Image Credit & Copyright: Planetary Society.
If you’re a member of the Planetary Society (which all space nuts should be), or even if you just love new technology and spaceflight in general you’re getting excited about this launch. Scheduled for launch on May 20, 2015 on a United Launch Alliance (ULA) Atlas V-501 rocket (Same launch that will carry the AFSPC 5 X-37B) LightSail 1 will be placed into orbit for testing.
So what the heck is a solar sail?: So this is a new technology, but is it a new idea? Nope; the idea has been in numerous sci-fi novels for a long time. For example, in 1865 Jules Verne encapsulated the idea in his book, “From Earth to the Moon.” About 100 years later, Arthur C. Clarke mentioned solar sailing in his short story “Sunjammer.”
In short, you can loosely equate it to a sailboat but instead of wind pressure blowing into your sail providing propulsion it uses solar radiation pressure in the form of protons (photons have no mass but it does have momentum) to act against the sail as propulsion to get around the solar system.
Back to LightSail1: LightSail 1 is a crowd funded project by the Planetary Society which was founded by Carl Sagan and currently headed by Bill Nye. The sail itself is a 32 m (344 ft.) square Mylar sail (technically 4, triangular sections) which, once deployed will be impacted by photons from the Sun. The transfer of momentum will then propel LightSail 1. This is beneficial because although this is a much slower process than chemical rockets, it’s a continuous acceleration which pays off over time by great speed as well as the mass saved by not needing fuel. And get this; the entire spacecraft will be deployed from a cubesat about the size of a loaf of bread! That’s efficiency!
The mission parameters are great but modest. The mission will be brief and will not leave Earth orbit due to the Atlas V releasing them at too low an altitude. According to the Planetary Society, after deployment from the Atlas V rocket which will be carrying the X-37B space plane, it will spend about a month in checkout phase to communicate with ground stations and allow time for other spacecraft deployed to leave the area. Once the sails deploy, the mission will last anywhere from two to ten days. That’s because, since LightSail 1 will remain in low Earth orbit (LEO) it will act as a drag chute once the sails are deployed. Atmospheric drag will then rapidly pull the spacecraft back to Earth for a fateful reentry.
The second step for the Planetary Society in the research and demonstration of this technology is slated to take place in 2016 as LightSail 2 will be launched onboard a SpaceX Falcon 9 Heavy rocket from Kennedy Space Center (KSC) Launch Complex 39-A (LC-39A). The F9H will release its payloads at a high higher altitude and will allow for LightSail 2 to gain enough solar momentum to break free of Earth.
Will this be the first solar sail?: There have been solar sails launched in the past, in fact back on June 21, 2005 the Planetary Society launched a solar sail called Cosmos 1 on a “Volna” ballistic missile from the Russian submarine “Borisoglebsk” from the Barents Sea but after liftoff, the rocket failed and the payload never reached orbit.
The first successful launch and deployment of a solar sail came on May 21, 2010 on an H-IIA rocket by the Japan Aerospace Exploration Agency (JAXA). The Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS) was a 20 m (66 ft.) square solar sail that spun at approximately 25 revolutions per-minute propelled only by solar radiation. On December 8, 2010 it passed Venus which completed its science objectives but even today is still being propelled by the Sun.
NASA tried their hand at a solar sail dubbed Nano Sail-D which launched and was lost on August 3, 2008 when the SpaceX, Falcon 1 rocket that was carrying it failed to reach orbit. Not one to quit, NASA successfully launched Nano Sail-D (or Nano Sail-D2 depending who you ask) on November 19, 2010 on a Minotaur IV Peacekeeper ICBM missile from Kodiak Launch Complex, Pad 1. It spent more than 240 days in Earth orbit collecting data on the up and coming technology.
Planetary Society: http://planetary.org/
Planetary Society LightSail 1: http://sail.planetary.org/
LightSail 1 on the Planetary Society Blog: http://www.planetary.org/blogs/jason-davis/2015/20150112-lightsail-test-flight.html