In an effort that will surely warm the heart of any Carl Sagan fan, more than 3,000 cosmically curious backers have made a Kickstarter campaign for LightSail, a citizen-funded spacecraft developed by The Planetary Society, an overwhelming success.
Less than three days after its launch and more than a month before its deadline, the campaign hit its $200,000 goal on Wednesday, May 13.
Bill Nye, CEO of The Planetary Society, created the Kickstarter earlier this week in the hopes of making a dent in the $1.2 million that the project had left to raise. LightSail's first full-blown spaceflight is slated for 2016, but it will be riding to space aboard an Atlas V rocket on May 20 of this year for a test run.
"It's going to be a big step for our little spacecraft and for space exploration writ large," Nye said in an AMA on Reddit yesterday.
As its name suggests, LightSail is propelled solely by light. However, we're not talking about fancy solar panels here — the LightSail will literally be pushed by light rays. Beloved astronomer Carl Sagan, the original host of the popular television series Cosmos, described the concept on The Tonight Show with Johnny Carson nearly 40 years ago (scroll down to see a video of the interview).
Light is made up of tiny packages of energy called photons. Any light source, be it a smartphone or the sun, emits light by shooting out a whole bunch of photons, which carry momentum as they travel. When the photons reflect off a surface of an object, they transfer some of their momentum to that object, effectively pushing it.
Of course, light does not push very hard, or else we would notice this force every time we switch on a light. To get around this issue, the "sail" part of the LightSail is made up of a very lightweight and highly reflective material called Mylar. Each spacecraft is only about the size of a loaf of bread folded up, but with its Mylar sails unfurled, its total surface area is nearly 350 square feet, meaning that many photons can hit it at once. This high-surface-area, low-weight design will help LightSail harness the momentum from each photon as efficiently as possible.
"LightSail will demonstrate that we can greatly reduce the cost of missions to other worlds in our solar system," Nye said. "It will be another step in democratizing space. It will enable more of us to learn more about what's up there."
