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Looking for life on Mars - with high-tech lawn darts

bobmcdonald-190.jpgBy Bob McDonald, Quirks & Quarks

A non-profit group of scientists is proposing a bunker-busting approach to exploring Mars, by sending missiles to the red planet to penetrate the surface and look for life below.

The project, called EXOLANCE, would piggyback on an existing Mars mission and use something like high-tech lawn darts. These would be released from the spacecraft at very high altitude and penetrate a metre or so into the soil. Instruments within the darts designed to withstand the tremendous force of impact would look for evidence of life beneath the surface where many exobiologists believe Martian life could actually exist.

The multitude of robots that have landed on Mars since the 1970s have failed to come up with any conclusive evidence of life in the soil. The only probe to actually carry biological lab experiments on Martian soil was Viking in 1976

The results looked promising, but were inconclusive. Since then other landers, such as the Curiosity rover, have found interesting chemistry on Mars, but that's it. There is a big difference between chemistry and biology.

The surface of Mars is a very hostile place for life to exist. The Martian atmosphere is very thin, so temperatures range from very cold to extremely cold. There is no ozone layer to protect the surface from ultraviolet radiation from the sun and almost no magnetic field to shield from solar and cosmic radiation. Humans who travel to Mars will find themselves in a very hazardous environment and will have to be shielded from radiation, perhaps by living underground.

But that doesn't mean Mars is a dead world. There is strong evidence that a permafrost layer exists just below the surface and life could potentially thrive there, just as it does in ice layers on Earth. So the idea is to use EXOLANCE to look into that permafrost layer.

The darts will be released as the spacecraft enters the atmosphere and before the parachutes open so it will be at high altitude still traveling at high speed. This will give the darts the momentum they need to penetrate the crust. When a dart hits the surface, it splits in two. A hardened tip with the scientific instruments digs down while the tail section, still connected by a wire, remains on the surface to act as a transmitter that sends signals up to a spacecraft orbiting the red planet, which then relays the data to Earth.

This is a brute force approach to Mars exploration. The cost would be relatively low because there are no expensive propulsion or guidance systems involved. The arrows simply ride in a quiver tucked in alongside a spacecraft on its way to Mars. A large number of these dropped all over the planet would sample a much wider area than rovers can cover, explore a variety of different terrains and also provide redundancy if some of them don't survive.

If this technique works on Mars, then perhaps it could also work on some of the moons of Jupiter and Saturn that have oceans of liquid water beneath their icy crusts. Our search for life in the universe may have to focus on finding it inside worlds, not on them. Perhaps the Earth is unusual with its life crawling around on the surface.

The idea of basically shooting at Mars harkens back to the science fiction ideas of Martian invaders that arrive in flying saucers carrying terrible weapons. The aeroshells that protect the robots as they enter the atmosphere look a lot like flying saucers. This idea turns the table. In effect, we are the aliens from another world invading Mars and shooting at it. Let's hope that if we do find life hiding beneath the surface, it doesn't retaliate.