S.1 Spacecraft Propulsion Systems Chapter 1: Introduction to ...

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Exotic Propulsion Methods: Antimatter and Photon Propulsion
“I have learned to use the
word ‘impossible’ with the
greatest caution.”
Wernher von Braun
Exotic Propulsion Systems are those “far out” ideas still
under study. They will be required for the ultimate dream of
space exploration to travel to other star systems, as
depicted in TV shows like ‘Star trek’. Two examples of such
exotic propulsion systems are outlined below.
Antimatter Propulsion: Matter- antimatter annihilation
offers the highest possible physical energy density of any
known reaction substance. Since matter and antimatter
annihilate each other completely, it is an incredibly
compact way of storing energy. E.g. a round trip to Mars
with a 100-ton payload might require only 30 gram of
antimatter. However, sufficient production and storage of
antimatter (with potential complex and high storage system
mass) is still very much in the future.
Photon Propulsion: The generation of usable thrust by
ejection of photons is still very hypothetic. The generation
of photons by e.g. laser technology and their subsequent
decay in space, involves the mass-energy transfer
expressed by Einstein’s equation, E = mc 2 . Consequently,
very large quantities of energy will be required even for
nominal levels of thrust. Possibly, matter-antimatter annihilation
can be harnessed for photon propulsion in the future.