Australian universities joined a European fleet of CubeSats to explore a little-known layer of the atmosphere.

In May 2017, the European Union led a mission called QB50 to launch a constellation of 50 mini-satellites from the International Space Station. The pocket-sized CubeSats set out to study the thermosphere, the layer of Earth’s atmosphere between 90 and 600 kilometres above the ground that carries signals from GPS and other satellites.

Three of the CubeSats were Australian, built by teams from the University of NSW, the University of Sydney, Australian National University (ANU), the University of Adelaide and the University of South Australia. They were tested and certified in ANU’s Advanced Instrumentation and Technology Centre at Mount Stromlo.

The QB50 mission sought to measure the density, temperature and composition of the thermosphere and the way it responds to space weather. Each of these cubes was 10 centimetres on a side, weighed around a kilogram and could be assembled into larger units.

“CubeSats were perfect for this mission. Being so small, their orbits decay and they are dragged down through the lower layers of the atmosphere. They stay up for around a year, take millions of simultaneous measurements and then burn up, so there is no space debris,” says Professor Christine Charles from ANU.

When solar flares hit the thermosphere, they can temporarily scramble satellite systems or knock them out completely. This radiation also heats and expands gases, creating unpredictable drag forces that can change the paths of orbiting satellites. The new observations will improve tracking of orbiting objects such as the International Space Station, satellites and debris.

The deployment is the culmination of work by more than 50 universities and research institutes from 16 countries and five continents.

Banner image: The Inspire-2 CubeSat being tested. Credit: University of Sydney