Undergrads Construct Cryogenic Star-Tracking Instrument

A team of undergraduates from the Rochester Institute of Technology (RIT) will soon deploy its Cryogenic Star Tracking Attitude Regulation System, a telescope and camera based “compass” for rockets that will orient the payload based on the images of stars. CSTARS uses a new kind of detector technology and will fly on a NASA technology demonstration mission scheduled in December.

The project is funded by a $200,000 grant from NASA’s Undergraduate Student Instrument Project Flight Research Opportunity program, designed to give undergraduates experience developing and flying experiments relevant to NASA’s mission.

RIT professor Michael Zemcov proposed the experiment to test detectors made of metal-oxide semiconductor, or CMOS, a promising new material that can operate at liquid nitrogen temperatures. Such cryogenic temperatures, according to Zemcov, can significantly reduce dark current in the sensor and increase instrument sensitivity. In contrast, the standard technology used in astronomical imaging and in consumer electronics—charge-coupled detectors, or CCDs—is inoperable at cold temperatures.

Zemcov says the students’ prototype represents a step toward a fully cryogenic optical detector that someday could improve the sensitivity of NASA’s deep-space cameras. The star tracker will fly in a technology demonstration payload on a suborbital sounding rocket that will launch in December from NASA’s Wallops Flight Facility on Wallops Island VA, with experiments from other universities and NASA laboratories. Sounding rockets are cousins of military ordnance, like surface-to-air missiles, that fly to an altitude of approximately 200 miles and represent an affordable way to conduct science experiments in space.

Following a successful initial flight, a second RIT-built instrument will fly on a NASA rocket experiment to measure the light from faint and distant galaxies. The Cosmic Infrared Background ExpeRiment 2, or CIBER-2, is led by the California Institute of Technology. Zemcov is a member of RIT’s Center for Detectors and the Future Photon Initiative and a co-investigator on CIBER-2.

“We needed to build a star tracker for this science payload,” Zemcov says. “The problem is that most of the detectors we have don’t work at the cold temperatures we require.”

The RIT student team brings the specialty of several disciplines to the project, from electrical engineering to computational mathematics and physics.

“The aim is to control this sensor and make it work at cold temperatures,” says Kevin Kruse, a fifth-year BS/MS electrical engineering major. “Then we’ll launch it into space to take pictures. A future mission would involve us guiding the rocket using the images we take.”

The team is mentored by Zemcov, Dorian Patru, professor of electrical engineering, and Chi Nguyen, a PhD student from Vietnam in the astrophysical sciences and technology graduate program.

“CSTARS will verify a new instrument design, so I’m interested in seeing how well the implemented instrument can meet our expectations,” Nguyen says. “As a graduate student, this project is an excellent opportunity for me to gain mentoring experience and experience working with NASA.”