The European Space Agency confirmed that its Helios-3 solar sail has deployed successfully in orbit. Telemetry shows the spacecraft extended its four lightweight composite booms, unfurling a 150-square-meter reflective polymer sheet without tearing.
Solar sails use the pressure of sunlight for propulsion. Although light has no mass, photons exert a tiny force when they bounce off a reflective surface. Over time, this constant push can accelerate a spacecraft to high speeds without carrying fuel.
Fuel-Free Deep Space Missions
Ground controllers in Darmstadt, Germany, reported that the sail has already adjusted its orbit using only sunlight. The success opens the door for low-cost scientific missions to the outer solar system, where carrying heavy propellant is the main barrier.
"This is a major step for deep-space transport," says mission lead yuki Tanaka. "We can now design missions to hover near the sun or visit multiple asteroids without running out of fuel."
Helios-3 will continue tracking orbit adjustments for another six months to test sail durability in solar wind.
