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The Planetary Society BlogBy Emily LakdawallaLou Friedman in Japan: Taking things slowly with IKAROS sail deploymentJun. 5, 2010 | 10:30 PDT | 17:30 UTC
Planetary Society Executive Director Lou Friedman was at JAXA's Japanese Space Exploration Center to observe the deployment of IKAROS' solar sails. He sent in this report at the end of a long day of activities on Saturday, Japan time. Thanks Lou! --ESL
by Lou Friedman Nothing comes easy. The IKAROS team has put discretion before valor and decided to delay the final stage of the deployment. The first stage of the deployment went well but they want to analyze the measurements they are receiving more closely before committing the final stage. I am disappointed, of course -- my own schedule is such that I must return to the U.S. on Sunday and thus I will miss the final deployment.
The complexity of the deployment makes it easy to understand both the caution of the team and the dangers inherent in it. Readers who review the description, or who have seen the video animation can appreciate that the dynamics involved are hard to predict and hard to control. The sail itself is only 7.5 microns thick and very flimsy. The centrifugal force that controls the deployment can be made wobbly by just a little asymmetry in the way the sail unfolds from its stowed position. The two-stage spinning method of deployment is elegant, but complex. Caution is certainly warranted. There is, however, a counter-argument in favor of doing things as quickly as possible before something else in the complex system goes wrong. We are undergoing a tradeoff on this very subject in our LightSail planning. I am in no position to second-guess the team here in Japan. To the contrary, given how well they have performed to date, I am sure they are making the right decision. So I will leave Japan having witnessed only a partial deployment, and uncertain about the rest of it. I have learned a lot here, and think the technical and program interaction among solar sail teams will lead to some great missions and great spacecraft in the future. In the meantime, it is back to home, and to focus again on our simpler but also elegant LightSail-1 so that it, too, can make its attempt to open up a new era in space transportation and exploration. Today's disappointment with the solar sail deployment was counter-balanced by the good news with the Hayabusa trajectory correction. It went perfectly and the spacecraft is now targeted for the Woomera desert region in Australia for a June 13 landing. The awesome adventure of Hayabusa is coming to an end. I will have more to say on that later.
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Also, I'm reminded of the cultural differences here. It is often claimed that Japan has a consensus culture. In that respect, but not others, it reminds of my native Sweden. Both former feudal cultures, both isolated (islands respectively part of a semi-island), both originating with margin agricultures demanding rigorous planning and timing. All factors depressing individual initiative and promoting cooperation.
If IKAROS is a let-down for impatient americans, remember the perseverance and sense of detail minutiae that lies behind the progress of Hayabusa!
Thirty-four years ago this July, the Viking mission team wanted Lander 1 to touch down on Mars on July 4th, 1976, but they carefully examined all of the desirable landing sites, which delayed the landing until July 20th. As Dr. Sagan said at the time, a crash landing on July 4th would not have been an appropriate 200th birthday gift for the United States.
Likewise, a tangled, hastily-deployed solar sail tumbling uselessly in orbit around the Sun would not be an achievement which Japan could remember with pride.