NASA just landed InSight, a robot geologist, on Mars

A major feat of interplanetary space travel took place on Monday. NASA’s InSight spacecraft landed on Mars to begin its two-year study of our neighboring planet’s core. It’s the first NASA Mars landing since the Curiosity rover touched down in 2012.

After a 300-million-mile journey, the lander touched down around 2:54 pm ET and took this picture of its landing site. (There’s a dust cover on the lens that’s covered in debris. But you can still make out the ground and horizon on Mars. Eventually, the dust cover will be removed and we’ll have clearer pictures from InSight.)

NASA/JPL

You can watch NASA’s live stream of mission control in the video below.

And here’s why the landing was so harrowing: Because the spacecraft is so far away, NASA’s mission scientists at the Jet Propulsion Laboratory in California, weren’t able to pilot InSight. Radio transitions to the lander are delayed by several minutes. And like the Curiosity rover, InSight had to land itself in only 6.5 minutes.

Now we just have to wait a few hours for confirmation that InSight’s solar panels have opened.

Landing a robot spacecraft on Mars isn’t easy

It’s a huge engineering feat to land on Mars, and not just because it’s millions of miles away.

The challenge: Red Planet has almost the same gravitational pull as Earth, but unlike Earth, it doesn’t have a thick atmosphere to help slow down spacecraft. InSight hit the Martian atmosphere traveling at 12,300 mph, and within 6.5 minutes, it had to slow down to 5 mph to land.

The landing occurred in a few stages that were all carefully programmed by NASA scientists. First, InSight detached from the “cruise stage” of the mission. This is the part of the craft that ferried it from Earth to Mars, and Insight needed to leave it behind in space.

Then Insight had to turn so its heat shield was pointed dead-on at the atmosphere, which started about 70 miles over the surface of the planet.

 NASA/JPL-Caltech

That heat shield protected it as it slowed down from 12,300 mph to 1,000 mph in just two minutes. Then, 10 miles above the surface, it jettisoned the heat shield and deployed a parachute. But the parachute wasn’t enough to slow the craft to landing speed.

This was the most harrowing part: InSight had to land itself, and it had to be ready for less than ideal conditions, like a dust storm.

About a mile above Mars, InSight let go of the parachute and turned on some thrusters. It had to quickly maneuver to not hit the jettisoned parachute.

Guided by radar, InSight used its thrusters to slow down to a soft landing. Upon landing, the thrusters had to turn off immediately. (If Insight tipped over on the surface, there would be no picking it back up.)

NASA/JPL-Caltech

InSight landed on a region of Mars called Elysium Planitia, a large, flat, plain on the equator. The site was chosen, in part, because InSight will be running on solar power, and it needed to be near the equator to get enough sunlight to stay powered for two years.

So what will InSight do there?

Now that InSight has landed, it’s staying put. It’s not a rover like Curiosity. And it doesn’t need to move because it’s not there to study the surface of Mars. InSight stands for “Interior Exploration using Seismic Investigations, Geodesy and Heat Transport,” and it’s there to study Mars’s core. It’s basically a robot geologist. Using extremely sensitive instruments, it will literally be able to feel the planet’s seismic activity and temperature, and record, for the first time, “Marsquakes.”

“Each Marsquake would be like a flashbulb that illuminates the structure of the planet’s interior,” NASA explains. “By studying how seismic waves pass through the different layers of the planet (the crust, mantle and core), scientists can deduce the depths of these layers and what they’re made of. In this way, seismology is like taking an X-ray of the interior of Mars.”

Insight will also be taking the temperature of Mars; the Heat Flow and Physical Properties Probe will hammer 16 feet down into the surface. The instrument will be able to determine how heat flows from Mars’s core to its surface, and help scientists understand if the cores of Earth and Mars formed in a similar way.

NASA/JPL

This is all important to study because scientists want to better understand how rocky planets like Mars, Earth, and Venus form. Underneath the surface of Earth is a molten-hot mantle upon which our landmasses (tectonic plates) float. Plate tectonics are responsible for much of the geologic activity on Earth, generating the energy for earthquakes and volcanoes. But Mars doesn’t have tectonics that are active like ours.

Scientists are curious why a rocky planet like Earth is so geologically dynamic, and why a rocky planet like Mars is so relatively still. Perhaps these insights will lead to a better understanding of why there’s life on Earth but not Mars.