Emily Lakdawalla • Nov 30, 2013
Chang'e 3 ready to launch to the Moon
Another brief mission status update: Here's China's official announcement that Chang'e 3 is set to launch tomorrow -- December 2 at 01:30 China time, or December 1 at 17:30 UT / 09:30 PT. I first reported this as just a rumor, but it's now been officially stated. The launch opportunity is a narrow, nearly instantaneous window each day, because the rocket will be sending Chang'e 3 on a direct lunar transfer trajectory.
What's funny is that the first reliable information I saw on the launch date didn't come from an official Chinese source; it came from the European Space Agency, whose ground stations will be actively supporting the launch and operations of Change'3 and its rover Yutu. Here are the details from that release -- note the December 14 arrival date, which is earlier than I had previously reported:
Chang’e-3 liftoff is set for around 18:00 GMT on 1 December, and the 15 m-diameter dish in Kourou will pick up the first signals around 18:44 GMT.
ESA's Estrack tracking station control room at ESOC, the European Space Operations Centre, Working with Chinese tracking stations, Kourou will support the mission through lunar orbit entry on 6 December continuing until just prior to its descent to the surface, expected around mid-day on 14 December.
The landing and rover operations on the Moon will be commanded via two Chinese tracking stations at Kashi, in the far west of China, and at Jiamusi, in the northeast.
“After the lander and rover are on the surface, we will use our 35 m-diameter deep-space antennas at Cebreros, Spain, and New Norcia, Australia, to provide ‘delta-DOR’ location measurement,” says Erik Soerensen, responsible for external mission tracking support at ESOC.
“Using this delta-DOR technique, you can compute locations with extreme accuracy, which will help our Chinese colleagues to determine the precise location of the lander.”
Together with Cebreros, New Norcia will record Chang’e-3’s radio signals during landing, which will help the Chinese space agency to reconstruct the trajectory for future reference.
A team of engineers from China will be on hand in Darmstadt. “While we’re very international at ESOC, hardly anyone speaks Mandarin, so having Chinese colleagues on site will really help in case of any unforeseen problems,” says Erik.
“Both sides are using international technical standards to enable our stations and ESOC to communicate with their mission and ground systems."
I hope we'll see updates on Twitter from ESA and ESA Operations about Chang'e 3 tracking status! Pro tip: You can try looking for images and news for yourself with a Google search on "嫦娥三".
Here's a Chinese state television report -- I don't know what the talking heads are saying, but the included mission animations are cool.
And here's a nice long computer animation of the spacecraft operating on the Moon (thanks to an Australian reader for tipping me to this animation).
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