SuitSat-2 Goes to College

SuitSat-1 was launched into space from the ISS in February 2006. [NASA Photo]

Frank Brickle, AB2KT (left, rear) and Bob McGwier, N4HY (right, rear) with part of their TCNJ SDR class. Stephen Hendrickson (center, front holding circuit board) designed the S band amplifier proposed for the AMSAT Eagle satellite. He won honorable mention at an international amplifier efficiency competition as the only undergradudate and the only person submitting above 1 GHz.

Bob McGwier, N4HY, discusses plans for SuitSat-2 during the 2006 AMSAT Space Symposium and Annual Meeting. McGwier is AMSAT-NA's vice president of engineering and a member of the AMSAT Board of Directors.

Lou McFadin, W5DID, heads the SuitSat-2 hardware team.

NEWINGTON, CT, Jan 24, 2006 -- Eleven electrical engineering students at The College of New Jersey had a hand in designing some of the software defined radio (SDR) hardware that will fly aboard SuitSat-2. The college seniors signed up last fall for "Software Defined Radio," taught by adjunct professors Bob McGwier, N4HY, and Frank Brickle, AB2KT -- both members of the Amateur Radio on the International Space Station (ARISS) SuitSat-2 team.

The second SuitSat will have a software designed Amateur Radio transponder (SDX) on board. SuitSat-2 is being viewed as a test bed for the hardware AMSAT hopes to launch on its Phase 3E Eagle satellite.

McGwier and Brickle designed practical, goal-based experiments for the students' projects with an eye toward turning out something that would be a useful SuitSat-2 component. Team members Steve Bible, N7HPR, and Joe Julicher, N9WXU, provided circuit boards employing "bleeding-edge" technology -- dsPIC33F 16-bit direct memory access digital signal controllers. Brickle says the circuits will serve as SuitSat-2's heart and brain.

Early on, the students studied signal processing and communication theory as well as what Brickle calls "esoteric corners of computer science." Then, using Matlab -- a high-level technical computing language -- the students implemented modulators and demodulators for SSB, FM, BPSK and AFSK.

"Students get a little bit of verbal swimming instruction, and then we toss them straight into the ocean," is how Brickle described the process.

By mid-semester, the students were designing their experiments and getting them up and running. Boards were powered up without diagnostic hardware or software, since that's how the circuitry will be on orbit -- "walking a tightrope without a net," as Brickle sees it.

"Given the complexity of what the SDR/SDX in SuitSat-2 will be required to provide, the applications will need to run in an unprecedented software environment: pre-emptive multitasking under freeRTOS," he explained. FreeRTOS is an open-source, round-robin operating system for embedded devices.

Instead of being scared off, the students ran with the challenge and demonstrated obvious enthusiasm, Brickle reports. "We will be doing a very good thing if we continue to involve these kids, and more like them, in our future AMSAT projects," he said. What surprised him most, he added, was that the students focused on taking new approaches to "very fundamental engineering issues that aren't flashy or trendy." McGwier remarked that both students and teachers shared in the excitement.

The SuitSat-2 team, under the leadership of Lou McFadin, W5DID, has been working on the design of a power converter for the solar panels, the internal housekeeping unit, the antenna mount, the transmitting and receiving hardware and how it will mount atop the suit's helmet. An ISS crew could launch SuitSat-2 during a spacewalk as early as next fall. SuitSat-2 could have an operational lifetime of six months or more.

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