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Chang'e 3 has arrived in lunar orbit

Posted by Emily Lakdawalla

06-12-2013 9:53 CST

Topics: mission status, Chang'E program

Just a quick update: via Xinhua news (in English), Chang'e 3 successfully entered lunar orbit today at 09:53 UTC, after a 361-second lunar orbit insertion burn.

Next steps for the mission, from this report (in Chinese, with helpful translation from a member of

Lunar landing is planned at 15:22-15:35 UTC on December 14.

The rover should be deployed from the lander at 20:38-22:21 UTC on the same day.

Then some time within the communication window on December 15 at 07:21-15:38 UTC, the lander and rover will photograph each other.

Mark your calendars! Here's an infographic about the mission -- in Chinese, of course. Anybody want to translate it? Here is the original PDF.

Chang'e 3 infographic
Chang'e 3 infographic
See other posts from December 2013


Or read more blog entries about: mission status, Chang'E program


Donald "Skip" Morrow: 12/06/2013 10:08 CST

Wow, do I have mixed feelings about this. I am excited about a rover driving on Luna, but I sure do wish it has an American flag on it.

Joseph Moran: 12/06/2013 10:14 CST

I don't mind the flags, I just wish the non-USA information was more accessible to a global audience. Perhaps TPS should consider hiring some staff fluent in Mandarin and Hindi?

Bob Ware: 12/06/2013 10:28 CST

Congratulations China! Best wishes for a successful landing and deployment of the rover!

Saul Cohen: 12/06/2013 11:44 CST

OK, let's see: "Today at 2:22 in the morning, ..." Whew, that exhausts my Chinese ability. I'm sure you can figure the rest from there. Seriously, tho, the sections at the top are (I think): Transfer segment Lunar braking Soft landing Going out on the moon (This section is probably most interesting. It discusses the procedure for checking out the landed craft and dispatching Yutu.) The bottom section says "The Lunar Palace (home of Chang'e (the princess, that is, haha)) will be in Sinus Iridium". Then it goes on to talk about why it has that name and some basic physical geography. The interesting bit is a discussion of 4 criteria they used to select the site: 1. Safe flat area; no rocks or craters that might disable the lander 2. Scientific value; geological features and regolith at landing point 3. Geometric constraints; they need a place with solar illumination and facing the Earth for communications 4. Nobody else has been there yet; they wanted to pick a spot other countries had not visited. Then they list 5 places that they considered: 1. Sinus Iridium 2. Mare Nectaris 3. Mare Humorum 4. Kepler Crater 5. Aristillus Crater It goes on to say that Chang'e 3 has onboard cameras and computers that will examine the lunar surface from a height of 100m to select the best landing site (automatically). The numbered list on the left with the pretty pictures describes the landing sequence. 1. Begin active deceleration at 15km. 2. Some kind of pointing adjustment between 15 and 2km. 3. At 100m, stop and hover for a while to find and avoid obstacles. 4. Descend 100m to 4m using thrusters. 5. Drop freefall from 4m. 6. After soft landing, release rover. Then the squiggly blue line describes step 6 in extended detail. Deploy solar panels, establish communications, unlock rover, deploy rover mast and panels, create panorama for rover navigation, move to surface (about 350 minutes), do local exploration (about 30 minutes). Caveat: I really am not very good at Chinese.

Stephen Uitti: 12/06/2013 01:34 CST

Shared this at work with someone who isn't usually terribly interested in space, but who knows the language as a native. He identified it as a daily newspaper instantly, then started getting some excitement.

tom6740: 12/06/2013 04:31 CST

This is an excerpt from the Beijing Evening News... I only translate the parts that are technically interesting. Abstract: basically stated that CE3 entered lunar orbit this morning. First section: CE3 directly enters lunar orbit which is a technique advancement. Second section: basically repeated the first section, but stated that there will be a maneuver on Dec 6 0950Z (I am sure this information is available elsewhere, but maybe this is the first time that CNSA explicitely state that). Third section: landing planned Dec 14, 1522-1535Z. A few lines about how the landing is performed. Forth section: Yutu will be deployed Dec 14 2038-2221Z, imagine is planned Dec 15 0721-1538Z. Lower half: a cartoon explaining the landing stages; right hand side - how the landing site, Sinus Iridum, is selected. There are some other candidates (could be the landing site for CE4). The exact possible landing sites are "selected" but not yet known. Hope these help...

Bob Ware: 12/06/2013 07:14 CST

Thanks Saul & Tom for your efforts!

FlyMeToTheMoon: 12/07/2013 03:03 CST

Last section (TOP): courtesy of Sangrakwol : 9 hours after pictures of the lunar surface After landing probe to achieve a soft landing on the lunar surface , first by Lunar lander vehicle charging on the lunar rover is initialized ; later, Rover establish a communication link with the ground , unlocking mechanism connecting the control solution Lock onto the transfer mechanism , which is commonly known as a ladder . After this, the Land transfers control mechanism motion detector to the lunar surface , leaving the rover Transfer mechanism . Landing the ladder down to the lunar surface , the rover was to go down. According to Plan, " rabbit " lunar rover will be on December 15 when 38 points to 04 to 06 21 Points, to achieve the separation of the lander . Although the " off " in height from only About two meters , but will have to spend nearly two hours , the difficulty is evident. According to the plan , at 15:21 on December 15 to 23:38 , the Lu , a nine hours after the rover separation , the two devices will begin Lee With their own camera , captured in pictures for each other lunar surface. According to reports , this time on the lunar rover and lander has five-star red Flag , though not necessarily inserted in the moon above, but together with the flag Shadow of operation can be achieved. After another two photographs , as well as Hope able to take photos of the flag back to the earth. According to two Were located in different locations , different " pictures " background pictures , both have monthly Rainbow Bay the ball on the ground , there will be 380,000 kilometers away blue planet.

cheng: 12/08/2013 12:01 CST

发射段:一箭入轨 Chang'e 1: GTO to phasing orbit to TLI orbit. Chang'e 2: directly to TLI orbit Chang'e 3: over a ton heavier than Chang'e 2, directly to TLI orbit.

cheng : 12/08/2013 12:06 CST

近月刹车:直接进入圆轨道 chang'e 3 is equipped with a newly designed variable thrust rocket engine to directly transfer the payload from tli orbit to the circular lunar orbit. in comparison, chang'e 1 and 2 were transfered from tli orbit to the elliptical lunar orbit then to the circular lunar orbit. this is due to limited fuel availability.

cheng: 12/08/2013 12:16 CST

软着陆:下降有动力 after 4 days in circular lunar orbit, chang'e 3 will transfer to an elliptical lunar orbit with the perilune point at 15km and the aposelene point at 100km. chang'e 3 will begin its descent at 15km at around 11:22PM~11:35PM 12/14/2013, (I believe the time is UTC+08:00. The descent engine will be ignited at 15km to decelerate, above 2km it'll have pointed its main engine downward, below 2km it'll be slowly descending. At 100m (328.084 feet) the payload will be hovering without receiving control from beijing. it'll utilize its camera and computer to identify the surface, and automatically select a plain to land on. at 4m (13.1234 feet) the descent engine will turn off, and the payload will land with a free fall.

cheng: 12/08/2013 12:22 CST

落月:9小时候月面留影 after the soft landing, first the lander will charge and initialize the rover; then the rover will start the communication link with earth control, unlock the locking mechnism, and move to the transfer mechnism (ladder). Then the rover will control the transfer mechanism to descend to the surface of the moon, and drive itself away from the lander. yutu (jade rabbit, the pet of the lunar princess in chinese folklore) will be separated from the lander at 4:38~6:21 12/15/2013, the descend will only be around 2 meters (6'7) but the entire process will take around 2 hours. nine hours after the seperation, the lander and the rover will capture some photographs of each other using the equipped cameras. and both are painted with the national flag, therefore, a color photo of the chinese national flag on the moon can be captured.

jumpjack: 12/11/2013 01:36 CST

@Cheng Thanks so much for these useful data! Google translation from chinese are quite disturbing and almost meaningless... Have you got any info about possible live streaming of landing?

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