Travel across the solar system could be reduced by two-thirds using revolutionary technology.
The time taken for probes to reach other planets could be dramatically reduced thanks to fusion-powered spacecraft which could launch within the next decade. That's according to Stephanie Thomas, vice president of Princeton Satellite Systems, who made the prediction during a presentation to NASA's Future In-Space Operations working group, as reported by Space.com.
A Direct Fusion Drive, or DFD, has been a holy grail of physicists for decades. The concept is based on the Princeton Field-Reversed Configuration reactor (PFRC) which uses magnetically contained hot plasma of helium-3 and deuterium to produce lots of energy - reportedly between 1 and 10 megawatts - with very little dangerous radiation. Whereas the PFRC is a closed system, a Direct Fusion Drive would use the energy produced to then heat up propellant outside the contained reaction, which is pushed out of an exhaust at the back of the drive, producing thrust.
The benefits to space exploration would be considerable. Most obviously, travel times would be drastically reduced. According to the project team, a DFD craft could deliver a 22,000-lb. probe to Saturn in around two years, and could reach Pluto in five. The current record for those journeys is 6.75 years (Cassini) and 9.5 years (New Horizons) respectively.
DFD would offer more than just forward thrust, however. Whereas traditional rockets burn off their fuel very quickly, a fusion reactor would continue to generate power long after launch. This would enable landers to operate for longer, and beam back high definition video. It would also be possible to use fusion to power NASA's proposed Gateway station in orbit around the Moon, as well as any bases established on the lunar surface.
All of this depends, of course, on a successful fusion reaction - something which had eluded scientists for many years, and which has still to be achieved by the Princeton team. The PFRC experiment is already into its second phase, however, with fusion expected to be successful by the time it reaches its fourth stage in the mid-2020s. A flight prototype would then follow, with a full DFD-powered craft potentially ready for launch as early as 2028 according to Thomas. As with all cutting edge space technology, it's a question of "wait and see" but the idea that something long regarded as science fiction is so close to fruition is undeniably tantalizing.