It’s hip to be square

By Bianca Nogrady

Like orbiting LEGO bricks crammed with tech, CubeSats are simple, customisable and the next big thing for communications, real-time weather warnings and eyes in the sky.

At a barely $100,000 a pop, they are also far cheaper than a typical Sydney house, which is why governments, states, companies, universities and even schools are putting their own satellites into orbit.

Space has opened up, and the gold rush is on. There is the question, however, of how many is too many.

CubeSats belong to the “smallsat” class, in that they weigh less than 600 kilograms. In fact, at just one kilogram, a single unit CubeSat weighs way less – but that’s not even their biggest selling point.

“The idea with CubeSats is they have a standard,” says Iver Cairns, professor in space physics at the University of Sydney and director of CUAVA – the ARC training centre for CubeSats, UAVs (Unmanned Aerial Vehicles) and their applications.

“They’re all approximately 10 centimetre by 10 centimetre by 10 centimetre cubes put together, there are standard electrical systems that people think would be useful, you can buy some parts commercially off the shelf, and that makes it so much easier to design.”

Several companies around the world sell standardised CubeSat frames – called the “bus” – and components, which makes it a relatively simple matter for those using them to add in their chosen payloads.

“The philosophy I like is that you buy the CubeSat bus and you put in the parts that matter to you, you put in the payloads, and you use your brainpower on the bits that are interesting to you, not on just the details of the engineering,” Cairns says.

The payload is the sexy stuff, and the reason CubeSats are so hot right now. They can carry a host of scientific instruments – imaging tech, radar, spectrometers, GPS, devices for measuring magnetic fields – all of which are being used to monitor and analyse Earth’s surface and atmosphere.

“Generally speaking, CubeSats initially were just a bit of a toy and people used them to test the capabilities to launch something into space,” says Adrian Rispler, CSIRO senior researcher and project lead on the CSIROSat1 CubeSat project.

“But now the CubeSats are moving more into a scientific benefit space, people are trying to do proper science.”

CubeSats are also expanding our understanding of the thermosphere – the atmospheric region around 85 kilometres to 600 kilometres above the planet’s surface, in which they orbit.

Home to the ISS and other low-orbit satellites, it remains relatively poorly studied because larger satellites can’t maintain orbit at such low altitude; atmospheric drag causes orbital decay far too quickly for such costly spacecraft. CubeSats, however, needn’t last as long, so they can orbit much lower.

The thermosphere is so-called because at its outermost edge, temperatures can be as high as 2000 degrees Celsius as the atmospheric particles absorb energy from ultraviolet and X-ray radiation, preventing them from roasting the Earth’s surface.

It’s also vital for long-range radio and satellite communications, so understanding the mechanics of this region is vital. A global collaboration of 28 countries – called QB50 – is planning to launch more than 50 CubeSats with the goal of advancing knowledge of the thermosphere; 36 have already made it into space.

At this relatively early stage of development, CubeSat research is also helping to design and build better, cheaper, more accessible CubeSats.

Bianca Nogrady is a Sydney-based writer. This is an excerpt from her feature article in the latest edition of Cosmos magazine. You can subscribe to Cosmos here.