Akatsuki spacecraft observes Venus

[lpetrich]

 Akatsuki (spacecraft), JAXA | Venus Climate Orbiter "AKATSUKI" (PLANET-C)

This Japanese spacecraft was launched on 2010 May 20, and on December 6 of that year, it tried to go into orbit around Venus. Instead of firing for 12 minutes, its orbital maneuvering engine only fired for 3 minutes, and the spacecraft did not slow down enough to go into orbit. It was kept going for the next 5 years in interplanetary space, and on 2015 December 7, it successfully went into orbit around the planet, using its reaction-control thrusters, mini rocket engines for orienting the spacecraft.

The orbital maneuvering engine uses hydrazine and nitrogen tetroxide, while the reaction control system uses only hydrazine. The RCS has much less exhaust velocity than the OME, so the spacecraft was left in a highly elliptical orbit without trying to get into a low orbit. Also, the nitrogen tetroxide was vented to make the spacecraft lighter.


AKATSUKI Science Data Archive
A new look at Venus with Akatsuki | The Planetary Society
Un nouveau regard sur Vénus avec AKATSUKI – Chez Damia Bouic (A new look at Venus with AKATSUKI)
Nouvelles images de Vénus par AKATSUKI – Chez Damia Bouic (New images of Venus by AKATSUKI)

Damia Bouic has taken Akatsuki's images and then enhanced them and false-colored them to bring out detail -- a *lot* of detail.
From her Planetary Society blog entry,

I focused on the data from two cameras. The UVI camera captures images in ultraviolet wavelengths, at 283 and 365 nanometers. It is intended to observe the atmosphere of the planet in great detail. These allow me to make false-colour images [using 283nm in the blue channel and 365nm in the red], after some small manipulation to build a synthetic green channel. The IR2 camera permits -- among other things -- a view of the intense heat emanating from the planet's atmosphere on its night side.

WMW (three professional scientists): UVI is seeing sunlight reflected from upper clouds and hazes lying at around 65-75 kilometers altitude. The IR2 camera reveals features in the lower clouds of Venus, at 48 to 55 kilometers above the surface. At these wavelengths, the clouds are backlit: darker regions in the images show thicker clouds.

Damia Bouic | The Planetary Society lists some of her other productions, like Mars panoramas. In Sunset on Mars | The Planetary Society, she describes what software she used: GIMP - GNU Image Manipulation Program, Pixelmator Pro (both of them more-or-less Photoshop Lite), and G'MIC - GREYC's Magic for Image Computing: A Full-Featured Open-Source Framework for Image Processing (something like ImageMagick and netpbm).


Finally, I must say that I'm impressed by how hot Venus is, for its infrared glow to be observable above its clouds.