Mississippi Native Cindy Stemple Helps Guide Next-Generation Robotic Lander to Testing Success at NASA's Marshall Center
In North Alabama in mid-July, as the heat index soars well above 100 degrees Fahrenheit and the air itself seems to sweat, you'd think it would be a relief to conduct complex hardware tests in a cool indoor laboratory. But NASA engineer Cindy Stemple is ready to move things outdoors, regardless of the sweltering temperatures. She's ready to see her latest project fly.
Stemple is flight control commander -- and wears other hats as needed -- for the Robotic Lander Development Project at NASA's Marshall Space Flight Center in Huntsville, Ala. Her team has spent the past 22 months designing and testing a sophisticated, next-generation robotic lander prototype the team has dubbed "MightyEagle." The project will help NASA devise a small, smart, low-cost lander that uses pulsed thrusters to gently ease itself onto the surface of the moon, near-Earth asteroids or other airless bodies -- leading to a new generation of robust, versatile, automated spacecraft that will explore and conduct science across the solar system.
The lander team includes Marshall Center engineers and their partners at Johns Hopkins University's Applied Physics Laboratory in Laurel, Md., and the Von Braun Center for Science and Innovation in Huntsville. The latter includes two Huntsville-based contributors: Teledyne Brown Engineering and Dynetics Corp. The Planetary Science Division of NASA's Science Mission Directorate in Washington directs the project.
Stemple and the team spent the first half of the summer testing the prototype in a U.S. Army propulsion test facility on Redstone Arsenal in Huntsville, home to the Marshall Center. The prototype is a tripod-like construct that is 4 feet tall and 8 feet in diameter. It weighs about 700 pounds when fueled, but you'd never suspect the weight as it smoothly lifts off the cement floor of the test chamber, hovering between 6 feet and 16 feet in the air.
As flight control commander, Stemple's got a lot to do with that smooth test run. "I work with the engineers in the planning and development phase of each hover test, preparing the sequence of commands to maneuver the test article," she says. "During the test, I provide command and control to support pressurization, fueling and flight of the prototype."
That's the fun part, she says -- preparing the system to operate on its own in distant, alien environments, particularly during tricky landing operations.
"Developing an autonomous, or primarily self-guiding, lander is important, because radio commands sent from Earth to another world experience time delays," she says. "If the lander encounters an obstacle in the final seconds before landing, it might be too late for a controller back here on Earth to intervene in time. That's why we're developing a smart vehicle with sophisticated sensors and self-analyzing, self-correcting capabilities, enabling it to troubleshoot and adjust without human intervention."
Stemple has a hand in that technology development as well. She serves as ground data systems lead, managing all the data systems used to command and control the prototype, and as software integration manager, overseeing all testing and integrating of the lander's flight software.
She juggles these roles with finesse, but she's happiest when she's putting MightyEagle through its paces: autonomous, closed-loop, free-flight test runs, hovering for up to 30 seconds at a time at various heights while Marshall engineers and their industry partners study its performance and refine its onboard sensors, avionics and power and guidance systems. To date, Stemple and the team have conducted more than 160 total tests on two lander prototypes: the "warm-gas," peroxide-fueled test article being put through the paces in the Army test lab; and an earlier, "cold-gas" version fueled with compressed air, which was completed and tested in just nine months.
The first hover flight in June sticks out in Stemple's mind as a highlight. "It was the culmination of many hours of tireless effort put into the development, integration and testing," she says. "It's been amazing to see what we've accomplished in such a short amount of time."
Now the team is ready to throw open the test facility doors and take the prototype outside for a new series of increasingly complex flight tests on the Army's Redstone Arsenal test range. During testing, set to commence in early August, the lander is expected to fly up to 60 seconds. Each test flight will involve a variety of high-flying ascent, descent and horizontal maneuvers.
Mention to Stemple the sizzling heat waiting for them out there and she just chuckles. She grew up in Long Beach, Miss., about 70 miles east of New Orleans on the Gulf Coast. She knows all about heat.
The robotic lander will know all about heat, too, in its travels -- and bone-chilling cold as well. On the lunar surface, for example, temperatures can climb as high as 260 degrees Fahrenheit during the day, then plummet to minus-279 degrees Fahrenheit overnight. Among its many areas of focus, the team is studying innovative thermal management systems and techniques to protect the craft no matter where its exploration missions take it -- enabling it to perform equally well in the frigid gulf of space or under the harsh glare of a sun unshielded by Earth's atmosphere.
Stemple can't wait. "I am very optimistic that the engineering innovations and the lessons learned in the development and testing of the lander prototype will inform a new era in robotic exploration," she says. "Robotic missions help us make exciting new discoveries in alien environments and demonstrate and validate vital new capabilities -- serving as vital precursor missions for more rewarding future human exploration of our solar system."
She smiles. "That's just cool," she adds, and goes back to readying the lander prototype for its days in the sun.
More about Cindy Stemple
Stemple is a 1985 graduate of Mississippi State University in Starkville, where she earned her undergraduate degree in computer science. After college, she worked as a software developer on the F16 program at General Dynamics in Fort Worth, Texas, then moved to Huntsville to work for SCI Inc. as a technical support specialist.
She joined NASA in 1987, initially designing data systems for testing the Chandra X-ray Observatory, which flew to space in 1999 and continues to unlock the mysteries of the universe, studying cosmic X-ray emissions 100 times fainter than any previous space telescope could see.
Among her many career highlights, she designed, developed and wrote software to test vital International Space Station science facilities, including the Microgravity Science Glovebox and the Materials Science Research Rack. The glovebox, flown to the space station in 2002, permits controlled scientific study of materials and samples on orbit, with real-time video and data access by scientists on the ground. The research rack, delivered to the station in 2009, allows for on-orbit study of a variety of materials, including metals, ceramics and glass.
In her spare time, Stemple enjoys boating, baking bread and traveling abroad with her husband Dan and their three children. As a two-time cancer survivor, she recently was selected as a “Hero of Hope” by the American Cancer Society. She serves as a motivational speaker, inspiring hope, courage and determination in the fight to eliminate cancer. She also volunteers as a “Reach To Recovery” area coordinator for the American Cancer Society and works with the Huntsville-area "Bosom Buddy" cancer support group.
For more information about NASA's Robotic Lunar Lander Development Project, visit:
Marshall Space Flight Center, Huntsville, Ala.