The point is, given power source type A with mass per watt B, payload C, and a
range of electric propulsion options, the one with 90% electric power source,
2.5% thruster, 2.5% propellant, 2.5% payload and 2.5% everything else
*probably* looks ludicrous from an overall mission cost or launched mass figure
of merit compared to tech which uses more of the initial LEO or HEO payload for
propellant.
If your vehicle shrinks overall as you decrease Isp, you're not optimal yet...
George William Herbert
Sent from my iPhone
On Feb 6, 2016, at 6:19 PM, "Ed LeBouthillier" <codemonky@xxxxxxxxxxxxx>
wrote:
Henry Spencer said:
"More efficient" in some sense, yes. Totally useless as main propulsion for
most missions -- needs far, far too much power per newton of thrust. Which
is why FEEP thrusters are seen only in "niche" applications with tiny
thrusts, like ultra-precise stationkeeping for LISA.
Probably.
My larger point is that there are other kinds of electrical propulsion worth
considering.
Dave W. might start by looking at surveys of different types of propulsion
available before settling on a particular one.
Each has different strengths and weaknesses.
Without knowing more about the particular aspects of the mission, it's hard
to know what to suggest.
For smaller vehicles like cubesats, some of the non-traditional propulsion
methods start being reasonable to consider as main propulsion.
New Space Engine Could Turn Tiny CubeSats into Interplanetary Explorers
http://www.space.com/21867-cubesat-deep-space-propulsion-kickstarter.html
Here are titles for some survey papers:
Thruster Options for Microspacecraft: A Review and Evaluation of
State-of-the-Art and Emerging Technologies
Juergen Mueller
A Survey of Micro-Thrust Propulsion Options for Microspacecraft and Formation
Flying Missions
Jeurgen Mueller et al
http://mstl.atl.calpoly.edu/~bklofas/Presentations/DevelopersWorkshop2008/session2/4-MicroThrusters-Juergen_Mueller.pdf
Electric Propulsion: Which One For My Spacecraft?
http://www.stsci.edu/~jordan/other/electric_propulsion_3.pdf
