Space Operations directorate of SA’s space agency marks two new developments

The Space Operations directorate of the South African National Space Agency (Sansa) recently achieved a new high when it successfully supported the simultaneous launch of four satellites. “Four Galileo satellites were simultaneously launched by an Ariane rocket from Kourou, [in French Guiana], on November 17,” explains Sansa Space Operations MD Raoul Hodges. “This is the first time we have done so many at once.”

The Galileo programme involves the creation of a constellation of navigation satellites, in parallel, and offers an alternative to the US global positioning system, the Russian Glonass and the Chinese Bei Dou satellite navigation systems. Galileo is a project of the European Union. At full strength, the Galileo constellation will comprise 24 operational satellites, plus six spares in orbit. They are placed in medium earth orbits, at an altitude of 23 222 km. Initial service should start by the end of this year. Each Galileo satellite has a mass of about 700 kg.

To support the launch, Space Operations used three of the antennas at its Hartebeesthoek facility, plus a fourth located in another country. The three Hartebeesthoek antennas employed were Sansa’s 12 m and 10 m diameter dishes and an 11-m-diameter dish belonging to French space agency CNES and hosted by Sansa. “It takes quite a technique to run so many antennas at once with a limited number of staff,” he highlights. “You use up all your redundancy. You have no backup available. It can be rather tense.”

This was not a single-day event. Satellites destined for medium (and higher) earth orbits cannot be lifted to such heights in one go. The launch rocket places them in a lower orbit, called the transfer orbit. There, they are often checked out to ensure all systems are working after the significant stresses imposed by the launch. Then the final stage of the rocket is fired and lifts them into their final orbits. Finally, they have to be positioned and orientated precisely. In the case of the four Galileo satellites, this whole process took more than a week, and Sansa Space Operations was involved throughout.

The 11 m CNES dish is the newest major antenna erected at Hartebeesthoek. It was commissioned in April, the project having been started in February last year. “The project involved the construction of infrastructure including an access road to the site and a support building, as well as the telecommunications fibre infrastructure, connecting the site to the main Space Operations control room,” reports Project Manager Gladys Magagula. The support building was constructed in full compliance with French standards. It is a standalone facility, with total equipment redundancy and the antenna and support building are remotely operated from France. Sansa’s role is testing and maintenance on a call-out basis.

“The facility has been running for more than three months and it has been very successful, with very few teething problems,” notes Hodges. “It serves telemetry, tracking and control functions for their fleet of research satellites. It is also used, when required, for launch support, but, under our agreement, they need our permission to do this as launch support is a major source of income for Sansa.”

What is now Sansa Space Operations (previously, the Satellite Applications Centre, or SAC, of the Council for Scientific and Industrial Research) has been working with CNES (Centre National d’Études Spatiales) since 1983. Previously, the French used SAC/Sansa’s 12 m dish antenna. But, in 2013, CNES decided to upgrade its S-Band communications network. (S-Band covers the frequency range 2 GHz to 4 GHz.) As part of this programme, they proposed establishing a facility in South Africa. In parallel, the South African and French governments signed a 40-year protocol agreement covering space activities.

“CNES, based on decades of experience of working with us, decided to put the facility at Hartebeesthoek. The project was fully funded by them,” he explains. “They brought out a company called Zodiac to erect the antenna, but the civils work was done by local contractors. Subsequently, Sansa signed a ten-year contract with CNES. This is not our first hosting agreement, but it highlights our continuing relationship with France and our importance in the global space sector, as well as the importance of the infrastructure we’ve created over the years.”