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Center Snapshot: Chris Kuhl
Chris Kuhl.

Image Above: Chris Kuhl from NASA's Langley Research Center is the chief engineer for MEDLI (Mars Science Laboratory Entry Descent and Landing Instrumentation). Credit: NASA/Sean Smith

By: Denise Lineberry

Chris Kuhl had to remind himself to blink as he closely watched a screen showing MEDLI (Mars Science Laboratory Entry Descent and Landing Instrumentation) data, and monitored tones outside of the "war room" at NASA’s Jet Propulsion Laboratory.

Starting five hours before Curiosity entered Mars' atmosphere, all the way through heatshield jettison, Kuhl, chief engineer for MEDLI, communicated data through his headset to the EDL team inside the "war room."

His nervousness was replaced with pride when he looked up and saw a photo of Curiosity's wheel on the surface on the Mars. And now, he's getting used to life without MEDLI.

"It's kind of bittersweet -- you put so much time and work into it, and it’s done its job and it’s done it well," Kuhl said. "Now you just wish you could get it back because everything is so well built."

The heat shield that houses the MEDLI instrumentation suite fell to Mars' surface after the separation phase of entry. Kuhl believes that the heat shield lies face-up on the surface, but another image from the Mars Reconnaissance Orbiter (MRO) should be able to confirm that.

For the past seven years, Kuhl has watched MEDLI grow from concept to reality as he traveled across the country, hand-carrying pieces of the instrumentation suite in a pelican case. From development to qualification, from integration to installation, he was there every step of the way.

MEDLI was led by Langley where the majority of design, assembly, and testing was conducted. It consists of 14 sensors that recorded heat and atmospheric pressure during the spacecraft's high-speed, extremely hot entry into the Martian atmosphere.

This was the first time NASA used this level of sensors to collect accurate, real-time, high-fidelity data of atmospheric entry at another planet.

"From end to end, the MEDLI team has included the best people to work for and with," Kuhl said. "The dedication and tenacity of this team is what made this a success, hands down."

Last week, the MEDLI team received their first complete data set, which is being analyzed. According to Kuhl, the measurements from all of the sensors looked good, with zero failures to report.

"I have to verify that this data is correct," Kuhl said. "We've received it from the spacecraft, and it goes through calibration before we hand it off to science teams and reconstruction teams. We also have to correlate the time stamps from our MEDLI data with the spacecraft clock time."

Once the team shifts into reconstruction activities, they will be able to reconstruct the trajectory using MEDLI data to determine what the flow was over the heat shield and to confirm if it was turbulent when they expected it would be. Further scientific investigation will determine what the sizing should be for the thermal protection system and for determining peak heating on the shield. Since MEDLI measured the atmosphere until it was released, it will also allow the team to do independent measurements to derive atmospheric density from the pressure sensors.

Having that knowledge is important to spacecraft designers – especially for developing Mars entry systems that are safer, more reliable and lighter weight.

"I hope we start sending more spacecraft to Mars. I hope this reinvigorates the interest to do this type of thing," Kuhl said. "Personally, it's been such a wonderful experience that I would love to repeat, and I would love to bring someone else along and have some of the younger engineers, up and coming, experience it."

His daughter Alyssa, 10, and son Evan, 6, are already sharing their father's interest in space and engineering – even more now that a piece of his work is on Mars. He and wife Nicole are still coming to grips with where his path has taken him since they met in high school, and then attended West Virginia Wesleyan together for their undergraduate, and Purdue University for their graduate degrees.

"It's been a once in a lifetime opportunity, but I hope I get to do it again," Kuhl said.  
The Researcher News
NASA Langley Research Center
Editor & Curator: Denise Lineberry
Executive Editor & Responsible NASA Official: Rob Wyman