasus can make much more gentle course corrections with just aerodynamics.
i suppose this is just because they have much more time and space to play with to make corrections because there is nothing around them.