Author Topic: H-IIA - Akatsuki - Venus Climate Orbiter (PLANET-C) - May 20, 2010  (Read 271859 times)

Offline seshagirib

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ohh....feels like a rerun of the Hayabusa return trip all over again

Offline TheFallen

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According to the link below, IKAROS made its flyby of Venus from a distance of 80,000 km on December 8...

http://www.isas.jaxa.jp/home/IKAROS-blog/i....php?itemid=786

I thought the solar sail wasn't suppose to fly past Venus till December 18.  Oh well.



Offline kevin-rf

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Do we know how similar was this propulsion system to the IHI propulsions system used on the AEHF-1? Curious...
If you're happy and you know it,
It's your med's!

Offline seshagirib

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Revised time line for second try:

http://www.spacedaily.com/reports/Venus_probe_may_get_2nd_chance_soon_999.html

"
.......
JAXA had said it would try again in six years, when Akatsuki approaches Venus once again, but now say it may be possible to decelerate Akatsuki slowly to let Venus catch up and try for an orbit in five years.
......
"

Offline Fuji

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From IKAROS blog.
In six months, the amount of acceleration of the solar light pressure over 100 meters per second.
In other words, over 360km per hour has been achieved by a solar sail acceleration so far.
http://translate.google.com/translate?u=http%3A%2F%2Fwww.isas.jaxa.jp%2Fhome%2FIKAROS-blog%2F%3Fitemid%3D803&sl=ja&tl=en&hl=&ie=UTF-8

Offline TheFallen

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IKAROS took this self-portrait with Venus in the background! (Darn it, JAXA... Release a larger size of this image) :)

http://www.planetary.org/blog/article/00002892/
« Last Edit: 01/26/2011 09:30 pm by TheFallen »

Offline TheFallen

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Here's a larger version of the IKAROS-Venus pic...taken from a JAXA press kit

http://www.jaxa.jp/press/2011/01/20110126_sac_ikaros.pdf

Offline Fuji

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IKAROS took this self-portrait with Venus in the background! (Darn it, JAXA... Release a larger size of this image) :)

I heard this photo data size is 67.8kbyte.
It takes Dec. 8th.
Now (Jan. 23), IKAROS's data rate is only 13 byte/Day (not 13 byte/sec) ;)
Data transfer are very tough work.
« Last Edit: 01/26/2011 09:14 pm by Fuji »

Offline Fuji

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Interesting interview.

IKAROS 's NEC development team is only two person :o

At first, Akatsuki will be launched M-V rocket. But, changed to the H-IIA.
In analyzing what can be found becomes a problem of excessive vibration while accelerating in the second stage. In order to solve the problem, 700kg additional dummy mass will be need. Launch weight of the Akatsuki is desighed to 500kg. launching the 700kg dummy mass to the Venus is futile.
Therefore, IKAROS project is started. Mr. Kawaguchi was proposed this plan in a week.
IIKAROS  was only 2.5 years from start to launch. Moreover, a total budget of 15 billion yen, an order of magnitude smaller compared to conventional spacecraft.

http://translate.google.com/translate?u=http%3A%2F%2Fwww.nec.co.jp%2Fad%2Fcosmos%2Fikaros%2F&sl=ja&tl=en&hl=&ie=UTF-8

Offline hop

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One year after launch, a very nice write up on IKAROS results http://www.isas.jaxa.jp/e/forefront/2011/tsuda/index.shtml

Offline Fuji

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Akatsuki's trouble report was released in Japanese.

Clogged fuel check valve (CV-F) was cause the trouble.
It assumed biproduct was generated from MON3 and N2H4 vapor, these are clogged the CV-F.

OME nozzle could be brokend (drop off the nozzle), but 60% thrust may be available.
OME test burn will be planed this September.

New Venus orbit injection plan is Nov. 2015.

If we can't use the OME, back up plan is considerd. We can use the RCS burn. In this case, to reduce the weight oxidizer will be dumped.

For reference, machine translation.
http://translate.google.com/translate?u=http%3A%2F%2Fjournal.mycom.co.jp%2Farticles%2F2011%2F07%2F04%2Fplanet-c_ome%2F&sl=ja&tl=en&hl=&ie=UTF-8
« Last Edit: 07/04/2011 02:41 am by Fuji »

Offline Fuji

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Akatsuki's OME test burn will be planed September 7 and 14.
First test burn is 2 seconds. Second burn is 20 seconds and also using the RCS thrusters for the attitude stability test.
If these test will good result, trajectry change OME burn (400 sec) will be held in November.
« Last Edit: 09/05/2011 11:59 pm by Fuji »

Offline bolun

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Bid To Salvage Venus Mission [Mainichi Daily News]

The Japan Aerospace Exploration Agency (JAXA) will fire the engine of its Akatsuki probe for two seconds Sept. 7 and 20 seconds Sept. 14 as it works to get the craft into orbit around Venus after failing to do so in December, the Mainichi Daily News reported Sept. 6.

JAXA scientists are studying methods of sending fuel to Akatsuki’s engine without using a defective fuel valve that caused it to overheat, the agency said. They may attempt to adjust the probe’s posture in November as part of an effort to get it into venusian orbit in 2015.

Read it at: Mainichi Daily News

http://www.spacenews.com/commentaries/110906-fromwires-jaxa-ignite-akatsuki-engine.html


Offline Fuji

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Test burn rusult was no joy  :(
Only 13% thrust was gained.
JAXA replaned next OME burn will be 5 seconds short test burn.

Offline robertross

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Test burn rusult was no joy  :(
Only 13% thrust was gained.
JAXA replaned next OME burn will be 5 seconds short test burn.

Thanks for the note Fuji.

Offline bolun

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September 9, 2011 Updated

AKATSUKI: Second orbit maneuver engine test plan changed

JAXA performed the first test jet thrust(*1) from the orbit maneuver engine (OME) aboard the Venus Climate Orbiter “AKATSUKI” (PLANET-C) on Sept. 7 as part of studying an orbit change plan for the AKATSUKI to meet with Venus. Through this test, we found that acceleration by the jet thrust was less than the expected value; therefore, we decided to shorten the time duration of the second test(*2) slated for Sept. 14 to about 5 seconds because the originally expected acceleration value was the baseline for the second test. We will jet the thrust for about five seconds again to reconfirm the thrusting condition of the OME.

The satellite is in good condition after the first test jet thrust.

*1: Test thrust aimed at quantitatively understanding postural disturbance (including horizontal thrust.) The thrust duration was two seconds as planned.

*2: The second test originally aimed to verify the attitude control logic. The planned thrust duration was 20 seconds.

http://www.jaxa.jp/projects/sat/planet_c/index_e.html

Offline bolun

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September 14, 2011 Updated

AKATSUKI: Second orbit maneuver engine test

JAXA performed the second jet thrust(*1) test from the orbit maneuver engine (OME) aboard the Venus Climate Orbiter "AKATSUKI" (PLANET-C) at the scheduled time of 11:50 a.m. on Sept. 14 (Japan Standard Time) as part of studying an orbit change plan for the AKATSUKI to meet with Venus. We have confirmed the jet thrust from the OME.

We will analyze acquired telemetry data, and study the orbit change plan of the AKATSUKI.

*1: The second test aimed at reconfirming the status of the jet thrust from the OME. The planned test duration was about five seconds.

 http://www.jaxa.jp/projects/sat/planet_c/index_e.html

Offline Fuji

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Again, second test burn result is no joy. Thrust level was small.
May be engine throat was heavy dameged.

Next option will be using the RCS. In this case, to reduce the spacecraft weight oxidizer will be dumped. Planned Venus orbit will be need to change. Some of the science objective will not achieved.

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