Morgan Roddy, a microelectronics-photonics doctoral student, recently won second place in a student design competition at the University Nanosatellite Engineering Consortium's Global Meeting in Varna, Bulgaria. The competition challenged students to design a deorbit system for CubeSats, a class of small satellites. Deorbit systems are important because international agreements dictate that any spacecraft must deorbit within 25 years to mitigate the accumulation of space junk.

Roddy's design, the Solid-State Inflation Balloon deorbiter, has three major components: a solid-state gas generator, an inflatable balloon and a package to store electronics and components throughout spacecraft operation. The gas generator is on a small chip that contains heaters positioned under 'micro-wells' of sodium azide. When the heaters activate, the sodium azide decomposes and produces nitrogen gas. The balloon then inflates with gas and the deorbit process begins by providing the spacecraft with more surface area for drag.

"Ultimately, my system can be thought of as a parachute for a CubeSat," Roddy said. "The only difference is the parachute happens to be a balloon."

The design would significantly reduce the deorbit lifetime of CubeSats. Currently, a CubeSat placed in a 550 kilometer orbit naturally deorbits in about 25 years. Roddy's design would see the same spacecraft deorbit in about a year for larger CubeSats and in about four months for smaller ones.

Additionally, Roddy's design could increase the altitude a CubeSat can reach. CubeSats are currently limited to a maximum altitude of 550 kilometers. However, the deorbit system Roddy has engineered could facilitate flying altitudes as high as 1,000 kilometers without violating the 25 year rule.

The deorbit design project is funded by the NASA Space Technology Mission Directorate's Small-Spacecraft Technology Program. Roddy, a Doctoral Academy Fellow, is the project's chief engineer and his adviser Adam Huang is the program manager.