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Akatsuki Venus Climate Orbiter
pandaneko
post Jun 1 2016, 09:09 PM
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QUOTE (Paolo @ Dec 7 2010, 07:30 AM) *
Just for statistics: if successful, Akatsuki will become the eighth Venus orbiter, after 4 Soviet ones, 2 US and 1 European.
Remarkably, no Venus orbiter has ever failed before reaching the planet, unlike the many (10) lost Mars orbiters


This is just accidental, is it not?

P
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colin_wilson
post Jun 16 2016, 09:27 AM
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For what it's worth, here's my list of Venus missions.
1 "Mission" = 1 launch. Multiple entry probes on one launcher are listed as one mission.
My tally of orbiters agrees with Paolo's!

Attached Image


Comments/corrections welcome
Colin

[Edit: OK, I realise there's now a wikipedia page showing a table of Venus missions, making my own table a bit redundant. In my defence, I don't think the wikipedia page existed ten years ago when I first compiled my list!]
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katodomo
post Jun 16 2016, 12:46 PM
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Since you list flybys - the table is missing Ikaros then. What's the P for under Type, Probe?
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Paolo
post Jul 29 2016, 07:04 AM
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a short update with lots of new images. first Venusian year in orbit
http://www.isas.jaxa.jp/e/topics/2016/0729.shtml
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JRehling
post Jul 29 2016, 06:44 PM
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Those images are great. What's impressive is the array of different wavelengths, some never seen before. I'm sure the data that's already been collected will alter our view of Venus's atmospheric dynamics. I can't wait to see the publications!
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pandaneko
post Jan 17 2017, 12:30 AM
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Just a little bit of information on Akatsuki observation as follows.

JAXA and groups such as Rikkyo University here reported on 17 January 2017 that there has been an arrow like pattern,
as long as 10,000km north-south on Venus. This pattern was seen at the cloud top level (approx. 65km)
of the sulfuric acid clouds covering entire Venus.

They believe that the pattern was produced as the atmospheric disturbance caused by the terrain below propagated to
the upper atmosphere. This pattern remained for more than 4 days undisturbed by the super rotation, an eastery wind
of more than 100m/second. Similar patterns were also observed at other times of observation.
 
Rikkyo University group noted the presence of a high land with more than 5km in height right bekow the pattern.
Their simulation confirmed that the pressure variations below 10km level spread through the atmosphere in wave like motion
and spread out to form an arc pattern at the height of 65km, affecting the cloud top temps as well.  

P
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antipode
post Jan 18 2017, 06:00 AM
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Nature Geoscience article. Abstract with some small images.

http://www.nature.com/ngeo/journal/vaop/nc...l/ngeo2873.html

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Paolo
post Jan 18 2017, 12:39 PM
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a release in Japanese, with descent size images:
http://www.isas.jaxa.jp/topics/000826.html
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Paolo
post Jan 19 2017, 12:48 PM
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I read the paper in Nature geo. the impressive thing is that the feature was visible in the very first IR images, taken barely 5 hours after orbit insertion!
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pandaneko
post Jan 22 2017, 01:13 AM
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QUOTE (Paolo @ Jan 18 2017, 09:39 PM) *
a release in Japanese, with descent size images:
http://www.isas.jaxa.jp/topics/000826.html


Isn't this because the super rotation has such a low density thing, so not affecting the arc very fast and
perhaps only a small amount of energy (whatever the source) is required to drive the super rotation to a very
high speed?

P
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rlorenz
post Mar 5 2017, 02:16 PM
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Some unhappy news
http://www.isas.jaxa.jp/en/topics/000902.html

Although the images have been coming in pretty well over the last year, and some good Radio Occultation
experiments have been done, the electronics unit that drives the IR1 and IR2 cameras suffered an anomaly in December, so for now
those two cameras have not been returning data. Recovery efforts continue. The ultraviolet, thermal IR and lightning/airglow
cameras are unaffected and continue to operate.

Ralph
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JRehling
post Jun 11 2017, 06:22 PM
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With the loss of the IR cameras coming about 10 months into the science mission, and with Akatsuki's orbit having a period of 8 days, it should have acquired up to 40 or so periapsis observations. That's still a wonderful return from the IR instruments if all those 10 months of data were successfully acquired. I'm looking forward to seeing the resulting research as publications come forth.
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Paolo
post Aug 29 2017, 02:14 PM
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A new press release (in Japanese only, for the time being): http://www.isas.jaxa.jp/topics/001069.html

And the related new Nature Geoscience paper (beyond the paywall): Equatorial jet in the lower to middle cloud layer of Venus revealed by Akatsuki
http://www.nature.com/ngeo/journal/vaop/nc...l/ngeo3016.html
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JRehling
post Aug 29 2017, 05:07 PM
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I'm not able to read the full article, and Google Translate renditions of Japanese may not be reliable, but I am once again appreciative of Akatsuki's results, and wonder – perhaps the full text makes this – if Akatsuki is once again seeing something new because of its unique instruments, or whether it is seeing something new because Venus in c. 2016 is quite different from Venus just a few years ago during Venus Express, Pioneer Venus, etc.

I've been imaging Venus in UV regularly this summer and a BAA alert was issued because of unusual patterns seen in some July 2017 UV images of Venus, including mine. (In fact, I initially thought I must have been doing something wrong when I saw them.) Venus's clouds and atmosphere are time-varying quite a bit more than what one sees in global scale imagery of, say, Saturn. Venus Express did a good job of monitoring Venus for many years, and Akatsuki has, possibly a shorter lifespan ahead of it, but we might learn some interesting things if we simply watch Venus from orbit for longer spans of time.
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Paolo
post Sep 8 2017, 05:32 AM
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the paper is now on arXiv:
Equatorial jet in the lower to middle cloud layer of Venus revealed by Akatsuki
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