Akatsuki Venus Climate Orbiter Options

[Paolo]

I thought it was time to start a separate thread on this mission, launching soon
some good medium-resolution images of the spacecraft are available on JAXA digital archives
http://jda.jaxa.jp/jda/p3_e.php?time=N&...mp;mission=4066

[elakdawalla]

I just want to chime in a note of thanks to you for your work in translating these documents, pandaneko.

[pandaneko]

Page-30

Example 3: Clarifyinng mechanism for complex patterns (UVI+LIR)

(1st character set after above in yellow box):

In particular, complex abosrption patterns in dark area

(2nd character set):

Are solar light absorbing materials lifted from lower height?
Are they newly chemically produced at cloud tops?
Are they moved horizontally?
What kind of convection, pulsage, random flow currents are involved?

(3rd character set in yellow box):

Very clear boundary between dark and light regions

(4th character set):

In particular, complex absorption patterns in dark area
Is there a barrier of horizontal mixture of absorbing material and haze (translation unsure, P)?
Is new aerosol produced in a particular area?

(5th character set):

Clarify air mass transport and change (?) process at cloud top from observing distribution of absorption materials and haze (UVI),
cloud temp. variation with height (LIR), wind velocity disribution form cloud tracing

P

[pandaneko]

I have this nagging thought. In fact, I have had it for long time by now.

If Akatsuki was able to enter a kind of orbit around Venus with its smaller
engines, then why did they bother with the larger engine that failed?

They could have designed a craft with a few more of these smaller engines and
made Akatsuki go around in a proper circle? Tha wouod have been a lot cheaper?

P

[JRehling]

No spacecraft has ever entered a close-in circular orbit around another planet without aerobraking. Orbits like that have only been achieved at Venus (Magellan being the only case) and Mars (several cases, but much less planetary mass).

An elliptical orbit with a low periapsis is pretty good for many scientific purposes. Akatsuki, like Venus Express, Mars Express, and all pre-Nineties Mars/Venus orbiters are/were able to get periodic close-ups along with regular global monitoring. Given that Venus doesn't have seasons, it seems like a pretty good option to have a Venus atmosphere observer in an orbit like Akatsuki's, to collect both close-up and global monitoring, although an orbit like that would have drastically compromised the goals of surface-mapping missions like Magellan or Mars Reconnaissance Orbiter.

[pandaneko]

An elliptical orbit with a low periapsis is pretty good for many scientific purposes.

Thank you for this. "periapsis" and a counterpart to it are the words I should have been using
in some places of my translation. Instead, I always use "nearest Sun"etc etc because I can never
distinguish them and remember which is which.

It took me 15 to 20 years to learn the difference between latitude and longtitude, after all.
So, my excuses...

P