SA readies for second satellite

By Leon Engelbrecht, ITWeb senior writer

Johannesburg, 07 Nov 2006

SA will next month launch its second satellite from a nuclear-powered Russian submarine in the Barents Sea, near the North Pole.

The 80kg micro-satellite, named Sumbandila, Venda for "lead the way", will be fired into space just before Christmas. SunSpace and Information Systems built the satellite under contract from the University of Stellenbosch for the government's Department of Science and Technology (DST).

SunSpace export manager Ron Olivier says Sumbandila cost R11 million to build, compared to the R8 million spent on its predecessor, Sunsat (Stellenbosch University Satellite), but is thrice as good.

"It has three times better ground resolution and, instead of a gravity gradient boom, which is not very stable, we can now, with three-axis stabilisation, keep it stable enough to achieve the 6.25m ground sampling distance objectives we set ourselves."

Olivier explains this means one pixel = 6.25 sq metres. Images taken by Sumbandila will be downloaded by CSIR engineers at its Satellite Application Centre, at Hartebeeshoek, near Pretoria, as the satellite crosses over.

Experiments

The satellite will also carry a number of experiments and an amateur radio payload. The CSIR will be responsible for the satellite's day-to-day operations, as well as telemetry, tracking, control and data capturing.

Olivier says Sumbandila was built under a R26 million contract, which includes launch and shipping costs, as well as funding used by Stellenbosch University to present post-graduate and PhD courses on satellite development.

Sunsat, or ZA-001, also built by SunSpace, was launched in February 1999 from Vandenberg Air Force Base, in California, on a Delta II rocket. It had a 23-month operating life and ceased functioning in 2001. It remains in orbit.

Sumbandila is currently at the company's Stellenbosch Technopark campus. Once launched, the company will be responsible for commissioning Sumbandila and for providing technical support during its planned three- to four-year lifespan.

"We expect her to last five years plus, however," Olivier says. Commissioning entails remotely switching the satellite on and "detumbling" it, as it will be "spinning at one heck of a rate", Olivier says.

Successful tests

Once stabilised, Olivier says, they will ensure the power system is working as designed and the solar panels are pointing to the sun and powering the satellite. They will also place Sumbandila in a sun-synchronous (on the sunny side of earth) polar orbit at an altitude of 500km.

The satellite recently successfully completed a series of performance tests at the Institute for Satellite and Software Applications, at Grabouw, near Cape Town.

The facility, now in the hands of the Department of Communications, was in the 1980s known as Houwteq, part of apartheid SA's space programme, which was central to a broader scheme to build a ballistic missile, tipped with a nuclear weapon.

Sumbandila will be handed over to the DST on 15 November and be shipped to a naval facility near Murmansk, in northern Russia.

Olivier says Sumbandila is all-South African, except for its batteries and solar panel substrate. He explains that, because the "power system went bonkers" on Sunsat, Sumbandila has a double dual redundant power system with space qualified battery cells.

"A lot of SA technology is riding on this satellite. We have tested it and every indication is that once it is up there it will work," Olivier said. Launch is scheduled for some time between 20 and 25 December.