First month in space

Sumbandila completed 457 orbits during its first month in space which corresponds to 0.1316 AU (1 AU = distance between Earth and Sun).  We managed to make successful contact with the satellite during all the available* passes over the Stellenbosch ground station, namely 107 (or roughly 23% of all orbits).  During these 107 ground station passes, we had a total contact time with the satellite of roughly 15 hours. 

* Passes with a maximum elevation angle of at least 4°.

First video received from the satellite

We are blessed - have received the first real-time video images from the satellite during the two morning passes!  The signal was simultaneously received by the ground station at Stellenbosch University and the one at SAC (Hartebeeshoek) - the one in Stellenbosch with a 4.2m dish and the one at SAC with a 10m dish.  The signal-to-noise ratio of the latter was obviously much better. 

You can see an edited version of the video below, captured in Stellenbosch.  At the time the satellite was moving over the North-Western corner of Namibia in a South-Western direction.  In the second half of the video you will notice the top part of a VHF antenna visible at the top of the frame.

Effects of radiation

We have noticed that some of the SRAM devices in use on the satellite are sensitive to Single Event Effects (due to radiation). This typically manifests as increased current.

All our electronics are protected by latch-up circuitry, but some of the increases in currents observed are below the set thresholds of the built-in trip functionality of these circuits.

We have now implemented a further protection mechanism in software which necessitated code uploads to the main on-board computer, some of the power distribution units, as well as the attitude computer.

In parallel we continue to perform minor commissioning activities and regular health checks. We plan to resume commissioning of the attitude control systems this week.