It’s easy for news like this to get lost in the tumult of global politics, but let me leave the discussion of Egypt and Tunisia to the better-informed and tell you about some interesting astro-news. NASA has successfully deployed Nano-Sail D (below), a 100 square foot solar sail in low Earth Orbit. The success of the mission was confirmed by amateur radio operators, who detected its signal beacon at 437.270 MHz. This success follows in the footsteps of the groundbreaking IKAROS mission, which deployed the first ever functioning solar sail to propel it towards Venus, where it flew by last month.
Solar Sails use light itself to power a spacecraft. As you may know, light is made of photons, and these photons have momentum, just like matter does. When a photon is absorbed or reflected by matter, it gives some momentum to the matter. This gives us a form of propulsion that doesn’t require any fuel whatsoever (provided you’ve got a healthy photon source like the Sun kicking around).
You can see how useful a solar sail could be in long journeys between the planets – you don’t have to take fuel with you, and the only thing that limits your range is how much electrical power you can store. NASA’s solar sail has this same problem – its batteries are limited, and as such the satellite is already running out of power.
These are the first steps towards an era of space exploration where fuel is an option, not a necessity. We can hopefully look forward to a future where satellites are no longer condemned to graveyard orbits because of lack of fuel, and are properly de-orbited and disposed of. In fact, there’s no reason why this technology couldn’t be put to use clearing out the space debris that encircles our planet.
Exciting stuff, no? While it’s not the most important piece of news this week, the team at NASA still deserve congratulating for bringing the future a step closer. Well Done!