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Chandrayaan-II, All Chandrayaan-II related articles
SpaceListener
post Sep 6 2019, 09:05 PM
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What problem coincidence of Vikram with the ones of Israeli Moon lander Beresheet.
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kenny
post Sep 6 2019, 09:11 PM
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Many congratulations to the Chandrayaan team for an excellent first attempt -- surely not the last from India.
Meanwhile the orbiter continues its scientific mission...
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Phil Stooke
post Sep 6 2019, 09:46 PM
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Very sad outcome but a great effort, and a lot will be learned from it. Meanwhile, as already said, a good orbiter mission to come. I look forward to seeing the site from orbit, but meanwhile here is an updated landing sites map.

Phil

Attached Image


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... because the Solar System ain't gonna map itself.
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Steve G
post Sep 7 2019, 04:31 AM
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The last two failed landing attempts really puts into context the genius of the Surveyor and Luna landing teams half a century ago using computer rooms and slide rulers. A real shame and just illustrates how unforgiving space can be.
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Phil Stooke
post Sep 7 2019, 06:17 AM
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Well said, Steve.

The live coverage included glimpses of this image:

Attached Image


It shows a specific landing area within the target ellipse. It should be easy to find in LRO images but so far I'm not able to identify it. The early morning illumination suggests to me it may be from the orbiter. It doesn't obviously resemble any LRO image I have seen yet. Scale is not clear, but another report in the Times of India said two specific sites 500 m by 500 m and 1.6 km apart had been picked in the landing ellipse.

Phil


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marsbug
post Sep 8 2019, 10:27 AM
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If this is accurate... https://mobile.twitter.com/ANI/status/1170610654232731648
... then the lander may be more-or-less intact, depending on the image resolution. A bad landing, as opposed to a crash, perhaps. That might be of some comfort to the ISRO team ifso.


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Thorsten Denk
post Sep 8 2019, 10:36 AM
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https://www.indiatoday.in/science/story/isr...6857-2019-09-08

QUOTE
The Indian Space Research Organisation has been able to identify the lander Vikram, but the condition of the lander is yet to be ascertained.


Thorsten
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marsbug
post Sep 9 2019, 03:54 PM
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The word from The Times of India is that Vikram is on the Lunar soil in one piece, but tilted on its side and possibly (probably imho) damaged after a hard landing. Even if it's functional there's a good chance the angle it's at will prevent communication, but the ISRO team will keep trying for the rest of the lunar day. Still, it looks like this was a hard but controlled landing, not a crash, and I think it's safe to say that Vikram fought right to the end. The ISRO team can be proud of their work, and the design is clearly up to the job - once whatever bug caused the hard landing is located and ironed out

https://m.timesofindia.com/india/isro-not-l...ow/71045854.cms

Edit:: India Today's report is that the lander is not confirmed as 'intact', although I wonder if some ambiguity of translation isn't creeping in here: "In one piece" could mean one pile of bits all in one spot, or one very oblate piece. It'd be tempting to translate that as 'intact' but optimistic... Still, my statements on the ISRO team stands, even if it turn s out to be one big metal pancake.

https://www.indiatoday.in/science/story/cha...7265-2019-09-09


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Steve G
post Sep 9 2019, 08:35 PM
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It might have had a similar fate as Luna 23 in 1974 which had a hard landing and tipped over. Intact, but loss of mission.
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Phil Stooke
post Sep 11 2019, 07:43 PM
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Yes... we could be in for a long period of argument as to whether it should count as a landing or an impact.

Meanwhile, this tweet is interesting:

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Ryan Watkins @Ryan_N_Watkins

official word is that @LRO_NASA will take an image of the Vikram landing site on September 17th. The incidence angle is pretty high, so it may be hard to see (could be in shadow).
#VikramLander #Chandrayaan2 @isro
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(Ryan is a researcher at the Planetary Science Institute in Tucson)

LRO is orbiting close to the terminator at the moment. As it crosses the landing site each month over the next few months the Sun will be higher and the view better.

Phil


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marsophile
post Sep 11 2019, 07:56 PM
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According to Wikipedia, the Chandrayaan II orbiter camera has a spatial resolution of 0.3 m from 100 km polar orbit, while the LRO camera is said to have a maximum resolution of 50 cm/pixel. If these figures are correct, is there any reason to hope the LRO images will be any better than the ones from the Chandrayaan II orbiter?
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marsbug
post Sep 11 2019, 08:48 PM
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There is the possibility that we may get to see the LRO images before we do the Chandrayaan 2 ones! ISRO, love you, but I've been spoiled by the relative hosepipe of data and images NASA prefers, as opposed to the more cautious approach.


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Phil Stooke
post Sep 12 2019, 01:12 AM
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The 50 cm pixel resolution for LRO's Narrow Angle Camera is based on its altitude, nominally 50 km for its main mission period. They have dropped to 25 km for high resolution imaging of Apollo sites (25 cm per pixel), but now they are in a low-maintenance orbit to extend operational life, and they are higher up: approx. 50 km at the south pole, 200 km at the north pole. Most images of the Chandrayaan 2 site now available are about 100 cm/pixel.

Chandrayaan 2's high resolution camera has 30 cm/pixel resolution from 100 km altitude. I would expect that C2 images could be 3 times better than any LRO images we are likely to see.

Phil


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John Moore
post Sep 12 2019, 02:24 PM
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Below, an overhead, animated attempt of the impact/hard-landing site (approximately at centre of Manzinus D), if indeed that is the actual site: showing the lighting/shadow conditions from 17 Sept., 12:00 noon UTC to 18 Sept., 12:00 noon UTC (note, libration effects have been removed simply for visualization).

John

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mcaplinger
post Sep 12 2019, 03:18 PM
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QUOTE (Phil Stooke @ Sep 11 2019, 05:12 PM) *
Chandrayaan 2's high resolution camera has 30 cm/pixel resolution from 100 km altitude.

I haven't been able to find very much technical information about this camera beyond this phone image of an old viewgraph about it which I've enhanced a little. I'll be very curious to see how well this performs; the high resolution coupled with a large number of TDI stages (oddly high, actually, I've no idea why they need so many) presents a lot of challenges. LROC NAC was a much more conservative design in most respects.

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Disclaimer: This post is based on public information only. Any opinions are my own.
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