One of the main reasons for exploring Mars is to hunt for life, past or present — especially microscopic life. But scientists want to make sure that if they find microbes on Mars, they’re actually Martian. So every Mars lander is kept especially clean to ensure it doesn’t carry any bugs from Earth.

Just how clean depends on where the lander is going. Any craft that’s aimed at regions where there might be water — the most likely places to find life — must be especially germ free.

Landers are assembled in cleanrooms, where dust, microbes, and other particles are filtered from the air. Workers wear special gear so they don’t sneeze on the craft or smear them with germy fingerprints.

Landers are sterilized as much as possible. Some parts are baked at high temperatures. Others are wiped with strong germ killers. And some are sealed tightly so any microbes are trapped inside. And the landers are routinely checked to make sure they stay clean.

Finally, the trip through space is likely to kill almost anything that hitches a ride. Even so, it’s possible that some microbes could survive.

Conditions on Mars are almost as harsh as those in space. Radiation, for example, probably has sterilized the top layer of the Martian dirt. So in recent years, some scientists have suggested making the rules less restrictive. For now, though, anyone planning a mission to Mars needs to stock up on cleaning supplies.

We’ll talk about one Mars mission tomorrow.

Script by Damond Benningfield

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