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The project, in concert with US government agency DARPA, aims to develop pioneering propulsion system for space travel as soon as 2027:
The project is intended to develop a pioneering propulsion system for space travel far different from the chemical systems prevalent since the modern era of rocketry dawned almost a century ago.
"Using a nuclear thermal rocket allows for faster transit time, reducing risk for astronauts," Nasa said in a press release.
[...] Using current technology, Nasa says, the 300m-mile journey to Mars would take about seven months. Engineers do not yet know how much time could be shaved off using nuclear technology, but Bill Nelson, the Nasa administrator, said it would allow spacecraft, and humans, to travel in deep space at record speed.
[...] Using low thrust efficiently, nuclear electric propulsion systems accelerate spacecraft for extended periods and can propel a Mars mission for a fraction of the propellant of high-thrust systems.
Also at CNN and Engadget. Link to Nasa press release.
(Score: 1, Disagree) by Anonymous Coward on Friday January 27, @10:50AM (4 children)
(Score: 2, Informative) by Anonymous Coward on Friday January 27, @01:37PM (2 children)
Acceleration is related to the change in momentum, which goes as the velocity of the ejecta, not the velocity squared.
(Score: 2) by HiThere on Friday January 27, @02:28PM (1 child)
True, it's velocity that is related to the square of the speed of the ejecta. It's still a quite significant difference. (OK, momentum too. But for figuring transit time velocity is the relevant one.)
I'm not quite clear on the limitations of the "nuclear-electric rocket" that they're proposing, though. My first guess was some fancy development of the ion-rocket, in which case it could run for a long time, but wouldn't produce that much thrust. However if they're ejecting reactor mass, you likely wouldn't want to use it where the exhaust could enter an atmosphere.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by crafoo on Friday January 27, @02:50PM
well, the nuclear rocket project was pretty cool, but yeah I think it was a vacuum engine not designed for atmosphere use. https://www1.grc.nasa.gov/historic-facilities/rockets-systems-area/7911-2/ [nasa.gov]
Pretty sure this new project is something new, but we have tried to use nuclear power for rockets and we even prototyped it out many decades ago.
(Score: 1, Informative) by Anonymous Coward on Friday January 27, @09:10PM
No it isn't. Momentum is linear. Kinetic energy is squared.
The relevant factor that makes this sort of nuclear rocket useful is that the exhaust velocity is determined by both the temperature of the exhaust and inversely by the molecular mass. H2 - O2 rockets are currently the best and they have an exhaust molecular mass of 18, giving a maximum Isp of about 420 before they melt the engine. Nuclear rockets can just heat up hydrogen and that has a mass of 2.
The NERVA rocket they developed back in the sixties and seventies had a tested Isp of 840 and was expected to reach about 1200 with further development.
https://en.wikipedia.org/wiki/NERVA [wikipedia.org]