REDMOND, Wash. — NASA’s Mars InSight lander touched down on a heavenly Martian plain Monday, marking the first successful landing on the Red Planet in more than six years.

“Touchdown confirmed! InSight is on the surface of Mars,” mission commentator Christine Szalai declared just before noon PT at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Minutes later, the lander sent back its first image, showing a wide expanse of flat terrain as seen through a dirt-flecked lens cover.

The touchdown came after a nearly seven-month, 300 million-mile interplanetary cruise from Earth, capped by “seven minutes of terror” during which the InSight spacecraft had to slow down from an entry velocity of more than 12,000 mph. The craft’s heat shield helped the lander withstand temperatures as high as 2,700 degrees Fahrenheit. To slow down further, the lander had to pop off its aeroshell, deploy its parachute, and then activate its 12 descent thrusters.

Each step along the way was monitored nervously at JPL, with updates delayed by the eight-minute light travel time between Earth and Mars. Mission controllers erupted in joy when the crucial confirmatory signals were received via two nanosatellites that monitored the descent as they flew by.

Applause erupted as well at Aerojet Rocketdyne’s facility here in Redmond, birthplace of the thruster system that helped the three-legged lander set down on Elysium Planitia.

“That’s a long way to go for a ride, isn’t it?” Scott Kimbrel, Aerojet Redmond’s chief engineer for propulsion systems, said after touchdown.

Ken Young, general manager of Aerojet Rocketdyne’s Redmond facility, said the landing was “like Christmas Day for us.”

“This is our eighth landing on Mars, and every one of them has had our propulsion system,” Young told reporters.

NASA Administrator Jim Bridenstine said President Donald Trump and Vice President Mike Pence watched NASA’s coverage of the landing. “They are overwhelmingly proud of everything that has gone on today,” Bridenstine said during a post-landing news conference in Pasadena.

Pence, who chairs the White House’s National Space Council, passed along congratulations via Twitter. “Truly a monumental achievement!” he wrote. And Trump referred to the landing during a campaign rally in Mississippi. “We have reawakened NASA, and that’s a good thing,” he said, employing a bit of political hyperbole.

The first picture of the Martian surface was relayed back to Earth by one of the MarCO nanosatellites that accompanied InSight during its cruise to Mars. It showed a wide-angle view of the vista in front of the landing site, and drew a fresh round of cheers in Pasadena when it was put up on the screens at JPL’s Mission Control.

Bits of debris from the landing obscured the view. “It’s nice and dirty,” the InSight mission’s principal investigator, Bruce Banerdt, told reporters at the news conference. Despite the dirt, a piece of Martian rock, the lander’s footpad and the bolts holding a dust cover over the lens could be seen in the frame. Pictures from that camera were expected to be clearer once the dust settled and the lens cover was removed.

Hours later, JPL reported that InSight’s solar arrays had successfully deployed, and that its batteries were charging as expected. The InSight team also passed along another picture, taken by a different camera that’s mounted on the lander’s robotic arm. The view is clearer, and shows the deck of the lander as well as Elysium Planitia in the background:

Data from Odyssey indicate @NASAInSight’s solar arrays are open and batteries are charging. The transmission also included this view from the instrument deployment camera, showing the seismometer (left), grapple (center) and robotic arm (right): https://t.co/yZqPextm89 pic.twitter.com/2kBHT5caGS — NASA JPL (@NASAJPL) November 27, 2018

Elysium Planitia’s name comes from the Latin words for “Heavenly Plain.” On the surface, InSight’s landing site looks far less spectacular than the rocky, hilly region where NASA’s Curiosity rover touched down in 2012. But that plainness is no handicap for InSight. This two-year mission, which is costing a little less than $1 billion, focuses on Mars’ interior rather than on its surface features.

The mission’s name is an acronym standing for “INterior Exploration Using Seismic Investigations, Geodesy and Heat Transport.” The lander’s instruments are designed to provide unprecedented data about the Red Planet’s inner structure, seismic activity and heat flow from the interior.

A radio science instrument will receive signals from Earth and send them back again, producing fluctuations that scientists can use to track the position of the lander precisely in space. Close analysis of the readings can tell scientists how big Mars’ core is, and what it’s made out of.

Such findings are crucial to understanding Mars’ history: Scientists believe that Mars once had an environment more like Earth’s, but lost most of its atmosphere and water due to a complex process that involved the rapid cooldown of its core.

InSight’s robotic arm will set down another instrument, known as the Seismic Experiment for Interior Structure, or SEIS. It’s a seismometer that can detect tremors as tiny as half the radius of a hydrogen atom.

SEIS is so delicate that it has to be contained in a vacuum chamber and shielded from Mars’ whisper-thin winds. Back in 2015, problems with the vacuum seal forced NASA to postpone InSight’s launch from 2016 to this year. But that delay’s nothing compared to how long JPL’s Sue Smrekar, deputy principal investigator for the InSight mission, has been looking forward to getting the seismic data.

“I personally have been waiting for this information for decades,” she said.

The readings should reveal what kinds of seismic activity take place on Mars, how often earthquakes occur, and even how often and how forcefully meteors hit Mars. That kind of information could be useful to future Mars explorers.

The third instrument is the Heat Flow and Physical Properties Probe or HP3 (“HP-cubed”), which is designed to take Mars’ internal temperature. HP3 is a “mole” that hammers its way down as far as 15 feet beneath the surface to see how heat is transferred from Mars’ depths to the surface. That’s an important question, because if there’s any life left on Mars, it’s likely to lurk beneath the surface where there’s a better chance of having access to warmth and liquid water.

Hoffman said InSight’s findings should shed new light on the processes that formed Earth as well as Mars.

“We can basically use Mars as a time machine to go back and look at what the Earth must have looked like a few tens of millions of years after it formed,” Banerdt said. “By doing that, we can then look at our physical models, our theories of how the Earth evolved, and understand why the Earth became the way it is.”

Once the instruments are deployed, NASA will be delivering regular snapshots of Mars as well as an unprecedented bonanza of data.

“I can’t wait to start seeing Marsquakes, start getting temperature flux data coming out of our HP3,” InSight project manager Tom Hoffman said. “That’s going to be truly amazing.”

Just don’t expect two-day delivery, even though the big event took place on Cyber Monday. Elizabeth Barrett, instrument operations lead at JPL, said it’ll be two or three months before all the instruments are set down on the ground, plus a couple of additional months for data collection to get into full swing.

This report incorporates material from previous articles about the Mars InSight mission.