At the launch pad: https://twitter.com/Longmarch13/status/1328528387204292608 …
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We still have no idea when it will land - I have seen Nov. 30 mentioned once but early Dec. is possible - but while the Chinese have 2 successful ones already, the 2 failed Moon landings still remind people that GNC is a harsh mistress.pic.twitter.com/KyOdQlpXpi
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With the lander probably a bit different from the ones used on Chang'e 3/4, even this part will still be a challenge to nail down. All these parts will apparently be observed by a descent camera like the last 2 landings, though the only official source is from a Chinese paper.pic.twitter.com/4STjkSxoEr
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Now the surface operations is rather spotty in terms of public info. It took me quite a long time to nail the scientific instrument suite that would help in the sampling: - Panoramic Camera (PCAM) - Lunar Mineralogical Spectrometer (LMS) - Lunar Regolith Penetrating Radar (LRPR)
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The only mention of the PCAM is the paper excerpt below - I'm not even sure where they are located, perhaps it's the rotating platform in the picture on the descent stage. I can't find their technical parameters either... (https://meetingorganizer.copernicus.org/EGU2016/EGU2016-3858.pdf …)pic.twitter.com/xZz5YUUurV
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The LMS is apparently a visual/near infrared spectrometer - according to https://meetingorganizer.copernicus.org/EGU2016/EGU2016-5644.pdf … this is similar to the VIS/NIR Imaging Spectrometer (VNIS) on the Chang'e 3 rover w/ some modifications. I can't find where it is (same as PCAM?) or its technical parameters.
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The LRPR works at 2 GHz frequency under the bottom of the descent stage and maps the regolith structure beneath it for ease of sampling/drilling analysis. Luckily we do have a detailed paper regarding its principles with photos: https://www.essoar.org/pdfjs/10.1002/essoar.10504784.1 …
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As for the most important part, sample retrieval, the landing site near Mons Rumker in Oceanus Procellarum is of new geological importance not seen in previous lunar samples.
@elakdawalla has it summarized here:https://www.patreon.com/posts/change-5-lunar-43869582 …Diesen Thread anzeigen -
And sorry for the interruption, but a certain insider has reported important timings of the mission! Launch time: 20:25 ~ 21:15 UTC on November 23 Landing time: Probably ~20:30 UTC on November 29 (base on MCC screen shots during final rehearsal) Source https://m.weibo.cn/u/5616492130 pic.twitter.com/f1SnOA8ZeD
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Also it appears that after McGregor Texas, Wenchang is also a major habitat of Rocket Cows (TM):pic.twitter.com/GYTWHDV0fr
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It seems that I won't have time to finish this overview until half a day later so I'll just leave you with views of the pad from last night and right now: https://twitter.com/Longmarch13/status/1330473033316802562?s=19 …
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Someone found this paper on the Lunar Mineralogical Spectrometer (LMS) and it's great! It's fixed to one side of the descent stage and points towards the soil sampling area. https://www.spiedigitallibrary.org/journals/Journal-of-Applied-Remote-Sensing/volume-13/issue-2/027502/----Custom-HTML----Spectrometers/10.1117/1.JRS.13.027502.pdf …
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Not much news yet, but the lenses are ready for tonight: https://twitter.com/Longmarch13/status/1330784069962117120 …
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Sun currently setting at Wenchang: https://twitter.com/Longmarch13/status/1330818792213995520 …
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So back to the mission, Chang'e 5 will combine scooping and drilling to obtain lunar (sub)surface samples, aiming for least 2 kg & w/ capacity for 4. Three-quarters by mass will be via scooping on the surface, with 1/4 from the drill that will reach 2.5 meters deep.
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Like the Soviet LSR missions of the 1970s, the deep drilling will provide layered sub-surface samples of the lunar crust. Detailed description of drilling bit and sample sealing can be found at https://ieeexplore.ieee.org/abstract/document/8607979 …. I'm not sure how samples would be put into the ascent stage.pic.twitter.com/T2V1Reh5tf
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The other method of sampling will be via a double scoop on the end of the robotic arm, assisted by twin cameras. IIRC some parts of it were designed by a team at Hong Kong Polytechnic University a few km from me, which has worked on Beagle 2 & Chang'e 3.pic.twitter.com/i8RbPPOChq
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Getting the sampling working as planned may be more difficult than it seems (ask
@NASAInSight's thermal probe or Apollo astronauts etc.), but here comes the hairy part of taking off from the Moon, 1st major launch from a major solar system object since Luna 24 of 1976:pic.twitter.com/lyrV6mbzL6
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So after ~2 days of surface operations the ascent stage will have only 1 chance to get to the right rendezvous orbit (15 x 200 km towards the orbiter at 200 km circular per a 2014 paper). Then it has to dock w/ it - never tried robotically that far from Earth.pic.twitter.com/d3f73nYjFR
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Those who have read the details of the
@NASA/@ESA Mars Sample Return mission plans would probably have a headache on this. Now the Chinese are attempting s/t only slightly easier all by themselves.pic.twitter.com/RJD6CLk0CX
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It appears the docking mechanism is some sort of "soft docking" one with claws on the orbiter/return capsule side. The sample container would slide (?) into the return capsule and then automatically sealed. Quite tricky to get that right it seems...pic.twitter.com/HbeGj4C4eh
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The orbiter would wait for ~10 days before making the TEI burn (can't remember why). Another 5 days would pass before they come across Earth around December 16-ish. The return capsule would separate from the orbiter at ~5000 km altitude.pic.twitter.com/jbHzIOsPH2
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Then came the hottest part of skip re-entry - so hairy that the Chinese rehearsed w/ the Chang'e 5-T1 mission way back in Oct./Nov. 2014. After bouncing back to 140+ km high the capsule would make a 2nd dip into the atmosphere before landing.pic.twitter.com/y3GwdgtBRt
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IF everything went as planned (a very big IF I shall say) the lunar rocks would land at the existing Shenzhou landing site in Inner Mongolia in mid December (per 1 source, Dec. 16 ~17:00 UTC). Quite a signal to the rest of the world about NASA's Artemis Program eh?
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As for the Moon rocks...well (naturally) the Chinese said that their own institutions will have priority in getting them (and it appears demand is overwhelming), but they did promise to share portions of them internationally.
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Well, that's it for my (way later than planned) walk through. Since the Chinese are full of stresses of risk we don't know what kind of coverage we'll get through to landing on the Moon and back. Sit back and wait is all we can do. ¯\_(ツ)_/¯pic.twitter.com/RvWcSPEL8P
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Ah, I can end this thread with the REAL launch window and target T-0! **T-0 is set for 20:30:12 UTC.** Launch window extends to 21:15:07 UTC.pic.twitter.com/85xkSCpyjf
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