Had hydrogen been used instead of helium, the company said the specific impulse
achieved would have been above the 600s threshold required for single-stage-to-orbit operations of a launch vehicle, which is not possible with chemical rockets.
The oxidiser: fuel (O:F) ratio moved closer to the target and a specific impulse
of 220 sec was achieved on firing number five.
Furthermore, AFIT performance calculations indicate that matching or improving the specific impulse
of the RL-10B2 results in a minimum stage-weight savings of 105 pounds due to the reduced estimated weight of the DEAN.
45 GHz RF waves and 2 kW of electricity, energy balance calculations determine velocities up to 50,000 meters per second or 5,000 seconds of specific impulse
This would be a leaky mirror, and some of the fragments would escape out the end--at least 50 percent, and Chapline hopes possibly 90 percent--producing a thrust that could have a specific impulse
up to 1 million seconds.
The new engine, which powers the upper stage of SpaceX's Falcon 9 launch vehicle, demonstrated a vacuum specific impulse
of 342 seconds - the highest efficiency ever for an American hydrocarbon rocket engine.
Therefore, the relation to the work programme "Alternative to hydrazine in Europe" is achieved by a replacement of the currently hydrazine based propulsion system with a green propellant system with higher specific impulse
The RL10B-2 is a unique cryogenic upper-stage engine that provides 465 seconds of specific impulse
and 24,750 pounds of thrust.
The Variable Specific Impulse
Magnetoplasma Rocket -- or VASIMR -- could cut space travel time by nearly a sixth of the time currently required.
But, according to a report in New Scientist, a new engine, called VASIMR (Variable Specific Impulse
Magnetoplasma Rocket), will have much more "oomph" than previous ones.
Chemical propulsion can provide high thrust, but is limited in specific impulse
(fewer than 500 seconds).
A GDM engine, Emrich said, would have a specific impulse
of around 100,000 seconds.