Earth is heavy, and we don't just mean in the "Back to the Future" sense. It makes it hard to escape from the surface. Escaping Earth is part of what makes space travel so expensive; every pound costs thousands upon thousands of dollars to just heft off the ground.
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But what if we were to launch from the moon instead? The moon only has a 1/6 our gravity. So after startup costs, the launch shouldn't be so bad in terms of expense. That's why one group of researchers suggest it's best to detour to the moon first on a journey to Mars.
This runs counter to a lot of the established wisdom, which says that a trip between Earth and Mars is long enough and we should minimize the time. But providing the moon already has a base in place to mine water and other resources, this should streamline the weight by 68 percent, say the researchers, led by Takuto Ishimatsu, now a postdoc at the Massachusetts Institute of Technology. The new study will be published in the Journal of Spacecraft and Rockets.
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Essentially, the moon would act as a vast pit stop. Rockets with fuel for more missions would launch from the surface. The Mars crew would grab these tanks as they orbited the moon, move them to a fuel depot - perhaps at a gravitationally stable point between Earth and the moon known as a Lagrange point. They'd fuel up and then start the long ride over to the Red Planet.
In an interview with Discovery News, co-author Olivier de Weck, a professor of aeronautics and astronautics at MIT, pointed out there are more things that need to be studied. The moon's potential for mining will be a big one. We also need to know how to handle cryogenic propellant - fuel that needs to be stored carefully at low temperatures to remain liquid - when launching rockets autonomously. So it's by no means a sure shot that we could go to Mars this way.
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We know there's water on the moon, but it's a big question as to how much there is. And there's also the question of patience - would we be willing to build a base on the moon first and wait to go to Mars?
In the 1960s, uniting Apollo spacecraft in Earth orbit was abandoned in part due to concerns about autonomous docking, de Weck pointed out. It made it simpler to go to the moon, but it also killed the plans of Wernher von Braun and others to create a human platform in space from which to launch many kinds of missions - not just to the moon.