Talk:Chandrayaan-2

Orbit track
Quote : ''The Chandrayaan 2, on the other hand, was launched to reach the landing site at the beginning of the lunar day, meaning every time it goes over the landing site it will either be dawn or dusk when there are longer shadows. --Dr Nirupam Roy, assistant professor of Physics at the Indian Institute of Science, Bengaluru.''

The orbiter's track shifts with time, and this -according to Roy- explains why the CY-2 orbiter has not imaged the lander optically whenever it is located above the lander. Cheers, Rowan Forest (talk) 00:04, 20 September 2019 (UTC)


 * CY-2 is in a "polar synchronous orbit" . Is that the same as a "polar Sun-synchronous orbit? Rowan Forest (talk) 00:21, 20 September 2019 (UTC)
 * Lander deployment occurred just after day-break so lighting conditions would not have been great and being polar region sun elevation is always low anyways resulting in long shadows. But CY-2's polar orbit is in no way fixed to day/night terminator as that quote and news report suggests. Earth's oblateness allows for sun synchronicity in near polar orbits but such synchronous orbit around moon with that altitude and inclination is not possible. Ohsin  02:16, 20 September 2019 (UTC)
 * OK, thanks for helping filter out the misinformation. Cheers, Rowan Forest (talk) 03:36, 20 September 2019 (UTC)

"95% Success"
Regarding my revert: the orbiter just entered lunar orbit, so I has not achieved any scientific success yet. A science mission without data return cannot be successful, right? This is another unfortunate misleading statement from Mr. Sivan because of the brevity of his comment. The 95% success refers strictly to the engineering milestones, such as orbiter safe, lander separation, deorbit, and the 4 stages of the descent & landing. I wanted badly to quote him in this correct context, but no publication has explained it correctly. As an example, the European Schiaparelli lander crashed; it was strictly an engineering mission, and since they obtained all the telemetry, it was officially declared a success. The engineering component of the Vikram lander and orbiter may very well be a respectable 95%, but the science part of mission, just got started, and it has yet to report any data. Cheers, Rowan Forest (talk) 23:20, 24 September 2019 (UTC)
 * Hello. I performed a partial revert of my deletion. Please take a look at this revision and source. Thank you for your patience. Rowan Forest (talk) 13:40, 25 September 2019 (UTC)
 * I think calling lander/rover mere engineering tests trivializes their importance and work put into them by science/engineering teams, they were not like Schiaparelli EDM which explicitly carried the demonstrator tag. Both were engineering firsts for ISRO but also central to the mission being one of the core objectives, consuming most of the R&D time, costs, causing the launch vehicle switch and most significantly dictating the much discussed landing site. Orbiter was ready 3-4 years ago even contributing hardware to MOM. The reference used has author postulating based on first official statement which has been contended by same author in his later reports. A hypothetical scenario where lander/rover would have survived post separation and orbiter for some reason ceased functioning, even then it could be easily spun into a "98% success" as well! These prompt official statements appear more inclined towards perception management due to high pressure awkward situation they created for themselves. Ohsin  08:00, 30 September 2019 (UTC)


 * I just tweaked the text again. I think it may be useful in dispelling the misinformation in the press, but please feel free to review or even delete the [percentage] entry altogether. I was just trying to accommodate Antares101 edit. Cheers, Rowan Forest (talk) 17:02, 30 September 2019 (UTC)
 * Scientists tell BBC they contest that number . Delete the entry? -Rowan Forest (talk) 05:28, 1 October 2019 (UTC)
 * Compiling criticism on claims and handling of situation in case this needs to be included in article.
 * Space is hard, but for all the support the Indian media wanted to give to Mr. Sivan, they are catching up to the inconsistencies (potentially false information) so this was unavoidable. Normally, we wait in Wikipedia for the final report stating their conclusions of the failure, and then we create a section dealing with that. But if they are shown to have intentionally released misleading or inaccurate information, then we should complement that future section with the inconsistencies stated by the officials themselves. Rowan Forest (talk) 15:32, 6 October 2019 (UTC)
 * So in an interview K Sivan has said that "‘98% success rate’ are not my words. That was the success rate given by the committee in its initial assessment."


 * But in his interview to state broadcaster Doordarshan twice he owns his words with "I would say"."I would say that it is a 90-95% of the technology demonstration already we have done. So in total the Chandrayaan-2 mission it is very close to 100% success, I would say."


 * Getting very close to be documented properly in its entirety. Ohsin  00:23, 20 October 2019 (UTC)

Science results
I am eager to open the "Science results" section for this article, but as of today, the updates amount to the commissioning of the instruments. If someone comes across published (peer-reviewed) articles on the mission's science, (expected in a few months) please bring them forth so we can document it. After all, this is the main purpose of the mission. Thank you. Rowan Forest (talk) 19:13, 10 October 2019 (UTC)


 * hi there! I have created a section for science results. ISRO have published a huge PDF on their website that's 100sbof pages long. I've summarised the main findings in that section. Bhanavnamboodiri (talk) 12:44, 20 October 2023 (UTC)
 * This page reached 'Good article' status after lot of effort. Use references when adding content. Here is one PDF with science results. Ohsin  18:09, 22 October 2023 (UTC)

"Thermal image"?
Lots of news outlets reported, and this Wikipedia article now says, that the lander was located on the surface by thermal imaging. There's just one problem with that: the orbiter doesn't appear to have a thermal camera. The orbiter does have an "Imaging IR Spectrometer" (though whether it's suitable for thermal imaging as well as its purpose of mineral mapping is unclear), and it was suggested to use it to find Vikram, but that has not been reported as having happened, and no such image from it has ever been published, to my knowledge. In the discussion up above (§Clarification needed), there's even a quote from K Sivan saying it was "a normal photo", not thermal. So, can we remove the erroneous mentions of thermal imaging from the article? While the cited sources may be "reliable sources" in general, that doesn't mean they never make mistakes, especially when reporting things secondhand. – PointyOintment ❬💬•⌨❭ 02:39, 26 September 2019 (UTC)
 * I agree, there has been no official comment on it and even K Sivan was vague about method of imaging so perhaps it should not be specified what kind of imagery it was till more details arrive. For what it is worth IIRS might have observed the surface exposed after impact, but we don't have many details on it. Ohsin  05:59, 26 September 2019 (UTC)
 * The ISRO sources, whether official or not, are definitely contradictory. I too am OK at removing the word "thermal", and simply state that ISRO claims some sort of imaging was done. Rowan Forest (talk)
 * Regardless of the technique allegedly used to image its location, why ISRO didn't mention its location? Why it was not shared with NASA's LRO team that is trying to help? NASA's statement mentioned that the lander may not even be in the vast area imaged by the LRO -and it did image the complete plateau and surrounding terrain.  Since they still don't know its location, it sounds like the CY-2 orbiter never actually imaged its location, never mind a high resolution image of the "intact lander tilted on its side". Question the answers.  Rowan Forest (talk) 17:13, 30 September 2019 (UTC)
 * Appears very likely those comments were hasty but Sivan did say they have located it. ""Yes, we have located the lander on the Lunar surface. It must have been a hard-landing," Sivan told PTI"


 * Another interview where he is claiming the same. Ohsin 00:33, 20 October 2019 (UTC)
 * Either they found it or not; it cannot be "found" and "not found" simultaneously. A NASA team is collaborating with ISRO on the search, that is no secret. NASA is very transparent compared with ISRO, and they stated it has not been found. Given the vast misinformation from ISRO since the crash, I would leave the article as it is now: "The mission's orbiter was reported to have imaged the location of the lander.[138] Unconfirmed reports, citing an ISRO official, stated that the lander was intact,[139] but there has been no official announcement by ISRO on the lander's actual location or physical condition."
 * I don't think we have to expand on the "found" & "intact" as it was not official and not substantiated, unless you want to create a section remarking the misinformation and/or conflicting information since the crash. If ISRO ever publishes the location and the image of the intact lander allegedly acquired over a month ago, then we will certainly reflect that. Why they have not shared the location with the NASA team that is helping them locate it? My opinion is that because of the Moon race, ISRO wants to claim a successful soft landing, but without any supporting evidence. Your thoughts?  Rowan Forest (talk) 01:26, 20 October 2019 (UTC)
 * "Found" part per chairman's words is official as he has more than once claimed it was located, but yes nothing backs it so far. The 'intactness' part is completely unofficial by anonymous sources and should be avoided as there is no accountability to them, ISRO has also denied those claims. Ohsin  03:17, 20 October 2019 (UTC)

ISRO may have imaged the expected landing zone (as NASA did x3), but the fact is that they have not found the wreckage yet. At least they now officially acknowledged that it crashed at high speed. It is disturbing that such public statement had to be forced by a politician. Rowan Forest (talk) 18:53, 2 December 2019 (UTC)
 * Indeed it is worth noting that another politician asked them directly location of lander and they didn't answer! With Vikram impact site now found by LRO I hope ISRO responds with a clarification. Ohsin  00:01, 3 December 2019 (UTC)
 * They must have published the impact crater just after I finished my search today. Thank you! Rowan Forest (talk) 01:42, 3 December 2019 (UTC)
 * An interesting observation here is that since the lander does not have a center engine, landing with a single engine meant it tumbled while falling, so their "official" explanation that it decelerated better than expected is not credible. Their engineering and achievements are amazing, so I don't understand the reason for the continuous BS. Failure is an option on the road to success. Rowan Forest (talk) 02:02, 3 December 2019 (UTC)
 * Lander does have a central engine, and |this slide from a press conference points it out. But yes very frustrating. I am waiting to see what other independent experts deduce from the debris field and its spread. Ohsin  03:05, 3 December 2019 (UTC)
 * Right, it was the early design that did not have it. The final design did. Thanks. Rowan Forest (talk) 17:52, 3 December 2019 (UTC)

Possible section on misleading information
Now since ISRO is reiterating that they had located the lander earlier perhaps this needs re-inclusion, the fact that they were trying to communicate indicate they had very rough location, they also denied reports on its 'intact' status too. They are not denying pinpoint location now publicly made available by NASA and per earlier comment by VSSC director were looking forward to receiving LRO images. Ohsin 16:34, 5 December 2019 (UTC)
 * It is a fact that ISRO had the telemetry all the way to impact, and yet ISRO refused to acknowledge the crash. They played NASA and wasted their Deep Space time hailing a dead rubble pile when ISRO knew perfectly well it was a dead rubble pile. I rather don't go into the pettiness of who took a picture of the impact crater first, because there is so much deliberate misleading statements from ISRO regarding the failed landing, including "lander intact and just tilted on its side". Did Mr. Sivan bothered to correct or clarify that key statement? ISRO never "denied" it was intact, on the contrary, they refused to comment, while an official said on TV it was intact but nobody within ISRO corrected/denied it, starting with Mr. Sivain. Rowan Forest (talk) 16:47, 5 December 2019 (UTC)
 * Just remember the ISRO statements during the first few days: only problem was a loss of communication, landed well and intact, have thermal image of it, not thermal image but a normal visual image, must restore contact, antenna pointing the wrong way because it is tilted on its side... etc, etc. They knew immediately it crashed at high speed and would not say so. Now that the impact crater is published for every one to see, ISRO wants us to have selective amnesia and believe they just admitted the failure in the beginning and released all data in time? Lets stick to facts and keep the false statements out without having to debunk them. They are too many. Alternatively, we have plenty of material to create a small section on the circus of misleading/controversial statements by ISRO, if you wish. Rowan Forest (talk) 17:03, 5 December 2019 (UTC)
 * I agree and I think Sivan's absurd response shows annoyance especially when CY-3 is being aired around to distract, but my dilemma is this is turning into big chunk to be kept out and if documented in some way citing reports with criticism like compiled above to make a mucky section it might attract lot of negative edit warring itself, which.. would be tiring to deal with. Btw if you can find that video of some officials claim on intactness it'd be great, I think I missed it very likely it was some 'TV expert' relaying misinformation. Ohsin  17:36, 5 December 2019 (UTC)
 * I think in the early days such section would have potential for an edit war. Since the conflicting information keeps flowing we may have to create that section but with careful neutral language presenting the conflicting info released, without editorial criticisms. I remember seeing a video of an ISRO official giving an interview in his office where he stated "they say the lander is tilted on its side, so the antenna may not be pointing on the correct direction." I will try to find it. Cheers, Rowan Forest (talk) 17:49, 5 December 2019 (UTC)
 * Here it is: PK Gosh, an official at ISRO. . Quote: "I heard that the lander was, actually, fallen on one side." (Video time mark at 1:05 minutes). He goes on to explain that nobody will straighten it up so the antenna and other payloads may not be functional.  Rowan Forest (talk) 17:58, 5 December 2019 (UTC)
 * Thanks, he is former ISRO official (retired). Channels often flock to them for comments but yeah irresponsible comments and channel didn't bother to clarify his status. 18:10, 5 December 2019 (UTC)


 * A good report noting the misinformation & inconsistencies: Vikram lander intact? Reports differ. Dated Sep. 10th. Rowan Forest (talk) 18:18, 5 December 2019 (UTC)
 * Another stern report on the lack of transparency, dating December 7: Rowan Forest (talk) 01:23, 9 December 2019 (UTC)
 * And admission, Sivan finally said, "Yes, yes...it is in pieces...!" Ohsin  21:59, 5 January 2020 (UTC)

Chandrayaan-3
As the mission is clear and officially confirmed now, I think the mission repeat can have its own separate article. I would like to know if anyone differs. Aman Kumar Goel(Talk) 14:13, 30 December 2019 (UTC)


 * I'm gathering article specific sources as now. By late this week, if no opposition to my proposal emerges, I will remove redirect of Chandrayaan-3 from this article and change it into a new page. Best regards. Aman Kumar Goel(Talk) 15:32, 30 December 2019 (UTC)


 * Until we have enough information about the mission, it will be a section of the "Chandrayaan-2" article. --Soumyabrata (talk • subpages) 11:10, 31 December 2019 (UTC)
 * I guess I can make sure it's not a stub. I have multiple sources now.Aman Kumar Goel(Talk) 11:29, 2 January 2020 (UTC)

Since it has been approved by Indian Govt. I think it is time to have new page for it. Ohsin 12:46, 1 January 2020 (UTC)
 * Created one here.Aman Kumar Goel(Talk) 11:29, 2 January 2020 (UTC)

LPSC 2020 papers
At least 12 papers are on CY-2 with one giving overview of mission with extra information that would be useful in article.

https://www.hou.usra.edu/meetings/lpsc2020/pdf/lpsc2020_program.htm#sess253

https://www.hou.usra.edu/meetings/lpsc2020/pdf/lpsc2020_program.htm#sess303

Ohsin 11:24, 1 February 2020 (UTC)

Need a section on Failure Analysis Committee Report
A notable aftermath of the Chandrayaan-2 mission was that the Failure Analysis Committee's report was not made public. Various sources have pointed out that this is unprecedented in the history of ISRO.

For example, an Indian Express article says, "In a break from precedence, the Indian Space Research Organisation (ISRO) is yet to make public details of a Failure Analysis Committee’s (FAC) report on the space agency’s Chandrayaan-2 mission, which looked at causes for the crash of Vikram lander on the Moon on September 7. This is unlike the ISRO’s previous record."

The Times of India says, "The Failure Analysis Committee (FAC) that looked into the matter is said to have completed its probe, but the complete findings have not been made public yet."

Another source, "The Indian Space Research Organisation (ISRO) has not publicly revealed the Failure Analysis Committee’s (FAC) report details of its Chandrayaan-2 mission, that looked at why Vikram Lander crashed on the Moon on 7th September."

I think this article needs an aftermath section with information on the FAC's constitution, conclusions and the non-release of its report in contrast to previous FAC reports. The parliamentary questions and the limited media interactions ISRO chairman had with media, where the software glitch was pointed out should also be part of this section.Fundamental_metric_tensor (talk) 05:13, 12 May 2020 (UTC)

Criticism from former ISRO chairman
News reports indicate that ISRO has been unwilling to comply with Right to Information requests and release the Failure Analysis Report. This has been criticized by the former chairman of ISRO, quoting, "A veteran scientist and former ISRO Chief said that ISRO’s decision may not be the best. “I don’t think the decision taken by ISRO is correct. ISRO has been doing a transparent job and has been a transparent organisation. Just by showing where and how it landed will not affect national security. They have given a lame excuse, that is all,” Dr G Madhavan Nair said." 

Criticism by a former head of the organization is serious and warrants a more prominent place in the article. I propose that we add a line in the intro to this effect. Fundamental_metric_tensor (talk) 04:35, 8 November 2020 (UTC)

Copyright problem removed
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Separate Vikram Lander section into its own standalone article?
There is a separate article for Pragyan rover but for Vikram lander, there is no dedicated article. The reason I suggest separating the article is because it seems like Chandrayaan 3 is also using a Vikram lander, and it feels strange linking this sub-section instead of a dedicated article on Vikram lander. Shouldn't we follow a similar structure as Pragyan rover for Vikram lander? --Molochmeditates (talk) 02:12, 23 August 2023 (UTC)


 * I don't know about separate article but CY3 linking here is completely wrong. CY2 Landing Module is very different from CY3 Landing Module, sharing the name (confusion courtesy ISRO). I suggest creating a completely new subsection in CY3 page for it. I am too caught up to contribute unfortunately. Ohsin  06:57, 24 August 2023 (UTC)