Yes, Ions are the masses which impart the propulsion thrust, The much less massive electrons need to be discarded to maintain charge neutrality.
The forces of solar photons are a side effect in the application of ion drives. Although the velocities of the ions in the propulsion jet stream are very high, as close to c, (3 x 10^8 m/s), as possible, they are still well below the speed of light. How are high are they in proposed (and already flown) ion drives? Let's search the Internet to find out. EAM ---- Original message ---- >Date: Mon, 20 Jun 2011 09:15:04 -0700 (PDT) >From: "John M. Steele" <[email protected]> >Subject: Re: [USMA:50686] Solar Electric Propulsion >To: [email protected], "U.S. Metric Association" <[email protected]> > > Ignoring relativity, the physical interpretation is > the velocity at which you can throw fuel mass > "overboard." If it is some kind of "ion drive" I > suppose you can't ignore relativity. > > The photons from the sun also act with direct force > on the solar panels. Past studies have looked at > solar sails, etc. Converting some of the energy to > an ion drive could be a way to "vector" the thrust > from the light pressure and provide more control. > > ------------------------------------------------ > > From: "[email protected]" <[email protected]> > To: U.S. Metric Association <[email protected]> > Sent: Mon, June 20, 2011 9:50:32 AM > Subject: [USMA:50686] Solar Electric Propulsion > The NASA John Glenn Center in Cleveland, Ohio is > requesting Proposals > for a demonstration of Solar Electric Propulsion, a > method of slowly thrusting > probes along spiral trajectories into the outer > regions of our solar system. > > The "specific impulse" (m/s) required for such > missions can only be achieved by electric propulsion > (not by chemical rockets) fueled by solar or nuclear > energy. > > Specific Impulse (thrust times time; divided by the > mass ejected by the rocket motor) (newtons x > seconds per kilogram) i.e. (kg x m/s^2) x s per kg = > m/s. > > In outdated studies, some engineers equated mass > with weight and got the less > acceptable result that pounds times seconds divided > by pounds equals seconds. > > Let's see if the winning proposal(s) can correctly > distinguish mass and weight? > > Gene Mechtly
