On 05/08/14 19:31, Keith Henson wrote:
Michael Clive <clive@xxxxxxxxxxx> wrote: snipWhy do I want to do this? This would change the entire game as far as mars colonization and settlement is concerned.Michael, I work on making power satellites economical. That's not of interest to SpaceX (Musk) but the propulsion problem is similar in delta V. I have not seen the paper, but someone quoted to me that they were seeing 30-50 micronewtons. Let's assume the power level was on the order of a kW and gave ~40 micronewtons or ~40 micronewtons per kW.
The power level was 28 watts. They also report a peak thrust of 116 uN at 16.9 watts.
According to the AIAA conference paper (?some of?) the tests were done at 5x10E-6 Torr - but according to the abstract they were done at atmospheric pressure.
The conference paper is available at http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0CD4QFjAG&url=http%3A%2F%2Fwww.libertariannews.org%2Fwp-content%2Fuploads%2F2014%2F07%2FAnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf&ei=b0vhU6OWDKqg0QXp1oDgAw&usg=AFQjCNHeHjRWnbBLno10pFZ0xgTkdAiGSA&bvm=bv.72197243,d.d2k&cad=rja
abstract at: http://ntrs.nasa.gov/search.jsp?R=20140006052If you want to try it yourself, yes, a 2.45 GHz oven microwave generator would be suitable, though a lower power tunable microwave source would perhaps be better. The vacuum chamber needs to be fairly large, but apart from that I don't see anything particularly expensive.
Though the paper does discuss a Mars mission, even so, the drive would not really be suitable for solar system use, except perhaps the further reaches.
It would only come into its own where final velocities above about 50 km/s are needed, and even a Vasimr drive would need a mass ratio well above 10.
It might be most useful in a nuclear-powered interstellar probe, at about 1% of the speed of light.
That's if it works at all .. -- Peter Fairbrother
For electric thrusters, a kg of reaction mass per second accelerated to 20 km/s (typical VASIMR) acquires a Ke of 1/2 mV^2. This takes 200 MW (at 100% efficient). The force is 1kg x 20,000 m/s or 20,000 Newtons, 100 N/MW or 0.1 N/kW, which is 100,000 micronewtons per kW. Reducing this number is the VASIMR efficiency (~70%) and the reaction mass fraction, which for LEO to GEO and this exhaust velocity is around 20%. Earth to Mars is similar. It's still 1000 times more energy effective to use ion engines, assuming I have not made some boneheaded error. Keith Henson, L5 Society founder and EE (if you still need one)