Week nine of the year will go down as quite an eventful week for ZACUBE-1 (TshepisoSat), literally dodging two bullets involving speeds in the kilometres per second range.

The first close approach notification arrived the morning of 25 February 2014 from the United States Joint Space Operations Center (JSpOC) through the The South African National Space Agency (SANSA) (A close approach notification is generated by the JSpOC to warn spacecraft operators when their spacecraft will come in close proximity to another object). The first order of business was the identification of the other object. In this case “SCC# 21422”. Our dance of death would be with the, now defunct, 2000 kg Russian built COSMOS 2151 launched in 1991. As ZACUBE-1 carries no propulsion system and with the COSMOS 2151 no longer functioning the only course of action was to closely monitor the situation.

It was determined that the close approach event would occur over the Antarctic and a search was started for possible ground stations that could listen for signals from ZACUBE-1 directly after the event. Help arrived in the form of our friends from the California Polytechnic State University in San Luis Obispo, California, United States. The Cal Poly ground station would see ZACUBE-1 approximately 30 minutes after the event and be able to listen for its transmitted telemetry beacon signal. In preparation ZACUBE-1 would be tracked and checked on the last two passes over South Africa (22:50 SAST 26/02/2014 and 00:26 SAST 27/02/2014) a few hours before the event to ensure that everything was OK and then again by the Cal Poly station.

With everything checking out and all systems nominal on the last pass over South Africa all we could do was wait for news from California.

Great success! With Cal Poly confirming that ZACUBE-1 was alive and well. We were able to further confirm this on the first pass over South Africa.

This would have been enough excitement for the week, but soon after verifying that ZACUBE-1 was OK we received our second close approach notification! This time involving a piece of debris from a METEOR 2-5 satellite. The plan would be much the same, but with the event taking place over Brasil we tried to make contact with some stations in Brasil. Unfortunately nothing was heard over Brasil, but we received notification of ZACUBE-1’s signal from the University of Florida and again from the California Polytechnic State University.

We would like to thank everyone that helped out during this time, hopefully I did not leave anybody out. The folks from Cal Poly, University of Florida, the Brazilian radio amateurs that tried on very short notice and SANSA.

ZACUBE-1 (TshepisoSat) image

Here is another picture of the sun!


ZACUBE-1 Close Approach Notification

One of the “Close Approach Notification” messages


Media Release from the South African Department of Science and Technology