Stray Signals

Amateur radio to the rescue of satellite

I-Inspire-2 is a 20 x 10 x 10cm CubeSat built by the University of Sydney in collaboration with the Australian National University and the University of New South Wales (Sydney)

WIA News reports:

On board the tiny spacecraft is an experiment, part of the QB50 project, designed to “explore the lower thermosphere, for re-entry research and in-orbit demonstration of technologies and miniaturised sensors”, as reported in earlier editions of the WIA broadcast.

Its operational frequency was coordinated by IARU to be in the satellite segment of the 70cm amateur band.

It was placed in orbit from the International Space Station in late May. The deployment was successful; however there were no signs of life when the ground stations started looking for it. The engineering group quickly tested various scenarios on the engineering model only to come to the conclusion that, due to the extended delay in the deployment, the satellite’s battery was likely to be depleted and the satellite was trapped in an endless loop, trying to deploy its antenna.

The engineering group suggested that the satellite is still listening albeit with its antennas in the stowed position. This meant that the satellite command receiver might have difficulty receiving any signals from ground control stations. A set of commands were devised which, if received, would instruct the satellite to wait until the battery is charged before attempting to deploy its antenna. Both UNSW and ANU ground stations transmitted the recovery command to the satellite; however after a week or so of no success it was decided that more transmitter power was required to overcome the lack of receiver sensitivity caused by the still stowed antenna. A request for assistance was passed to EME operators around the world and many responses were received.

The greatest hope for a successful recovery was thought to be PI 9 CAM using high power and a 25 m dish, normally used for radio astronomy but also EME. They were scheduled to transmit on the weekend of June 10-11.

On Sunday June 11, during the morning pass, Rob VK1KW reported a strong signal every 30 seconds on I-Inspire-2’s frequency. Dimitris VK1SV who is part of the ANU team, verified reception from home around midnight. The following morning Dimitris drove to the ANU ground station and was able to send commands to the satellite for the first time since it was deployed. Many other radio amateurs around the world also reported reception of the beacon. The satellite had come back to life!

This is a wonderful example of successful collaboration between radio amateurs and the academic community. If a frequency outside the radio amateur band had been used, it is doubtful that the satellite would have been brought back to life.

The crew of I-Inspire-2 wishes to thank all radio amateurs involved and is looking forward to a successful collection of data for the scientific experiment!

I-Inspire-2 official web site: http://sydney.edu.au/inspire-cubesat/project/index.shtml

( Dimitris Tsifakis VK1SV/VK2COW )

Source WIA News http://www.wia.org.au/members/broadcast/wianews/

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