Frida Space

Akatsuki Venus Orbital Insertion

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PLANET-C1.jpg

Japan's Akatsuki spacecraft is visiting Venus for the second time -- this time to stay, hopefully.

The JAXA spacecraft had failed orbital insertion in 2010, with its main engine prematurely shutting down less than 3 minutes into a 12 minute burn due to a salt formation. On December 7, Akatsuki will attempt a second orbital insertion manoeuvre, a 20 minute, 33 second burn that will be carried out by the spacecraft's 20 N, RCS thrusters. The thrusters have already been tested for 10-minute burns, which is still way beyond the very short angular-moment-dumping manoeuvres they were designed for. However, on a positive note, the engineers have managed to make the spacecraft a bit lighter by dumping 65 kilos of propellant from the main engine tank.

During its 5-year unplanned heliocentric cruise, Akatsuki has almost always been inside Venus' orbit, exsposing itself to temperature and radiation conditions 37% worse than those planned. The probe reached its last perihelion in August and is now getting further away from the Sun.

Also, even if Akatsuki succeeds in this second orbital insertion attempt, it will be on a not-so-scientifically-rewarding orbit, at least compared to the original orbit it was designed to reach. The new orbit will have a period of 15 days, instead of the 30-hour-orbit engineers and scientists originally hoped for. A manoeuvre scheduled for March should lower the orbital period to around 9 days.

Despite everything, there are some good signs: three of Akatsuki's five camers have recently been turned on for the first time in more than four years and everything seems fine with them. The other two will be activated only after the orbital insertion burn.

The orbital insertion burn is slated to start 541 km above Venus' surface.

Sources: SpaceflightNow and Polluce Notizie

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1 hour ago, cantab said:

RCS for emergency propulsion, now there's something every KSPer knows :D

Word :D Hopefully RCS will be up to the task. Bad orbit is still better than no orbit at all.

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On a serious note, if Akatsuki fails insertion, that means we won't have any probes nowhere near the closest planet to Earth for approx. a decade, if not more. That would be an incredible setback in planetary science, especially considering Venus' important role in understanding the evolution of our own Earth.

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If RCS fails, just get Jeb out and perform the "Scott Manley Maneuver" ;)

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3 hours ago, cantab said:

RCS for emergency propulsion, now there's something every KSPer knows :D

Its Kerbal if the pilot gets out and uses his jet pack to push his ship around.

Circularize the orbit by jeb, some have even managed to return to kerbin. (Not withstanding that 10 MP is not sufficient and jet packs get infinite refuel).

 

 

1 hour ago, Frida Space said:

On a serious note, if Akatsuki fails insertion, that means we won't have any probes nowhere near the closest planet to Earth for approx. a decade, if not more. That would be an incredible setback in planetary science, especially considering Venus' important role in understanding the evolution of our own Earth.

Remember Hayabusa I, the Japanese are awfully clever on thinking up work arounds. The odds that Hayabusa would deliver its cargo back to earth and be recovered were like a million to one against. 

One that I can think of use the solar panels as sails (needs an ion drive to balance). Thing about space an non-inertial reference frames, you have alot of time to tinker with 'stuff'

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7 hours ago, PB666 said:

Remember Hayabusa I, the Japanese are awfully clever on thinking up work arounds.

True, and I really hope you're right. We really need a constant presence of robotic eyes around Venus. A decade-long gap in close-up data would be catastrophic for planetary science IMHO.

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Akatsuki had 100 metal plates, used as balancing weights. A few of those plates bore images of the virtual singer, Hatsune Miku*, the result of a successful >10,000-signature petition supported by Prof. Seiichi Sakamoto of JAXA.

*what you're seeing is "Hachune Miku" (the chibi version)


miku-space-probe.jpg

Edited by Pipcard

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20151206_20151109_akatsuki_traj-01.png

8 hours to orbital insertion!

A timeline from Emily Lakdawalla:

  • Dec 7 04:30 JST / Dec 6 19:30 UT / Dec 6 11:30 PST: Usuda Deep Space Center begins tracking Akatsuki.
  • Dec 7 08:22 JST / Dec 6 23:22 UT / Dec 6 15:22 PST: Akatsuki enters Venus' penumbra.
  • Dec 7 08:51 JST / Dec 6 23:51 UT / Dec 6 15:51 PST: Akatsuki fires one set of RCS thrusters for 20 minutes, 33 seconds to enter Venus orbit.
  • After the firing, Akatsuki will automatically rotate to prepare for a second attempt at orbit insertion with its opposite set of RCS thrusters. Akatsuki will wait for instruction from Earth to find out if the second attempt is needed.
  • Dec 7 12:00 JST / Dec 7 03:00 UT / Dec 6 19:00 PST: JAXA will hold a press briefing from Sagamihara. At the press briefing, they will only be able to say whether or not the attitude control system functioned as commanded. It will take until December 9 to confirm that the spacecraft successfully entered Venus orbit. Another press briefing is scheduled for that day.
  • December 7, afternoon (Japan time): Canberra Deep Space Network begins tracking Akatsuki.

This website looks like it will be hosting a live webcast of the event. However, it's in Japanese, so my interpretation is based on not-so-reliable-Google Translate.

All the info in the main post remains valid. Fingers crossed... go Akatsuki!

 

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Here's a link to a live simulation of the spacecraft, and we've got an hour left!

Akatsuki is at about 20,000 km from venus now...

Edited by SaturnianBlue

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Also, found an Akatsuki livestream on youtube, the commentary is in Japanese however.

4500 kilometers now! I believe they are talking about the engines.

 

Edited by SaturnianBlue

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It is burning now. Six or so minutes to perivenus (or whatever it is).

EDIT: 5 minutes

EDIT: 4 minutes

EDIT: 3 minutes

EDIT: 2 minutes!

EDIT: 1 MINUTE...

Edited by Findthepin1

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Akatsuki passed 541 km above Venus' surface a couple of minutes ago and now is gaining altitude. In the meanwhile, the manoeuvre continues, with 450 seconds left.

T-400 in this moment.

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8 minutes ago, Findthepin1 said:

It is burning now. Six or so minutes to perivenus (or whatever it is).

EDIT: 5 minutes

It's called Pericytherion. :)

So far I think they are saying, the data coming in says all things are going well, but remember, there's a 9 min delay...

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4 minutes ago, Stone Blue said:

Darn it!... I just missed sunrise...

Off topic, anyone notice the Pleiades and Orion?... :)

Yea, it's a really beautiful animation!

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200 or so seconds left. I just realized Venus is close enough to Earth at the moment to be seen reasonably through a telescope, but isn't close enough to the Sun that it isn't visible. 1 minute to burn completion.

Edited by Findthepin1

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