How do lunar rovers work? -Pedro, 10

Dear Pedro,

When I got your question, I started to imagine what it would be like to drive a rover on the moon. As we bounced along craters, we could kick up moon dust and stop to gather samples of moon rock.

Rovers on the moon, and other kinds of exploration vehicles, have helped us learn about places that are hard for humans to reach on their own. Each rover has a mission and they need a few key things to work.

First, a rover vehicle needs a power source. Some rovers are battery-powered, like the lunar roving vehicle. Other rovers use solar panels to harness energy from the Sun. These solar panels are usually on top of the rover. The electricity they produce powers the wheels and the sensors the rover uses to conduct science experiments.

Scientists and engineers ask questions about what job they want a rover to do, and the environment where the rover will be working. The moon, for example, has no air. The tires we Earthlings have on our bikes and cars wouldn’t work on the moon. In fact, these kinds of tires would explode there. On lunar roving vehicles, tires are made up of a steel wire mesh. They support the rover’s weight, and astronauts don’t have to worry about getting a flat tire.

While lunar roving vehicles required astronauts to drive them, some rovers go on solo missions. Well, they aren’t totally alone. As they dig in the extraterrestrial soil and take pictures of these distant places, they communicate what they learn back to Earth.

Scientists send out computer commands that tell the rover what to do using super-powerful radio transmitters. The rover’s antenna helps send and receive the messages. It takes about a one second delay to command a rover on the moon and up to 22.5 minutes to communicate with one on Mars.

I decided to meet up with my friend Phil Engel to learn more about Mars rovers. He and a team of fellow student engineers from Washington State University recently brought back their award-winning rover from a global competition at the Mars Desert Research Station in Utah.

Their rover has an arm, or excavator, to dig for samples of dirt. The rover also uses sensors—like those you can buy to test your garden’s soil—to get the scoop on what’s in the dirt, including its temperature, humidity, and saltiness.

“What a rover vehicle does on Mars is pretty simple,” Engel said. “But what we are doing here on Earth with that rover is pretty extraordinary.”

While it might not sound exciting to look for dirt, these samples can tell us a lot about the planet or moon. The elements in these samples can help us find answers to some of our big questions about life on Mars—if there used to be life there, if there’s life now, or if life could be there in the future.

Whether on Mars, the moon, or even remote places on our own planet, rovers roam around to help us explore and discover. Who knows—maybe one day you’ll help find new ways to make them work and build rovers that are out of this world.

Sincerely,

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr.Universe@wsu.edu