Nuclear power may give NASA’s long-range missions the speed and range that combustion engines cannot, but research is sputtering for lack of funds. NASA’s head of the Prometheus program, Al Newhouse, said the agency has $US3 billion for the next five years. “Beyond that, we know we need more money,” Mr Newhouse told AFP. “We are at a very early stage of this program. It has been in existence for slightly under a year.”