RussianSpaceWeb has reported that the possible landing sites for Chandrayaan-II called Luna-Resurs by the Russians have been selected. The selection is not final and seems to have been made (or covers only the Russian angle of the story) by Russian space organizations.

There is a detailed account of the selected landing sites for Chandrayaan-II here: http://www.russianspaceweb.com/luna_resurs_landing.html

Pradeep

Thanks, Pradeep!

South polar region, huh? Interesting! There's some pretty rough terrain down there, though the planners seem well aware of it based on the article.

Much more info on site selection here. Chandrayaan 2 is called Luna-Resurs (Moon Resource) in Russia, and it's one of a pair of missions, the other called Luna-Glob. Luna-Resurs was supposed to fly in 2013 but may be delayed into 2014 by Indian issues, mainly with the launch vehicle, I believe. Luna-Glob will launch a year later. LR goes to the south, LG to the north. Now that they have found hydrogen in illuminated areas as well as permanent shadows the whole question of studying it is much easier, so the sites are no longer very close to the poles.

This link goes to an intro page from which you can link to numerous presentations, most of them in English. Thanks to our Russian colleagues for making them available.

Phil

http://www.iki.rssi.ru/eng/conf/2011-lg/index.html

I am resurrecting this ancient thread because, after a long wait, Chandrayaan 2 will soon be launched to the Moon.

The links above give some information on very early thoughts about this mission, which was to be a joint India-Russia flight. The Russians called the mission Luna-Resurs (resources), and they would provide a lander and in some versions of it, a rover as well. India provided an orbiter and a mini-rover as well as a launch. Later the Russians pulled out and India took over all aspects of the mission.

The site selection work described above went through multiple phases in Russia. When India took over they did some of their own work on site selection. See this report from LPSC in 2015:

https://www.hou.usra.edu/meetings/lpsc2015/pdf/1351.pdf

Some work has been done since by two groups that I am aware of, but I am waiting for a paper release before I can say more. Don't pay too much attention to press reports which are almost always out of date.

The rover mission is only intended to survive one lunar day, and its activities will be recorded here.

Phil

Some landing site news:

http://www.sciencemag.org/news/2018/01/ind...on-s-south-pole

This article says that the site will be on a "plain between two craters, Manzinus C and Simpelius N, at a latitude of about 70° south", in other words here:

Click to view attachment

The coordinates are approximately 70.8 south, 22.9 east.

The article has a horrible representation of the zone of previous landings with red dots apparently purporting to be old landing sites, but they are just random. Really, how hard would it have been to do that right? However, we may have a site at last. I hope there will be something about it at LPSC - whose abstracts will be released on Friday!

Phil

Thanks, Phil...have added a Wiki Chandrayaan-2 page for such.

John Moore

I can confirm there will be new details at LPSC... plus a whole lot on Chinese sites.

Phil

Cheers. Phil...the LPSC abstracts are never short of wonderful disclosures - particularly, concerning research about the Moon. So much appreciation to YOU for the updates and links.

A possible alternative Chandrayaan-2 site (PDF file) - east of Klaproth A (68.2S, 21.84W), that may be another area for the upcoming mission - if announced in the 49th LPSC Conference

John Moore

Yes - here is the location of that site - in the white box.

Phil

Click to view attachment

Here is the location on LRO Quickmap 3D

Phil, Seán...very nice, different perspectives.

Looking forward to the mission.

John Moore

The Chandrayaan 2 launch is postponed until October. That may mean that it and Chang'E 4 will be driving around on the Moon at the same time, keeping any lunar cartographers out there pretty busy.

Phil

https://www.hindustantimes.com/india-news/i...UL4SDa17GJ.html

Launch will now be no earlier than 3 January 2019, and the lander has been named Vikram after V. A. Sarabhai, regarded as the initiator of the Indian space program. No word I am aware of concerning a name for the rover.

Phil

https://timesofindia.indiatimes.com/india/c...ow/65945202.cms

description of changes to Chandrayaan 2, which leaves me concerned that more testing might be needed and could lead to further delays. I hope everything will be OK. I would not want to see a premature launch just to meet a schedule.

Phil

That's got to be a typo!

Based on the image, wouldn't a go landing attitude allow sunlight to reach the rover? Or it is a matter of not being able to guarantee the panels face the right way during landing?

Chandrayaan-2 launch now NET May.

https://www.asianage.com/science/010419/isr...ay-k-sivan.html

Thorsten

Another month, another date: mid-July.

https://twitter.com/isro/status/1123612384336027650

And that tweet has a name for the rover, Pragyan, meaning Wisdom according to Wikipedia, or Knowledge according to New Delhi TV.

Phil

India's Chandrayaan 2 lunar mission to the Moon has successfully launched today, 22 July 2019 (at 0913 GMT) from its space centre in Sriharikota, near the Bay of Bengal.

Already having separated from its launcher's second stage and now in Earth orbit, Chandrayaan 2 is expected to touchdown on the lunar South Pole some time in early September 2019.

The mission includes both a lander and rover (also with an orbiter overhead); where all three include various research instruments (13 of Indian, 1 of NASA) used in areas, for example:
looking for water and minerals signatures, and the study of moonquakes and possible future landing sites...amongst other activities. The orbiter has eight instruments, the lander with
four (including the NASA instrument), while the rover has the remaining two.

On touchdown, the solar-powered rover will off-load from the lander after some four hours, where it will then mainly rove around the surface during lunar day-long (14 earth days) stints.

Finally they're on their way.

Lunar Landing is expected Sept 7 at 2:50 AM Indian Standard Time or Sept 6 at 21:20 UT.
Friday evening for Europe, afternoon for America.



I wonder why all the time they say "on the South Pole".
The landing Site is at 70°S, this is still 600km from the pole.
It's the nearest lunar soft landing to a pole ever, but not yet "on" the pole...

Thorsten

Here is a set of 'finder' maps for the primary landing site and the alternative site.

Phil

Click to view attachment

Just querying: while during the long, lunar day (14 earth days) stints that the Chandrayaan 2 rover (Pragyan) is expected to undergo near/below the 70.0s degree South Pole environment, will
the different, southerly periodic lighting conditions, let alone the temperatures changes, affect the amount of days that the rover can rove (I'm thinking that the various powering down/up
periods might be shorter: simply due to less illumination time on the solar panels at such latitudes, but then, do the lower temperature differences, lighting conditions counteract such - allow longer exploration times).

John

Gratz to ISRO on a successful launch.

Perhaps the 'noon naps' that Yutu has been commanded to do to avoid overheating might not be necessary, if the sun never gets too high above the horizon?

I'm certainly looking forward to surface images, both in terms of long shadows and Earth near the horizon....

The amount of solar radiation that the panels receive will depend upon the angle between the panels and the Sun. The angle of the ground to the Sun is irrelevant. The imagery I see online indicates that the solar panels are not horizontal, so I presume that they will be oriented for better energy production.

Hi all!

Some thoughts:

"Noon naps" (here in Spain: siesta) are probably not necesary, because the sun never rises more than 20deg above the horizon. This keeps the surface temperature rather low.
Thermodynamic equilibrium:
- Max. solar irradiation on horizontal surface: 1367W/m² x cos(70°) = 470W/m²
- Thermal reradiation: 470 = 5.67e-8 x T^4
=> Noon-Temperature T = 301K = 28°C (like here last night )
This is approximately, no reflection of sunlight or emittance of IR <1 was included.
But in any case, not as hot as on other places.

At the time of landing, the terminator is at 0deg longitude. The landing site is at 23°E, this means that at this site, the sun is already 1.5 Earth-days up. This has to be taken into account when somebody speaks about "14-Earth days operation time". It will be not more than 12.5 Earth days. If they achieve night survival, then it will be more of course. (This does not take into account possible "seasonal effects". As the Moon's axis is tilt only 1.5° vs the ecliptic, this is normally negligible, but not when coming close to a pole. 70°S is not yet close enough to be important, but I wouldn't be surprised if they could win (or loose) another half a Earth-day or so. And, of course!, terrain also matters! If there's a small hill in the west, the sunset might be significantly earlier.)
If somebody wants to do detailed calculations, this great page helps: https://trek.nasa.gov/moon/index.html

The solar panels of the lander and the rover are mostly vertical. As far as I can see on the photos, neither panel is steerable.
The lander has one side (I suppose this will face south) with the rover and without solar panels, another two sides (I suppose facing east and west) with solar panels, and one side (I suppose facing north) that's never visible in the photos, so I don't know what's there. Hopefully another solar panel. If not, they will have a hard time around local noon.
The lander has one solar panel that can be flipped to vertical, but doesn't seem to be steerable! This means that the lander should always move or at least park in a sun facing direction! Remember, over the lunar day, the sun will move in the sky from east (at the horizon) to north (elevation <20°) to west (again at the horizon).

I wonder how they will manage the landing on a safe spot. The sun is very low during landing, and the shadows will be very long. A system like the one used by Cháng'é-3 and 4 (imaging, terrain recognition) will probably have a hard time to work.

Shadows, yes, it will be interesting to see how they will hamper (or not?) the navigation of the rover.

Somebody knows what capabilities they have to detect water?
I don't expect it directly on the surface, but not too many cm below, there might be traces.

Now let's cross fingers that they are successful with the flight and the landing. This place will give a first small hint about how the conditions on the real pole might be.

Regards
Thorsten

While fully admitting to not understanding the temperature/power complexities of sunlight falling on the lander and rover solar panels at such extreme latitudes, your description, Thorsten, is wonderful. Thanks

John

Note that the lander and rover are not expected to survive the lunar night. Their mission will last one lunar daytime, 14 Earth days, according to mission materials. I'm a little confused by this number because I can't imagine a successful landing during the very twilit high-southern-latitude dawn; it seems to me they'll have to land under relatively high sun conditions. But that's speculation on my part.

The statement is ambiguously worded, but I think they are saying 'the lander and rover will last for one lunar day' and 'one lunar day is 14 Earth days'. I saw it said somewhere that the landing is about 36 hours after sunrise, so you are quite right that the actual surface missions must be shorter. We can probably expect a maximum of 12 days operation. We had better hope a noon siesta is not required!

Phil

Thanks, I had missed that detail. I'm still impressed by a landing 36 hours after sunrise at that latitude!

The Chadrayaan-2 mission seems to be proceeding according to plan, the probe having successfully completed all the Earth orbit raising manoeuvres on August 6. The next orbital change is the trans-lunar injection, scheduled for August 14.
Here is a comparison table for the attained and planed orbits.
Click to view attachment

The information is taken from the Updates web site and the mission plan
Fernando

Success for Lunar Tranfer Trajectory:

https://www.isro.gov.in/update/14-aug-2019/...sfer-trajectory

Here is an updated table with the latest information.

Fernando
Click to view attachment

https://www.isro.gov.in/update/20-aug-2019/...orbit-insertion

Lunar orbit!

Phil

https://www.isro.gov.in/sites/default/files...moon_photo1.png

First image of the Moon, with the Orientale basin at the top and north at upper left.

Phil

That's an amazing picture. Our moon is so wonderfully diverse and interesting. I can never get bored gazing at its majesty.

Well, looks like all went well on the fifth manoeuvre, 1 Sept, 2019, and also an update, 2 Sept, 2019, on the successful separation of the Vikram Lander (with the Pragyan rover onboard) from the orbiter.

Below image (Credit: ISRO): a tentative plan over the next few days up to the 7 Sept, 2019...when India's engineers' nerves will undoubtedly be fraying towards a successful landing.

John

The Vikram lander has reached its final orbit (35 x 101 km) before its descent to the Lunar surface (scheduled for Sept. 7).
https://www.isro.gov.in/chandrayaan2-latest-updates

The sun is about to rise on the landing site, and the high resolution camera on the orbiter is supposed to image the site for final site planning. The resolution will be about 30 cm/pixel, better than a standard 50 cm/pixel LROC NAC image and almost as good as the low altitude images (25 cm/pixel) NAC obtained over several of the Apollo sites. It will be great to see the site before and after landing with this camera, and really nice to see images of other sites with the same camera if they are taken. For instance, LRO images of the Chang'e 4 site are about 1 m/pixel, so this camera might give us 3x better resolution. I hope the camera team plan images of other sites at that resolution.

Phil

Below, an approximate render of the lighting conditions of the 6 Sept, 2019 (round 6.00 pm UTC )…for successful landing of Vikram. Simpelius N and Manzinus C, lie roughly at the centre of the ellipse.

John

At this moment, Vikram will start the descending trajectory shortly.

Live feeds not looking good; it seems the lander deviated from its trajectory in the final moments of the descent a few minutes ago. No downlink

A steeper inclination than the planned trajectory indicates some failure propulsion along without a downlink signal. I am afraid that Vikram has not landed as planned, softly. The last info from the panel was that its altitude was 1 km above the surface at 59 m/s (an acceptable landing speed must not be greater than 15 m/s). The people from the operation center are uneasy trying to figure out this incident.

Rough luck, that. Space is hard! Hope ISRO can swiftly recover from this failure.

India Today's live feed reporting that all was well up to an altitude of 2.1 kilometres. Communication was lost after that. Sounds like the issue was to do with the 'fine braking' phase - a misfiring or failed engine, perhaps?

Aaaaaaah....damn.

My most sincere sympathies to the Chandrayaan II team. There is absolutely nothing easy nor routine about landing on another world. This was a truly brilliant & ambitious effort, and though lessons learned are always painful they are always invaluable as the only real way forward to new futures.

What problem coincidence of Vikram with the ones of Israeli Moon lander Beresheet.

Many congratulations to the Chandrayaan team for an excellent first attempt -- surely not the last from India.
Meanwhile the orbiter continues its scientific mission...

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

Click to view attachment

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.

Well said, Steve.

The live coverage included glimpses of this image:

Click to view attachment

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