Before it hits the Martian dirt, the latest rover is kept very, very clean

After a two-year delay, NASA engineers are putting the final touches on the next Mars rover. The six-wheeled vehicle, dubbed Curiosity, cost rough $2.5 billion and will launch later this year. In the meantime, the rover is kept very, very clean.

“Oh we’re cleaning all the time," says Sarah Marshall. "Cleaning, picking up and mopping.”

Marshall is in charge of keeping the Mars rover facilities spic and span. It’s not because the scientists are hypochondriacs. It’s because even the smallest bacteria can travel with the rover to Mars.

“We don’t want to introduce any particles on Mars that are coming from Earth," Marshall explains. "We want to have it as pure as we can so when we go up there we know we are looking at real Mars molecules.”

Otherwise, she says, scientists could think they discovered Martian life, when in reality it was just a germ that hitchhiked from Earth.

The rover is kept in what’s known as a clean room, a closed off area with filtered air and sterile surfaces. Marshall says scientists can’t even bring in a regular pad of paper since it sheds small fibers.

“We’re not messing around.”

Marshall makes all visitors put on what she calls a "bunny suit," a full body outfit that covers everything but the eyes. Marshall says even that much skin can be a problem though since she sometimes finds eyelashes on the equipment.

After the suit is on, visitors enter the air-shower. It blasts people with air to blow away any loose particles.

Once inside the clean room the rover is clearly visible. It's roped off but scientists like Matt Horner are allowed to go near it. He's helping to build the machine but even he has never actually touched it with his own skin.

The Curiosity rover is bigger than the last two Martian rovers, Spirit and Opportunity. It’s about the size of a Jeep. It has six aluminum wheels and it’s covered in wires and antennas. It literally weighs a ton. On Mars though, it will weigh about a third of that.

“It really is a mobile science lab," says NASA engineer Matt Horner. "It has instruments throughout that can do science and report back to earth.”

The rover’s main goal is to find out what Mars is made of. It has a robotic arm with a drill on it that can dig into rocks. It has a mineral and chemical lab inside it that can analyze samples and beam the results back to earth.

On the rover’s top side is a device that looks like a movie projector on a pole. It’s called the chem cam – but it’s better described as a rock-vaporizing laser.

“We can actually point at the rock from about 30 feet away, shoot a laser and it produces actually quite a small spark and vaporizes just a little bit on the surface on the rock," Horner explains.

He says that using the laser, scientists can determine the mineral composition of a rock from a distance.

All this science will be powered by a small nuclear generator. The rover’s mission is planned for two years, but engineers estimate that given the generator’s lifespan, the rover could keep running for over a decade.

Project manager Pete Theisinger says that’s plenty of time for the rover to answer some important questions.

“If we discovered preserved organics, hydrocarbons on Mars, that would be the home run,” Theisinger says.

Hydrocarbons are the building blocks of life. Theisinger says, if the rover detects those there's a good chance there was once life on Mars and could be again.

He says another key mission of the rover is to help scientists figure out the past of this mysterious plant.

“Mars was warmer and wetter in the past," he says. "It’s very cold and dry now. What happened? The water was forced to go under ground and freeze. Maybe some of it was lost to space. Why did all that happen, what were the things that caused all that to happen?”

Theisinger says our own planet has gone though major changes in the past – and with growing concern over potential climate change, he says there is a lot our blue planet can learn from the red planet.

“This idea that things change slowly may not be right. You may get to a tipping point and discover that things change rapidly. So those are all good questions to ask with respect to our own little blue ball, the place we live.”

These are the deep questions Theisinger hopes the Curiosity rover will answer once it gets its wheels in the Martian dirt. For now though, it waits, clean as a whistle, for launch day.