Making light work of space travel

Pip Moss, Content Manager for Antenna gallery, explains one of the latest developments in space exploration, the LightSail, created by The Planetary Society.

Are we alone in the universe? Do other habitable planets exist? Where will we go when Earth can no longer support us? Age-old questions like these continue to drive our desire for deep space travel. But if we’re to venture far beyond the planets in our solar system, we need a new method of travel. Our closest star system, Alpha Centauri, is 4.37 light years away. If it were possible to use current fuel-based space shuttles to get there, which it’s not, we’d be looking at a journey time of about 165,000 years. Even if we took advantage of gravitational pull to slingshot a craft in its general direction, the same technique that sent Voyager-1 into interstellar space, you’d still be left with an eta of many thousands of years and would have to pass the Sun to get the top speed needed.

That’s why solar sails are being touted as the future of space exploration. This lightweight, completely fuel-free system enables spacecrafts to be ‘pushed’ through space thanks to the momentum that photons of light transfer when they bounce off its highly reflective sails. As long as there’s a continuous source of light, the craft can be continuously ‘pushed’ forward, faster and faster.

Leading this field is The Planetary Society with their crowd-funded solar sailing satellite, LightSail™. Folded up to the size of a loaf of bread, the LightSail cubesat needs to hitch a ride to space aboard a rocket. But once released, about 720km above Earth, it can unfurl its 32m2 sails and start its journey.

The non-profit organisation has been talking about solar sails for over 40 years, but it wasn’t until 2000 that work on the idea began.

In 2015 though, the team’s hard work paid off when LightSail successfully flew in a deployment test. With this great achievement under their belt and a replica model of the LightSail satellite now on display in our interactive Antenna gallery, Bill Nye, Planetary Society CEO and American science educator, gave us a quick update on what’s to come when he came to visit:

‘We’re planning on launching LightSail-2 as soon as we can, hopefully as early as autumn 2017. The satellite is built and ready to go, we just have to wait for the new rocket to be ready. We are excited to be aboard a SpaceX Falcon Heavy!’ Bill Nye.

According to experts, a solar sail craft could make the trip to Alpha Centauri in just 20 years, which is why it’s now the focus of project Breakthrough Starshot whose ambition it is to do exactly that. Relying on solar rays alone, it would take a month for LightSail to reach the same speed as a jet airliner. But with enough time and light exposure, it’s hoped solar sails could be propelled to 15-20% of light speed, faster than any spacecraft that currently exists. At some point, when it got too far from the Sun, LightSail would stop accelerating, but without enough gravity to slow it down it would continue to travel at its top speed indefinitely.

The LightSail model will be on display in our interactive Antenna gallery until mid-April 2017. Visit our website to find out what else is currently on display in the gallery.

Video Credits:

LightSail Flight by Light – Behind the scenes at The Planetary Society
Credit: The Planetary Society

LightSail Then and Now – In 1976, Carl Sagan appeared on The Tonight Show to talk about a crazy new idea: solar sailing.
Credit: The Planetary Society

LightSail – Bill Nye at the Science Museum, March 2017
Credit: Science Museum Board of Trustees