Solar storms force Australian satellites to an early demise
Unpredictable solar activity is causing satellites to fall to Earth. Intense solar phenomena contributed to the premature end of the mission for three Australian Binar satellites, prompting specialists to re-evaluate space weather forecasts and their impact on technology.
Last week, three Australian satellites from the Binar program, managed by Curtin University, prematurely re-entered the Earth's atmosphere, where they burned up. Their mission ended after only two months, even though they were initially planned to be in orbit for six months. The Binar-2, 3, and 4 satellites were not the only victims of high solar activity—the recent increase in solar phenomena has been causing trouble for satellite operators worldwide, as reported by The Conversation.
What is happening on the Sun?
The solar cycle lasts approximately 11 years and is characterized by changes in the sun's magnetic field. When solar activity reaches its peak, the frequency of phenomena such as sunspots, solar flares, solar winds, or the stream of charged particles increases. Although this cycle is known, accurately predicting solar activity is difficult—the Sun's processes are complex, and predictions are often inaccurate.
The current phase of the cycle, known as Solar Cycle 25, surprised scientists with a level of activity 50% higher than predicted. This has been accompanied by spectacular auroras that have been visible much closer to the equator than usual in recent months. High solar activity threatens satellites, astronauts, and radio communications, necessitating greater precision in space weather forecasts.
Space weather refers to phenomena outside our atmosphere, mainly from the Sun, that affect the Earth. Increased solar activity causes more solar flares and stronger solar winds, which increase the flow of charged particles that can damage satellite electronic systems. For satellites in low Earth orbit, atmospheric conditions also increase air resistance, causing faster descent.
Low orbits include the International Space Station and Starlink satellites, which can adjust their position using propulsion systems. However, university satellites, like Binar CubeSats, rarely have such capabilities and rely entirely on space weather conditions.
According to scientists' forecasts, solar activity will decrease and may reach a minimum by 2030, which suggests less challenging conditions for future missions. The Binar programme continues to work on future satellites, which may likely encounter more favourable conditions.
