Japan's IKAROS Solar Sail Mission Extended for a Year

26 January 2011 11:58 am

TOKYO—Success is paying off for Japan's IKAROS solar sail mission: The team behind the spacecraft confirmed today that it flawlessly completed all the performance tests set for it during its planned 6-month life. As a reward, the Japan Aerospace Exploration Agency (JAXA) has extended the mission to March 2012.

"In half a year, we accomplished all the mission objectives," said mission manager Osamu Mori, of JAXA's Institute of Space and Astronautical Science in Sagamihara, near Tokyo. "Now we've set new objectives."

Launched 21 May along with JAXA's ill-fated Akatsuki Venus probe, IKAROS (the Interplanetary Kite-Craft Accelerated by Radiation of the Sun) successfully used centrifugal force to unfurl its 20 meter diagonal, 0.0075 milimeter thick polyimide sail and relied on the pressure of photons streaming from the sun for acceleration. Controllers tweaked the craft's attitude by turning liquid crystal devices on and off to vary the reflectance (and thus the photon pressure) across the sail. All of these accomplishments were spacefaring firsts, Mori says. (Two previous solar sail missions by other countries foundered on rocket failures.)

While sailing, the craft's suite of scientific instruments caught gamma ray bursts, collected data on space dust, and participated in very long baseline interferometry observations of celestial objects.

With the extended lease on life, the team will try new navigational tricks, such as varying the sail's angle toward the sun and changing the craft's trajectory. Mori called these "risky" maneuvers because they are not sure if the sail will remain fully extended. They intend to model the sail's behavior and the craft's response to plan future solar sail missions.

Their next solar sail project is already in the works. They intend to pair a solar sail 10 times larger than that of IKAROS with the ion engines that took the Hayabusa satellite to asteroid Itokawa and back for a mission to Jupiter. They are eyeing a 2019 or 2020 launch so this craft can rendezvous with planned U.S. and European missions for joint observations of the solar system's largest planet.

Separately, NASA on 21 January announced that its solar sail mission, NanoSail-D, once thought lost due to a malfunction, successfully deployed its sail and is working as planned. Solar sailing could usher in "a new age of discovery in the solar system," said Mori.

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