As sun nears peak of solar cycle, small satellites are paying the price Premium

Three Australian CubeSats from Curtin University's Binar Space Program burned up due to high solar activity.

Last week, three tiny Australian satellites from Curtin University’s Binar Space Program burned up in Earth’s atmosphere. That was always going to happen. In fact, Binar means “fireball” in the Noongar language of the First Nations people of Perth.

When a satellite is in low Earth orbit (2,000 km or less), it experiences orbital decay as it drags closer and closer to the surface, eventually burning up.

But these cube satellites (CubeSats), known as Binar-2, 3 and 4, entered the atmosphere much sooner than originally planned. They only lasted for two months – a third of what was expected. This significantly reduced valuable time for science and testing new systems.

The reason for their untimely demise? Our Sun has kicked into high gear, and the Binar satellites are far from the only casualty. Recent high solar activity has been causing an unexpected headache for satellite operators in the last few years, and it’s only increasing.

Solar activity includes phenomena such as sunspots, solar flares and solar wind – the stream of charged particles that flows toward Earth.

This activity is a product of the Sun’s ever-changing magnetic field, and approximately every 11 years, it completely flips. At the midpoint of this cycle, solar activity is at its highest.

While this cycle is known, specific solar activity is challenging to predict – the dynamics are complex and solar forecasting is in its infancy.