
Akatsuki probe successfully enters Venus orbit, returns images - panglott
http://www.cnet.com/news/japans-akatsuki-orbiter-sends-back-triumphant-venus-images/#ftag=CAD590a51e
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johnm1019
Can anyone comment on why this image from the article has a perfectly straight
white line in it? Seems suspicious. It appears to be just a smidge above the
belt line.

[http://cnet4.cbsistatic.com/hub/i/r/2015/12/09/bccd7491-ac30...](http://cnet4.cbsistatic.com/hub/i/r/2015/12/09/bccd7491-ac30-4f00-bdcd-84f78cf47924/resize/970x546/3bd645efd2cf5ddeca52172945a30f92/akatsukivenus2.jpg)

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teraflop
It's probably just the equator.

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SoulMan
Good one :)

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tomr_stargazer
Does anyone know if the probe lost five years of expected lifetime due to its
five-year delay (original orbital insertion expected back in 2010) or whether
it was able to effectively "hibernate" or otherwise conserve its fuel and
energy since then?

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benten10
From the wiki[0]:

> This required placing the probe into "hibernation" or safe mode to prolong
> its life beyond the original 4.5-year design. JAXA expressed some confidence
> in keeping the probe operational, pointing to reduced battery wear, since
> the probe was then orbiting the Sun instead of its intended Venusian orbit

>At a press conference on 10 December, officials reported that Akatsuki's
engines fired for less than three minutes, far short of what was required to
enter into Venus orbit

>Three peri-Venus orbital maneuvers were executed on 1 November,[11] 10 and 21
November 2011 using the RCS thrusters. A total delta-V of 243.8 m/s was
imparted to the spacecraft. Because the RCS thrusters' specific impulse is low
compared to the specific impulse of the OME, the previously planned insertion
into low Venusian orbit became impossible. Instead, the new plan was to place
the probe in a highly elliptical orbit with an apoapsis of a hundred thousand
kilometers and a periapsis of a few thousand kilometers from Venus.

[0]:
[https://en.wikipedia.org/wiki/Akatsuki_(spacecraft)#Orbit_in...](https://en.wikipedia.org/wiki/Akatsuki_\(spacecraft\)#Orbit_insertion_failure)

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david-given
It's worth emphasising that the OME (the main engine) and the RCS (the
attitude thrusters) both run on hydrazine fuel, but the OME also has a
separate tank of oxidant. So, the OME is a bipropellant engine, while the RCS
is a monopropellant engine, which is why the OME is more efficient.

(Aside: that's actually a really neat trick, and this is the first I've heard
of it being used.)

After the OME engine nozzle broke off and the engine became useless, the tank
of oxidant became useless mass. (65kg.) So they dumped it overboard, simply
venting it out the broken rocket nozzle. (Yes, the did point the vehicle in
the right direction so that they could get some momentum change out of it.)

Making that decision, to dump irreplaceable fuel overboard because of a
conclusion you've reached by looking at some telemetry graphs, is one that I
am very glad I wasn't the one to have to make.

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eponeponepon
How long has it been since we last had new close-up photos of Venus? I know
there's been nothing from the surface since the Russian landers, but was
Magellan the last fly-by?

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Sharlin
ESA's Venus Express orbited Venus from 2006 until January 2015 when, its fuel
spent, it burned up in the atmosphere as planned.

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mpnordland
Why is this cnet.com.feedsportal.com? seems suspicious

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rwhitman
It appears to be a redirect URL from some sort of 3rd party RSS feed
syndication

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panglott
Sorry, I must have copied the link from the DuckDuckGo News search, rather
than the redirect. It should point to [http://www.cnet.com/news/japans-
akatsuki-orbiter-sends-back-...](http://www.cnet.com/news/japans-akatsuki-
orbiter-sends-back-triumphant-venus-images/)

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dsfsdfd
Although the surface is very unpleasant indeed - it is hypothesised that there
are habitable bands in the atmosphere.

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daveguy
habitable*

*survivable in terms of temperature. It still has a 96% carbon dioxide, oxygen free atmosphere, so not directly habitable. The temperature is about room temperature at an altitude of 55km with atmospheric pressure (and T=75C) at about 50km. Earth atmosphere would float in the more dense carbon dioxide atmosphere of venus. You could conceivably have an airship full of earth atmosphere where the cabin is within the balloon.

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Drdrdrq
Could plants survive at 55km altitude?

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daveguy
Good question. Seems like they could -- although co2 might be toxic at given
levels like o2 would be at 3-4x concentration for us. I don't know about what
else they would need -- surely some other nutrients that aren't just floating
around. Wouldn't it be awesome if we could just throw some single celled
lighter-than-co2 algae in there that could float and produce oxygen and
nitrogen. Wait 10,000/100,000/1,000,000? years and just fly around the newly
atmosformed atmosphere.

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blueflow
The name made me remember some childhood anime antagonists.

 _sigh_ i miss those times.

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ZenoArrow
That show you're referring to is still going, currently going through some
filler episodes but it should be back to canon in the new year. The next
generation has just started as well.

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dvh
Akatsuki means "red moon" so it probably appeared in many animes before THAT
one.

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Nadya
暁 is not 赤月

As /u/ZenoArrow pointed out, it means "dawn" or in some contexts, "in the
event... (of)"

It's used as the title for Akatsuki no Yona (Yona of the Dawn) but is
otherwise only really known for being a certain group of characters from a
certain anime which was implicated.

There are also a few characters who share the name, such as Akatsuki Ousawa.
But that would refer to an _individual_ and not a _group_.

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ilovefood
Those machines send out information from millions of km away, yet sometimes I
can't get a decent mobile connection. o_o

