A quick update on the recently-launched IKAROS Japanese solar sail spacecraft: Earlier this week the Japan Aerospace Exploration Agency (JAXA) reported visual confirmation that IKAROS’s solar sail has fully expanded as designed.
As you can see, a complete success! Congratulations are in order all around to the IKAROS team as the craft enters into its full test mode and JAXA sees just how fast they can get this thing to go.
…But the real story here to me, considering that IKAROS is now on its way to Venus, is “How did they get this picture?” The image is much too close for a remote telescope to have taken it. It’s almost as though some unsung hero behind the lens stepped outside for a moment to snap a quick shot.
Enter the little camera that could:
Unassumingly called “separation camera 1,” this tiny wireless device – one of two twin cameras small enough to fit inside a film canister that were packed next to IKAROS’s central structure – was launched away by spring and grabbed the hero shot of the solar sail as it drifted away.
What a cool idea, and it was flawlessly executed, to boot.
So, here’s to you, Separation Camera 1. IKAROS gets all the glory, but without you, we’d have never seen it.
Chronicles of an Atomic Astrowright 
@Astrowright
Apparently, Jaxa have now measured and confirmed the acceleration of Ikaros due to photons.
http://www.jaxa.jp/press/2010/07/20100709_ikaros_e.html
(also here:
http://inhabitat.com/2010/07/16/japans-ikaros-spacecraft-successfully-propelled-by-solar-sail/
with some corrections in the comments)
I can’t work out what this means in terms of actual long term achievable velocity.
How long would this take to get to Pluto or Alpha Centauri compared to a ‘standard’ probe like Voyager, MRO etc?
Can you help?
Thanks
Felix,
First, thanks for reading!
To your question, I’m operating in a bit of a vacuum without JAXA’s real IKAROS velocity data, but I can make an educated guess. The short answer is that the time a solar sail probe would take to get to Pluto, nearest star system, etc., would be on par with current conventional methods. The trade-off is that the solar sail requires no onboard fuel and very little in terms of onboard equipment. That space is now freed up for other things (instruments, etc.) A problem with the solar sail is that its effectiveness decreases with distance from the sun, so I don’t see it becoming a practical solution to interstellar travel. It may, however, lead to the development of far more cost-effective exploration of the solar system.
For specific achievable velocities, I’d recommend researching ion drives. The solar sail system operates similarly to a reverse ion drive, where small masses of ionized particles are forced away from a spacecraft continuously, (as opposed to conventional rockets that “burn” for a short pulse of high-force acceleration.) With ion drives, the long-term velocity can be quite great.
In the absence of real numbers, I hope this helps! Feel free to follow up any time, and I invite more questions if you have them.
Cheers,
Ben