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PHYSICS OF THE IMPOSSIBLE
for example, the VAS I MR (variable specific impulse magnetoplasma
rocket), which uses a powerful jet of plasma to propel it through space.
Designed by astronaut/engineer Franklin Chang-Diaz, it uses radio
waves and magnetic fields to heat hydrogen gas to a million degrees
centigrade. The superhot plasma is then ejected out the end of the
rocket, yielding significant thrust. Prototypes of the engine have already been built on Earth, although none has ever been sent into
space. Some engineers hope the plasma engine can be used to power
a mission to Mars, significantly reducing the travel time to Mars, down
to a few months. Some designs use solar power to energize the plasma
in the engine. Other designs use nuclear fission (which raises safety
concerns, since it involves putting large amounts of nuclear materials
into space on ships that are susceptible to accident).
Neither the ion nor the plasma/VASIMR engine, however, has
enough power to take us to the stars. For that, we need an entirely new
set of propulsion designs. One serious drawback to designing a starship is the staggering amount of fuel necessary to make a trip to even
the nearest star, and the long span of time before the ship reaches its
distant destination.
SOLAR SAILS
One proposal that may solve these problems is the solar sail. It exploits
the fact that sunlight exerts a very small but steady pressure that is sufficient to propel a huge sail through space. The idea for a solar sail is
an old one, dating back to the great astronomer Johannes Kepler in his
1611 treatise Somnium.
Although the physics behind a solar sail is simple enough, progress
has been spotty in actually creating a solar sail that can be sent into
space. In 2004 a Japanese rocket successfully deployed two small prototype solar sails into space. In 2005 the Planetary Society, Cosmos Studios,
and the Russian Academy of Sciences launched the Cosmos 1 space sail
from a submarine in the Barents Sea, but the Volna rocket it was being
carried on failed, and the sail did not reach orbit (A previous attempt at
PHYSICS OF THE IMPOSSIBLE
for example, the VAS I MR (variable specific impulse magnetoplasma
rocket), which uses a powerful jet of plasma to propel it through space.
Designed by astronaut/engineer Franklin Chang-Diaz, it uses radio
waves and magnetic fields to heat hydrogen gas to a million degrees
centigrade. The superhot plasma is then ejected out the end of the
rocket, yielding significant thrust. Prototypes of the engine have already been built on Earth, although none has ever been sent into
space. Some engineers hope the plasma engine can be used to power
a mission to Mars, significantly reducing the travel time to Mars, down
to a few months. Some designs use solar power to energize the plasma
in the engine. Other designs use nuclear fission (which raises safety
concerns, since it involves putting large amounts of nuclear materials
into space on ships that are susceptible to accident).
Neither the ion nor the plasma/VASIMR engine, however, has
enough power to take us to the stars. For that, we need an entirely new
set of propulsion designs. One serious drawback to designing a starship is the staggering amount of fuel necessary to make a trip to even
the nearest star, and the long span of time before the ship reaches its
distant destination.
SOLAR SAILS
One proposal that may solve these problems is the solar sail. It exploits
the fact that sunlight exerts a very small but steady pressure that is sufficient to propel a huge sail through space. The idea for a solar sail is
an old one, dating back to the great astronomer Johannes Kepler in his
1611 treatise Somnium.
Although the physics behind a solar sail is simple enough, progress
has been spotty in actually creating a solar sail that can be sent into
space. In 2004 a Japanese rocket successfully deployed two small prototype solar sails into space. In 2005 the Planetary Society, Cosmos Studios,
and the Russian Academy of Sciences launched the Cosmos 1 space sail
from a submarine in the Barents Sea, but the Volna rocket it was being
carried on failed, and the sail did not reach orbit (A previous attempt at