DYNACUBE TO EXPLORE THE SOUTH ATLANTIC ANOMALY

After launch DynaCube, a one-unit CubeSat being constructed by Interns at the Denel Dynamics Engineering Academy will be exploring the South Atlantic Anomaly during orbits over the area.

The South Atlantic Anomaly (SAA), off the coast of Brazil, is an area where the Earth's inner Van Allen radiation belt comes closest to the Earth's surface dipping down to an altitude of 200km This leads to an increased flux of energetic particles in this region and exposes orbiting satellites to higher than usual levels of radiation. The effect is caused by the non-concentricity of the Earth and its magnetic dipole. The South Atlantic Anomaly is of great significance to satellites and other spacecraft that orbit the Earth at several hundred kilometres altitude; these orbits take satellites through the anomaly periodically, exposing them to several minutes of strong radiation, caused by the trapped protons in the inner Van Allen belt.

NASA has reported that modern laptops have crashed when space shuttle flights passed through the anomaly, and the SpaceX CRS-1 Dragon spacecraft attached to the International Space Station during October 2012 experienced a transient problem as it passed through. It also here where SunSat, South Africa’s first satellite, stopped operating when it onboard computer was damaged.

DynaCube includes  sensors to measure radiation levels, magnetic flux, structural temperature chances, the effect of radiation on commercial off-the-shelve components (COTS) and the effectiveness of the radiation shielding. “Unlike other cubesats, DynaCube has a solid space frame to give more protection to radiation”, Rick Botha, Project Manager of the payload said.

DynaCube Project Team leaders  (L-R) Rick Botha, Jean-Paul Appel, Esabe Brink, Yoshlyn Naidoo, Motheo Motlhabane, Yolandi Young

The team, all engineers who graduated from various universities in South Africa, spent last year working on the project to gain practical experience before they are assigned to various departments in the company. The Interns were tasked with designing, manufacturing and commissioning a 1 U Cube Satellite and its associated ground support systems. Three teams were formed, with each team having specific objectives. Team Ground Zero was responsible for the Ground Control Station as well as communications equipment on-board the satellite. Team Virtuoso was responsible for the On-board Computer (OBC), the power system, the satellite structure and telemetry data. The main tasks of Team Frodo were to specify the satellite payload, the required sensors, the attitude control and the launch of the satellite.

It was decided, in the early stages of the project, that a duplicate satellite should be built which will remain on Earth to allow software maintenance and troubleshooting on the ground before uploading changes and updates to the satellite in orbit.

The secondary payload is a camera capable of taking images and sending them to the OBC for storage. It was decided that a VGA serial JPEG camera would be used, as it would be able to take photographs fast enough to prevent blurring, whilst also doing its own image processing.

The launch will most likely only happen close to the end of 2013 and possibly only as late as the end of 2014. The funding of the launch, which may be as high as R1 300 000, is a challenge that still needs to be overcome.

 All systems have been tested and are now ready for integration. Although the Interns have come to the end of their year and will start their careers in various departments of Denel Dynamics, they are dedicated to complete the project in their free time. Currently three of the group have obtained their amateur radio license. DynaCube will operate on Amateur Radio frequencies which were coordinated by the IARU Satellite Advisory Panel. DynaCube will operate on a downlink of 145,980 MHz, an uplink on 435,050 MHz  with a tracking beacon on 145,840 MHz.

Esabe Brink, inside the  DynaCube Ground station

Listen to an interview with members of the DynaCube Team here