Thursday, March 27, 2008

Space Access 2008 - Vincent Cate and Henry Cate Jr., on Fully Reusable Lunar Transport

My father and brother believe that space tethers provide a way to save on the energy equations for getting into space. Vince gave the presentation.

The basic idea of a rotating tether is a large mass that has a rope moving around and around. A large rope reaching down towards to the Earth is moving slower than the orbital speed and much faster when it reaches the high point.

The Moon's orbit is in a different orbital plane than the equatorial orbits around the Earth. Changing orbital planes takes energy. Vince and my father are proposing a two stage tether transportation system. One rotating tether is in orbit around the earth and throws space craft to the moon. The second tether is in orbit around the moon. It receives the objects.

Throwing an object affects the orbit of the tether. A key part of the plan is to also catching an another object as it comes back. This balances out going with in coming.

The basic approach is to have a base on the equator which launches a rocket. The rocket flies up, catches the end of the tether. The tether continues rotating and pulls the rocket up to above the anchor then releases the rocket. The rocket coasts out past the moon, makes a change in the orbital plane and comes to the moon. Near the moon the second tether catches the rocket and slows it down. A reverse process sends payloads back to the Earth.

A key feature of this proposal is a huge savings in energy. It could be ten times cheaper in the amount of fuel needed.

This system could also be used to toss objects to Mars or the asteroids. When tossing objects out the orbit of a tether, the tether loses kinetic energy, which has to be replaced.

One hard issue: no one has caught an object on a tether in space.

The full agenda

Technorati tags:

No comments: