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Lesson 35 |
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Space odyssey |
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When will it be possible for us to think seriously about colonising Mars? |
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The Moon is likely to become the industrial hub of the Solar System supplying the rocket fuels for its ships, |
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easily obtainable from the lunar rocks in the form of liquid oxygen. |
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The reason lies in its gravity. |
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Because the Moon has only an eightieth of the Earth's mass, |
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it requires 97% less energy |
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to travel the quarter of a million miles from the Moon to Earth-orbit than the 200 mile-journey from Earth's surface into orbit! |
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This may sound fantastic, but it is easily calculated. |
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To escape from the Earth in a rocket, one must travel at seven miles per second. |
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The comparable speed from the Moon is only 1.5 miles per second. |
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Because the gravity on the Moon's surface is only a sixth of Earth's (remember how easily the Apollo astronauts bounded along), |
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it takes much less energy to accelerate to that 1.5mps than it does on Earth. |
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Moon dwellers will be able to fly in space at only three percent of the cost of similar journeys by their terrestrial cousins. |
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Arthur C.Clark once suggested a revolutionary idea passes through three phases: |
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1. 'It's impossible--don't waste my time.' |
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2. 'It's possible, but not worth doing.' |
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3. 'I said it was a good idea all along.' |
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The idea of colonising Mars--a world 160 times more distant than the Moon--will move decisively from the second phase to the third, |
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when a significant number of people are living permanently in space. |
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Mars has an extraordinary fascination for would-be voyagers. |
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America, Russia and Europe are filled with enthusiasts--many of them serious and senior scientists who dream of sending people to it. |
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Their aim is understandable. |
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It is the one world in the Solar System that is most like the Earth. |
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It is a world of red sandy deserts (hence its name--the Red Planet), |
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cloudless skies, savage sandstorms, chasms wider than the Grand Canyon and at least one mountain more than twice as tall as Everest. |
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It seems ideal for settlement. |
