For alumni Chapin and Akgiray, forgetting leads to unforgettable success

ECE News

Tom Moone, ECE ILLINOIS
10/11/2012

Story Highlights

  • ECE alumni Elaine Chapin and Ahmed Akgirary were two engineers who helped design and build the radar system for Curiosity, the Mars Rover.
  • Their innovative radar system essentially forgot and then reacquired all pertinent information ever 50 milliseconds.
  • This design helped make the radar more robust and able to adjust to changing situations.

ECE alumni Elaine Chapin (left) and Ahmed Akgiray worked at NASA's Jet Propulsion Laboratory on a team that designed and built the radar system used for Curiosity, the Mars Rover.
ECE alumni Elaine Chapin (left) and Ahmed Akgiray worked at NASA's Jet Propulsion Laboratory on a team that designed and built the radar system used for Curiosity, the Mars Rover.

Throughout much of our growing up years, we have often heard people telling us how important it is not to forget anything. Don’t forget your keys. Don’t forget your homework. Forgetting was always something bad, something to be avoided.

In fact—not to name names—but you, too, may have had a grade school teacher famous for her favorite phrase: “Two words to failure: I forgot.” (Not that you’d still be scarred by those words decades later or anything.)

ECE alumni Elaine Chapin (MSEE ’92, PhD ’96) and Ahmed Akgiray (MSEE ’07) have helped to turn that phrasing upside down. Not only did forgetting not lead to failure, but in fact planned forgetting led to a truly spectacular, out-of-this-world success.

Working at NASA’s Jet Propulsion Lab (JPL), Chapin and Akgiray were two engineers who helped design and build the radar system that enabled Curiosity, the Mars Rover, to successfully land on the Red Planet.

Chapin, who was the integration and test lead on the project, explained that they had named their system Dory, in honor of the character from the film Finding Nemo. Part of the humor and charm of Dory in the film was her short-term memory loss, an inability to remember the recent past. The radar system designed by Chapin and her team acted similarly: “Every 50 milliseconds, the radar forgets everything about where it is,” explained Chapin. “It starts over and starts redoing its estimate. Every 50 milliseconds it says, ‘Oh look, there’s Mars!’ And then it sends to the spacecraft the information about the distance from the radar to the ground and how fast the relative velocity is between the ground and the radar.”

The radar system that Chapin and Akgiray worked on can be seen at the top white part of the circular portion of the image. The bottom portion of this image is the heat shield.
The radar system that Chapin and Akgiray worked on can be seen at the top white part of the circular portion of the image. The bottom portion of this image is the heat shield.

This system was a radically different design than had been typical in other radar systems.  “The other landing radars have always a system where they ‘lock,’” said Chapin. “They look once for the ground, and then once they find the ground, they only look for the ground in a very narrow range very close to what their last measurement was. The problem with that is that you can get funny things where, for example, if the heat shield is falling away, it thinks the heat shield is the ground, and it thinks the spacecraft is actually flying upward instead of falling downward.”

Often, the radar system would be the one system the people in the project were most worried about during entry, descent, and landing. In the case of the new system Chapin and Akgiray worked on, this was no longer the case.

They both worked on the system from 2007 to 2010, when it was turned over to the Assembly, Test, and Launch Operations group. Akgiray then moved on to work on a PhD at Caltech. Though Chapin had turned over the project, she was still involved as the next team did several tests with the system as well to make sure it would work as intended. Several times Chapin was called to answer some questions.

On August 5, 2012, the final test of the system was made when the Rover landed on Mars. It was, of course, a success.

And on that day, they had some intense emotions. Akgiray talked about his experience: “I was watching the landing on TV with my daughter. She’s five—and I’m not sure she appreciates all the details. She was disappointed there wasn’t live video of the landing. But nonetheless, seeing daddy jump up and down and hands waving all around—she was sort of surprised. This was a tremendous opportunity. I was instrumental in getting the most scientific advanced laboratory on Mars. And we were the only country to do that, and it was an incredible feeling to be part of all of this.”

Elaine Chapin will be giving a talk as part of the ECE Explorations series on October 31. She will discuss her work on the radar system for Curiosity.

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