Future of Space Exploration

Solar Sails

Traditional space exploration has been powered by chemical fuelled rocket engines. Our journeys have been limited by the amount of rocket fuel a spacecraft can carry. The weight of a space shuttle at launch is 95 percent fuel.

Further exploration of our solar system and beyond have been halted by the simple fact that our technology is limited to rocket propulsion systems and that this fuel is heavy and runs out. The furthest man has been is the moon and this displays the shortcomings of rocketry.

International Space agencies have proposed methods of transportation that would allow us to go further into space than ever before. Space sails are Nasa's greatest hope for Interstellar travel. The space sails will be made of ultra light carbon                     Image courtesy of Nasa materials developed by Energy Science Laboritories in San Diego, California. The lightweight materials are extremely strong and can withstand very high temperatures.

The advantages of solar sails is their lightweight nature, durabilty and no requirement for rocket propulsion. In fact it will be the Sun's energy that will propel itself into space with. The sail will be driven by photons; particles of energy that sunlight and other forms of electromagnetic radiation is emitted. A solar sail is a very large mirror that reflects sunlight. As the photons of sunlight strike the sail and bounce off, they gently push the sail along by transferring momentum to the sail. Because there are so many photons from sunlight, and because they are constantly hitting the sail,
there is a constant pressure exerted on the sail that produces a                       Image courtesy of www.Space.com                 constant acceleration of the spacecraft. Although the force on a solar-sail spacecraft is less than a conventional chemical rocket, such as the space shuttle, the solar-sail spacecraft constantly accelerates over time and achieves a greater velocity.

Hopes for the new technology is high at the Marshall Space Flight Center in Huntsville, Ala. Laser and microwave
sails are being developed here. High energy laser and microwave beams fill the sails and will propel the probe into
space. The energy beams could be provided by an orbiting satellite. The interstellar probe would be launched from space, then the material would unfurl like a fan once deployed.

"This is a stretch goal that is among the most audacious things we've ever undertaken" said Les Johnson, manager of Interstellar Propulsion Research at the Marshall Center

Proposed for launch in a 2010 timeframe, the interstellar probe will travel 23 billion miles or 250 astronomical
units. As it continues to be pushed by sunlight,the solar sail propelled vehicle will at the peak of it's acceleration travel 90km/s or 324,000km/h. If the solar sail probe is launched in 2010, it pass Voyager in 2018; going as far in eight yaers as Voyager has in 41 years. The sail will be the largest spacecraft ever built, spanning 440 yards!