Watch NASA's Next Mars Lander Spread Its Wings Preparing for May Launch

NASA is busy running its last tests on the next robot to report for work on the Red Planet, the Mars InSight lander, due to launch in May. On Tuesday, the lander aced perhaps the coolest test to watch: unfurling the wing-like solar panels that will be stashed inside the rocket at launch.

With the tests successfully completed, the panels have been folded back up, and they will remain stored until InSight lands and sets up shop on Mars.

01_24_mars_insight_solar Testing the solar panel arrays on the Mars InSight lander to make sure they open properly on arrival. NASA/JPL-Caltech/Lockheed Martin

On Mars, those panels fuel the robot and its science. They'll have to make due with less than half the sunlight that they would receive here on Earth. Light on the Red Planet has also been bounced around by the planet's atmosphere and is sometimes blocked by giant dust storms that can last for weeks on end.

The panels will power a host of scientific tools—not just cameras, but also a probe that can measure the temperature of the planet's interior and a seismometer that will feel for so-called marsquakes, tiny tremors that could reveal the structure of the planet.

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With those instruments, Mars InSight will run a range of tests designed to help scientists understand what's happening deep within the planet. Other Mars missions, like the Curiosity rover, have just barely started that exploration. The data Mars InSight collects should tell scientists how the planet formed and how active it is today.

"Think of InSight as Mars' first health checkup in more than 4.5 billion years," Bruce Banerdt, the mission's principal investigator, said in a press release. "We'll study its pulse by 'listening' for marsquakes with a seismometer. We'll take its temperature with a heat probe. And we'll check its reflexes with a radio experiment."

Those experiments will last at least two years here on Earth, the equivalent of one Martian year. It was originally due to launch in 2016, but was delayed after a failure was detected in the seismometer instrument.

Mars InSight has just 100 days before its launch window opens on May 5. Before then, it still needs to make its way to California, home of the air force base it will launch from. Then it will take six months to reach Mars before it again unfurls its solar panels and gets to work.