Bruce Banerdt has the job he’s been dreaming of since he was a child growing up in the California desert, watching Neil Armstrong’s “giant leap for mankind” on TV. “I always wanted to go to space,” he says.
Not that Banerdt is an astronaut. He’s principal investigator for a Mars mission. Astronauts, he realised growing up, spend a lot of time running other people’s experiments. Banerdt wanted to go to space, but he also wanted to run experiments he himself helped concoct, even if that meant managing them robotically from Earth. “I got to feeling that would be one of the best ways of going to space,” he says.
So, he majored in physics, then got a PhD in geophysics. In the process, he landed the job that put him on track to his dream: an internship at NASA’s Jet Propulsion Laboratory in Pasadena, California.
That was 1976. The internship turned into a part-time job, which in turn became full-time after he completed his PhD at the neighbouring University of Southern California.
He’s been there ever since. “I only ever did one job interview in my life,” he says with a laugh.
Along the way, he developed an interest in using remote sensing methods such as seismology and variations in gravitational and magnetic fields to peer into the cores of terrestrial-type worlds, including Venus, Mercury and the Moon. “But Mars has always been my favourite,” he says.
Mars is where he’s working right now, via NASA’s InSight Mars Lander.
InSight was conceived as a billion-dollar project to put a seismometer on the surface of Mars in the hope of using the Red Planet’s occasional marsquakes to probe its interior. Launched in 2018, it’s now been there for more than 1,000 sols (Mars days, slightly longer than Earth’s) and recently detected its three largest marsquakes, ranging from magnitude 4.1 to 4.2. By earthly standards, those aren’t huge, but they are big enough to make Banerdt very happy, because the bigger the quake, the easier it is to study how its seismic waves were altered as they bounced around the Martian interior en route to InSight’s seismometer.
Furthermore, the detection of these quakes probably wouldn’t have occurred had he and his team not made a daring decision.
InSight’s solar panels had been getting dusty, and no handy dust devils had come along to scrub them clean, as had happened repeatedly for the solar-powered Spirit and Opportunity rovers. With power down by nearly 80%, it was a mounting crisis in which Banerdt says the most likely outcome would have been having to shut down the seismometer.
Instead, the team made the bold call to use the lander’s robotic arm to sprinkle sand on the upwind edges of the solar panels and let the wind use it as a whiskbroom to brush away enough dust to keep the lander functional. The idea, Banerdt admits, sounded so preposterous that when it was first suggested it was pretty much laughed out of the room. “The last thing you want to do is put more dirt on the panels when they’re getting dirty,” he says.
But it worked – and as principal investigator, it was Banerdt who made the final call.
The title “principal investigator” makes it sound like Banerdt’s job is primarily science: investigating, researching, writing journal articles. And while principal investigators do get their names on journal articles, traditional science isn’t actually the job. “My [traditional] science career kind of ended when I became a principal investigator,” he says.
Banerdt’s role is more like a CEO. “The job definition is being responsible to NASA for the overall success of the mission,” he says.
How to do this is up to the individual principal investigator, he adds. Some prefer to direct from the metaphorical equivalent of 30,000 feet, delegating many of the details to the engineering team. Others are more proactive, working with the engineering team to make sure that decisions made early in developing the mission don’t accidentally interfere with the scientific goals.
“I’ve been very hands-on,” he says. “To me, the secret is you need to know a little about everything. There are a lot of people who make great decisions in their own field. But you have to have someone in the middle who knows the trade-offs – someone who understands the science, who knows the engineering, who knows the politics. To me, that’s the secret of being a principal investigator: being able to balance the expert decisions and come up with the best decision overall.”
It’s also a major time commitment. NASA generates some missions on its own, but for the majority of them, it has a lengthy process in which prospective principal investigators compete to convince the agency that their projects are the ones NASA should fund.
“I first got involved in looking at building a seismometer to go to Mars in the late 1980s,” Banerdt says.
At first, it was merely a sideline interest, but as time passed, he found himself more and more involved, making presentations at scientific meetings, meeting with people at lunches, and talking with colleagues about the science such a mission would gather, and how important it was.
“The first thing a principal investigator has to do is sell the mission,” he says. “For basically two decades, I was in sales mode.”
In interviews, Banerdt appears to have the gift of gab. He has the rare ability to talk not just in complete sentences but complete paragraphs. But, he says, that wasn’t a skill he was born with.
“I’m not a natural schmoozer,” he says. “I’m a very shy person by nature.” Left to his own devices, he says he’d have locked himself in his office and written “massive amounts of code that would simulate the physics of planets”.
When the mission was approved, the job turned to oversight and administration, including sifting out priorities in order to fit the budget. “If you had an unlimited pot of money,” he says, “you could solve all your problems.” But in the real world, “you have to pick and choose – where you’re going to take risks, and where you’re not going to take risks. That’s a lot of what I end up doing. ‘This is a problem we’ll spend time and money solving; this other we’ll spend less on.’ I get lots of advice, but I’m the one that has to make the decisions.”
But with that came the ultimate reward, when as principal investigator he got to be in the control room at launch and, at the right moment, give his go-ahead.
“I got to say, ‘The principal investigator is go for launch.’ That’s an incredible experience for a kid who grew up in a little town in the middle of the desert, dreaming of space.”