Author Topic: LIVE: Chang'e-2 (China's second lunar probe) - Long March 3C - October 1, 2010  (Read 187837 times)

Offline 20350902

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anybody know what the two sentences in purple between the L2 orbit and the Toutatis flyby mean?
http://ww1.sinaimg.cn/large/58b49184jw1dzubmjhtyhj.jpg
The first of the two has the same structure as the two previous purple phrases. I guess these denote 1st, 2nd and 3rd maneuvers. The last purple line may denote the approach TCM.

The last purple "第四次机动控制" = "4th TCM"
White text:
"150万公里" = "1.5 million km"
"700万公里" = "7 million km"
Orange text:
"5小时椭圆轨道" = "5-hour elliptical orbit"
"中途修正" = "mid-way correction"
"捕获点" capture point (likely to be the point of L2 orbit insertion)
Red text:
"李萨如轨道" = "Lissajous orbit"
« Last Edit: 12/15/2012 09:38 AM by 20350902 »

Offline Nathan

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This is fantastic!
Given finite cash, if we want to go to Mars then we should go to Mars.

Online plutogno

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anyway, kudos to the Chinese!
this is the most interesting space story from China in 2012. far more interesting than those boring taikonaut flights!

Offline Star One

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Can we now expect the official end of mission to be declared, I assume its now exhausted all its propellant after this extended phase of its mission?

Online plutogno

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I assume its now exhausted all its propellant after this extended phase of its mission?

there is some 30 m/s of delta-V remaining. it's not much and probably no meaningful missions would be possible, but I sincerely hope that they will try to get as much deep space tracking and navigation experience as possible and keep contacts as long as possible

Offline Star One

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I assume its now exhausted all its propellant after this extended phase of its mission?

there is some 30 m/s of delta-V remaining. it's not much and probably no meaningful missions would be possible, but I sincerely hope that they will try to get as much deep space tracking and navigation experience as possible and keep contacts as long as possible

Thanks. Good points especially if they do intend to send vehicles to the outer planets such as Jupiter.

Online Phillip Clark

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I assume its now exhausted all its propellant after this extended phase of its mission?
there is some 30 m/s of delta-V remaining. it's not much and probably no meaningful missions would be possible, but I sincerely hope that they will try to get as much deep space tracking and navigation experience as possible and keep contacts as long as possible
Thanks. Good points especially if they do intend to send vehicles to the outer planets such as Jupiter.

Their next goal is their first (successfully-launched) mission to Mars.

Online plutogno

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plus, experience in VLBI tracking (which I understand was key to achieving such a close flyby) would be very useful also for precise lunar landings from Chang'e 3 on

Offline gwiz

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It's carrying a couple of instruments that could still return good data on the solar wind and cosmic radiation.

Offline Zero-G

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According to Zhou Jianliang, deputy chief designer of Chang'e-2 monitoring and control system, there were 120 m/s of delta-v left before they decided to fly to Toutatis. Currently, the remaining delta-v is less than 10 m/s.
"I still don't understand who I am: the first human or the last dog in space." - Yuri Gagarin

Online plutogno

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Currently, the remaining delta-v is less than 10 m/s.

interesting. does it mean that the optimized trajectory I summarized here http://forum.nasaspaceflight.com/index.php?topic=19644.msg961832#msg961832 was not eventually implemented?

Offline Zero-G

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Currently, the remaining delta-v is less than 10 m/s.

interesting. does it mean that the optimized trajectory I summarized here http://forum.nasaspaceflight.com/index.php?topic=19644.msg961832#msg961832 was not eventually implemented?

You mentioned three maneuvers (on 15 April, 31 May and 25 Sept.) in your post, but according to the picture discussed here http://forum.nasaspaceflight.com/index.php?topic=19644.msg992172#msg992172 there were four maneuvers. This may explain the difference.
"I still don't understand who I am: the first human or the last dog in space." - Yuri Gagarin

Offline JimO

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The fly-by was just confirmed by CCTV that it will take place today.

http://news.cntv.cn/china/20121213/100038.shtml

Sorry to come late to the party, but this is the only report i've seen that indicates the chinese made an advance alert the ecounter was about to happen. Just what was said in this broadcast and how long before encounter was it aired?


Online Kryten

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 There was more indication than that, just not in a very high profile way; for example, here is a Xinhua article from July that mentions it as part of an overview of CNSA plans in general.
« Last Edit: 12/17/2012 08:14 PM by Kryten »

Offline JimO

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There was more indication than that, just not in a very high profile way; for example, here is a Xinhua article from July that mentions it as part of an overview of CNSA plans in general.

There was also a science conference paper with the precise encounter date.

What I'm trying to determine is this: were there ANY Chinese media reports in the days prior to the encounter, that the encounter was about to happen?


Online plutogno

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Jim, I have been monitoring the Chinese online press everyday for weeks before the encounter and there was next to nothing. I think I have posted everything that I have found either here or on unmannedspaceflight.com

Offline Star One

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Jim, I have been monitoring the Chinese online press everyday for weeks before the encounter and there was next to nothing. I think I have posted everything that I have found either here or on unmannedspaceflight.com

That's curious, even if they were being cautious I would have thought for something like this there would have been more coverage?

Offline JimO

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Two more weeks and not even ONE more mention in the Chinese news media? Very odd.


Online Galactic Penguin SST

Two more weeks and not even ONE more mention in the Chinese news media? Very odd.



Not exactly mainstream media, but there are reports about the fly-by and the achievements by various organizations during the last few days (translate this forum page to see a few of them).

And Xinhua News just made an article about CE-2 crossing the 10 million km mark from Earth on January 5: http://news.xinhuanet.com/mil/2013-01/08/c_124199889.htm
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Online plutogno

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Chinese sources have always been quite silent on this one, especially after it left moon orbit. I'm waiting for technical papers to know more.
BTW it''s the western media silence that shocks me more. not a single word in any specialized magazine and journal like Science, Nature or Aviation Week. it looks like CE2 never existed...
finally, I hope we will know something more next week when a presentation is scheduled to be given at the Small Bodies Assessment Group http://www.lpi.usra.edu/sbag/meetings/jan2013/agenda.shtml