2010/05/23

Sailing On A Star

Friday morning, JAXA launched an H-IIA missile from Tanegashima Space Center. On board were four small earth orbit satellites built by Japanese universities as well as the main attraction - Akatsuki, a craft which will carry out an extensive study of the atmosphere of Venus. Also onboard was Ikaros, a "space yacht" built by JAXA which is testing the use of the sunshine for propulsion.

Here's the launch and separation of Akatsuki from the launch vehicle (2 min 46 seconds)


The next clip runs about 12 minutes and details (with English subtitles) the Akatsuki spacecraft and mission. It's quite impressive and if all goes well, will provide a wealth of information about the climate of Venus, which in turn may help us to better understand our own planet.



As a sailor, I was curious about the Ikaros mission. Particularly, how one could use sunlight to "tack" "upwind" in space to a planet closer to the Sun. Essentially, the sail is set so that the spacecraft's orbital velocity around the sun is slowed by the wind (charged particles thrown off by the Sun). In other words, the sail is used as a brake. As the velocity drops, the craft's orbit gets smaller - closer and closer to Venus. I found a website at Cal Tech with an excellent explanation of this - Tacking Solar Sails .

The Ikaros space craft (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) carries a sail that is just 0.0075mm thick wound around its core. Ikaros will spin and unwind the sail using centrifugal force. When deployed, the square sail will measure 46 feet on a side. This clip is in Japanese, but you can get the (ahem) drift by watching the animation. There are thin film solar cells and dust counters attached to the sail. In addition to testing the sailing concept, the development of this craft and a much large one later on, will lead to lower cost solar cells - an important element of Japan's efforts to reduce greenhouse gas emissions.



Fair winds Ikaros and Akatsuki.

JAXA website is here: Japan Aerospace Exploration Agency

2 comments:

Don Snabulus said...

That is very, very neat. It is really unfortunate that the media in my country are so myopic to the scientific accomplishment of people outside the US. Luckily, we have you to point us the right way. ;)

I wonder if they used sailing terminology when naming various parts.

ladybug said...

This is really very interesting! I wonder what scientific data we'll find out? In any case it may not be reported out here...so we'll have to rely on you to give us updates!

Also, I'm sending you an e..had some problems posting on one of your other sites FYI...