ENGI

inky:

NASA’s decision to engineer its replacement for the space shuttle using imperial measurement units rather than metric could derail efforts to develop a globalised civilian space industry…

If you go to NASA’s home page, it seems pretty elementary and user friendly; but a lot of people forget that NASA is one of the world’s oldest and elaborate aerospace/aeronautics institutions, and naturally organizations of such age have accumulated a wealth of information and secrets.

This website lists some of NASA’s subdomains, where you can find thousands of terrabytes worth of useful information that they’ve stored up over the years. A lot of them are interesting and worth checking out if you want to snoop around for a few hours. Personally I use the NASA Technical Reports Server (NTRS) most of the time to look up research articles and other references, as in my post about Advanced Hall Electric Propulsion.

We’ve be exploring space for decades now, but we’re still using chemical propulsion systems; kind of like how we’ve been driving for over a hundred years but still using chemical combustion to power our cars. While we’re on the eve of producing more efficient cars, rocket propulsion has fallen behind in some aspects.

This NASA report talks about one of these propulsion methods, called Hall effect type propulsion. Unfortunately it has only seen low-scale space applications like maneuvering satellites. Hall thrusters, commonly known in sci-fi as “ion thrusters” uses a magnetic field to turn a stream of neutral gas (usually Xenon, Krypton, or another noble gas) into positively charged dense ions, which results in thrust. It produces a large specific impulse, but unfortunately has a high velocity-to-weight ratio; meaning it is highly efficient at producing thrust per unit of fuel, but at relatively low velocities.

For more information and to see a Hall thruster in action, visit this page at the NASA Glenn Research Center.