Speaker
Description
Slow interstellar travel (at speeds well below the speed of light) is the only form of interstellar travel we are sure we will be able to pursue in a not too far future. Other alternatives, up to FTL voyages, are still speculative and, while hoping that they will be possible, for now we should concentrate on what we are sure we can do.
In a paper published at the 75th IAC the author discussed the technological advances required to launch an interstellar human colonization mission to the nearest stars known to have planets (perhaps easily terraformable ones), mostly concentrating on propulsion.
The result was that a slow-boat type generation ship, travelling at about 1% of the speed of light requires a thruster able to work at an ejection velocity of more than 2×107 m/s. With a thruster operating in variable exhaust velocity (VEV) conditions, it is possible to build a ‘slow boat, travelling at 1% of the speed of light with a payload plus structure mass ratio of about 50%, which is an interesting result owing to the large payload required, including not only the people, their life support system and consumables, but also the landing vehicles and the habitat on the destination planet, or the devices to build it from locally available materials.
An ejection velocity of 2×107 m/s (a specific impulse of 2 million seconds) requires an advanced nuclear fusion thruster (which needs just the application of well known physics) or an antimatter drive (which requires much greater development efforts).
The aims of the present paper are to investigate on the possibility of decreasing the mentioned requirements on propulsion technology by using a multistage architecture and on further discussing various other aspects which must be solved before attempting getting out of our solar system, such as
• Ethical aspects, which are determinant in choosing the mission architecture,
• Minimum crew size,
• Role of hibernation, even partial hibernation, in such a mission, and
• Possibility of building the spacecraft in space.