It appears that the $50SAT Amateur Radio “PocketQube” microsatellite — also known as Eagle 2 (MO-76) — has finally gone silent, a couple of days short of 20 months in orbit. The satellite, which did not carry an Amateur Radio transponder, transmitted on 437.505 MHz at a power of 100 mW. In a Yahoo Groups posting, one of its developers Michael Kirkhart, KD8QBA, said the last time he was able to hear the satellite was on July 19.

“It was fun while it lasted,” he told ARRL this week.

Launched in late 2013 from Russia, $50SAT was a collaborative education project of Prof Bob Twiggs, KE6QMD, of Kentucky’s Morehead State University, and three other radio amateurs — Howie DeFelice, AB2S; Stuart Robinson, GW7HPW, and Kirkhart.

“Our best guess as to what happened is the solar cells have been slowly damaged due to sputtering,” Kirkhart said in his Yahoo post. “All the high-energy particles from the solar wind can effectively ‘sandblast’ the satellite, and since our cells had no protective cover glass, this will cause the surface to slowly become diffused, and thus cause the output of the cells to drop. We knew this would happen. What we did not know is that $50SAT would operate long enough where this would become a problem; our bets were on the battery failing first.”

Kirkhart said the mission now has transitioned into the how-long-will-it-stay-in-orbit? Phase. He cited one de-orbit prediction of May 2017. The “$50” was a bit of an exaggeration; the tiny satellite actually was constructed from about $250 worth of parts. — Thanks to Michael Kirkhart, KD8QBA