Eye in sky enhances view on the ground

Defence’s Buccaneer Main Mission (BMM), launched before the end of this year, will look down at the Ionosphere from an orbital altitude of about 500km.

DSTG’s Monique Hollick and Lachlan Symonds work on the BMM satellite at the National Space Test Facility (NSTF) in Canberra. Picture: Mark Jessop

How does a satellite improve the performance of a radar?

If it’s a high-frequency (HF) over-the-horizon radar such as the RAAF’s Jindalee Operational Radar Network, using a satellite is essential. The skywave JORN radar bounces its signals off the ionosphere, anything from 60 to 600km above the earth’s surface, in order to detect targets 3000km away. If you want to enhance JORN, or even just to calibrate it accurately, you need to be able to look at both sides of this atmospheric layer.

That’s the main purpose of Defence’s Buccaneer Main Mission (BMM), which DSTG’s Platforms Division is running in partnership with the University of NSW in Canberra. To be launched before the end of this year, it will look down at the Ionosphere from an orbital altitude of about 500km.

The satellite’s principal sensor is an HF receiver with four very slim 3m antennas in what BMM manager Chris Peck describes as “bow-tie” configuration.

The satellite will fly through the HF radar’s pencil beam to ensure it is the correct shape when it hits the ionosphere; if it’s not, the satellite will tell DSTG. The aim is to enhance the accuracy and resolution of JORN and its performance as a long-range threat detector over the next few decades.

The Buccaneer Main Mission consists of a single 6U CubeSat manufactured by Adelaide-based Inovor Technologies, selected following an open tender. It weighs 8kg and measures about 30cm x 20cm x 10cm, according to David Lingard, DSTG group leader space operations.

The four antennas consist of tightly wound strips of metal held in place by what amounts to fishing line. Once in orbit, electrical power melts the fishing line and the antennas uncoil progressively.

The BMM will have a camera and retractable mirror, the Mantis, which can image all four antennas to ensure they have deployed properly, as well as other targets.

Dr Matt Tetlow.

“Within the satellite platform itself are a range of sensors, actuators, radios, batteries, solar panels and more to control and task the satellite,” Inovor Technologies chief executive Matt Tetlow says.

“For example, star trackers to measure the positions of stars to help determine the orientation of the spacecraft, and reaction wheels to help reorientate it.”

At its Edinburgh laboratory, DSTG has built a secure satellite management facility with UHF and S-Band communications links, as well as a laser-based ­optical communications link; there’s also an iridium communications link aboard the BMM to provide 24/7 connectivity, even when the satellite is out of sight of Edinburgh. This facility is also designed for future space missions, Lingard says.

The BMM satellite will be launched by a vendor selected by the US Department of Defence under the 11-nation Responsive Space Capabilities R&D Memorandum of Understanding. It isn’t designed for a long life so will remain aloft for about 12 months.

As well as enhancing the calibration and performance of JORN’s three radars, at Laverton in Western Australia, Alice Springs in the Northern Territory and Longreach in Queensland, the Buccaneer program will help Defence build the enduring skills necessary for space operations. Defence’s JP9102 satellite communications project, which is worth nearly $7bn, is due for approval this year with more to follow in subsequent years, and its growing space workforce needs to quickly become expert in designing and integrating payloads, launching them and managing them properly.

Skills learned on the BMM include engineering for lightness and simplicity, the need to ­package the satellite extremely densely while avoiding electromagnetic interference, and building a sovereign supply chain.

The aluminium mirror was polished in Adelaide while “shake and bake” environmental testing was done in Canberra at the ANU and radiation testing was done by the ANU as well as the Australian Nuclear Science and Technology Organisation (ANSTO) at Lucas Heights near Sydney.

The “shake and bake” trial tested the satellite’s ability to withstand the vibration of launch and the harsh temperature differences in space.

“It was great to see how well the platform performed in the testing and was a valuable experience for the team, but we also learned some key aspects to improve our design for the future,” Tetlow says.

Some things you can only learn by doing. Space is one of them.