Akatsuki (spacecraft)

[14] Akatsuki is Japan's first planetary exploration mission since the failed Mars orbiter Nozomi probe which was launched in 1998.

[16] Observations include cloud and surface imaging from an orbit around the planet with cameras operating in the infrared, visible and UV wavelengths to investigate the complex Venusian meteorology and elucidate the processes behind the mysterious atmospheric super-rotation.

The five imaging cameras are exploring Venus in wavelengths from ultraviolet to the mid-infrared:[20][21] A public relations campaign was held between October 2009 and January 2010 by the Planetary Society and JAXA, to allow individuals to send their name and a message aboard Akatsuki.

[24][25] Names and messages were printed in fine letters on an aluminium plate and placed aboard Akatsuki.

On 4 May, Akatsuki was encapsulated inside the large payload fairing of the H-IIA rocket that launched the spacecraft, along with the IKAROS solar sail, on a 6-month journey to Venus.

[29] The spacecraft was launched on 20 May 2010 at 21:58:22 (UTC) from the Tanegashima Space Center,[17] after being delayed because of weather from its initial 18 May scheduled target.

[31] The orbit insertion maneuver was confirmed to have started on time, but after the expected blackout due to occultation by Venus, the communication with the probe did not recover as planned.

[34][35] At a press conference on 10 December, officials reported that Akatsuki's engines fired for less than three minutes, far less than what was required to enter into Venus orbit.

JAXA developed plans to attempt another orbital insertion burn when the probe returned to Venus in December 2015.

This required placing the probe into "hibernation" or safe mode to prolong its life beyond the original 4.5-year design.

It was concluded that the remaining combustion chamber throat was completely destroyed by transient ignition of the engine.

[45] Extended operations are approved until the end of 2020, with further mission extensions to be considered based on the spacecraft's condition at that time.

[51] Scientists on the project termed the feature a "gravity wave" in the planet's winds above the Aphrodite Terra region of rift valleys and mountains reaching heights of over 4,000 metres (13,000 ft).

[12][13] The mission is collecting data in all relevant spectral bands from ultraviolet (280 nm) to mid-infrared wavelengths (10 μm).

[52] Images from the Akatsuki orbiter revealed something similar to jet stream winds in the low and middle cloud region, which extends from 45 to 60 kilometres (28 to 37 mi) in altitude.

[54] They also published results on equatorial winds at the cloud-top level by tracking clouds on the UV spectrum.

[51] By the year 2019, the first results about the morphology, temporal changes[56] and the winds at the middle clouds of Venus were published and merited the cover in Geophysical Research Letters, reporting unexpectedly high contrasts that might indicate the presence of absorbers like water.

Configuration of Akatsuki spacecraft (left) and a photograph of the spacecraft with the solar array paddles being folded (right) [ 10 ]
Schematic of the three-dimensional observation by Akatsuki [ 10 ]
Akatsuki
The launch of Akatsuki
Animation of Akatsuki trajectory from 21 May 2010 to 31 December 2016
Akatsuki
Venus
Earth
Sun
Movement of the spacecraft orbit and Venus in a Sun-Earth line fixed rotating coordinate in the original plan. Numerals in the figure indicate days after VOI. [ 10 ]
Animation of Akatsuki 's trajectory around Venus from 1 December 2015
Akatsuki · Venus