As human made probes increasingly expand our knowledge of the solar system, there are scientists who dream of even wider voyages, to other stars. When such ambitious undertakings eventually take place, there is a good chance they will use a little known British project conceived in the seventies as a starting point.
Project Daedalus was the brain child of the British Interplanetary Society, and the concept was simple; come up with plans for an unmanned space probe that could reach Barnard’s Star (some 5.9 light years away).
A total of 11 engineers and scientists worked on the project between 1972 and 1977. The parameters they worked with were fairly simple. The technology used had to either exist, or be on the horizon in the very near future. The design had to be versatile enough so that it could be used to explore a number of nearby interstellar solar systems. The probe, while unmanned, had to be able to reach a neighboring star within the lifetime of a human being .
Barnard’s Star was chosen over the closer Alpha Centauri system, because at the time it was thought the most likely candidate to contain planets.
The distances involved meant that existing propulsion systems could not be used. Instead, the team settled on using a fusion power source. In essence, mini thermonuclear bombs would be used to push the Daedalus craft up to 12 percent of the speed of light.
Construction of the probe would occur in orbit around the Earth. As planned, the Daedalus craft would have weighed approximately 54,000 tonnes. Of that, 500 tonnes would be the probe’s payload, with most of the remainder consisting of fuel. That fuel would consist of deuterium and Helium-3; the Daedalus team proposed mining Helium-3 from Jupiter, since it is extremely scarce on Earth. The space craft would have been constructed largely of beryllium, a substance able to withstand temperature extremes.
Most of the probe's 50 year voyage would be spent hurtling towards its target. Given the high speeds the spacecraft would need to reach, and the impossibility of rapid deceleration given the technical guidelines the team was working with, the actual time Daedalus would spend in the Barnard Star system would be very short (a few days in fact). The Daedalus team proposed that 18 sub-probes be launched from the main probe to carry out an extensive (but quick) exploration of the star and any planets around it. After its brief rendezvous with another solar system, the probe would speed aimlessly into deep space, a testament to mankind's quest to explore the universe.
Project Daedelus is relevant today as a starting point for interstellar exploration. It was the first serious attempt to solve some of the challenges such an enormous undertaking would present. While we are still a long way from reaching the point where a spacecraft like Daedelus is a possibility, the project showed that reaching for the stars could be more than a science fiction fantasy.