above for ease of reference

page 13

3.5 Orbit control method from now based on the test firings

We have, from the aruguements put forward up until the last page, following understandings.

• We will not be able to obtain specific impulse required for the orbit control using the damaged OME burner.


• We have done our best, based on our ground tests, to alleviate the ignition schocks. However, we now think that the burner damage continued to progress further.

From these understandings we think it only proper to carry out further operation based on the following policy.


• Any further orbit control for the purpose of Venus reunion and subsequent orbit insertion attempt will be made using the single liquid RCS engines (hydragine fuel only).


• We will jettison all of the oxidiser by mid October to reduce useless mass in order to meet the nearest sun approach orbit control in November.



• We should note that all of our further operation will be based on the understanding that the fuel side high pressure gas supply line's reverse flow stop valve continues to mulfunction and also that a tiny amount of pusher gas supply is still being maintained.

end of page 13


(I have no information yet of oxidiser jettisonning. P)

above just for ease of referencing

4. Discussing nearest sun orbit control

4. 1 Operation by jettisoning the oxidiser


As seen in the previous section it is now thought approapriate to carry out orbit control operation by the RCS engines ( Plan 2 in Sec 2.2 Trade-offs in Venus reunion orbit control)

In order to carry out an effective orbit control by the RCS (4.1.2) it is vital to lose unrequired oxidiser to reduce the probe mass.

With oxidiser jettisoning operation we need to be careful because;

injector might freeze as we inject liquid oxidiser into vaccum

temperature of each section of the probe members including the propellant valves might exceed the allowed limits

With these in mind we have conducted ground test experiments (left schematic bellow: for example 3 seconds injection at an interval of 60 seconds was made three times) and thermal analysis (right schematic bellow: for example 600 seconds continuous injection) in order to come up with a safe method for jettisoning the oxidiser.

We will from now on obtain orbital data and through these data will carry out oxidiser jettisoning operation in early to mid October this year.

(there are two schematics after this)

(Lefthand schematic's caption says) : Temp history of each section of the injector (ground test example) (vertical is temp in deg C and horizontal is time in second)

Jettisoning period : 60 seconds
Jettisoning duration per each jettisoning : 3 seconds

in red : reverse (or rear) side of the injector
in green : injector's injection face
in blue : Akatsuki's measurement points equivalent

(Righthand schematic's caption says) : Temp history of sections around OME as the oxidiser is jettisoned (thermal analysis example) (vertical is temp in deg C and horizontal time in minute)

Oxidiser jettisoning : 600 seconds (this refers to the period as indicated on the graph by the short horizontal line with two arrow heads)

in red : OME propellant valve temp (fuel side)
in green : OME injector temp
in blue : OME propellant temp (oxidiser side)

end of page 14

P

thanks Pandaneko. this confirms what I suspected: that oxidiser will be jettisoned through the OME injectors

above for ease of reference

page 15

4.2 Discussions for the long duration firing of the RCS engines

RCS is a single liquid thruster and obtains its propulsive power by gassifying the fuel by catalytic decomposition. We therefore looked at various points of concern during the long duration firing such as;

power decrease and/or unstable power generation through catalyser damage and deteriolation
power decrease and/or unstable power generation through burn loss of the catalyser supporting system

⇒ RCSs on board Akatsuki have been used on various science satellites with proven record of reliability

With Akatsuki it is expected that cumulative firing length will be some 4,000 seconds (continous burn is at the most 2,000 seconds). Against this we have achieved in QT tests on ground a maximum of 23,000 seconds cumulative burn (6,000 seconds continous) and we are satisfied that the burn pressure was normal and there has been no report of catalyser deteriolation.

(after this there are two graphs and one image and I will deal with these before translating the concluding remarks)

(Caption of the first graph is) : History of internal burn pressure during 6,000 seconds continuous firing tests (QT) (example of result)

(vertical axis here is the burn pressure and the horizontal is time in second. Caption on the graph itself says "constant burn pressure")

(the small entry on the right is an image and its caption says: "RCS catalyser (image))


(caption of the second graph says) : History of the propellant valve temp (analysis) around the time of RCS continuous burn for 2,000 seconds

(Upper curve caption is) : Sun side propellant valve
(Lower curve caption is) : Opposite Sun side propellant valve

(Vertical here is RCS thruster propellant valve temp and the horizontal is time in minute)

(the zone indicated by the two-way arrows is the duration of continuous burn)

Looking at temps of RCS and surrounding areas

• RCS is designed to be capable of long duration firings (as stated above) and the probe itself is hadly thermally affected by the burn

• We also looked at the possibility of RCS temp increase by the heat soakback after burn (propellant valves in particular) exceeding the allowed value

⇒ We are now satisfied through thermal analyses that temps such as the propellant valve temp will remain within the allowed values even after RCS continusous firings

end of page 15

Paolo, if I may, do you know what went wrong with Nozomi? I did look into JAXA archive and did not find anything, as I remember it now. I and my colleagues at that time were very much intereted in the British Beagle and thought Nozomi as a backup for what we had in mind. I remember one of them shouting to me to say "No hope for Nozomi!" and that was that.

I have remained too busy for the next 10 years or more to ask why...

P

pandaneko,
I don't have the original references at hand now, but here are some sentences from the forthcoming "Robotic Exploration of the Solar System - part 3" book:

above just for ease of reference only

Paolo, thanks. Interesting, valve failure and power down. Hopefully, I may find something in ISAS archive. Anyway,

page 16

4.3 Orbit plan from now on

(immediately after this there are two schematics)

(caption with the left schematic says): solar orbits (sun circulating orbit) (current orbits) Relative positions of the probe, Venus and the earth (and these are indicated by the circles, from the innermost (probe) to the outermost (Earth))

(caption for the large arrow in the middle is): Insertion into Venus circulating orbit

(here, I must tell you that I am not familiar with the expression for circulating around something, just going around in general as opposed to something more specific like sun synchronous orbiting)

(caption for the right schematic is): Akatsuki circulating orbit (image)

(caption near Venus lower down says): (original plan) Venus circulating orbit with 30 hour period


• We are plannning to conduct orbit control in the first half of November 2011 using the RCS engines in order to meet up with Venus in 2015. With this operation the probe will be subjected to thermal environment well beyond the design conditions and we will be forced to operate the probe beyond its original design lifetime, and we will be taking every precaution. Re-insertion into Venus orbit will be carried out in 2015 and beyond.



• Since we will be using less powerful RCS engines instead of a healthy OME our current prediction indicates that the probe will be flying in an orbit whose furthest position from Venus is much higher than originally planned. The latest capacity of the RCS engines will be updated by the data to be gained from our operation in orbit control from now on.


• Orbit life expectancy, nearest and furthest positions, and period of the probe will be variable from now on depending on the results of orbit changes and the health of the probe. We will be taking the best options in choosing the right orbit inclination angle (I know there is a better expression, P) and we are also looking at the possibility of orbit insertion after meeting up with Venus a couple of times.

In any event we will be guiding the probe into the best orbit in order to comply with the requests from the science community who wish to maximise the return from this mission.

end of page 16

P

above for ease of reference

P17

5. Schedule for orbit control with respect to the nearest sun approach

(this is a flow chart page and the top scale refers to the months, from August (8) to November (11))

(starting block says) : 1st and 2nd test firings on 14th and 17th September (this year, 2011)

(question box say): Can OME be used?

(NO is given a caption which says): orbit control by RCS

(dotted line refers to OME, not adopted)

(the oblong bottom box says): discharging the oxidiser in early to mid October

(box after this oblong box says): rehearsal in late October

(last box says): nearest sun orbit control in early November

end of page 17

page 18 (last page of this document)

6. Summary of this 4th investigation report

1. Following actions/notes have been taken for the future orbit control, including the ground tests with OME


• Re-igniting the damaged burner may well lead to further damage due to ignition schocks

破損した燃焼器に再着火すると，着火衝撃により破損が進行する可能性がある.
• From results obtained during the experiments for the ignition schock characteristics we were able to identify possibile conditions for use on the probe in orbit in order to reduce ignition impacts and thus made a plan for test firings desgined to decide whether or not we will be able to use the OME.



2. These test firings in orbit were made on 14th and 17th of September and we arrived at the following conclusions.



• OME propulsion was only 40N or thereabout and we will not eb able to obtain the specific impulse required for further control in orbit.


• OME burner is thought to have been further damaged and we must not make use of it any further.


• For any further orbital control we will have to be content with the RCS engines and with them we will still aim for Venus reunion and subsequent orbital insertion.


• Since RCS is of only single liquid type we will discard all of the oxidiser.



3. Plan for future operation including Venus reunion and orbit insertion



• After discarding the oxidiser we will carry out the nearest sun orbit control operation in early November.


• For the reunion with Venus and orbit insertion thereafter we will be closely working with the science community in trying to decide the best orbit and orbit insertion method based on the result of the nearest sun approach operation of this time and future health of the probe, and the results of the RCS firings.

end of page 18 and end of the report


Paolo

I searched around last night, not inside JAXA nor ISAS, but in the general world of the internet, for further Nozomi failure information. I am satisfied that there are (amazingly) ISAS and JAXA documents, not as quite detailed as those on Akatsuki, but sufficiently informative.

Do you think these will be of any use at this late stage for light readings? If so, where might I upload them to? I could not find any trace of a suitable platform inside Mars. Not a lot, perhaps 20 to 30 pages as I will have to devide these 3 single and seperate documents into manegeable size for a day's translation.

P

Pandaneko, just to stress once more how useful your posts are.
concerning Akatsuki, we are now past mid-October, but I have yet to see any news on the oxidiser dump
concerning Nozomi: documents would be interesting, from an historical point of view, thanks. take your time, anyway, and don't stress you too much!

I have got my answer from Akatsuki_JAXA tweets + google translate:

Thanks, Paolo

I did another search today. Would you believe it? I found a proper and very detailed report on the failure of Nozomi, a final report made to the Space Activities Commission (SAC). It no longer belongs to JAXA and is archived elsewhere. No wonder I did not find anything of this sort inside JAXA or ISAS. This report, from the quick glance I made, is about 85 pages long. I may turn out to be wrong, but one of the pages I had a quick glance towards the end of this report seemed to have that page number.

I will start a fresh thread soon inside Mars and start translation. I am feeling sorry and sympathetic towards the poor Nozomi.

P

this was posted earlier today (without any link or other references) on the NASAspaceflight forum:

a new pdf release by JAXA http://www.jaxa.jp/press/2011/10/20111026_sac_akatsuki.pdf

Thanks, Paolo

There is nothing we do not know on pages 1 to 3. These pages talk about history up until now. So, my translation starts with page 4 as follows.

page 4

３．Operation of oxidiser dumping

This was conducted on 6th, 12th, and 13th October 2011 for 6 minutes, 9 minutes, and 9 minutes respectively.

(There are two graphs here)

(with the graph on the left the vertical is temp and the horizontal is time in minute relative to the start of dumping of NTO)

(This graph is the temp history and)

red: fuel propellant valve temp
blue: oxidiser propellant valve temp
purple: oxidiser tank temp
green: injector temp

(with the graph on the right the vertical is acceleration in m/sxs and the horizontal is the measued value of acceleration)

(there are 4 zones from left to right and the are)

blue: test discharge (1 min)
red: 1st discharge (6 min)
green: 2nd discharge (9 min)
purple: 3rd discharge (9 min)

(top left character string says) : RCS settling (3 seconds)
(bottm righ string pointing to a sudden drop says) : end of discharge


Although power is supplied to the propellant valve on the fuel side while discharging operation is in progress there is no cooling by fuel available. Thus, it was feared that the temp of the fuel side propellant valve might exceed the allowed limit. Also, freezing of the OME injector was feared. However, we judged that discharging operation was feasible from the ground tests and analyses as long as we divide the operation into several times. It was confirmed that the discharging operation was completed at the 3rd time without exceeding the allowed temp limit.


The sudden drop in acceleration during the 3rd discharging operation indicatef that pressurising helium gas pushed through and discharging was complete as planned.

end of page 4 (and 2 more pages to go and they will follow tommorrow)

P

Thanks again for these ongoing posts.

I'm wondering if this is a spaceflight first (dumping oxidiser this way) ?
I could imagine it may be - these are rather unusual circumstances.

above for ease of reference

page 5

４．Considerations relating to orbit control by RCS


1. Maintaining the thermal balance in the thruster 's catalytic layers during the continuous firing

Main points of concern with the continuous firing of RCS and our current stance are as follows.

By adopting the orbit control attitude (＋X pointing in the sun's direction) the ＋X side of the thruster will be in a thermally difficult state. However, analyses confirmed that the temp of the catalytic layers during the burn will be in an equiribruim state.



2. Temp rise of the propellant valve by the heat soakback (*) after the continuous firing

Although the temp of the thruster valve will increase by the heat soakback after the continuous firing it was confirmed that the rise will remain within the allowed temp range.

* This is a occurrence in which the temp of the propellant valve kept cooled by the supplied fuel will increase by the heat conducted from the hot burner after the continuous firing of the engine


3 Temp increase of various parts of the probe due to the attitude maintenance operation during the continuous firing

Orbit control attitude (+X sun pointing direction) will lead to temp increase in the various parts of the probe. However, we will change back to +Z sun pointing direction immediatelyy after the firing and it was confirmed that all parts of the probe will not exceed the allowed temp range.


Conclusion:

Based on the report of 30 September at the investigation meeting regarding the RCS continuous firing and records of similar burning in orbit by other satellites in addition to above further consideration as reported here we reached a conclusion that an orbit control firing by RCS will be conducted in November this year during a nearest sun approach.

end of page 5

P

above for ease of reference

page 6


５．Orbit control plan at the nearest sun (I know that there is a special term for this, but I keep forgetting it and I am more comfortable with nearest sun, P) point

(There is a schematic and I will translate the character strings on it later. Main texts first)

Orbit control by the RCS engines at the nearest sun approach point



（1st control on 1 November） ΔV : 90m/s

（2nd contorl on 10 November） ΔV : 90m/s
（3rd control on 21 November) ΔV : approx. 70m/s

We will carry out the 3rd control by taking into account the result of ultra accurate measurement of orbits effected by earlier two controls (thrust direction and magnitude will be dependent on the errors due to the first two controls).


※ These orbit changes are carried out in order to reunite with Venus after 2015.


※ There is a possibility that our orbit control plan may be altered depending on the assessment taking place from now on.

(the schematic title says): Relative positions between the probe, Venus and the earth at the time of Akatsuki orbital controls

(the unit, both vertical and horizontal, is 10 to the power of 8km)
(outer circle is earth, inner circle is Akatsuki and in between is the Venus orbit)

(2 characters around 9:00 are): top is Sept 2011 and bottom is test firing

(bottom character on Venus orbit is): Nov 2011

(on earth orbit at 1 O'clock is): Nov 2011 (and at around 3:00 on the same earth orbit is ): Sept 2011

(at around 4:30 on Akatsuki orbit is): nearesst sun orbit control

end of page 6

P

above for ease of reference

page 7

６．Summary of this report

１．Akatsuki's current health and operational plan from now

– All insturments on board are healthy and the satellite is circulating around the Sun

– From the in-orbit firing of the OME conducted in September this year (2011) we judged that OME will not be able to produce an effective propulsion required for further orbit controls and that any further orbit control will have to be achieved by the RCS engines

– Dumping of unrequired oxidiser was conducted in October this year in order to reduce the satellite mass and this operation was confirmed to be a success from telemetry data, all aprts of the satellite not exceeding the allowed limit in temp.

2． Nearest sun approach orbit control

– Orbit control by RCS engines is planned for November this year as the satellite makes a nearest approach to the Sun.

– We investigated the risks involved in the orbit control by RCS and it has been confirmed that there is a good scope for safe operation.

– Orbit control will be divided into three parts, each taking place on 1, 10, and 21 November and depending on our further consideration and the outcome of controls the orbit control plan may change.

end of page 7 and end of this particular report

P

thanks Pandaneko, very informative, as always!

If the Japanese pull this off it will be another 'snatching victory from the jaws of defeat' performance. They seem to do their best when their missions are in deep doodoo!

P

This morning I was surprised to find that there is to be a news coverage of Akatsuki during this evening's 7 O'clock TV news. It is only half an hour to go. This sort of coverage is very rare here. As far as I can recall about the only TV coverage for even Hayabusa was at the time of its disintegration...

So, I am intrigued.

P

I watched this TV news last night. A few things.

1. Although I am used to seeing graphs all neatly compiled for reports in the course of my translation this was the first time that I had seen a raw graphical output for Akatsuki. It was a horizontal line of about a foot in length and the delta V gain bit was a short (an inch or so) straight line at an angle, about 30 degrees, I would say. These magnitudes are judged relative to human size seen in the control room. It was pleaseing to see this output. It was like having a freshly baked bread right in front of me!

2. The intro said "a new (after the failure) period of a few days against the originally planned 30 hours circulation period" and at this point my brain went "???". I had all along viewed the current operation as a cosmetic excercise and in any event I was under the impression when I was translating for the new orbit that it was going to be anything from a few weeks to a few months.

As far as I am wishfully concerened "a few days" is 3 days and that is 72 hours. Does this not mean that I might be able to watch some lightenings as I had hoped to watch? I love lightenings, celestial or otherwise.

P

here is a short release (in Japanese) on yesterday's burn
http://www.isas.jaxa.jp/j/topics/topics/2011/1101.shtml

Thanks, Paolo

The press release reads as follows.

"About the orbit control of Akatsuki during the nearest sun approach


1st of the orbit control by RCS was conducted for some 10 minutes from 13:22 on 1 November (JST). We will be analysing the telemetry data to reflect the finding with the 2nd orbit control firing planned for 10 November."


end of presss release

P

I know that people will laugh at me for all sorts of reasons.

However, I will say this for record!

We should forget about dual liquid engines for orbital operation and instead use smaller single liquid attitude control engines for all orbital operations including orbit insertion.

Instead of having half a dozen smaller engines why not have a dozen of them? I have not heard of a single case of these attitude controlers going out of control. I am saying all this because of a simple fact that larger and more complex engines seem to fail without fail!

Pandaneko

Well, this is exactly the trade that any system design has to make.... unfortunately such decisions have to be made on very
incomplete data : larger engines do not always fail, and small monopropellant thrusters are not immune to failure
either. Consider the following :
1. you'd need 20 (not an extra 6) small 20N thrusters to give you the thrust of the biprop engine. Even if the individual
failure rate of these engines is lower than the biprop, there are now 20 of them to go wrong (e.g. a valve stick 'on')
2. the specific impulse of the monoprop is less (and small thrusters are also less efficient than a large one). Via the
rocket equation, this can have a huge impact on the vehicle mass.
3. the root cause of the Akatsuki failure (viz poor helium flow through the check valve on the fuel-side pressurization)
might have caused enough underperfomance of a monopropellant system to prevent orbit insertion anyway.

So what you suggest makes sense, and engineers do it when they can get away without a big engine, but
missions typically demand the performance that only a biprop can give.

Thanks, Ralph

I have been frustrated a lot. I want to see lots and lots of different facets of our other planets. I probably have another 25 years and these satellites keep failing. I wish they launched at least one satellite every year. Yes, trade-offs..., yes, and thanks again for further thoughts.

Pandaneko

actually, this has been done on the MRO, which used six monopropellant engines instead of a larger, bi-prop one to perform Mars orbit insertion

They were all significantly more powerful than a usual RCS thruster. They were, infact, the descent engines for the 2001 lander.

This news just in. (21:09 31 January 2012, The Yomiuri newspaper)

JAXA announced that they will try and re-insesrt Akatsuki into Venus orbit in December 2016, if the prove conditions remain good.

In this case, Akatsuki's orbit will be oval in shape and it will have to observe Venus from a distance. However, according to JAXA there will not be much of a problem in observing clouds and atmosphere of Venus.

Akatsuki used its smaller engines in November last year to correct its course and is programmed to have its closest encounter in November 2015. However, forcing Akatsuki into a circular orbit at this time will mean an orbit which is not really ideal for atmospheric observation. It is for this reason that they want to opt for June 2016, which is the next closest encounter.

However, missing the earliest opportunity means physical deterioration of the probe and JAXA are saying that they may try re-insertion in November 2015, if the conditions are found to be bad by then.

P

Cool! Thanks for the update.

December 2016 isn't too bad, less than 5 years from now. Past missions like Hayabusa showed that the Japanese design a lot of flexibility/versatility into their spacecraft and that helps getting them through tight spots like this one. If they're not too unlucky with solar activity, we might be seeing some first-rate Venus science come 2017..

Some Japanese followers of mine on Twitter have said that it's actually not December 2016 they were discussing, but June 2016. Also, apparently the choice of 2016 for orbit entry isn't as set in stone as Yomiuri makes it seem. At the press briefing they seemed to have been discussing trade-offs between degradation of the orbiter's systems and the fact that with every Venus swingby they do, they can improve the scientifically useful characteristics of the orbit they can achieve on the next encounter.

The Sankei newspaper here carried an article about Akatsuki's failure as follows. Time stamp for this article is 19:24 31 January 2012. I believe that this will be the general public's understanding of this failure. It goes as follows.

"Failure cause is bad design. Venus probe Akatsuki, fuel did not reach its engine. 19:24 31 January 2012."

"Space Activities Comission (SAC) accepted a report submitted by JAXA on the causes of orbit insertion failure of Akatsuki that the failure was due to the valve mulfunctioning which prevented the flow of fuel to the engine.

According to this report a larger than assumed amount of salt was formed during the 6 months flight to Venus by the reaction of evaporated oxidiser and fuel. This adhered to the valve for the fuel tank, preventing opening of the valve for fuel supply.

The reaction between the oxidiser and fuel itself had been predicted at the desing stage. However, the design team failed to predict that the valve component problem would lead to more than 100 times the amount of oxidiser migrating into fuel than assumed. Adding to this, part of inspection and testing had also been skipped due to cost and time constraints.

Prof Y Inatani of JAXA commented that it was outside their expectation and that a well thought design should have prevented it during the design stage. Akatsuki is still flying, powered by smaller engines with a view to trying re-insertion in 2016."

P

Thank you, P.

And as usual there is never enough time, testing, or money.

But afterwards, there always is learning. It's a truly ancient, perhaps inevitable, pattern.

Yes, I imagine somewhere on a stone tablet or cave wall is something to this effect:

FINDING ON MAMMOTH HUNT

We fail to to kill mammoth today

We check with spear design team

We find spear design team did not attach spearpoint to spear

Also, spear throwing team not properly trained due to time constraints, and was throwing wrong end of spear to mammoth

We will miss ZOG greatly


Ha, maybe that's what cave paintings really are, instruction manuals!

some rare scientific results from Akatsuki's Venus flyby
Characteristic features in Venus’ nightside cloud-top temperature obtained by Akatsuki/LIR
JAXA has a summary (in Japanese only) on the mission webpage

Thanks, Paolo

What follows is the first of my translation which may last for a few more days. This actually comes from ISAS (now part of JAXA) web pages.

[11 May 2012]

It is almost 2 full years since the launch on 21 May 2010. Thank you for your continuing interest in Akatsuki.

2011 for our Akatsuki operation team was filled up with new challenges, such as the firing test of the damaged main engine, reduction of the probe mass by releasing the oxidiser, orbit changes by the smaller attitude control engines.

We are still preparing ourselves for the 2015 re-union, but at the same time we have been making the best use of this period and conducted a few observations such as "Looking at Venus from 1300X 10,000 km", "Solar uki has corona observation by shatting up radio waves (My translation can be very wrong, P)", and these have been reported at various international meetings.

Akatsuki is very fortunately flying without any hithces. Here, now, we offer our sincere apologies for the lack of information over the past 12 months. What follows is , albeit very brief, our account of the orbital control operation since the autumun of last year.


"Akatsuki's new orbital plan"

Akatsuki started its new orbital journey in November 2011. By firing 4 small attitude control engines for a long time indeed, 3 times over the period and it managed a delta V approx. 240 m/s and entered into an orbit which ensures an encounter in November 2015.

(end of translation of this particular session)

After this there are a few more remarks which we already know from my past translations. The point of this article is (I think) that Akatsuki is still flying healthy and we may even get scientiffic results in 2015.

P

[8 June 2012]

Venus night side temperature distribution seen by the LIR camera

(actually, there two more reports in between, but they relate to Venus going across the Sun. So, I am not translating them. P)

An attempt was made to capture the image of Venus by the onboard camera on the night of 9 December 2010 while Aklatsuki was limping away from Venus, being very much mindfull of the scar on its bottom. At this time Akatsuki was already 600,000 km away from Venus, but the LIR camera managed to capture the whole surface.

There had been a few sporadic spectrographic observations made both from the ground stations and space probes this was the first ever snap shot of this kind.

During the two minutes period in which 32 cumulative images were to be made the attitude of Akatsuki was somewhat disturbed. To combat this issue we position -corrected these cumulative images and layed them over one another and actually came up with a slightly better image in terms of resolution.

If you take a look at this image and analyse the so called peripheral temperature reduction by which the surface temperature of Venus seems to go lower as you look away from the centre of the disk towards the peripheral area. By analysing it carefully we concluded that the reason is due to the reduction in number of cloud particles in the upper atmosphere of Venus.

Observed absolute temperatures are staying relatively higher compared with past observations. This is thought to be due to the fact that the temperatures are actually rising, or alternatively we are looking at the lower layers with higher temperaturers seen through thinning upper layer clouds.

In addition, we can observe at the poles low temperature band zones (Polar clour) and similar band structures in mid to lower attitude areas with even finer temp. distributions on a much smaller scale. At the polar regions we may even be seeing polar dipole regions with high temperatures.

Akatsuiki is in good shape except for the main engine. The next earliest opportunity for re-insertion is end 2015. Once placed in its final circular orbit we expect to be able to obtain far superier resolution on a continuous basis.

(end of translation, P)

an interesting paper on orbit strategies for the return of Akatsuki to Venus
THE TRAJECTORY CONTROL STRATEGIES FOR AKATSUKI RE-INSERTION INTO THE VENUS ORBIT

an update (in Japanese only at the time) on Akatsuki's observations during solar conjunction
http://www.jaxa.jp/press/2014/12/20141218_akatsuki_j.html

Here it is in English: http://global.jaxa.jp/press/2014/12/20141218_akatsuki.html

Here is the English version. http://global.jaxa.jp/press/2014/12/20141218_akatsuki.html

Something very interesting I saw at NASA Spaceflight: http://forum.nasaspaceflight.com/index.php...7343#msg1307343



I'm not sure exactly what this means, possibly a different Venus orbit insertion date and/or a different Venus orbit.

The manager must have great control over physics and gravity if his approval is required. I, too, would seek his favor.

Bummer. They're close enough to the sun to no doubt have a gagillion non-Newtonian effects

There appeared a short article in today's Yomiuri newspaper here saying that
JAXA will try Akatsuki re-insertion into an elliptical orbit in early December this year.

Fuel left is just enough to try once and once only. P

Fingers crossed!

According to NHK VOI will be on December 7: http://www3.nhk.or.jp/news/html/20150127/k...5007881000.html

Yes indeed : I trust you and I can't say it better !

ah, the only addition here is that apparently Akatsuki will be scorched during February and August. P

Spaceflight Now has an article on the next try.
Don't know if there's anything new there but it seems like a good summary for those (like me) who haven't been fully paying attention.