Friday, September 30, 2011

Electrodynamic Tether Propulsion- can you use it for Single Stage to Orbit?

The idea is to get that final bit of thrust needed in order to get to orbit.  By the time a spacecraft is to that point, it will be hypersonic, but less than orbital velocity.  The idea is to be able to reduce mass using propellant-less thrust.  The same system can be used later for reentry as well.

In an earlier post, getting energy from reentry was discussed so as to provide active cooling.  That method entails a means to reject energy into space by way of a solid state laser.  By using a similar method, generating electricity from heat, you can store- via a capacitor- some of these electrons not used for active cooling. Upon reaching sufficient altitude, deploy an electrodynamic tether and send the current into the tether which will add lift.  That gives a propellant-less boost, saving mass and helping get to orbit.   The same tether's current can be reversed and be useful in storing electrons for the descent back down.  The energy will go into the capacitor, causing drag, while the tether will used a little later on in order to provide lift so as to slow down the descent.  This bleeds off energy while keeping the use of mass to a minimum.

Both systems, laser cooling, and electrodynamic tethers, will be useful in ascent and descent, while helping save enough mass so as to make the Single Stage to Orbit concept more feasible.

No comments:

Post a Comment