Jason DavisJan 26, 2015

It's Official: LightSail Test Flight Scheduled for May 2015

Ten years ago this June, a Russian submarine in the Barents Sea launched a ballistic missile toward space. 

Originally designed as a rocket of destruction, the Volna—Russian for "wave"—carried an instrument of peace: the world's first solar sail, Cosmos 1. Financed entirely by private citizens, The Planetary Society's spacecraft was set to become the first object to rely solely on sunlight for propulsion. 

But 83 seconds into the flight, things went awry. A turbopump inside the rocket shut down. The engine fell silent. And the Volna coasted quietly to a height of 75 kilometers before tumbling back into the sea. 

This May, The Planetary Society will try again. The first of our two member-funded LightSail spacecraft is slated to hitch a ride to space for a test flight aboard an Atlas V rocket. The 3-unit CubeSat—about the size of a loaf of bread—will spend about a month in orbit. There, it will communicate with the ground, deploy its solar sails and send images back to Earth.

LightSail website

Visit our new LightSail website

In honor of our May 2015 test flight, we're releasing a brand new LightSail website. The project's new home includes spacecraft details, a mutli-part history series, and a multimedia gallery.

The first LightSail spacecraft won't fly high enough to escape Earth's atmospheric drag and demonstrate true solar sailing. But the shakedown cruise will test out all of the CubeSat's critical functions, paving the way for a full-fledged solar sail flight in 2016. The second flight will launch aboard SpaceX's new Falcon Heavy rocket.

In December, LightSail completed its final qualification tests and was cleared for flight by engineers at the California Polytechnic State University (Cal Poly) in San Luis Obispo, Calif. Cal Poly provides the P-POD (Poly-Picosatellite Orbital Deployer) container that will spring the spacecraft loose from its Atlas V rocket. The 2015 test flight is sponsored by NASA's Educational Launch of NanoSatellites (ELaNa) program, which helps CubeSat providers find ride-sharing opportunities. The rocket's primary payload is classified, and will launch from the Cape Canaveral Air Force Station in Florida.

The CubeSat will spend four weeks in a checkout phase, communicating with ground stations at Cal Poly and the Georgia Institute of Technology (Georgia Tech) in Atlanta, Ga. The prolonged checkout ensures LightSail will have time to drift away from other spacecraft released during the flight, ensuring reliable two-way communications with the ground. Three electromagnetic torque rods aboard the spacecraft will interact with Earth's magnetic field, firing at regular intervals to orient the spacecraft. After the checkout period, LightSail's four solar panels will swing open, revealing the inside of the tightly packed CubeSat. A small motor will extend four, tape measure-like metallic booms from the spacecraft's lower compartment, tugging four, triangular Mylar sails out of storage. The sails have a combined area of 32 square meters. 

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LightSail short film: Flight by Light The first of The Planetary Society’s two LightSail spacecraft will ride to space aboard an Atlas V rocket in May 2015. The mission is a shakedown cruise designed to test out the CubeSat’s critical systems.Video: The Planetary Society

During the four-week checkout period, the spacecraft's orbit will decay only slightly. But once the large sails are deployed, LightSail will be quickly pulled back into the atmosphere. Orbital models show an expected sail lifetime of just two to ten days. While the first LightSail mission will be short, it will provide crucial engineering data in preparation for the 2016 flight, which will attempt true solar sailing at a circular altitude of 720 kilometers.

LightSail is equipped with two, inward-facing cameras that provide 360-degree coverage of the sails. The cameras are attached to the spacecraft's solar arrays and swing outward just before sail deployment. They will capture timelapse images of the deployment sequence, revealing how the large sail performs in a microgravity environment. 

The results of the May 2015 test flight are of particular interest to NASA, which is gearing up for two small-scale solar sail missions of its own. Through a series of technical interchange meetings, LightSail managers and engineers have been sharing data with teams from the Jet Propulsion Laboratory and Marshall Space Flight Center. In 2018, NASA's NEA Scout and Lunar Flashlight spacecraft will ride to the moon aboard the inaugural flight of the Space Launch System. NEA Scout is slated to spiral onward to visit a near-Earth asteroid, while Lunar Flashlight will remain at the moon, using its solar sail to reflect sunlight into permanently shadowed lunar craters. Both spacecraft are 6-unit CubeSats with sail areas double those of LightSail. 

Depending on LightSail's final May 2015 launch date, sail deployment could occur in early June—just a couple weeks shy of the 10-year Cosmos 1 anniversary. A successful mission would be a watershed moment for The Planetary Society, which is now celebrating its 35th year as an organization. But the first flight of LightSail is still a test, designed primarily to shake out bugs lying in wait for the second mission. Success is certainly not a guarantee.

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LightSail onboard camera timelapse This timelapse was created using images from LightSail's onboard cameras, which captured a sail deployment test at Cal Poly San Luis Obispo on Sept. 23. LightSail is equipped with two fisheye cameras that will record the spacecraft's sail deployment in space.

After Cosmos 1 failed to reach orbit in 2005, the honor of the world's first solar sail went to Japan's IKAROS, a Venus-bound spacecraft launched in 2010 alongside the Venus Climate Orbiter. Later that year, NASA launched Nanosail-D, a technology demonstration CubeSat that tested the viability of using solar sails to deorbit spacecraft. Using private donations, Planetary Society co-founder Louis Friedman led the charge to develop a more advanced version of Nanosail. The new spacecraft, built by Stellar Exploration Technologies in San Luis Obispo, Calif., added functionality that would allow it to attempt controlled solar sailing.

The project is now under the direction of Doug Stetson, the founder and principal partner of the Space Science and Exploration Consulting Group. LightSail's primary contractor is Pasadena, Calif.-based Ecliptic Enterprises Corporation. Ecliptic's flight system experience includes RocketCam, a family of onboard video systems used on rockets and spacecraft. 

Both LightSail spacecraft are expected to be visible from the ground when their sails are deployed. We're working on a dashboard to display ground tracks and telemetry data, giving citizens around the world to catch a glimpse of our solar sails shimmering in the sunlight.

For more information, check out our new LightSail website at sail.planetary.org.

You can access our official LightSail test flight press release here.

LightSail spreads its sails
LightSail spreads its sails The Planetary Society's LightSail spacecraft sits on its deployment table at Cal Poly San Luis Obispo following a day-in-the-life test on Sept. 23, 2014.Image: Justin Foley

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