New Propulsion Systems

Trips to the ISS or to the Moon— and the far longer journey to Mars—still rely on conventional rocket launch and propulsion systems. Alternative systems will be needed for longer flights to explore deep space beyond the solar sys­tem. Scientists are investigating ion engines to replace chemical-fuel rockets
for long missions. An ion engine ejects positive ions (electrically charged parti­cles) to propel the spacecraft. It gives just a small thrust, but it is very effi­cient, needs little fuel, and can be made very light. Over many months, an ion – engine spacecraft could accelerate to very high speeds.

Another possibility is the solar-sailed spacecraft. A solar sail is a panel made from reflective materials; instead of catching the wind like a sailing ship, the solar sail is “blown along” by streams of light particles (photons) emitted from the Sun. A solar spacecraft would not need to carry onboard fuel. Although acceleration is slow to start with, it could eventually reach speeds of

200,0 miles per hour (322,000 kilome­ters per hour). Such a craft could travel
to the edge of the solar system in eight years, compared with the forty years taken by the Voyager 1 spacecraft.