“Touchdown confirmed,” said Allen Chen ’00, SM ’02, to an eruption of cheers, high fives, hugs, and joyful tears in the Mars Science Laboratory (MSL) cruise mission control room at the Jet Propulsion Laboratory in Pasadena, California, in early August.
The crowd at mission control was celebrating the success of a never-before-tried landing sequence that had engineers, mission managers, and VIPs—not to mention viewers worldwide—on the edge of their seats.
Chen, one of the many MIT alumni who worked on the project, was the entry, descent, and landing operations lead for the MSL Curiosity rover and monitored telemetry through what the team called the “seven minutes of terror.”
Lead flight director David Oh ’91, SM ’93, ScD ’97, calls that night “the best reality TV ever.”
“This kind of business requires a million things to go right,” says Fuk Li ’75, PhD ’79, director of the Mars program that includes MSL.
The entry sequence had to brake a craft speeding into the Martian atmosphere at 13,000 miles per hour, pop the chute, lose the heat shield, fire the rover and its sky crane out of a protective shell, and deploy the crane to lower the six-wheeled robot on cables to a soft landing. And then the sky crane had to cut the cables and jet away to a safe distance so as not to crush the $2.5 billion national asset just deposited on the surface. On top of that, the orbiting Odyssey satellite had to be in proper orientation to deliver the news—good or bad—in close to real time (a 15-minute delay was as near as it could get).
Everything worked perfectly. For the engineers, who’d practiced landing often (and always with simulated faults and bad telemetry), the smooth landing was what made it most surreal.
The miniature geology laboratory, safely on Mars, soon began wheeling toward Mount Sharp, investigating rocks and soil along the way for signs that Mars could once have been habitable.
“It’s a big, mean exploring machine,” says Noah Warner ’01, SM ’03, PhD ’07, a member of the Curiosity team. “It’s a beast.” Tall enough to drive over rocks one meter high, it’s the biggest thing ever landed robotically and the first Mars rover equipped to drill. It also features the ChemCam laser, which vaporizes parts of rocks to measure their chemical composition, and that’s one more MIT connection: the lead ChemCam engineer is chemist Lauren DeFlores, PhD ’08.
The idea of the sky crane—with Allen Chen’s name on the patent—was born in a brainstorming session that went something like this: We can’t use airbags (as the smaller twin rovers Spirit and Opportunity did in 2004), because the one-ton rover is too heavy. If we land the rover on a platform (to protect the legs), we need a way to get it onto the ground. That means it will have to roll down a ramp, but what if the rover lands on a tall rock, or on a hill, and the whole assembly is tilted? Then we’d need ramps of different lengths. Well, why don’t we just land it on its wheels? How do we do that? Dangle it from above … Eureka!
Li says one of the best parts of his job as program director was convincing NASA headquarters that the sky crane “wasn’t just crazy; it was crazy good.”
The MIT Aero-Astro Crowd
Chen and many other MIT Aero-Astro graduates attribute their success to the department’s focus on systems engineering, the result of a late-1990s department redesign that brought the “conceive, design, implement, and operate” (CDIO) cycle to the forefront. Chen was in the first class of the hands-on program.
“In aerospace, you really can’t think of all these different engineering disciplines in isolation, because you end up with something that’s too heavy or too bulky to fly,” says Aero-Astro professor David Miller ’82, SM ’85, ScD ’88.
As part of the Aero-Astro redesign, a unifying first-year class for undergraduate Course XVI majors covers fundamental disciplines in aerospace engineering that are normally taught in separate courses—including topics such as aerodynamics, structures, and systems and signals—to show how they are related and to inspire more efficient designs. Senior-year project classes give students design and building experience, plus the critical collaboration skills necessary to excel on real-world engineering teams.
That approach encourages the flexibility engineers need at JPL, where they tend to flow from job to job as different stages of the mission require. Erisa Hines, SM ’05, worked on Curiosity’s course corrections and attitude turns during its 352-million-mile flight to Mars; now she’s working on surface mobility for the rover as it becomes more autonomous. During development, Beth Dewell ’02 worked with the thermal group to figure out where to place more than 20 small heaters to keep the rover’s external parts warm, served as a lead systems engineer for launch, transitioned to backing up the rover’s main computer during flight, and then joined the team sequencing activities for Curiosity’s first five sols, or Martian days, after landing.
The JPL-MIT Connection
Warner, who plans and uplinks the rover’s current daily activities, says NASA’s “very focused goals” make a perfect fit for MIT people, who are “really inspired by technical challenges: things that have not been done before, or trying to find new ways to solve very difficult and important problems.”
That helps at JPL, where problems are often abstract and unconstrained, says Jennifer Trosper ’90, Curiosity’s mission manager. At MIT—as at JPL—”you aren’t babied,” Trosper says. “They throw some huge—what you believe to be impossible—problem at you and say, ’Due by Friday.’”
But walking through the halls at MIT, “you get the sense that nothing is impossible,” says Bryn Oh ’95, who met her husband, flight director David Oh, in the MIT Chamber Music Society. They and their three children found themselves in the media spotlight as the Mars-time family—they shifted their schedule to approximate Martian time for the month of August so Bryn and the kids could share the experience. Although a sol is only 40 minutes longer than an Earth day, the Ohs had to time-shift by a full hour each day to be back on Earth time by the start of school in September.
Curiosity’s mission—and the personalities behind it—have attracted much public interest and support. Bobak Ferdowsi, SM ’03, the flight director whose patriotic haircut (a red-and-blue Mohawk with white stars bleached in) brought him instant Internet fame and multiple marriage proposals via Twitter on landing night, says that “sharing the experience with somebody” is part of the excitement of the “high-risk, high-reward” project.
Social media and ubiquitous computer use—plus Google hangouts, Spreecasts, and Reddit’s Ask Me Anything—have allowed greater-than-ever public access to the mission. “It’s like the public is coming along for the ride with us—like they’re a part of the mission,” Warner says. And that’s the goal, he adds: “This rover is everyone’s.”