Last week, three small satellites from Curtin University’s Binar Space Program in Australia burned up in the atmosphere of Earth. While these CubeSats—Binar-2, 3, and 4—were expected to last six months, they only lasted two due to increased solar activity, significantly shortening their time for scientific research and testing.
Why is the Sun more active?
Solar activity, including phenomena such as sunspots and solar flares, is driven by the Sun’s magnetic field, which flips approximately every 11 years. At the midpoint of this cycle, solar activity peaks. The Sun is currently more active than predicted in this 11-year solar cycle, known as Solar Cycle 25, with indicators showing activity at 1.5 times expected levels.
The impact of space weather on Earth and space
Space weather, largely originating from solar activity, impacts Earth in various ways, including the appearance of auroras, which have become more intense and visible closer to the equator than usual. Increased solar activity also brings higher risks for satellites.
The extra energy from solar flares and solar wind causes Earth’s outer atmosphere to expand, leading to increased drag on satellites, especially those in low Earth orbit. While some satellites like the International Space Station and Starlink have thrusters to counteract this drag, smaller CubeSats like the Binar satellites lack these capabilities, making them more vulnerable to orbital decay.
Looking ahead
The sun’s heightened activity is expected to slow by 2026, with a return to a solar minimum anticipated by 2030. The Binar Space Program’s experience underscores the impact of solar activity on space missions, demonstrating a need for improved space weather forecasting. Despite the challenges, the Binar team is moving forward with plans for future missions, continuing their work in space research and technology.
