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Privately-funded Solar Sail Prepared For Launch

A test flight of The Planetary Society's small LightSail Spacecraft is set for May

2 min read
Privately-funded Solar Sail Prepared For Launch
Team members Alex Diaz (left) and Riki Munakata (right) with the LightSail spacecraft. The solar sail booms will extend from the bottom.

In a parallel universe, a NASA-sponsored experimental solar sail—the largest ever built—would be launching into space next month along with the solar wind-monitoring DSCOVR spacecraft. That won’t happen in this universe: NASA cancelled the Sunjammer launch last year due to scheduling concerns, and it’s not clear when, or even if, the sail will get another opportunity to fly.

But there is a bright spot on the near horizon for solar sail tests. The space advocacy organization The Planetary Society today announced that a date has been set for the first flight of its LightSail spacecraft. The 30-centimeter-long CubeSatan increasingly popular class of small spacecraftis set to take off from Cape Canaveral Air Force Station in May as a secondary payload on an Atlas V rocket.

Solar sails are propelled by the momentum that photons impart when they bounce off a reflective surface. This method of propulsion can provide slow but steady acceleration to high speeds, which could cut down on the cost and mass of interplanetary missions. With the assistance of a powerful laser beam, the same technique might be used to propel spacecraft to interstellar mission speeds.

Solar sails “will ultimately eventually take a lot of missions a long, long way,” Planetary Society CEO Bill Nye told the New York Times. He said that this spacecraft—and a second one set to launch next year—together cost less than US $4 million to build. 

This first LightSail, integrated and tested by the Pasadena, Calif.–based Ecliptic Enterprises, will spend a month or so in orbit before it unfurls Mylar sheets along 4-meter-long booms to create a 32-square-meter sail. The first flight will be a shakedown mission to test sail deployment and other aspects of the spacecraft. But the sailing will have to wait; the spacecraft will be carried to a fairly low orbit where it will experience significant drag from the atmosphere. The second spacecraft, slated to launch in 2016 on a SpaceX Falcon Heavy rocket, will reach a higher orbit where solar pressure can be used to maneuver.

Other spacecraft have used radiation pressure to adjust their orbits, and solar sails have already had a few successful missions. In 2010, the Japan’s space agency JAXA launched a solar sail called IKAROS (short for Interplanetary Kite-craft Accelerated by Radiation Of the Sun) on a mission past Venus. And in 2011, NASA successfully unfurled NanoSail-D, also a compact CubeSat, in low-Earth orbit.

The new Planetary Society mission comes some 10 years after its first solar sail spacecraft, Cosmos 1, fell to Earth after a rocket failure. 

The Planetary Society's Jason Davis writes that the team has been sharing data with NASA teams that are working on additional solar-sail-bearing CubeSat missions. The space agency aims to launch at least two such missions (not all payloads have been selected yet) on the maiden voyage of the new heavy-lift Space Launch System, which could happen as early as 2018. One of the spacecraft, Lunar Flashlight, will use its solar sail to maneuver and to reflect light onto the moon's south pole.

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Top Tech 2022: A Special Report

Preview two dozen exciting technical developments that are in the pipeline for the coming year

1 min read
Photo of the lower part of a rocket in an engineering bay.

NASA’s Space Launch System will carry Orion to the moon.

Frank Michaux/NASA

At the start of each year, IEEE Spectrum attempts to predict the future. It can be tricky, but we do our best, filling the January issue with a couple of dozen reports, short and long, about developments the editors expect to make news in the coming year.

This isn’t hard to do when the project has been in the works for a long time and is progressing on schedule—the coming first flight of NASA’s Space Launch System, for example. For other stories, we must go farther out on a limb. A case in point: the description of a hardware wallet for Bitcoin that the company formerly known as Square (which recently changed its name to Block) is developing but won’t officially comment on. One thing we can predict with confidence, though, is that Spectrum readers, familiar with the vicissitudes of technical development work, will understand if some of these projects don’t, in fact, pan out. That’s still okay.

Engineering, like life, is as much about the journey as the destination.

See all stories from our Top Tech 2022 Special Report

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