[cripplecreek]

Vasimr engines are technologically possible with speeds as much as 10% to 15% of light speed possible. The real problem arises with the fact that they need to be VERY large for any kind of real human spaceflight.

Vasimr engines were among the leading prospects for project Deadelus but we're still years from building in space where it would have to be done at enormous cost.

[GeronL]

goodness!!

[jaz.357]

A simple Infinite Improbability Drive!

[fieldmarshaldj]

Zero’s too busy promoting trains and putting people on food stamps.

[PIF]

Project Deadelus was proposed to use fusion “bombs” instead of real fission bombs like the Project Orion proposal: http://www.daviddarling.info/encyclopedia/D/Daedalus.html

Nuclear-pulse engines would produce the plasma to propel the ship..

Deadelus needed to be large (54,000 tons) since its mission was to go to Barnard's Star.

Vasimr (Variable Specific Impulse Magnetoplasma Rocket) engines are another kettle of fish entirely: http://www.spaceflightnow.com/news/n1006/01vasimr/

Vasimr engines produce plasma via argon gas, electricity, super-conducting magnets, and a nuclear powered generator.

Vasimr engines are small and are at development stage 6, with stage 7 flight test in the next few years.

A 39 day trip to Mars would require a ship similar in size to a 747 jumbo.

Ad Astra Rocket is the main developer with NASA:
http://www.adastrarocket.com/aarc/