A Manned Mission to Mars
The space age started in 1957 with the launch of the first artificial satellite by the Russians – Sputnik 1. Since then there have been manned missions to the moon, spacestations and spacewalks, scientific instruments in space, satellites used to transmit TV and phone calls, operate the global positioning system, and unmanned missions to other planets in the solar system.
It has been a long time now since man landed on the moon, and dispite the list of achievements above, nothing comparable has happened since. The next major step in space exploration may well be a manned mission to Mars. Such a mission may be the only way of answering once and for all the question: has there ever been life on Mars?
Such a mission may turn out to be the single most important, most complicated, most expensive mission ever undertaken by man. It will probably be too expensive for any single country to undertake by itself and there are many technical obstacles to be overcome.
A manned mission to Mars would involve travelling about 240,000,000 km. At an average speed of about 40,000 km/h – typically of the the speed of objects in the solar system – this would take about 240,000,000 over 40 = 6,000 hours or about 18 months.
This means a crew would have to take 18 months supply of food and fuel. All of that food and fuel has to be lifted off the Earth's surface in the first place and on arrival at Mars, a lot of fuel has to be burnt to slow the craft down so it can enter orbit. Then maybe a surface vehicle has to be launched from orbit to land on the planet, with enough fuel to take off again. To return back to Earth more fuel has to be burnt up to leave Mars orbit and return to Earth. In addition, they must be some margin for error, so that if the orbit has to be altered or some fuel is lost, the craft should be able to return to Earth. If the spacecraft is damaged in some way, a rescue mission may not be possible, so extra safety features and margin for error must be built into the craft.
To minimise the weight of the craft, many of the supplies could first be lifted separately into orbit and taken on board the craft once it reaches Earth orbit. Waste water and waster gases on board can also be recycled to be re – drunk and re – breathed. This has been a feature of the space stations for decades. New engine technologies are being developed, which use ions accelerated by electric fields to provide thrust instead of chemical fuels. The ions may be made from atoms sucked into the engine from space through an inlet, as opposed to rocket engines which must use fuel carried inside the engine. These 'ion engines' together with their fuel are much lighter than rocket engines and have a much longer range.
There are also the effects on the astronauts to consider. They must be shielded from coasmic rays, kept warm, and undertake regular exercise because the absence of gravity in space will lead to muscle wastage and health problems.