Officially, NASA has been charged with sending astronauts to Mars sometime in the 2030s. Toward that end, according to a Friday story in Universe Today, space agency engineers at the Marshall Space Flight Center are looking at an old concept for interplanetary travel, nuclear thermal engines. However, some doubts have been expressed whether NASA will be granted the budget to develop such engines.
A nuclear thermal rocket uses a nuclear reactor to superheat liquid hydrogen into plasma that is then channeled through a nozzle to generate thrust. The amount of thrust generated is far greater than can be achieved with a chemical rocket. Trip times to Mars would be reduced by about half.
Source:
http://interstellar-news.blogspot.com/2015/01/nasa-looking-at-nuclear-thermal-rockets.html
