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Tiny KickSat “Sprite” Satellites May Not Deploy

05/05/2014

Because of a technical problem, the KickSat CubeSat may not be able to deploy its cargo of tiny “Sprite” satellites, Project Manager Zac Manchester, KD2BHC, announced on May 3. The Sprites, each about the size of a small cracker, would be the smallest satellites ever to orbit Earth. Manchester said an unexpected reset of KickSat’s master clock may mean that the CubeSat won’t be able to release the 104 Sprite satellites before it deorbits and burns up in the atmosphere. He further explained that ground controllers can’t command the Sprites to release, because the uplink radio used to trigger deployment is unable to power up until the spacecraft’s batteries reach 8 V. The batteries have been “holding steady” at 6.5 V, he said, and he doesn’t anticipate the voltage increasing to the required level before the satellite drops out of orbit.

“As those who’ve been keeping up with the telemetry data coming in from KickSat may have noticed, the packets we’ve been receiving have changed in the last couple of days,” Manchester said. “This was due to a hard reset of the ‘watchdog’ microcontroller on KickSat — the sort of ‘reptile brain’ of the satellite that manages turning on and off the rest of the subsystems and keeps the master clock.”

Manchester, a Cornell graduate student in aerospace engineering, believes the culprit is radiation, rather than power issues. The reset restarted the Sprite deployment countdown at 16 days — to May 16. Manchester said it looks like KickSat will lose orbit before then, although he held out a slim possibility that it could stay up that long.

“We’ve spent the last couple of days here at Cornell trying to think of every possible contingency, but it seems there aren’t very many options right now,” he said. “While the situation looks a little bleak, there is still some hope that the batteries may recharge sufficiently to command the satellite. There is also a small chance that KickSat could remain in orbit until the May 16, at which point the timer would set off the deployment as originally planned.”

The satellite launched successfully April 18, and the ground control team at Cornell as well as several Amateur Radio operators around the world made contact with the spacecraft. KickSat went into space with the third SpaceX ISS resupply mission, and the Sprite satellites were to deploy in early May.

The KickSat beacon transmits on 437.505 MHz and 2401-2436.2 MHz. Telemetry packets — transmitted every 30 seconds when the satellite is powered up and 250 seconds when it’s charging — include information such as battery charge state, temperature, and Sprite deployment status. All of the Sprites operate on the same frequency — 437.240 MHz,

 

 

Manchester said the KickSat team will continue tracking the satellite over the next few days — “with the help of the ham community” — tracking its battery voltage and the Sprite deployment status. “Thank you again for your support,” he added. “I promise that this won’t be the end of the KickSat project.”

 

 



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