LightSail 2 will be propelled by sunshine
The Planetary Society
SpaceX is set to launch an experimental spacecraft next week on the third flight of its Falcon Heavy rocket. The craft, called LightSail 2, was developed by space advocacy group The Planetary Society and harnesses sunshine to “sail” through the heavens.
A light sail is a spacecraft equipped with a large mirrored surface. As photons from the sun bounce off it, they impart a small amount of energy and push the spacecraft forward. Japan’s space agency launched the first solar sail into orbit in 2010, and NASA launched one later that same year.
The Planetary Society, led by Bill Nye, launched LightSail 1 in 2015 for a test flight, and despite issues with software and batteries it unfolded its sail successfully before falling back into Earth’s atmosphere.
LightSail 2 will take the test one step further, launching to a higher orbit before unfolding its silvery 32-square-metre sail. The higher orbit will mean there is less atmospheric drag, so the spacecraft should be able to use sunlight for controlled flight for up to a year.
The spacecraft is about the size of a loaf of bread and made up of three modules: two holding sails that are just 4.5 micrometres thick – thinner than a human hair – and one containing the control systems, sensors and cameras.
Ultimately, the goal is to show that light sails are a reasonable way to propel small satellites through the solar system. Light sails have also been proposed as a way to achieve interstellar travel without needing tonnes of fuel that would make the spacecraft too heavy – they accelerate slowly, but constantly, meaning it is theoretically possible to build up incredible speeds.
The Falcon Heavy rocket is due to lift off from the Kennedy Space Center in Florida on 24 June. The rocket will also carry a satellite testing a new, more efficient and environmentally friendly propellant for spacecraft and an extraordinarily precise atomic clock that might eventually be used for a sort of interplanetary GPS.