Published : Tuesday, November 6, 2018 | 6:31 PM
A former mission director at the Jet Propulsion Laboratory in Pasadena, who played an important role in NASA’s Phoenix Mars Lander and Mars Odyssey projects, among others, is now back at Purdue University in Indiana working on fine-tuning a means to retrieve old spacecraft, defunct satellites and spent rockets left suspended in Earth’s atmosphere – before they become a real problem.
Dr. David Spencer is a Purdue alumnus, and he’s now back at the university as associate professor of aeronautics and astronautics and director of Purdue’s Space Flight Projects Laboratory, after 17 years at JPL and eight years t Georgia Tech.
His team at Purdue now aims to develop a system that in the future would “de-orbit” spacecraft launched by companies like SpaceX, OneWeb, and Boeing, as the spacecraft complete their missions.
“There are a number of high-value orbits that have become so populated with defunct satellites and debris spacecraft that they’re approaching a tipping point,” Spencer said in a Purdue University release. “Once that tipping point is reached, a cascade of uncontrolled collisions can occur, rendering the orbit unusable. And into the mix the thousands of satellites that companies plan to launch into orbit in the next several years, and the problem becomes much worse.”
Spencer graduated from Purdue University in 1991 with BS and MS degrees in Aeronautical and Astronautical Engineering, and from there joined JPL, where he was deputy project manager for the Phoenix Mars Lander, mission manager for the Deep Impact and Mars Odyssey projects, and mission designer for Mars Pathfinder and TOPEX/Poseidon.
He left JPL in 2008 to join the Aerospace Engineering faculty at Georgia Tech, where he obtained his PhD in Aerospace Engineering in 2015. At Georgia Tech, Spencer founded the Center for Space Systems, and was the Co-Director of the Space Systems Design Laboratory.
Spencer also assumed the role of mission manager for The Planetary Society’s LightSail 1 spacecraft, which launched in May 2015. He is the project manager for a second LightSail spacecraft, LightSail 2, planned for launch this year.
At Purdue, Spencer’s team saw the potential to use a reverse concept of LightSail in “de-orbiting” space junk: instead of the solar sail propelling spacecraft to higher orbits, the type of deployable sail they’re developing would slow down aging spacecraft.
“Using many of the same technologies as solar sails, the application we’re working on here is a drag sail,” Spencer said. “Instead of pumping up the orbit, we want to remove energy from the orbit by increasing the drag area and using the atmosphere to slow down the spacecraft causing it to deorbit.”
The drag sail system Spencer and his team of students are developing can launch with satellites and be deployed at the end of the satellite’s mission to pull them out of orbit, the statement said.
“De-orbiting” old spacecraft and satellites would not only provide more room for new and improved satellite technology, but it would also help keep astronauts safe from collision with orbital debris while they are in the atmosphere.
When Spencer came to the university in 2016, he aimed to develop a small satellite program that would take students through the full life-cycle of a space flight project, including design, fabrication, testing and operations. But in addition to getting students involved with spacecraft development, he wanted the spacecraft they designed to have cutting-edge applications for advancing aerospace technology – such as tackling the issue of orbital debris.
“Working with students on projects that will advance the aerospace industry and benefit society overall, that’s really rewarding,” Spencer said.
Spencer’s work aligns with the university’s Giant Leaps celebration as part of Purdue’s 150th anniversary. One of his most ambitious goals is to have Purdue lead a planetary mission within the next 10 years, utilizing small satellite technology such as CubeSats, a type of miniaturized satellite used for research.
Spencer is the author of numerous technical publications in the fields of planetary mission design, flight operations, and system engineering.