This is something that has not been covered by news nor (as near as I can tell) has it been the subject of a press release. But it is fairly well known to those in the business.
NASA Ames brought a 1.2 MW, 110 GHz gyrotron for testing beamed energy propulsion. They still need the power supply, which is 70 kV at 30 A but it's a relatively small cost compared to the gyrotron. Up close it will provide well over 10 MW/m^2.to test hydrogen heaters. They intend to offer the use o it the same way as the wind tunnels, as a national engineering test asset. I think it is an accepted truth that you need single stage to orbit and that it must be a reusable launch vehicle to get the cost to GEO down to where power satellites make sense economically. Given the current state of material science and the best exhaust velocity you can get from chemical propulsion, neither of these are feasible. To put numbers on the problem, it takes 9000 m/s to get into LEO. For 4500 m/s rocket engines, that's a delta V of twice the exhaust velocity. The rocket equation gives a mass ration of 7.4 which means the vehicle and payload can't be more than 13.5% of the takeoff mass. For a vehicle to be reusable, the accepted minimum structure is 15%, leaving less than zero for payload. (Skylon cheats by burning air partway up, but it's not enough to get a lot of payload to LEO.) But if you have 9000 m/s exhaust velocity, which can be done with hydrogen heated with microwaves or lasers, then the mass ratio is a little less than 3. So vehicle and payload can be 36% of takeoff mass. If half vehicle and half payload, that's 18% each. So a 300 ton vehicle with a dry mass of 54 tons could put 54 tons in LEO. The falling cost of microwave power and laser power makes these options possible. Beamed energy propulsion doesn't make economic sense unless you are moving cargo volumes in the hundreds of thousands of tons per year-- which happens to be the right size for a serious power satellite project. I should also add that I never thought NASA would do something so sensible. Those of you who know Pete Warden might send him a thank you note.. Keith PS https://www.fbo.gov/index?s=opportunity&mode=form&id=6ee365a77d240df7a668f5746cf71665&tab=core&_cview=1 _______________________________________________ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
