Gases
in Experimental and Future Rocket
Propulsion
Systems
Within the next 10 years, modern
rockets, such as those launching the space shuttle and the Saturn 5 will be
obsolete. Chemical rockets have finally
reached the pinochle of their evolution and researchers have finally turned
their attention elsewhere.
Future Rockets will be separated into three categories, launch vehicles,
inner-solar system, and interstellar rockets.
By separating the functions of a rocket, each type will perform their
given task better.
Launch vehicles will continue to be driven by chemical rockets because
they require high amounts of thrust over the small distance required to escape
the earth’s gravity.
The space shuttle, designed and built in the late sixties-early
seventies is finally going to be replaced as the premier launch vehicle in the
world. The X-33 prototype has finally
begun testing. The X-33 is totally
reusable; it doesn’t require expensive booster rockets and extra fuel tanks to
achieve orbit. Its chemical rockets are
all it needs. Fueled by liquid hydrogen
and liquid oxygen, the X-33 will be able to blast more mass for less cash out
of the earth’s gravitational field. The
Venture Star will quickly replace the X-33.
The Venture Star will be three
times as large and carry many times the payload.
Inner-solar system rockets will probably use a solar driven ion drive
(see diagram). The ion drive uses
electricity generated by solar panels to ionize xenon. The xenon ions are then electrostatically
accelerated by a series of solenoids and released through a 30-cm nozzle. This engine is very fuel-efficient, it produces
10 times the specific impulse (ratio of thrust to propellant used), and it is
also much faster. Unfortunately the
amount of thrust provided is very small only 92mN at peak efficiency. This means that while the ion drive can go
faster and farther, it’s acceleration is much slower. The Deep Space 1 experimental spacecraft is
currently testing this drive system, as one of it’s many new experimental
technologies.
Interstellar drives are not quite so well developed. One possibility is a nuclear rocket. This drive uses a fission reactor to
superheat hydrogen gas and transform it into high-energy plasma, which then
leaves the reaction chamber at high speeds.
These rockets would be about 5 times as fast and strong as a current
chemical rocket. The only downside to
this drive is that it would require much more radiation shielding than any
other type of rocket to protect it’s human cargo. This rocket would also release massive
amounts of radiation into the surrounding space, fine for deep space where such
radiation would be like a drop of water in the pacific, but absolutely fatal
for the Earth.
The ultimate source of power and propulsion in space would be the Matter/Anti-Matter
Drive. Deuterium and anti-deuterium (deuterium
that has been magnetically reversed) would annihilate each other producing
massive amounts of energy. This energy
would be used to create plasma to drive the rocket near the speed of light. Small amounts of anti-matter have been
created for a few seconds in laboratories in Boston using particle accelerators,
but no method of containment has been successful.
The future of space travel is by no means decided. The drive systems I have explained are only
possibilities. Who knows what advances
science will make? Tomorrow everything
we know to be true could be turned upside down and a new concept will emerge
and bring humanity to the stars.