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Paul Allen Launches Commercial Spaceship Project
smitty777 writes "The phrase 'Where do you want to go today?' takes on a whole new meaning as Paul Allen, Microsoft co-founder and the world's 57th richest man in the world, looks to create a new spaceship company. Stratolaunch Systems plans to bring 'airport like operations' to the world of private space travel. Partnering with Burt Rutan, the plan is to field a test within five years and commercially available flights within ten. Spacecraft will be air-launched from a giant, six-engined aircraft. There is more information available on the Stratolaunch homepage."
...Department comes:
the world's 57th richest man in the world
Paul Allen for the money spigot, Burt Rutan for the carrier aircraft, and Elon Musk/SpaceX for the rocket stages. When I worked on such concepts many years ago at Boeing, we generally found that launching from altitude like that doubles the payload compared to the same rocket starting from the ground, so it makes a lot of sense from an engineering and cost sense, as long as the carrier aircraft costs less than the rocket stages per flight (normally easy to do).
This design overcomes one limitation we had at Boeing, which was the 747 was not quite large enough in it's current form. By going to six engines of the same size as the 747 uses, they solved that problem. Eventually they can also look at flying back the first rocket stage, for even more savings. Once it is empty of fuel, the rocket stage does not weigh much, so it would not take much in the way of wings, landing gear, and some small jet engines so it can fly to a landing. Without knowing how far it will go on a ballistic arc doing it's launch job, it is hard to say if it should fly back to the launch site, or fly forward to another landing location.
Getting into orbit isn't about altitude - it's about velocity. If you look at the energetics of any rocket, about 95% of the energy produced goes into the kinetic energy of velocity - with only about 5% going into the potential energy of increased altitude. Having a jet impart the initial ~600mph to the rocket stage is a huge savings, particularly given the non-linear nature of the propellant economics.