Friday, September 25, 2009

Fantastic Future Friday: Water, Water Everywhere

Water is the key to life, and by extension Space Exploration. The human body needs 3 to 4 liters of water everyday just to survive. So that’s why it is so fantastic that there has been two discoveries of water on other worlds this week.

The first discovery this week was of water on the surface of the Moon. Phil Plait over at Bad Astronomy does a great job of explaining how the water was found and how the amounts of water were calculated in his post “Water on the Moon…? Yup it’s real” I can’t explain how the three spacecraft Cassini, Deep Impact, and Chandrayaan-1 found the water without seriously plagiarizing his post, so I won’t even try.

Basically they found that on the surface of the Moon there is between 0.1 and 1% water. This translates into roughly a liter per cubic meter. While this is less than the most arid regions on Earth, which have 1 to 5% water volume, it still means any settlement on the Moon will have a source of water that they don’t have to bring from Earth.

The importance of this can’t be overstated as in order to get one pound of material into low Earth orbit it takes 24 pounds of fuel, at the minimum. To get material from the Earth to the Moon takes even more. If a lunar settlement can get even a fraction of its water needs from the lunar soil, it can translate into tons of material that doesn’t have to be lifted out of Earth’s gravity well.

If we can find ice deposited by comets in the craters near the poles, where sunlight can’t reach it, this would be an even better source, but having a confirmed source of water on the Moon means that plans for a Lunar Settlement can proceed with plans of using native water letting it expand much quicker than if all the water the settlement needs had to be brought up from Earth.

This discovery could also mean that we can send humans to Mars cheaper than if there was no water source on the Moon. The biggest obstacle in sending a human crew to Mars is cosmic rays and solar radiation.

The ISS is inside Earths magnetic field which shields it from this radiation, the Apollo astronauts only spent 8 days outside of Earths magnetic field and were exposed to the same amount of radiation that a worker in an atomic energy plant receives in a year.

Any expedition to Mars will require astronauts to spend up to 6 months in space, each way. This adds up to a lifetime’s worth of exposure during the round trip.

One proposed solution is to have the astronauts travel inside a large water tank. The outside walls of the craft would hold a few feet of water that the crew could use on the journey. This would lower the exposure to radiation during the trip.

If they can get their original supply of water from the Moon this would lessen the amount of mass needed to be lifted off the Earth. Once on Mars they could refill these water tanks, which brings me to the next discovery announced this week. Water has been found on Mars.

We have known water ice was present on Mars since the first telescopes saw that Mars had icy poles. This discovery shows that water ice is present just below the surface much closer to the equator than was previously thought.

With this discovery a mission to Mars can count on having all the water they need for living on the planet and as a fuel for getting back home.

These two discoveries are showing we have all the resources we need to open up the inner solar system we only need to have the will to take advantage of them.

That will lead to a fantastic future.

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