But there's been nothing like it since. If it worked, great. If it failed, try something else. But we haven't. In fact, at NASA's Marshall Space Flight Center in Huntsville, they're already at work on the next generation.
Engineers here talk without flinching of robot ships that can go to the next star.
If that works, a ship with a small fuel tank could jet space travelers from Earth to Mars in a matter of weeks. Today's probes must conserve their fuel so carefully that the trip takes almost a year. Engineers dream of spaceplanes propelled toward orbital speed by a long track of high-powered magnets. They even look to the sun's rays and the possibility that the pressure of the photons in them can be harnessed to propel a craft through space. NASA believes advanced rocket technology can open up exciting possiblities.