AMSAT MPPT Goes to Infinity and Beyond

AMSAT, the Radio Amateur Satellite Corporation, joined forces with students from Rochester Institute of Technology to create a MPPT attached to a Fox-1B CubeSat. It successfully launched into orbit on November 18th strapped to the back of a Delta II rocket. This analog MPPT, or Maximum Power Point Tracker, is used for optimizing the draw of a power cell in correspondence to the output of solar panels on the 10cm x 10cm satellite. In a nutshell, this works by matching the voltage of the two together. If you haven’t gotten a chance to play around with one of these first hand, Hackaday’s own [Elliot Williams] wrote up a thorough explanation of the glorious MPPT’s efficiency.

This little guy is currently hurdling along in an orbit every 90 minutes. During each of these elliptical trajectories, the satellite undergoes brutal heating and cooling cycles. The team calculated that this package will undergo a total of 29,200 orbits around Earth during its 5 year mission. This means that there are 29,200 tests for it to crack — quite literally — under pressure. To add another level of difficulty, the undergrad team didn’t have funding for automated board assembly. This meant that they had to hand solder over 400 micro components onto this board, adding additional human error to be accounted for in the likelihood of a failure. But so far, this puppy is going strong. This truly shows the struggles that can be overcome with a little elbow grease, hard work, and plain ‘ole good engineering.

They created some sharp-looking documentation for this project. I would highly suggest taking a couple of minutes to read their Fox-1 MPPT document if you are interested in seeing the carefully thought out design in detail. The collection of schematics shown above was used to predict the maximum power point voltage. The analog computer used Y = mX + B to accurately predict the MPPT based off of solar panel temperature. In doing this, they were able to account for radiation in orbit causing bit flips. Understanding all of these factors was essential for the success of this tiny beast.

We would like to say good luck to the RIT team of Bryce Salmi, Brenton Salmi, Ian MacKenzi, and Daniel Corriero in their future endeavors. Sending anything into space and then keeping it running once it gets there is no easy task, and there is already another MPPT set to launch on a Fox-1E CubeSat aboard a Virgin Galactic Launcher One in December, 2017. Check out some of the necessary testing they did on it below to ensure that this would be a successful mission. Let us know if you think this is as awesome of a collaboration as we do.