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IKAROS JAXA Solar Sail mission
Norm Hartnett
post Oct 18 2010, 04:04 PM
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IKAROS has spin up today. This is a very long time 2rpm.
A high spin rate, increasing the spin stiffness (as a frame) in space
Try to maintain a constant attitude.
Conversely a low spin rate will be strongly influenced by movements of the solar light pressure.
Adjusting the spin rate means that a balance of both to take advantage of this
I can do to change the direction of the desired position.

The IKAROS 10/18
Solar Distance: 0.84AU
Earth Distance: 28891627km, RA =- 132.6 , declination =- 23.5
Venus Distance: 0.11AU
Attitude: spin rate = 2.1rpm, sun angle = 4.3deg

(Earth Distance 0.19AU)

Sun angle has been decreasing for several weeks now I wonder if they are "coming about" and reversing the "thrust" vector? One of the animations I saw seemed to indicate that might happen as they approached Venus.
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Norm Hartnett
post Nov 5 2010, 05:06 PM
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The IKAROS 11/05
Sun Distance: 0.77AU
Earth Distance: 33318160km (0.22AU), RA=-146.5deg, Dec=-15.3deg
Venus Distance: 0.06AU (8975880km)
Attitude: Spin Rate=1.7rpm, Sun Angle=16.4deg

Blog entries are becoming sparser and apparently there are fewer communications periods as JAXA increasingly focuses on the Akatsuki Venus mission.
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Paolo
post Dec 12 2010, 10:05 PM
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while Akatsuki was being recovered, IKAROS also flew by Venus last 8 December, some 80,000 km away
http://www.isas.jaxa.jp/home/IKAROS-blog/i....php?itemid=786


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punkboi
post Dec 13 2010, 02:19 AM
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Interesting... I thought IKAROS wasn't suppose to pass by Venus till December 18


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pandaneko
post Jan 24 2011, 02:19 PM
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I am posing a very stupid question, I think...

Akatsuki has sped by Venus, right?, and IKAROS has done that, too? That means they are going in the same general direction. My question is this. Can they not direct IKAROS to Akatsuki and take a look at Akatsuki's nozzle skirt? After all, we have another 5 to 6 years.

As I am not sure as to what IKAROS's ultimate goal, I just thought that it can get closer and closer to Akatsuki. Does it have a telephoto lens, bet not...

With future missions we do need engineering cameras!!!

Pandaneko
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gwiz
post Jan 24 2011, 03:04 PM
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They passed Venus at very different distances, which means that IKAROS (80000 km) would have been less deflected by the gravity of Venus during the fly-by than Akatsuki (600 km). Add to that that Akatsuki also performed the incomplete injection burn as it passed the planet. As a result, the two would have been on rapidly diverging trajectories after the Venus encounters.
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Gsnorgathon
post Jan 24 2011, 08:45 PM
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In addition, Ikaros has only engineering cameras designed to monitor sail deployment. They're pretty low-res, and have a very wide field of view that would make getting a good view of Akatsuki very difficult. The danger of a collision between the two spacecraft would be too high.

OTOH, the thought of Akatsuki taking a self-portrait as reflected in Ikaros's sails is truly delightful! But will have to stay just a thought, alas.
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Hungry4info
post Jan 24 2011, 11:25 PM
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Akatsuki should cast a shadow, having IKAROS close by would allow something for that shadow to fall on. You could just image that shadow. I would figure it could be done at a greater separation than would allow for Akatsuki to image its reflection.


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djellison
post Jan 25 2011, 12:43 AM
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You can't be serious H4I, Ikaros and Akatsuki are going to be thousands, probably millions of miles apart.
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Hungry4info
post Jan 25 2011, 01:31 AM
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Oh I know. I thought it was understood we were just throwing ideas out there in a hypothetical situation.
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...But will have to stay just a thought, alas.


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Gsnorgathon
post Jan 25 2011, 10:44 PM
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I was thinking that it would make a great demonstration if Ikaros could be maneuvered to rendezvous with Akatsuki at some point during the next few years... but yeah: just tossing around hypotheticals.
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pandaneko
post Jan 26 2011, 12:51 PM
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QUOTE (Gsnorgathon @ Jan 26 2011, 07:44 AM) *
I was thinking that it would make a great demonstration if Ikaros could be maneuvered to rendezvous with Akatsuki at some point during the next few years... but yeah: just tossing around hypotheticals.


Before the demise of Akatsuki I was not terribly interested in this craft. I just thought of it as a planar object going around in space. Now, I just wonder, do they at JAXA know where it is going? Or, are they supposed to know where it is going?

With every other space craft people who sent them out there must have pre-determined flight plans for them to follow, including when the project is supposed to end. For instance, Prof Kawaguchi with Hayabusa, he apparently said he considers that the end of Hayabusa project is when international calls are invited later this year. That is simple and clear.

With this planar space craft I have not been able to find anything about its future whereabouts. I am just intrigued to know what is going on...By the way, there was an article in yesterday's Asahi newspaper about a space net that JAXA want to send up into near earth orbits in a few years time to capture space debris and burn them out with the net on destructive re-entry.

Pandaneko

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punkboi
post Jan 26 2011, 07:44 PM
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IKAROS took this self-portrait with Venus in the background! (Darn it, JAXA... Release a larger size of this image) smile.gif

Thanks to Emily for the heads-up: http://www.planetary.org/blog/article/00002892/


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elakdawalla
post Jan 26 2011, 08:23 PM
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Based on @ikaroskun's tweets I'm pretty sure this is the largest size available -- if I am translating correctly, it took days or weeks to even download thumbnail images at IKAROS' current distance from Earth.


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punkboi
post Jan 26 2011, 09:46 PM
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Here's a larger version of the IKAROS-Venus pic...taken from the JAXA press kit

http://www.jaxa.jp/press/2011/01/20110126_sac_ikaros.pdf
Attached thumbnail(s)
Attached Image
 


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