“Bill Nye the Science Guy” is a phrase with which nearly every geek on the planet is familiar. Nye is a champion of science and intellectual curiosity, and Krypton Radio fans will know him as a recurring guest speaker on Planetary Radio, one of the newest additions to the Krypton Radio family of programming.
Bill Nye is also the spokesman for a daring new space science project: the Lightsail.
From the Kickstarter (already fully funded), here is Bill Nye introducing the project:
I’m Bill Nye, CEO of The Planetary Society. Yes, the Science Guy is also the Planetary Guy. I invite you to come along on a cosmic journey with me by participating in a mission to sail a spacecraft, a tiny CubeSat no bigger than a breadbox, on beams of light. Imagine it: unlimited free energy from the Sun will provide CubeSats with propulsion and revolutionize access to space for low-cost citizen projects—projects like ours or by teams of students and faculty at universities. This means that spacecraft, especially small ones like CubeSats, won’t have to carry heavy fuels into orbit, and that the acceleration will be continuous. Even better, this is a journey that is directly funded by the world’s citizens, like you, rather than by governments. LightSail™ is truly “the people’s spacecraft.”
Our LightSail mission will be the culmination of the hopes and dreams of our visionary founders, Louis Friedman, Bruce Murray and Carl Sagan. Some of you may remember Carl famously promoting solar sailing on Johnny Carson’s The Tonight Show.
LightSail™ is a citizen-funded project by The Planetary Society, the world’s largest non-profit space advocacy group. We’re sending two small spacecraft into Earth orbit carrying large, reflective sails measuring 32 square meters (344 square feet).
The first mission launches tomorrow, May 20 between 10:45am & 2:45pm EDT! You can get live updates on this historic mission here.
It’s a shakedown cruise. The first Lightsail spacecraft will hitch a ride to orbit aboard an Atlas V rocket. It won’t take the cubesat high enough out of the Earth’s atmosphere for solar sailing, but they’ll able to test the sail’s deployment sequence and run orientation and control tests, and get some amazing pictures at very least. The second mission will be a full system test, to prove that the idea of sailing on light beams alone actually works.
Solar sails use the sun’s energy as a method of propulsion—flight by light. Light is made of packets of energy called photons. While photons have no mass, a photon traveling as a packet of light has energy and momentum.
Solar sail spacecraft capture light momentum with large, lightweight mirrored surfaces—sails. As light reflects off a sail, most of its momentum is transferred, pushing on the sail. The resulting acceleration is small, but continuous. Unlike chemical rockets that provide short bursts of thrust, solar sails thrust continuously and can reach higher speeds over time.
LightSail is a CubeSat. These tiny spacecraft often hitch rides to orbit aboard rockets carrying bigger payloads. CubeSats have standard unit sizes of 10 centimeters per side. They can be stacked together—LightSail is a three-unit CubeSat about the size of a loaf of bread.
Once in space, LightSail’s solar arrays swing open, revealing the inside of the spacecraft. Four tape measure-like metal booms slowly unwind from storage, unfolding four triangular, Mylar sails. Each sail is just 4.5 microns thick—one-fourth the thickness of an average trash bag.
Three electromagnetic torque rods aboard LightSail will interact with Earth’s magnetic field, orienting the spacecraft. Ground-based lasers will measure the effect of sunlight on the sails. As LightSail breezes around the Earth, its shiny sails will be visible from the ground. We’ll organize viewing campaigns to show people where to look.
In 2016, LightSail will be enclosed within Prox-1, a small satellite developed by the Georgia Institute of Technology (Georgia Tech) to autonomously inspect other spacecraft. Both satellites will be lifted into orbit by the Falcon Heavy, a new heavy-lift rocket built by private spaceflight company SpaceX.
LightSail and Prox-1 will be released into an orbit with an altitude of 720 kilometers (450 miles), high enough to escape most of the planet’s atmospheric drag. Prox-1 will eject LightSail into open space. Later, it will rendezvous with LightSail and inspect it. When LightSail unfurls its solar sails, Prox-1 will be nearby to capture images of the big moment.
As hard core science fiction fans, we’ve known about this concept for decades by another name: the “solar sail”. It’s a means of propulsion; a vehicle is deployed in open space, then deploys a sail made of very thin material that collects the inertial impulse of photons, using the power of sunlight alone to propel them outward into deep space. The effect was first postulated in 1610 by Johannes Kepler, observing the effect of solar wind on the tails of comets and theorizing that something must be pushing on those tails to deflect them and that this force might be something that could be harnessed to move a craft.
Lightsail is an exciting project, and you can play a direct hand in the exploration of space by contributing to the Kickstarter.
Let’s see what’s out there.
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