NASA - propel spacecraft by producing a "pellet-beam" of microscopic particles travelling at very high speed (over 74 miles per second) using laser blasts. The concept could dramatically shorten the time it takes to explore deep space. Where Voyager 1 took 35 years to reach interstellar space (the heliopause, roughly 123AU from the Sun), a one-ton spacecraft could reach 100AU in just three years. It could travel 500AU in 15 years. See
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