The idea of solar sails carrying satellites and humans into space has been something bandied about for decades, but has only been relegated to the pages of science fiction. Now, in 2015, science fiction is about to become science reality: On Wednesday, May 20, LightSail, a citizen-funded project by The Planetary Society, will ride its way into space aboard a United Launch Alliance Atlas V Centaur upper stage. According to the organization, this prototype of LightSail won’t travel high enough above the Earth’s atmosphere to “sail,” but it will test its sail deployment sequence. In 2016, LightSail will be ejected into space by the satellite Prox-1 following their delivery to an orbit with an altitude of approximately 720 kilometers (450 miles). These payloads will be launched by a SpaceX Falcon Heavy.
Solar sail technology has the potential to send payloads such as CubeSats to planetary destinations without the use of expendable chemical fuels. The project, which is being funded by Planetary Society members and public donors, was discussed by the organization’s CEO Bill Nye in a Reddit “Ask Me Anything,” on Tuesday, May 12. When asked to best explain the concept of sails, Nye answered: “Photons (particles of light) have no [mass], but they are pure energy, and they have momentum. So, in the vacuum of space, we can design a very low mass spacecraft with a very large reflective area, and it will get a continuous push.” LightSail is 344 square feet across and is in line with the spaceflight innovations envisioned by The Planetary Society upon its founding, which took place in 1980.
Jason Davis, embedded reporter with The Planetary Society, spoke with AmericaSpace about the project, its heritage, and where it is going.
AmericaSpace: Carl Sagan (co-founder of The Planetary Society) discussed the concept of using solar sails as far back as the 1970s. Now, in 2015, the prototype for LightSail is about to be launched. How do you think this further contributes to Sagan’s legacy?
Jason Davis: The Planetary Society was originally founded to demonstrate popular support for planetary exploration. In the first issue of our member magazine (The Planetary Report, which we still publish today), Sagan wrote that he also believed we could “provide some carefully targeted funds for the stimulation of critical activities.” We’ve supported dozens of such projects over the years, but LightSail, as well as its short-lived predecessor, Cosmos 1, is one of the most ambitious. Projects like LightSail are exactly what Sagan had in mind, so we’re proud to be a part of that legacy.
AmericaSpace: This concept was previously explored with Cosmos I and NanoSail-D (the first version), but neither payload made it into orbit. This launch must be bittersweet in that it seems like it was a long time in coming. What is the excitement level concerning LightSail’s “birth”?
Davis: Actually the second Nanosail-D made it into space and had a deployment issue that eventually worked itself out, and it lasted in orbit for quite some time. It was part of the inspiration for LightSail—Louis Friedman, one of our co-founders, believed we could build our own Nanosail-D and improve upon the design.
Nonetheless, it’s been a long time coming for the Society. Friedman and Bruce Murray (another co-founder) worked on a Halley’s Comet solar sail concept at NASA in the late ’70s and early ’80s, and then there was Cosmos 1. LightSail itself faced funding and technical challenges, but we finally got this test flight to the launch pad. The atmosphere at the Society is pretty incredible right now. We keep reminding ourselves that this is just a test (things are bound to go wrong), with the real show scheduled for 2016, but it’s hard not to get swept up in the excitement.
AmericaSpace: What kinds of functions on LightSail will be tested during this mission? Approximately how “high up” will LightSail be traveling?
Davis: The main objective is to verify sail deployment. That’s currently scheduled to occur autonomously 28 days after deployment, with an option for an earlier manual deployment. We still can’t disclose the orbital parameters at this time due to the nature of the primary payload, the Air Force’s X-37B spaceplane, but we’ll be in low-Earth orbit. We’ll have a real-time Google map showing some of those details after launch.
AmericaSpace: LightSail is being funded through the Planetary Society’s members and private citizens. How much did it take to bring this prototype to fruition, and how much will it take to get the 2016 version into Earth’s orbit? What does this effort say about the public’s interest in spaceflight and future space propulsion methods?
Davis: The project was started in 2009. It took a long time to find a free ride to orbit that’s high enough to escape most of Earth’s atmospheric drag (the Falcon Heavy flight will drop us into a 720 kilometer orbit). Combine that with a few technical problems, and the project was sent into temporary hiatus. That changed a couple of years back when we secured some new funding and brought in a new project manager, Doug Stetson, and a new prime contractor, Ecliptic Enterprises Corporation. Ecliptic is best known for the RocketCam systems used on space shuttle launches.
The full price tag for both missions is expected to be $5.45 million, and our Kickstarter aims to raise $200,000 of that. I think the fact that we’re on track to meet that goal within a couple days shows how eager folks are to contribute to space exploration.
(Author’s note: The Kickstarter quickly reached its $200,000 goal, but is still accepting donations through June.)
AmericaSpace: Where do you see LightSail or similar technologies going in 20 years?
Davis: CubeSats are already a cool way for universities and small groups to do an actual space mission on the cheap. The educational and real-world experience value of flying a CubeSat can’t be overstated—in many cases, these are scaled down versions of full-fledged NASA missions. Since a limiting factor of CubeSats is a lack of propulsion, solar sailing could be a game-changing technology. In 20 years, we’d be thrilled to see a fleet of low-cost solar sailing CubeSats leave Earth orbit for the Moon, Lagrangian points, or Mars. Hopefully with LightSail, we’ll help make that a possibility.
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