 Orion is one of very few interstellar space drives that could theoretically be constructed with available technology, as discussed in a 1968 paper, "Interstellar Transport" by Freeman Dyson.Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society (BIS) to design a plausible interstellar unmanned spacecraft that could reach a nearby star within one human scientist's working lifetime or about 50 years.A dozen scientists and engineers led by Alan Bond worked on the project.