Updated 10:10 p.m. Eastern with solar array deployment.

PASADENA, Calif. — NASA’s InSight spacecraft successfully landed on Mars Nov. 26, completing a journey of nearly 500 million kilometers and starting a mission to study the planet’s interior.

The Lockheed Martin-built spacecraft touched down on Elysium Planitia near the Martian equator at 2:52:59 p.m. Eastern. Telemetry from the lander, relayed by a pair of cubesats called Mars Cube One (MarCO) passing by the planet, confirmed that the lander had made it safely to the surface. It transmitted an X-band “beep” seven minutes after touchdown, as planned, confirming it was operating. NASA announced about seven hours after landing that InSight had deployed its two solar arrays.

“We got very close to the bullseye” in terms of the landing site location, said Tom Hoffman, InSight project manager at the Jet Propulsion Laboratory, during a press conference a little more than two hours after landing, but noted he didn’t have the precise location yet of where the spacecraft touched down.

The landing site features level terrain with very few rocks, the topography sought by project scientists in order to most effectively be able to deploy the spacecraft’s main instruments. “We’re at less than two degrees of tilt,” said Bruce Banerdt, principal investigator for InSight at JPL. “It makes our job very easy to do. It’s time to get going.”

With the landing, InSight will begin a prime mission scheduled to last two years to study the composition and structure of the planet’s interior. The spacecraft is equipped with two instruments, a seismometer and a heat flow probe, to carry out those measurements.

However, it will be several months before InSight starts collecting data from those instruments because of the time required to identify the best locations around the lander to place the instruments, and then to install them in those locations.

“Once we get to the surface, InSight is a slow-motion mission,” Banerdt said at a briefing Nov. 25. “We take our time getting our instruments down. It’ll probably take at least two, probably more like three months, maybe even longer to get our instruments down. It’s going to us take a month or so to get them all calibrated.”

He said it would take nearly the full primary mission to get answers, depending on how many “marsquakes” the seismometer is able to measure. “The more marsquakes, the better,” he said. “The more shaking it does, the better we can see the inside.”

Problems with the seismometer, provided by the French space agency CNES, caused InSight to miss its original launch window in March 2016. The instrument was redesigned and completed in time to allow InSight to lift off on an Atlas 5 from Vandenberg Air Force Base in California May 5.

InSight has an unusual degree of reliance on international partners for a NASA science mission. In addition to the seismometer, the heat flow probe was provided by the German space agency DLR. Those international contributions accounted for about $180 million of the mission’s overall cost, including launch and operations, of nearly $1 billion.

“It is unique in terms of just how much is being done elsewhere,” said Thomas Zurbuchen, NASA associate administrator for science, Nov. 25. “We believe in the United States that leadership and collaboration are not contradicting values.”

NASA Administrator Jim Bridenstine noted at the press conference that he spoke on the phone after the landing with both President Donald Trump and Vice President Mike Pence. “They are overwhelmingly proud of everything that has gone on here today,” he said. “What an amazing day, and they are so grateful for all of the hard work of everybody in this room.”

Hoffman thanked the mission team for their work leading up to the landing, which for many involved missing the Thanksgiving holiday last week as InSight neared Mars. “Today, it was all worth it.”

For Banerdt, the mission is an opportunity to realize a long-held dream of measuring seismic activity on Mars. Prior to the landing, he recalled being at JPL, as a graduate student, for the landings of the NASA’s twin Viking spacecraft in 1976. Those landers also carried seismometers, but didn’t provide useful data.

He “got the mission bug” in the late 1980s to do a Mars mission to measure seismic activity there. “I’ve really been working pretty steadily for 25 to 30 years on this,” he said prior to the landing. “I’m a patient person, as well as persistent.”

At the post-landing press conference, Banerdt recalled the thrill of seeing the first images from Viking more than 40 years ago and compared it to the first images transmitted by InSight shortly after landing. “Now, I’m looking at this first image from InSight, and it’s like a full circle, a whole career of working towards understanding Mars better.”