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selvaarchi
2015-Sep-11, 09:21 AM
Akatsuki - This compact spacecraft was developed by JAXA to observe Venus from orbit with a set of innovative cameras to monitor its climate, weather, and surface. Unfortunately its first attempt at orbital insertion in 2010 failed. Now after 5 years, Japan has another chance to try again. If all goes well, it will happen on 7th of December this year.

http://www.thespacereview.com/article/2822/1


Now, nearly five years later, JAXA says that it has made the final trajectory adjustments to allow Akatsuki to try again. In July 2015, Akatsuki’s hydrazine thrusters nudged its path to line up for an orbit insertion on December 7. The reduced performance of the monopropellant system will not allow the original orbit to be attained: the spacecraft can only just be captured into a long orbit (perhaps 5000 x 300,000 kilometers) that will take it much farther from Venus than the original mission plan. However, there will be opportunities to use the instruments at the original ranges, as well as further away (figure 12). Software has been developed to crop out the interesting segments of images (i.e. “subframing”) taken at longer ranges where Venus will fill only part of the field of view, allowing more efficient use of the data link. And Akatsuki's novel instruments still have exciting potential for new discoveries.

Swift
2015-Sep-11, 10:34 AM
Good luck Akatsuki, you get the prize for persistence.

geonuc
2015-Sep-11, 02:02 PM
Do I have this right? The spacecraft failed to enter orbit five years ago, so it instead did a fly-by. Now it's in a position to try again? How fortuitous is that? I would have thought that the first failure would result in the craft being tossed out into interplanetary space without hope of ever being useful. Is this just luck that the unplanned trajectory five years ago was such that the propulsion systems still had the capacity to put the craft on a course back to Venus?

Swift
2015-Sep-11, 02:40 PM
Do I have this right? The spacecraft failed to enter orbit five years ago, so it instead did a fly-by. Now it's in a position to try again? How fortuitous is that? I would have thought that the first failure would result in the craft being tossed out into interplanetary space without hope of ever being useful. Is this just luck that the unplanned trajectory five years ago was such that the propulsion systems still had the capacity to put the craft on a course back to Venus?
The linked article gives huge amounts of detail about the whole failure and recover and I would not say it was fortuitous (well, some aspects were). It was JAXA working very hard to slowly get the spacecraft back to where it was supposed to be, using backup systems.

geonuc
2015-Sep-11, 03:53 PM
The linked article gives huge amounts of detail about the whole failure and recover and I would not say it was fortuitous (well, some aspects were). It was JAXA working very hard to slowly get the spacecraft back to where it was supposed to be, using backup systems.

I read the article and how the craft was put into a resonant orbit with Venus (not that I know what a resonant orbit is). My question is whether that bit was lucky because a resonant orbit would be one they could recover from, or was the craft capable of recovering from a wide range of post-fly-by trajectories?

Maybe I'm not expressing myself well. I'm asking the question: "were they lucky?", not making a statement about how they were lucky.

Squink
2015-Sep-15, 01:03 PM
Awesome!
Can we call it 夜明けゾンビ (Dawn zombie) now?

marsbug
2015-Sep-15, 04:57 PM
We saw with hayabusa - JAXA are incredibly tenacious and inventive. I'd read that they always planned this, and I'm really hoping to have another craft in orbit about venus before too long

selvaarchi
2015-Nov-20, 07:56 AM
An update of the status of Akatsuki as it approaches its D day - 7th December. Keeping fingers crossed and good luck.

http://spaceflightnow.com/2015/11/18/tiny-thrusters-to-do-heavy-lifting-as-japanese-probe-approaches-venus/


Imamura said the Akatsuki spacecraft, named for the Japanese word for dawn, will zoom 541 kilometers, or 336 miles, above Venus for a 20-minute insertion burn using the probe’s secondary attitude control thrusters. Japanese ground controllers have programmed the probe to use the backup rocket jets after a faulty valve knocked out Akatsuki’s main engine during its first attempt to enter orbit around Venus in December 2010.

Four of the eight attitude control thrusters aboard Akatsuki will fire for 20 minutes and 33 seconds to slow the spacecraft down enough for Venus’ gravity to pull it into an egg-shaped orbit that skims above the planet’s cloud tops on the low end and ranges several hundred thousand miles in altitude at peak altitude.

The reaction control thrusters, originally designed to help point the spacecraft, were not rated for such a hefty propulsive maneuver.

“In the original plan, we used these RCS (thrusters) only for attitude control — mostly using these thrusters only for unloading angular momentum — so we did not expect such a long (burn),” Imamura said last month in a presentation to NASA’s Venus Exploration Analysis Group. “So yes … this kind of operation is rather dangerous, but in the previous (burns) already conducted, we have already tested 10 minutes of propulsion, so 20 minutes is not very long compared to the (maneuvers) we have already conducted.”

Swift
2015-Nov-20, 02:26 PM
Good luck Akatsuki

KaiYeves
2015-Nov-20, 03:56 PM
Good luck Akatsuki

Seconded.

selvaarchi
2015-Dec-07, 08:50 AM
JAXA has performed the attitude control engine thrust operation of the Venus Climate Orbiter “AKATSUKI” for its Venus orbit insertion from 8:51 a.m. today Japanese time. It will take a few day before they can confirm if it has been successfully inserted into Venus orbit. Good luck AKATSUKI

http://global.jaxa.jp/news/2015/#news6425

selvaarchi
2015-Dec-08, 11:38 PM
More details in spaceflightnow.com.

https://spaceflightnow.com/2015/12/06/japanese-space-probe-to-steer-into-orbit-around-venus/

Officials confirmed the burn went as planned early Monday.

“It is in orbit!” wrote Sanjay Limaye, a planetary scientist based at the University of Wisconsin in Madison, in an email to Spaceflight Now.

“They were cautiously optimistic before the burn, but confident. Now smiling!” reported Limaye from Akatsuki’s mission control center in Sagamihara, Japan. He is is a NASA-sponsored participating scientist on the Akatsuki mission.

It could take a few days to precisely measure Akatsuki’s trajectory to verify it is in the proper orbit around Venus, officials said.

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KaiYeves
2015-Dec-09, 06:10 PM
More details in spaceflightnow.com.

https://spaceflightnow.com/2015/12/06/japanese-space-probe-to-steer-into-orbit-around-venus/

Officials confirmed the burn went as planned early Monday.

“It is in orbit!” wrote Sanjay Limaye, a planetary scientist based at the University of Wisconsin in Madison, in an email to Spaceflight Now.

“They were cautiously optimistic before the burn, but confident. Now smiling!” reported Limaye from Akatsuki’s mission control center in Sagamihara, Japan. He is is a NASA-sponsored participating scientist on the Akatsuki mission.

It could take a few days to precisely measure Akatsuki’s trajectory to verify it is in the proper orbit around Venus, officials said.

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Here's hoping everything turns out to be A-OK once the trajectory is measured.

ravens_cry
2015-Dec-09, 08:17 PM
Still, it made orbit. Great work by everyone involved!:clap:

selvaarchi
2015-Dec-09, 09:32 PM
It is now confirmed it has made it. We now have a satellite going around Venus. Congratulations Japan. ☺

http://global.jaxa.jp/news/2015/#news6466

As a result of measuring and calculating the AKATSUKI’s orbit after its thrust ejection on Dec. 7, JAXA found that the AKATSUKI was inserted into the Venus orbit.

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Squink
2015-Dec-10, 01:33 AM
According to link:

regular operation is scheduled to start in April, 2016.

selvaarchi
2015-Dec-10, 11:50 AM
AKATSUKI takes the 1st photo of Venus ☺

https://spaceflightnow.com/2015/12/09/akatsuki-probe-relays-its-first-images-from-venus-orbit/

Japanese scientists released Wednesday the first views of Venus captured by the Akatsuki spacecraft after arriving in orbit this week, setting the stage for regular observations of the planet’s blistering atmosphere over the next few years.

The Japanese space agency — JAXA — also confirmed Akatsuki is in a good orbit around Venus after a 20-minute firing of four of the spacecraft’s maneuvering thrusters beginning at 2351 GMT (6:51 p.m. EST) Sunday.

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selvaarchi
2015-Dec-12, 08:24 AM
Emily Lakdawalla as usual has done a wonderful job describing JAXA'S feat of placing the satellite around Venus. In fact the orbit they obtained was better than expected. The first 3 photos is also included. She also explains what they are doing to have the satellite fully operational by end March next year and their future plans.

http://www.planetary.org/blogs/emily-lakdawalla/2015/12091630-akatsukis-new-orbit-first.html

JAXA held a press briefing today to confirm the successful arrival of Akatsuki into Venus orbit -- an even lower orbit than they'd hoped to achieve. Akatsuki is Japan's first successful planetary orbiter. It's been a long time coming: today's announcement came twelve years to the day after Japan had to abandon efforts to put Nozomi into Mars orbit. The presenters were project manager Masato Nakamura (中村), trajectory engineer Chikako Hirose (廣瀬), and project scientist Takeshi Imamura (今村). There were three main topics: Akatsuki's orbital trajectory, new images, and science plans.

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banquo's_bumble_puppy
2015-Dec-12, 09:47 PM
Applause! Good job.

bknight
2015-Dec-13, 12:21 PM
Perseverance and good ground analysis of the original failure proved a winning combination to save a mission.

selvaarchi
2016-Jan-09, 01:42 PM
Within two weeks in orbit Akatsuki is already providing new information about Venus.

http://www.gizmodo.com.au/2015/12/weve-never-seen-venus-roiling-storms-like-this-before/


The first images of Venus from its solitary, tardy orbiter are already revealing new secrets about its cloud dynamics. The fourth of the Akatsuki spacecraft’s cameras sent back new details on cloud structure for the planet’s roiling storms that we’ve never seen before.

KaiYeves
2016-Jan-09, 04:28 PM
Within two weeks in orbit Akatsuki is already providing new information about Venus.

http://www.gizmodo.com.au/2015/12/weve-never-seen-venus-roiling-storms-like-this-before/

Yay!

scampagn
2016-Mar-25, 01:58 PM
I read the article and how the craft was put into a resonant orbit with Venus (not that I know what a resonant orbit is). My question is whether that bit was lucky because a resonant orbit would be one they could recover from, or was the craft capable of recovering from a wide range of post-fly-by trajectories?

Maybe I'm not expressing myself well. I'm asking the question: "were they lucky?", not making a statement about how they were lucky.

Akatsuki was not in a resonant orbit after the failed orbit insertion. However, some time after the failed orbit insertion, Akatsuki performed a large deep-space burn with the small attitude control thrusters, that change the trajectory into a free return orbit. Akatsuki would eventually re-approach Venus, and with a much smaller speed, that would allow it being captured even without the main engine. So , it was not luck, it was control.
Details are in "Design of the Recovery Trajectory for JAXA Venus Orbiter Akatsuki", Campagnola and Kawakatsu. Apologies if I share my own article: in 2010 I was a postdoc at JAXA , and we proposed the recovery maneuver to the Akatsuki team, shortly after the failure.

selvaarchi
2016-Mar-25, 09:57 PM
Akatsuki was not in a resonant orbit after the failed orbit insertion. However, some time after the failed orbit insertion, Akatsuki performed a large deep-space burn with the small attitude control thrusters, that change the trajectory into a free return orbit. Akatsuki would eventually re-approach Venus, and with a much smaller speed, that would allow it being captured even without the main engine. So , it was not luck, it was control.
Details are in "Design of the Recovery Trajectory for JAXA Venus Orbiter Akatsuki", Campagnola and Kawakatsu. Apologies if I share my own article: in 2010 I was a postdoc at JAXA , and we proposed the recovery maneuver to the Akatsuki team, shortly after the failure.

Thanks for sharing. It was have been a wonderful feeling watching it actually happen. Congratulations :clap:

Welcome to the forum.

selvaarchi
2016-May-19, 05:21 AM
Akatsuki officially begins science mission at Venus :rimshot::clap:

http://spaceflightnow.com/2016/05/17/japanese-orbiter-officially-begins-science-mission-at-venus/


Five months since a belated arrival at Venus, Japan’s Akatsuki spacecraft has officially started a modified scientific survey of the sweltering, shrouded planet’s atmosphere and climate.

The probe’s science cameras are collecting regular images of Venus’s exotic clouds, and Japanese engineers are optimistic Akatsuki can remain operational for at least two years, and perhaps through 2020.

Akatsuki braked into orbit around Venus in early December, five years later than originally planned after it missed an arrival opportunity in 2010.

Scientists checked out the orbiter’s science instruments since the craft arrived at Venus, and declared Akatsuki operational in April, according to the Japan Aerospace Exploration Agency. One of the spacecraft’s instruments, the lightning and airglow camera, is still being calibrated before it shifts to regular observations, JAXA said.

selvaarchi
2016-Jun-13, 03:53 PM
Phil Plait on the latest scientific findings from Japan's Akatsuki (“Dawn”) spacecraft.

http://www.slate.com/blogs/bad_astronomy/2016/06/13/japanese_space_probe_akatsuki_is_now_sending_back_ images_and_data_from_venus.html




And now Akatsuki is returning science to Earth. The image above is a combination of two infrared shots at wavelengths of 1.735 microns (shown as red) and 2.26 microns (shown as blue); a pseudo-green frame was crated combining the two together. The color choice is a bit odd, since usually the longer wavelength image is shown as red. But who am I to argue with such a phenomenal image?

The bright white crescent on the left is the day side of Venus, and the orange band is actually twilight; the ridiculously thick atmosphere of Venus (90 times the pressure of Earth’s atmosphere at ground level!) spreads out the sunlight, causing a wide band of scattered sunlight.*

But it’s the structure of the clouds on the night side of the planet that’s so amazing. The two different wavelengths used are sensitive to different sized cloud particles in Venus’ atmosphere and really show the atmospheric structure.

01101001
2016-Aug-08, 02:20 AM
JAXA: July 19, Happy birthday, Akatsuki (http://www.isas.jaxa.jp/e/topics/2016/0729.shtml)


On July 19, Akatsuki celebrated 1st Venus's year anniversary (a year on Venus is 225 Earth days). Akatsuki keeps working well and continues to gather lots of data. The four cameras aboard the Venus Climate Orbiter "Akatsuki" keep sending down images.

Whole-Venus images, at various wavelengths.

selvaarchi
2016-Oct-23, 04:06 PM
We now get a photo of the night side of Venus.

https://trkendall.wordpress.com/2016/10/23/jaxaakatsuki-imaging-of-the-night-side-of-venus/


JAXA/Akatsuki imaging of the night side of Venus

Sardonicone
2016-Oct-24, 12:55 PM
This is such a "little engine that could" story. Very awesome they were able to salvage the mission and get into orbit after a long wait.

selvaarchi
2017-Jan-18, 04:34 AM
Akatsuki observes giant wave in Venus atmosphere.

http://www.skyandtelescope.com/astronomy-news/japans-akatsuki-spies-massive-wave-on-venus/

"A monster wave roils in the atmosphere of Venus. The Akatsuki orbiter team, under the Japanese Aerospace Exploration Agency (JAXA), recently revealed images of the huge bow-shaped wave in the upper atmosphere of Venus.

The finding comes from data Akatsuki gathered in late December 2015 and early January 2016, shortly after orbital insertion. The team released the results on January 16th in Nature Geoscience. The spacecraft's Longwave Infrared Camera (LIR) and the Ultraviolet Imager (UVI) captured the images of the Venusian atmosphere."

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selvaarchi
2017-Jan-20, 01:24 PM
The nail biting story of how Akatsuki successfully entered the Venus on its second try 5 years later.

http://www.boulderweekly.com/features/akatsuki-returns-from-the-dead/

"It is Dec. 7, 2015. We’re in Sagamihara, Japan, a little southwest of Tokyo. On a clear day like today, you can just make out the silhouette of Mount Fuji in the distance. We are standing outside of the control room of the Japanese Aerospace eXploration Agency (JAXA), watching as a spacecraft named Akatsuki is preparing for its arrival at Venus.

Success here means the beginning of a promising collaboration between JAXA and NASA scientists — mostly between JAXA and Boulder scientists, since four of the eight scientists chosen by NASA to work with the Japanese on this ground-breaking mission are based in Boulder. The team includes myself, along with Mark Bullock, Kandis Lea Jessup and Eliot Young, all from the Southwest Research Institute."

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selvaarchi
2017-Mar-04, 04:26 PM
😣two camers of Akatsuki stop working 😣

http://www.isas.jaxa.jp/en/topics/000902.html

"JAXA decides that two of five cameras on-board Akatsuki (1-µm and 2-µm cameras) pause scientific observations. Other cameras (longwave-infrared camera, ultraviolet imager, and lightening and airglow camera) continue normal operation.
On 9 December 2016, the electronic device, which controls both 1-µm (IR1) and 2-µm (IR2) cameras, indicated unstable power consumption and it became unable to control IR1 and IR2. The team started recovery trials on 10 December but the symptom remains to date."
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selvaarchi
2017-Aug-30, 12:17 PM
Akatsuki spots winds at a speed of 288 kph to 324 kph near the planet's equator.

http://www.asahi.com/ajw/articles/AJ201708300046.html


Savage winds exceeding 288 kph were detected near Venus' equator by the space orbiter Akatsuki, the first discovery of its kind, the Japan Aerospace Exploration Agency (JAXA) announced on Aug. 29.

The winds, named “equatorial jet” by the research team, were found from July to August 2016 when an infrared camera captured images of areas about 45 to 60 kilometers above the planet's surface. The areas are invisible at optical wavelengths due to extremely dense clouds of sulfuric acid. The camera spotted thick clouds traveling at a speed of 288 kph to 324 kph near the planet's equator.

The discovery was published in the online version of the British scientific magazine Nature Geoscience on Aug. 28.

selvaarchi
2018-Jan-17, 04:33 AM
Feast your eyes on enhanced pictures of Venus by Damia Bouic taken by the UVI camera and IR2 camera of Akatsuki. the enhanced pictures have been interpreted for us by scientist Widemann, Marcq, and Wilson.

http://www.planetary.org/blogs/guest-blogs/2018/0116-a-new-look-at-venus-with-akatsuki.html


This blog post is a collaboration between an image processing enthusiast (Damia Bouic) and three professional scientists (Thomas Widemann, Emmanuel Marcq, and Colin Wilson). Bouic has dived into a data set and processed images, and Widemann, Marcq, and Wilson have interpreted them. In the blog post below, the scientists' words are set off in block quotes preceded by "WMW"; the rest of the text and all the images are Damia's work

selvaarchi
2019-Jan-11, 11:36 AM
Akatsuki helps scientist identify giant pattern in the clouds of planet Venus.

http://www.spacedaily.com/reports/Giant_pattern_discovered_in_the_clouds_of_planet_V enus_999.html


A Japanese research group has identified a giant streak structure among the clouds covering planet Venus based on observation from the spacecraft Akatsuki. The team also revealed the origins of this structure using large-scale climate simulations. The group was led by Project Assistant Professor Hiroki Kashimura (Kobe University, Graduate School of Science) and these findings were published on January 9 in Nature Communications.

selvaarchi
2019-Sep-24, 03:11 PM
"Venus puts on variety show among its cloud-tops"

http://www.spacedaily.com/reports/Venus_puts_on_variety_show_among_its_cloud_tops_99 9.html


Studies of the cloud-tops of Venus by JAXA's Akatsuki spacecraft show striking variety in wind speeds year-on-year and between the planet's northern and southern hemispheres. The first fine-scale observations of cloud-top temperatures have also revealed a tendency for clouds to converge towards the equator at night, in contrast to poleward circulation seen previously in daytime studies.

The results, which have been presented at the EPSC-DPS Joint Meeting 2019 in Geneva, provide new insights into the mystery of why the Venusian atmosphere rotates much faster than the planet itself.

Prof. Masato Nakamura, Project Manager of Akatsuki at JAXA, said: "The Venusian 'super-rotation' is most pronounced at the tops of Venus's clouds, making this an important region for understanding the dynamics of the planet's atmosphere. The Akatsuki mission is in a highly elliptical orbit around Venus that enables the spacecraft to image both the north and south hemispheres of the planet simultaneously."