How Fast Is Solar Sail?

Solar sails use no fuel — just the pressure of sunlight on huge reflective sheets. Acceleration is glacially slow, but cumulative; over months, a solar sail can exceed any chemical rocket. The 2010 Japanese IKAROS was the first successful interplanetary solar sail.

Solar sails accelerate using only photon pressure from the Sun — over months they can exceed any chemical rocket, with zero fuel cost.

• No fuel needed at all
• Slow but cumulative acceleration