Artist impression of the Project Orion spacecraft traveling through the solar system. Image Credit: NASA

The distance to the nearest star, in perspective. Notice the logarithmic scale. Image Credit: NASA

Reaching for the Stars. Part 2: Practical Interstellar Travel

By David Darling

The idea of journeying to the stars is nothing new. As early as 1929, the British scientist J. D. Bernal wrote about the possibility of generation ships—enormous spacecraft, like miniature worlds, which would take hundreds or thousands of years to reach their goal and aboard which many generations of travellers would live out their lives. In both science and science fiction, concepts such as suspended animation have also been used to allow people to cross the light-years to other stars, even at relatively low speeds.

But, almost certainly, practical interstellar travel will demand that vehicles reach far higher speeds than any that have been achieved in spaceflight to date. This in turn will mean that new forms of propulsion have to be developed that go beyond the capabilities of chemical rockets or even ion engines.

One of the first practical designs for a robotic interstellar probe was that of the British Interplanetary Society in the mid-1970s. Known as Project Daedalus, it called for a ship to make the voyage to Barnard’s Star, a red dwarf 5.9 light-years away, in a travel time of 50 years, powered by a nuclear-pulse rocket that could propel the craft to about 12 percent of the speed of light (36,000 kilometers per second). This type of engine, which would use a series of nuclear fusion explosions—effectively, hydrogen bombs—had already been studied by Freeman Dyson and his colleagues as part of Project Orion in the 1960s.

Read more: Reaching for the Stars. Part 2: Practical Interstellar Travel « AmericaSpace.

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