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The Lunar Atmosphere and Dust Environment Explorer (LADEE) entered lunar orbit 2013-10-06, and Chang'e 3 landed 69 days later producing dust and gas on 2013-12-14.

These were both quite interesting missions, the Chang'e-3 is the first lunar lander of the 21st century, operated an ultraviolet telescope on the moon, and deployed it's companion Yutu - the first lunar rover of the 21st century as well. LADEE made super-sensitive measurements of trace gas and tiny dust particles above the moon and tested an optical comms link between lunar orbit and Earth.

I remember reading about the timing of the two events - that Chang'e-3 was announced to be landing during LADEE's initial baseline calibration measurements, some of which are summarized in China's 1st Moon Lander May Cause Trouble for NASA Lunar Dust Mission, but I never heard what actually happened.

Wikipedia mentions it here but is inconclusive. So was the baseline calibration disrupted or did the landing provide additional science value? If the latter, please cite some example, thanks!

China's Chang'e 3 spacecraft, which was launched on December 1, 2013, and entered lunar orbit on December 6, (25) was expected to contaminate the tenuous lunar exosphere with both propellant from engine firings and lunar dust from the vehicle's landing. (26) While concern was expressed that this could disrupt LADEE's mission, (26) such as its baseline readings of the Moon's exosphere, it may instead provide additional science value since both the quantity and composition of the spacecraft's propulsion system exhaust are known. (27) Data from LADEE may be used to track the distribution and eventual dissipation of the exhaust and dust in the Moon's exosphere. (27)(28) It may also be possible to observe the migration of water, one component of the exhaust, giving insight on how it is transported and becomes trapped around the lunar poles. (29)

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It did perform the observations, but nothing was detected. Here is an article that covers this

Surprisingly, the LADEE science teams' preliminary evaluation of the data has not revealed any effects that can be attributed to Chang'e 3. No increase in dust was observed by LDEX, no change was seen by UVS, no propulsion products were measured by NMS. Evidently, the normal native lunar atmospheric species seen by UVS and NMS were unaffected as well. It is actually an important and useful result for LADEE not to have detected the descent and landing. It indicates that exhaust products from a large robotic lander do not overwhelm the native lunar exosphere.

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  • $\begingroup$ Hey great find! It sounds as though LADEE wasn't close enough to the actual de-orbit and landing see much (and probably wouldn't be considering the low inclination compared to the landing site) and there wouldn't be enough gas or dust to spread out over millions of square kilometers to see later. I get the feeling that it almost says - but not quite - that it was actually probably a non-issue to begin with. Thanks for finding this! $\endgroup$ – uhoh Oct 30 '16 at 17:03

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