Mission SammyOne

The Backup Tracking Device



Though GSM+GPS seems to be reliable, I needed a backup device that did NOT use the GSM network.

This I found in SPOT Messenger. This is a small device that talks straight to satellites reporting its GPS position. It's very strong and its Lithium batteries work for weeks. It's also known to have worked for other balloon projects. I bought it for only EUR 109 as a smaller new model was coming out. However, I had to pay EUR 135  to use the SPOT mapping service for a year. Expensive! The SPOT would send its position every 10 minutes to a satellite. The satellite will relay it to a website where the GPS from the SPOT becomes visible to me.

I tested the little orange device and had average results. In about 50% of the time, SPOT was able to relay its position to one of the satellites. The biggest drawback is that the SPOT must face the open sky with its front side. If the capsule lands upside down and stays that way, the SPOT won't work. SPOT can report positions up to an altitude of 21000ft. So, again a black hole in telemetry. Anyway, SPOT is going to fly. It's the only affordable device I could find.

Now I have two separately working devices that will assist me in finding back the payload but still not a real tracking device.

I decided to leave it that way as I was running out of budget and I was not sure about which GPS device would work above 18000m. I did think of some other solutions with triangulations but then I would have needed a HAM radio license.

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The Backup Tracking Device

This is my sturdy and expensive SPOT, the Satellite Tracker that I used as a backup recovery device. After the tests I had not a lot of faith in it. But in the end it came back with the right landing coordinates. Well done SPOT.