From 1973 to 1978, the British Interplanetary Society (BIS) conducted a study – Project Daedalus – into the plausibility of an unmanned interstellar spacecraft. It was the first study to propose such a mission, but ultimately proved that it could be done.
Project Daedalus was a direct response to a paradox proposed by physicist Enrico Fermi in the Forties. As we touched on earlier, Fermi suggested that Interstellar travel was Impossible, as statistically the universe should be teeming with intelligent life but no one had ever been in touch with us. This study was successful in disproving his theory.
The target selected for the theoretical spacecraft was Barnard’s Star, a low-mass red dwarf six light years from Earth that could be the host of several terrestrial planets. The aim was to determine if a spacecraft with modern or upcoming technologies would be capable of reaching the star in 50 years, within a human lifetime. The result proved unequivocally that such a mission would be possible.
A whole host of factors were considered in the study including navigation, communications and overcoming interstellar dust. The rocket would have to be a two-stage, unmanned and autonomous vehicle powered by nuclear fusion. The nuclear-fusion drive would accelerate the rocket to 12 per cent the speed of light, but there would be no method to slow it down. Instead, after a journey time of 40 years, the probe would fly past Barnard’s Star in just a few days. However, there would be considerable opportunity to also observe any surrounding planetary system.
Project Daedalus demonstrated that with modern or near-future technology, interstellar travel is feasible. The only obstacles are money and global stability. No one nation could undertake such an endeavour alone, and thus an International effort would be the only option – much like the case of building the ISS.
To date, Project Daedalus remains the most comprehensive and plausible engineering study ever conducted for an Interstellar probe. Several other projects have aimed to build upon its findings and continue reaching for the stars. Project Icarus Is a direct descendent, refining the technologies to make a more modern equivalent, while the 100 Year Starship study is examining the possibility of organising an interstellar mission by the 2100s.
British Interplanetary Society interview with Nick Spall
We talks to a key member of the British Interplanetary Society who currently leads UK human spaceflight co-ordination efforts.
Tell us more about Project Daedalus.
Project Daedalus would use a massive pellet-driven nuclear pulse rocket engine to accelerate an unmanned probe to 12 per cent the speed of light to reach Barnard’s Star in about 50 years. It would carry sub-probes and would be able to move on to other stars as part of an extended mission plan. With the emerging and exciting exoplanet research results providing new stars of interest, future targets for such a probe are multiplying all the time.
Do you feel that the current state of space exploration is hindering such a mission?
Interstellar travel will be extremely expensive, so the first step is to reduce the cost of getting to Earth orbit – that is being achieved by cheaper capsule design right now.
Given time, once new propulsion techniques are developed, the cost of faster long-distance probes will come down to be more viable and, within this century, I see early unmanned probes going beyond the solar system.
In some ways, of course, this has already started with the Pioneer and Voyager deep-space probes of the Seventies, but it will be many thousands of years before they arrive near any star system.
If money wasn’t an object, how soon do you think we could launch an interstellar mission?
It would take at least 30-50 years to develop the starship design and build it. For the future, of course, whole communities may travel to stars on permanent missions. These would involve ‘world ships’, perhaps on converted asteroid bases, using solar sails etc, with closed-loop ecosystems to sustain crews for decades or even centuries.
Realistically, when do you think we’ll send a manned spacecraft to another star or exoplanet?
Assuming the Earth survives long enough – say, the next 100-150 years ahead – eventually humans will be living outside the confines of the planet, colonising the inner solar system, and eventually travel to the nearer stars will definitely occur, in a similar way to 16th-century navigators discovering the New World and going beyond. Interstellar travel is inevitable, given time. As the great Russian space scientist Konstantin Tsiolkovsky once said: “The Earth is the cradle of mankind, but one cannot live in the cradle forever.”