Preparation is one of the chief watchwords for those in the field of engineering, so it came as somewhat of a surprise when Dr. Jeng Yen admitted he was completely caught off guard when he saw photos and a video that were recently snapped by his wife, Renee Wang.
“All right!” Yen is heard exclaiming, his right fist thrust upward as he surveyed what was unfolding via his laptop.
One can forgive both his temporary lapse of attention as well as that brief moment of exultation considering Yen was witnessing the successful landing of the Perseverance rover on the surface of Mars last Thursday. The seven-month, 300 million-mile journey successfully completed, Yen will now busy himself with the joyous task of remotely driving Perseverance, which is approximately the size of a standard automobile, as it conducts its mission to collect samples of rock and soil from the surface of Mars to detect possible signs of ancient life on the Red Planet.
It’s the San Marino resident and NASA employee’s third rover mission, previously having worked on the 2003 deployment of Spirit and Opportunity, and 2012’s Curiosity. Yen was quick to point out that he drove the latter while he was a member of the San Marino school board, on which he served from 2006 to ’14.
Yen will soon transition his lifestyle over to what he calls “Mars time,” after the sun sets (on Mars) until it appears above the horizon to announce the next “sol,” interplanetary vernacular for “day.”
“The rover can only operate during daylight hours on Mars,” Yen said. “During these hours we create the command sequences and evaluate what the rover did the previous day. We decide what we are going to do during the next sequence and send the next series of command sequences. When the rover goes to sleep, we go to work.”
During one of the team’s 10-hour shifts, two or three engineers are looking at the “downlink” to evaluate the previous days’ performance by the rover while a similar subset decides what to do next. In a single communication, NASA sends “a whole package of commands, thousands,” Yen said. “We cannot joystick the rover while it is on Mars.” An army of “hundreds of engineers constantly evaluate the data after it is received from and before it is beamed up to Perseverance.”
Yen’s vocation is “very specialized,” in his words, with only 20 or so qualified to do the job. Yen said that during the next few months several more specialists will receive on-the-job training.
A mission requiring such a collegial effort became even more challenging during the COVID-19 pandemic as tasks often completed through simple face-to-face conversations suddenly carried the burden of working remotely. Yen has remained mostly in his San Marino home, but recently returned on occasion to mission headquarters in La Cañada Flintridge, where he will gradually be more present.
“This was pretty tough for us,” said Yen, who carried out most of his preparation with his team via Webex virtual transmissions. “We had several months where we had to work on the hardware and the ground systems needed for the rover, and then all of a sudden everyone had to work from home. I think that is why you saw me jumping up and down when we landed. It was a very bittersweet year.”
The actual landing brought Yen particular joy considering the massive amount of preparation necessary to get the rover into space and the fragility of the spacecraft and propensity for disaster.
“Even though we have done this before, Mars can throw surprises at you left and right,” Yen said. “You can have difficult weather or high winds upon landing and at the last minute you might have to find a new place to land that had not been tested before. A small cable can break and if something is just a little off, you can have a disaster. The rover has an entry speed at the Mars atmosphere of 12,500 miles per hour. You are basically shooting a bullet into the Martian atmosphere and then slowing it down until it hovers over the surface of the planet and then safely lands. As an engineer, you have done all that you can do and then you have to have faith. That is why I jumped up and down.”
His two terms on the school board were just a sample of Yen’s commitment to public service. In 2003, he founded San Marino High School’s award-winning Titanium Robotics team and he regularly shows up at the annual “roll-out,” an event where the squad’s mostly completed robot is shown to the public for the first time. His influence has even gone “full circle” as they say, reaching at least virtually to the surface of Mars: Amanda Chung, a 2009 graduate of SMHS and former member of Titanium Robotics is now a member of Yen’s Perseverance team at NASA.
“It’s interesting,” Yen said, always the master of understatement.
Yen has a daughter, Adrea, a 2012 graduate of SMHS who in 2016 received a diploma from Washington University in St. Louis and works in the tech industry. An accomplished volleyball player at SMHS, she displayed remarkable jumping ability that rivaled her father’s interest in interplanetary space travel.