‘Touchdown confirmed’ for Mars mission

LA CANADA FLINTRIDGE, Calif. — After traveling 300 million miles through the solar system, NASA’s InSight spacecraft descended through the Martian sky Monday and touched down safely on the smooth surface of Elysium Planitia shortly before noon.

The news elicited cheers, high-fives and fist-bumps from the scientists and engineers assembled at the Jet Propulsion Laboratory in La Canada Flintridge. It means that the two-year mission to study the inside of Mars — formally called Interior Exploration using Seismic Investigations, Geodesy and Heat Transport — is a go.

“Touchdown confirmed,” mission commentator Christine Szalai announced at 11:54 a.m.

InSight launched from California’s Vandenberg Air Force Base in May and, after an uneventful seven-month cruise, closed in on Mars over Thanksgiving weekend. That meant engineers spent their holiday finessing the spacecraft’s final approach.

They checked and double-checked InSight’s trajectory, aiming it toward a 6-by-15-mile keyhole in the Martian atmosphere that would guide the vehicle toward a carefully chosen landing spot on the ruddy surface. On Sunday afternoon, they gave the spacecraft one final nudge.

Weather forecasts from NASA’s Mars Reconnaissance Orbiter showed that the outlook was sunny with a low chance of dust storms, so engineers skipped their last chance to tweak InSight’s landing procedure Monday morning. The pieces were in place; there was nothing more for Earthlings to do.

At 11:39 a.m., InSight screamed into the Martian atmosphere and, as expected, lost communication with Earth. A focused quiet fell over the rows of engineers in mission control at JPL, as everyone waited for signals confirming that InSight had made it through a series of crucial steps. Some hunched close to their computer screens, others glanced around for updates.

In this room, engineers have seen the delicate dance of entry, descent and landing go flawlessly — and fatally — on previous missions.

Unlike on previous missions, however, the InSight team had the benefit of two experimental satellites that tracked InSight’s progress. The Mars Cube One satellites, known as MarCOs, locked onto the spacecraft before it entered the Martian atmosphere and continuously relayed information back to mission control.

The signals were delayed by the eight minutes it took for radio waves to travel from Mars, meaning InSight’s fate had already been sealed by the time anyone at JPL heard about it. Still, the team members — all clad in burgundy shirts emblazoned with the InSight logo — watched with rapt attention.

First, radio telescopes in West Virginia and Germany registered a slight change in the frequency of InSight’s signal, indicating that its parachute had inflated and the craft had slowed down. A round of applause rippled through mission control; one engineer flashed a thumbs up.

Seconds later, InSight discarded its heat shield and deployed its legs. Then it informed the MarCOs that its radar found the ground, again prompting restrained clapping in mission control. Two engineers turned to each other and high-fived.

“This is really good news,” said Rob Manning, JPL’s chief engineer.

After it shed its back shell and chute, InSight fired its retrorockets. Szalai kept announcing its altitude as the craft floated down to the surface: 400 meters above Mars, 300 meters, 200 meters.

The tension grew as the numbers fell. “The hairs on the back of my neck would start rising a little bit higher and a little bit higher,” said project manager Tom Hoffman.