‘Terror,’ ‘thrill’ of landing on Mars
Rover workers dedicate years for this moment
On Thursday, NASA’s newest rover Perseverance will attempt to land on Mars.
The nail-biting descent from orbit to the ground is known as the “seven minutes of terror” because so many things have to go right to pull it off.
During that seven minutes, hundreds of engineers at Jet Propulsion Laboratory who have worked on the mission will be standing by to see if nearly a decade of work pays off.
Al Chen, a Mars landing veteran, has been thinking about what he’ll say to the team to calm any game-day nerves.
But what do you say to a group that has worked thousands of hours over almost a decade to achieve one goal?
“I want to tell everyone that we deserve victory,” said Chen, the lead of the Entry, Descent and Landing team at NASA’s Jet Propulsion Laboratory in California. “We’ve done everything we can to make ourselves have a good seven minutes to make sure we get to the ground. Even if it doesn’t happen. If Mars snatches it away or if something goes wrong, we should be able to rest easy because we’ve done everything we can.”
To land safely on the red planet, Perseverance must survive thousands of degrees of heat created during entry.
It must rapidly decelerate from 12,000 mph to 2 mph in seven minutes aided by a supersonic parachute inflating in less than a second under tremendous forces. And finally, it must land in a safe spot among steep cliffs, sand dunes and large boulders.
“There’s a thrill of trying to do something that’s only been done a handful of times and it’s hard every time,” Chen said.
Seriously hard. NASA first attempted to touch down on Mars in 1970 but that spacecraft crashed during a massive dust storm.
In the last 50 years, only eight landings have been successful.
At JPL’s mission support center, engineers will be nervously waiting for the first signal from Perseverance transmitting that it has touched down.
It’s a moment that Swati Mohan has been working toward for the last eight years.
“I’ve been on Perseverance longer than I’ve been at any school. I’ve been on Perseverance longer than my younger daughter is alive. It’s just taken up such a large portion of my life for so long.”
Mohan is the guidance, navigation and controls operations lead and says the last few years preparing for this day have been grueling.
“The last three to four years especially, then the pandemic on top of it has kind of added another layer of stress.”
Mohan says working from home due to COVID- 19 has made communicating clearly a critical component for their success.
“The saving grace for our team is that we’ve had so many working with each other for six to eight years so there is that level of familiarity of being able to pick up on inflections, voices, body language even over Zoom of what’s critical or not,” she explained.
In fact, Chen describes the team’s closeness as a family.
“We have a text group chat going and the day somebody renamed that chat group ‘EDL family’ was maybe my favorite day on this project,” Chen said using NASA’s acronym Entry, Descent and Landing.
“It’s one thing to work together on these grand engineering challenges and deal with technical engineering issues. It’s another thing to do it with people you really care about. And when you can do both at the same time, I feel very fortunate.”
Chen cut his teeth working on the Curiosity rover landing over 10 years and was the operations lead for the entry descent and landing system when it landed in 2012.
Over 3.5 million people viewed the landing online, and the video of the JPL team celebrating their success went viral.
Chen can be seen in the front row as he announced the spacecraft’s mission milestones, including the moment of truth.
“Touchdown confirmed. We’re safe on Mars,” Chen said, barely audible under the roar of cheering.
Looking back, Chen says he’s grateful that doing the commentary kept him busy during the most stressful part of the landing.
“It gave me something to think about as opposed to just worry.”
This time, that job will go to Mohan. “Al has been a tremendous resource because I didn’t work Curiosity landing,” Mohan said. “So bringing that knowledge has been incredibly helpful.”
“I told her that although she’s written things down that she expects to say, just think and react. You know what’s going on, you know the system very well. There’s no reason to look at your notes at that point. Just trust yourself,” Chen said.
Both will report to work at 5:30 a.m. the day of the landing and jump right into their duties.
“There’s very little that can go wrong and you’ll still make it. There’s no partial credit on this test,” Chen said.
About an hour before landing, the team will make a pivotal decision to turn off the transmitter, leaving Perseverance on its own.
“At some point, we stop trying to talk to the vehicle and say you know ‘that’s it. We’re done communicating with you, good luck, we’ll see you on the ground.’ So there is a moment of letting go. It’s hard to do after this long,” Chen explained.
If all goes well, Perseverance will touch down on Mars about an hour later.
“The mind-bending part is that entry, descent and landing takes about seven minutes and the radio waves take 111⁄2 minutes to get from Mars to Earth, so by the time that we find out Perseverance has hit the top of atmosphere, it’s been on the ground for a few minutes already, one way or the other.”
The moment will be exhilarating but also bittersweet because it will signal the end of their time on the project and with the team.
Mohan compares the feeling to knowing a favorite TV show series is coming to an end.
“It’s sort of like that where you’ve been working on something day in and day out for seven to eight years and now you’re coming up on the series finale and for better or worse after that day it’s done and you’re not going to be working on it anymore after landing day regardless of what the outcome is.”
For his second Mars landing, Chen plans to savor the moment more than the first time.
“At the time eight years ago, I don’t think I appreciated it. I’ve got a greater perspective on what that journey is like and having done it again, how much joy it brings you in doing it even though it’s hard and there are sleepless nights and long hours, but in the end no matter how it goes, I’ll treasure the time that I had together with my team.”