Electric Rockets Set To Transform Space Flight 114
An anonymous reader sends this quote from an article at Txchnologist:
"The spectacle of a booster rocket lifting off a launch pad atop a mass of brilliant flames and billowing smoke is an iconic image of the Space Age. Such powerful chemical rockets are needed to break the bonds of Earth's gravity and send spacecraft into orbit. But once a vehicle has progressed beyond low-earth orbit chemical rockets are not necessarily the best way to get around outer space. That's because chemical propulsion systems require such large quantities of fuel to generate high speeds, there is little room for payload. As a result rocket scientists are increasingly turning to electric rockets, which accelerate propellants out the back end using solar-powered electromagnetic fields rather than chemical reactions. The electric rockets use so much less propellant that the entire spacecraft can be much more compact, which enables them to scale down the original launch boosters."
Ion Drive isn't new (Score:5, Informative)
This is old technology and the benefits of this have already been realized in many satellites. There is literature going back well over a decade documenting the trade space.
Thought it was about VASIMR. (Score:3, Informative)
Turns out I was wrong. I made myself sad. Here's the technology that might actually transform space flight.
http://www.adastrarocket.com/aarc/ [adastrarocket.com]
http://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket [wikipedia.org]
The guy who invented it is an ex-Astronaut and VASIMR (or its tech underpinnings) was his PhD thesis at MIT for Applied Plasma Physics. I guess what I'm saying is he isn't a crank.
Re:Ion Drive isn't new (Score:5, Informative)
More like decades; quoted from Wikipedia,
The official father of the concept of electric propulsion is Konstantin Tsiolkovsky as he is the first to publish mention of the idea in 1911. However, the first documented instance where the possibility of electric propulsion is considered is found in Robert H. Goddard's handwritten notebook in an entry dated 6 September 1906. The first experiments with ion thrusters were carried out by Goddard at Clark University from 1916–1917.The technique was recommended for near-vacuum conditions at high altitude, but thrust was demonstrated with ionized air streams at atmospheric pressure. The idea appeared again in Hermann Oberth's "Wege zur Raumschiffahrt” (Ways to Spaceflight), published in 1923, where he explained his thoughts on the mass savings of electric propulsion, predicted its use in spacecraft propulsion and attitude control, and advocated electrostatic acceleration of charged gases.
A working ion thruster was built by Harold R. Kaufman in 1959 at the NASA Glenn Research Center facilities. It was similar to the general design of a gridded electrostatic ion thruster with mercury as its fuel. Suborbital tests of the engine followed during the 1960s and in 1964 the engine was sent into a suborbital flight aboard the Space Electric Rocket Test 1 (SERT 1). It successfully operated for the planned 31 minutes before falling back to Earth.
Re:Oh course you can. But ... (Score:4, Informative)
Yeah. Dawn's ion engines (linked to in TFS) have a very high ISP (3100s), but an equally low thrust (90 mN).
As a comparison, the F-1 engines on the Saturn V Stage I-C had pretty low ISP (about 250s), but a massive 34 MN of thrust.
Basically you can have high ISP (electrical) or high thrust (chemical), but not both.
Unless you go VASIMR, of course, and we're not quite there yet.