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Travel to Mars

© Zany

We have all seen the pictures sent back from Mars by the Rovers - Spirit and Opportunity. President Bush has proposed returning astronauts to the Moon then continuing on to explore Mars. Mars is about 78,300,000 km from the Earth. That is nearly 200 times the distance to the moon. What exactly is involved in going Mars? What are some of the risks?

One of the first things to consider, is the launch. According to Michael Duke in The Rational for Exploring Mars, exploration of Mars is a three year commitment with a limited capability to return. The astronauts cannot just decide to return. The alignment of the planets must be such to allow them to return. Fortunately for us NASA has created a web site, Basics of Space Flight, so we can get an idea of what is involved. If we look specifically at Interplanetary Trajectories, we will find an explanation on how to get a spaceship to Mars using the least amount of fuel. This method is called the Hohmann Transfer Orbit. For a more mathematical discussion take a look at Mars Academy or Hohmann Transfer Orbit. A bibliography of Hohmann can be found at Walter Hohmann's Roads in Space (Adobe Acrobat Reader is needed to view this web page. It is a free download). Ok, we managed to insert our spacecraft into the Martian orbit, so we're all set. Not quite. Since the objective is to explore Mars, the spacecraft and Mars must meet up. The ideal situation is for the spacecraft to meet Mars as it enters its orbit. An opportunity to do this occurs once every 25 months. How easy or how hard is it to do this? Lucky for us someone has been keeping score. Expensive Hardware Lobbing shows at present the score is 20:17 in favour of Mars. Click on the link for Mars to get a play by play.

Presently, space travel is accomplished using chemically propelled rockets. Getting to Mars using this type of rockets would require a great deal of fuel. How much fuel? Take a look at Houston are we there yet?. Payload is defined as anything on the mission that is not fuel or fuel tanks. A low payload mass fraction (ratio of mission payload mass to total mass) indicates low efficiency (i.e.according to the web site, to get six people to Mars, the launch mass would be more than 1,000 metric tons of which 90 per cent would be fuel!) That's just to get there. What about getting back? Obviously, travel to Mars will mean developing new, more efficient engines.

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