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.