Ikaros hasn’t flown too close to the sun. It’s flown just close enough to ride the light.
Japan’s space agency JAXA confirmed on Friday that its solar sail project, Ikaros, achieved another of its goals: The sun’s photons pushed against the sail and accelerated the craft.
The effect stems from the cumulative push of light photons striking the solar sail. When measured together, it adds up to a small continuous thrust that does not require fuel use by the Ikaros craft. JAXA engineers used Doppler radar measurements of the Ikaros craft to determine that sunlight is pressing on the probe’s solar sail with a force of about 1.12 millinewtons (0.0002 pounds of force) [MSNBC].
Japan launched Ikaros in May and unfurled the sail in June. Now, JAXA scientists say, “with this confirmation, the IKAROS was proved to generate the biggest acceleration through photon during interplanetary flight in history.” Coming soon: A controlled flight in which the researchers turn the sail toward or away from the sun to control Ikaros’ velocity.
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Image: JAXA

July 14th, 2010 at 3:48 pm
The press release wasn’t vetted very well. It says it is experiencing a thrust of 1.12 milli-newtons and a net acceleration of 0.114g or about 1.1 meter/second squared.
Unless the entire satellite only masses 1 gram that is pretty unlikely.
July 15th, 2010 at 6:06 am
I would add Benjamin, that calling this an “interplanetary flight” is a bit of a stretch. I dont want to take away the success of working technology here…but interplanetary flight???
Talk about hamming it up.
July 15th, 2010 at 9:17 am
m @2 : Wikipedia says: “The craft will spend six months traveling to Venus.” There is going to be a flyby, apparently.
And g, in this case, means grams, not 9.81 m/s^2. They are talking about a force of 1.12 mN, which is the Earth weight of a 114 mg object.
July 15th, 2010 at 10:17 am
did they get that from star wars 2?
July 16th, 2010 at 9:34 am
I love it when a staple of hard science fiction, something that should work in theory, is made to work in practice.
July 30th, 2011 at 1:06 am
Just wanted to let you know that I enjoy reading your posts. Dont have much to add, cheers!