Chandrayaan 3: Launch and Discussions

[juvva]

----

I wonder if the slight repositioning helped with slight inclination/orientation to sun or earth..

The pics look nice !

And @calculating thrust to lift off from the moon - I doubt that this was particularly relevant.. for the actual calculations..

does not look like any significant orientation change from the shadows in the the pre and post hop images.

but why are the ramp deployed images(pre and post hop) looking so different ?

[SriKumar]

^^^

The picture on the left has Pragyaan still on the ramp before it rolled down- no tracks.
The picture on the right does not have Pragyaan and also is zoomed out. This also means that the left picture is during lunar sunrise i.e. 10 days ago- see shadows. i agree that the orientation change is not significant.

[Barath]

Remember the link @SSridhar posted ?
Chandrayaan-3: Mission goals met, Vikram, Pragyan to be put to sleep Sunday

Chandrayaan-3 project director P Veeramuthuvel told to TOI in an exclusive interaction.

“A full lunar day is from 0° Sun elevation angle to 0° angle. But the mission is not designed like that. For landing, the angle requirement was 6-9° elevation and we managed to land when elevation was 8.75°. For operations, we need a minimum of 6° elevation angle because our cameras and other systems are characterised for that. It's also for solar panels to remain optimal. Once it goes below 6° elevation, there’s a long shadow,” he said.

There doesn't seem to be much rotation, the view remains very similar (and moved back along the camera axis). But even a couple of degrees of elevation might make a difference and not be very perceptible to the human eye

[NRao]

The hop was 40 cm verticle and 30-40 cm lateral.

Reorientation is unlikely.

[putnanja]

In this post-image, I think we can make out four depressions corresponding to the four legs of Vikram on the right of the image.

[Amber G.]

1) What if we fire this for 10 seconds every day(not the propulsion) but sending power internally.
2) May be in next mission - Invent an adapter for Rover to get energy from lander during winter days.

Infact, whatever we are doing is a new avenue from here on. Possibilities, possibilities everywhere.

RHU, which are of the size of a c- cell, developed and available to ISRO, are much simpler solutions... For background see my post a few posts above.

Apollo 11,Apollo ( contained two 15W RHUs), Pioneer 10 & 11 ,Voyager 1 & 2 - of old days, all used it - proven technology and easy to get/implement if we need it.

[sanman]

Perhaps a subsequent hop like this provides useful data for some eventual future sample-return mission one day?

Think about it -- all you need is that rover to come back with some rocks, and then take off from the surface again, and dock with orbiter that then takes you back to Earth.

ISRO will soon do the SPADEX mission (Space Docking Experiment), which will have 2 satellites dock and transfer fluids, etc (eg. refueling)

So we seem to be preparing the necessary technologies required for such future feats.

[Amber G.]

Have to post this beautiful illustration from CanberraDSN ( Part of NASA's Deep Space Network. Managed in Australia by CSIRO)

[neeraj]

Hop video

[bala]

beautiful illustration from CanberraDSN

Image is a beautiful depiction of Chandrayaan-3 and pragyan on the South Pole of the moon. Tis my desktop background.

[sanman]

[sanman]

I knew Carl Sagan very well (over 25 years) but I have not heard of it before. He did not talk about it and in none of the books/articles I have seen, he mentioned it . Yet the items presented in the video are basically correct, and main-stream newspapers did have articles. So the video is quite well and well produced.
Carl Sagan who was student of Kuiper (also worked with Urey, Gamow, Chandrasekhar) has written *several* books and articles -- both for scientists and popular. (We both are physicists and have a great interest in astronomy/astrophysics). I highly recommend his books and extremely popular COSMOS series. (If you have not seen it, it is as good as it gets for any student for astronomy). Voyager record, which has greetings in many languages , Greetings in all Indian languages (including Rajasthani were recorded by a few of Indian grad students in Cornell. )..

(In younger days he did have top/secret clearance but later he never worked for military etc .. he was quite against using science for anything other than peace ... and had great relationship with international scientists)

Amber ji,
Prof Carl Sagan was at Cornell in Ithaca, NY. Have you ever been there? If so, had you ever met a Prof Ravi Sudan? He was a plasma physicist there.

[Amber G.]

OT but Short answer Yes, Sagan and Ravi Sudan both were in Cornell .Cornell/Ithaca (and Up State NY) already had quite a few Indian's in late 60's (when I came ) ( I did not chose Cornell for grad school but it was one of my top choices - and have attended seminars etc there ).Prof Ravi Sudan was already a big-shot/well-known in Plasma Physics -- He came to Cornell when he was already well known.

Cornell is a beautiful place.. Lived in that area for many years and have lot of family still in that area. (My niece went for UG, My son as a post-doc and many of my friends went to school or taught there) -- I have visited the place many times and keep visiting it even after all these years..) ..

[Piyal.g]

Negotiating craters... U Turn from the edge of the crater ..... Walking on the edge of the crater......

Pragyan must have been trained on Indian .no-roads'.

Pragyan is an Indian Boy, no amount of potholes can stop him.......

[sanman]

OT but Short answer Yes, Sagan and Ravi Sudan both were in Cornell .Cornell/Ithaca (and Up State NY) already had quite a few Indian's in late 60's (when I came ) ( I did not chose Cornell for grad school but it was one of my top choices - and have attended seminars etc there ).Prof Ravi Sudan was already a big-shot/well-known in Plasma Physics -- He came to Cornell when he was already well known.

Cornell is a beautiful place.. Lived in that area for many years and have lot of family still in that area. (My niece went for UG, My son as a post-doc and many of my friends went to school or taught there) -- I have visited the place many times and keep visiting it even after all these years..) ..

Glad you met Dr Sudan. He was a beloved uncle of mine.

https://news.cornell.edu/stories/2009/0 ... an-dies-77

[Piyal.g]

Have to post this beautiful illustration from CanberraDSN ( Part of NASA's Deep Space Network. Managed in Australia by CSIRO)

It would be great if the rover could have clicked the lander's pic with Earth in its back ground. It has 11 cameras onboard, some of the cameras definitely have some pics of the earth. Need to wait for ISRO to share them publically someday. Can the angle of the earth at the South Pole be a hindrance in getting good pictures?

The Hop test shows us the quality and ruggedness of our Lander. Beautiful legs and shock absorption pads. Last week, I was discussing about a hypothesis if the lander could hop to another location where sunlight is available. Isro proved me partially correct, however, it will need a lot of fuel which will increase its weight. As the moon's gravity is 1.62 m/s² and with no atmosphere available on the moon it can coast with little thrust and drop at desired location.

I still believe the Lander will wake up on the 22nd Sep, though the rover's chances are 50:50. Is it possible we have installed an RTU unit inside the lander but not declared it? Maybe Isro will surprise us the next lunar morning once the design is tested and successful.

[Amber G.]

^^^ Thanks. May be, you should write/post about his contributions in our Physics dhaga.. One of the great scientists/physicists of that era (and in the same neighborhood) along with George Sudarshan, Narinder Singh Kapany, Mehtas... (who not only did good work in physics , inspired many of us in our generation )..

[SriKumar]

So is the orbit shown in sankaranet accurate i.e. did CY3 essentially traverse the same path as represented here.
https://sankara.net/chandrayaan3.html

I am talking specifically about the lunar orbit insertion portion of it (and not the other parts) i.e. after the end of TLI and before CY3 settles in a lunar orbit. The change from essentially an equatorial plane to a polar plane is seen. TIA.

[Amber G.]

So is the orbit shown in sankaranet accurate i.e. did CY3 essentially traverse the same path as represented here.
https://sankara.net/chandrayaan3.html

I am talking specifically about the lunar orbit insertion portion of it (and not the other parts) i.e. after the end of TLI and before CY3 settles in a lunar orbit. The change from essentially an equatorial plane to a polar plane is seen. TIA.

The orbits shown are extremely accurate -- they are based on *actual* ISRO/JPL data. (that's why some times we have to wait till the data is available and update the orbits after the events which required burns, have taken place)

This includes the part you are talking about.
I can clarify more, if you describe what part is not accurate..(though a screen shot or which time you are looking at)
)
Meanwhile this may help -

The axis this animation is using:
z - axis points toward ecliptic pole.
xy is ecliptic plane. x - axis towards vernal equinox.
(No axis points towards sun or earth - which are moving)

There are three other planes: Earth's equatorial plane , Moon's equatorial plane, and plane of moon's orbit around earth. (One has to be careful, exactly what you mean by 'polar' plane or 'equatorial' plane... as xy plane is neither (exactly) earth's equatorial plane or moon's.).
(Change in inclination is easier to see - (at least from mathematical point of view) - if you see it in xy-yz-zx projections)

Also - you may want to see S^3 (and my ) post(s) about orbit inclinations -- about ISRO performing 'magic'.. that is carefully selecting orbit inclination(s) right almost from start so that after TLI, LOI itself was quite efficient and LBN#2 got it to almost polar orbit around Moon.

[madhu]

There has been some discussion about remaining day light near Vikram:

. Sun is quite low at present..so power generation is low too... ityadi.. ityadi...

“ A full lunar day is from 0° Sun elevation angle to 0° angle. But the mission is not designed like that. For landing, the angle requirement was 6-9° elevation and we managed to land when elevation was 8.75°. For operations, we need a minimum of 6° elevation angle because our cameras and other systems are characterised for that. It's also for solar panels to remain optimal. Once it goes below 6° elevation, there’s a long shadow,..”

Currently, the battery is fully charged and the solar panel is oriented to receive the light at the next sunrise

While we all wait for the dawn in September at Shivshakti point ..

Just for fun, and knowledge here are few questions for those who are not annoyed by math:

Assuming it is now: September 4, 2023 6:30 AM (IST) (= 2023/09/04 01:00 UTC)
Q1 - What is the elevation of Sun at Vikram Now?
Q2 - When will sun set ? ( Date, Time in Hours, Minutes)
Q3 - When will be the first rays of sun will hit Vikram ?
Q4 - When will the elevation reach 6 degree?
Q5 - When will be the next 'noon' (Highest elevation of the Sun in the vicinity)?
Q6 - When will be the next dawn (or noon) in October?
Q7 - What is the length of the "day" (Noon in September to Noon in October.

And a 3 more (or less) challenging questions:
Q8 Where and when can one see Brightest star Sirius and second brightest star Canopus (There position on a given date or time of their rise or setting)
Q9 - How long does it take for these stars to make a full cycle (time it takes that it repeats it's position in the sky.
Q10 - What planets are visible in the night sky ?

---
Give your values here in this thread. Curious to see the values posted here -- Discussing the math can be done in the math dhaga..

Code: Select all

import math
from datetime import datetime, date, timedelta


# Latitude and longitude of ISRO bangalore location (in degrees)
earth_latitude = 12.8984834
earth_longitude = 77.55906449999998

# Latitude and longitude of Moon's location (in degrees)
moon_latitude = 69.367621  # °S Example latitude on the Moon
moon_longitude = 32.348126 # °E Example longitude on the Moon

# Date (in days from the start of the year)
day_of_year = 247  # Example: September 4th
year = 2023 # Initialize year 

# ------------

# Approximate number of days in a lunar month
lunar_month_days = 29.53

# Calculate the lunar day (phase of the Moon)
lunar_day = (day_of_year % lunar_month_days) + 1

# Approximate lunar day length (in hours)
lunar_day_length = 24.0 / lunar_month_days

# Calculate the lunar time (in hours) since sunrise
lunar_time_since_sunrise = (lunar_day - 1) * lunar_day_length

# Convert lunar time to degrees of longitude
lunar_longitude = moon_longitude + (lunar_time_since_sunrise / 24.0) * 360.0

# Calculate the angular distance between Earth and the Sun
earth_sun_angle = (day_of_year - 1) / lunar_month_days * 360.0

# Calculate the difference in longitude between Earth and the Sun
sun_longitude_diff = earth_longitude - lunar_longitude + earth_sun_angle

# Calculate the sunrise and sunset times
sunrise_time = 12.0 - (sun_longitude_diff / 15.0)
sunset_time = 12.0 + (sun_longitude_diff / 15.0)

print(f"Sunrise on the Moon: {sunrise_time:.2f} hours")
print(f"Sunset on the Moon: {sunset_time:.2f} hours")

Sunrise on the Moon: -182.20 hours
Sunset on the Moon: 206.20 hours

[Amber G.]

Pragyan rover shares lunar image with 3D feel

Anaglyph is a simple visualization of the object or terrain in three dimensions from stereo or multi-view images.

The Anaglyph presented here is created using NavCam Stereo Images, which consist of both a left and right image captured onboard the Pragyan Rover.

In this 3-channel image, the left image is positioned in the red channel, while the right image is placed in the blue and green channels (creating cyan). The difference in perspective between these two images results in the stereo effect, which gives the visual impression of three dimensions.

Red & Cyan glasses are recommended for viewing in 3D

NavCam was developed by LEOS / ISRO. Data Processing is carried out by SAC / ISRO

[Amber G.]

Meanwhile: Japan's rescheduled moon mission to kick off on Sept 7
The live coverage of the launch of the X-Ray Imaging and Spectroscopy Mission (#XRISM) and the Smart Lander for Investigating Moon (#SLIM) onboard the H-IIA Launch Vehicle will start around 8:10 am (JST)on September 7/23:10 pm (UTC) on September 6.

[Amber G.]

Opportunity to win rs 100,1000: (Easy win, if you followed this dhaga

@mygovindia
has organised Chandrayaan-3 MahaQuiz honouring India's amazing space exploration journey, to explore the wonders of the moon, and to demonstrate our love of science and discovery.

All Indian Citizens are invited to take the Quiz at https://isroquiz.mygov.in

[disha]

Atcually Giordano Bruno was burnt at the stake for proposing SOlar centered universe and stars being distant suns.

https://en.wikipedia.org/wiki/Giordano_Bruno

Thanks for bringing up Giordano Bruno. Yes, Bruno was burnt at the stake for his very radical theories of helio-centric system(s) and for some reason the only name I could recollect was "Bruno Mars"

Anyway, I think all Indians and all-of ISRO are feeling the following, definitely till Sep 22:

[disha]

Wow... is this true?

US Plan to nuke the moon to show its superiority

Yes, the above is true. US has hidden away those discussions as "top secret". Just shows how much US was interested in actual science then. BTW, the physics behind the plan was calculated among others by one Carl Sagan. It was assigned to him by Uncle Sam, that is to check if it is feasible to set off a nuke on Moon, which he could not talk, but his biographer found it out since he mentioned it in his resume while he applied for a position in UC Berkeley.

[disha]

... Last week, I was discussing about a hypothesis if the lander could hop to another location where sunlight is available. Isro proved me partially correct, however, it will need a lot of fuel which will increase its weight. As the moon's gravity is 1.62 m/s² and with no atmosphere available on the moon it can coast with little thrust and drop at desired location.

I still believe the Lander will wake up on the 22nd Sep, though the rover's chances are 50:50. Is it possible we have installed an RTU unit inside the lander but not declared it? Maybe Isro will surprise us the next lunar morning once the design is tested and successful.

First of all, I hope you are correct on the bolded part. We all wait with baited breath. And no, there is no RTU in the lander. ISRO has been very forthcoming with data, and is transparently putting the data out there (it is a different issue with a different team on how that data is put out there), so ISRO would have declared that it carries RTU or not. And if the lander wakes up, it will be a remarkable feat of ISRO's engineering.

Coming to hop test, yes, that was a very good bonus. Nanjumar'ji in one of his post pointed out that the lander has some ~140 Kg of fuel and surmised on can it be returned to Earth. At that point, I was of the opinion that ISRO should do a hop test (I might have mentioned it in post, but not finding it now).

The reason for the hop test, as Sanman'ji surmised correctly, is to pave way (or gather data) on what it takes to return a sample back to Earth. Maybe C4 can be a sample return mission. And C5 can be a "hopper". Yes, it will take additional fuel, but there are some inherent advantage with an "hopper"compared to Rover.

The advantage will be the ability to reach centers of certain craters which a rover may not be able to reach. C5 can be either a "hovering hopper" where it actually launches itself, rises up and hovers over the right spot and lands down gently or a "parabolic drop hopper", where it launches itself into a parabolic trajectory and drops to a point. Also can the parabolic hopper use springs instead of rocket fuel? It may take multiple hops, but the point is to reach a particular spot, either a single hoppity-hop or multiple hops.

Israelis are designing a hopper-lander for the moon south pole. So the idea is not new.

Also in C5, if ISRO can put an RTB or RTU, that will be great! ISRO will definitely need RTB's if it needs to go beyond Mars.

[SriKumar]

So is the orbit shown in sankaranet accurate i.e. did CY3 essentially traverse the same path as represented here.
https://sankara.net/chandrayaan3.html

The orbits shown are extremely accurate -- they are based on *actual* ISRO/JPL data. (that's why some times we have to wait till the data is available and update the orbits after the events which required burns, have taken place)

This includes the part you are talking about.
I can clarify more, if you describe what part is not accurate..(though a screen shot or which time you are looking at)
)
Meanwhile this may help - The axis this animation is using:
z - axis points toward ecliptic pole.
xy is ecliptic plane. x - axis towards vernal equinox.
(No axis points towards sun or earth - which are moving)

There are three other planes: Earth's equatorial plane , Moon's equatorial plane, and plane of moon's orbit around earth. (One has to be careful, exactly what you mean by 'polar' plane or 'equatorial' plane... as xy plane is neither (exactly) earth's equatorial plane or moon's.).
(Change in inclination is easier to see - (at least from mathematical point of view) - if you see it in xy-yz-zx projections)

Also - you may want to see S^3 (and my ) post(s) about orbit inclinations -- about ISRO performing 'magic'.. that is carefully selecting orbit inclination(s) right almost from start so that after TLI, LOI itself was quite efficient and LBN#2 got it to almost polar orbit around Moon.

Thanks for confirming.

Yes I did see all the posts you mention above. I only wanted to confirm this was still true after the actual orbit is known. Indeed I was a little loose with my term 'equatorial' plane. i meant it for the moon (while knowing its axis is inclined by 1.5 degrees to the ecliptic). I looked at sankara.net's orbital paths and the LOI trajectory in the XY plane and one sees that:
1. The lander was placed 'ahead' of the moon i.e. it 'intersected' lunar orbit around earth and got there before the moon did, and 2. appears to come to a stop (almost) because the approaching moon pulls it towards itself, and 3. then retraces its path towards the approaching moon a bit before going into orbit, but is now in a polar plane.
Quite interesting....I was wondering how it went from an essentially an 'equatorial' plane to a polar plane without significant thrusters. The LOI trajectory shows it clearly.

Of course, ISRO achieved this in 2008 (as I understand it, it orbited the poles .....inferring from the fact that it detected water at the poles), so I guess no surprise that they did it a third time in 2023.

[Piyal.g]

Meanwhile: Japan's rescheduled moon mission to kick off on Sept 7
The live coverage of the launch of the X-Ray Imaging and Spectroscopy Mission (#XRISM) and the Smart Lander for Investigating Moon (#SLIM) onboard the H-IIA Launch Vehicle will start around 8:10 am (JST)on September 7/23:10 pm (UTC) on September 6.

Interesting design, a small package with a lot to offer. I will keenly watch its progress as our next mission is with them.

[Piyal.g]

... Last week, I was discussing about a hypothesis if the lander could hop to another location where sunlight is available. Isro proved me partially correct, however, it will need a lot of fuel which will increase its weight. As the moon's gravity is 1.62 m/s² and with no atmosphere available on the moon it can coast with little thrust and drop at desired location.

I still believe the Lander will wake up on the 22nd Sep, though the rover's chances are 50:50. Is it possible we have installed an RTU unit inside the lander but not declared it? Maybe Isro will surprise us the next lunar morning once the design is tested and successful.

First of all, I hope you are correct on the bolded part. We all wait with baited breath. And no, there is no RTU in the lander. ISRO has been very forthcoming with data, and is transparently putting the data out there (it is a different issue with a different team on how that data is put out there), so ISRO would have declared that it carries RTU or not. And if the lander wakes up, it will be a remarkable feat of ISRO's engineering.

Coming to hop test, yes, that was a very good bonus. Nanjumar'ji in one of his post pointed out that the lander has some ~140 Kg of fuel and surmised on can it be returned to Earth. At that point, I was of the opinion that ISRO should do a hop test (I might have mentioned it in post, but not finding it now).

The reason for the hop test, as Sanman'ji surmised correctly, is to pave way (or gather data) on what it takes to return a sample back to Earth. Maybe C4 can be a sample return mission. And C5 can be a "hopper". Yes, it will take additional fuel, but there are some inherent advantage with an "hopper"compared to Rover.

The advantage will be the ability to reach centers of certain craters which a rover may not be able to reach. C5 can be either a "hovering hopper" where it actually launches itself, rises up and hovers over the right spot and lands down gently or a "parabolic drop hopper", where it launches itself into a parabolic trajectory and drops to a point. Also can the parabolic hopper use springs instead of rocket fuel? It may take multiple hops, but the point is to reach a particular spot, either a single hoppity-hop or multiple hops.

Israelis are designing a hopper-lander for the moon south pole. So the idea is not new.

Also in C5, if ISRO can put an RTB or RTU, that will be great! ISRO will definitely need RTB's if it needs to go beyond Mars.

Yes, the Hop test is one thing that proves many technical features for the future:
1) robust design - can restart its engine after staying off for so long, handled the radiations and extreme temperature quite well.
2) It was able to retract and then Redeploy all its instruments including Ramp. Enable it to do tests at different locations. Get more data
3) It will come in handy while doing manned missions or sending samples back to Earth. If we want to set up a small science and research centre on the moon will need lots of small carriers that can travel to and fro between Earth and the moon. Supplying vyomanauts with crucial supplies.
4) By chance in the future we have to do a hard landing and if the orientation of the module is not correct we can correct it afterward.

[Najunamar]

Also if the subsurface temparatures are much more stable (as has been hypothesized) then future base may be under the regolith and supplied via such ships (combined fuel for return?)

[Amber G.]

<snip>

Thanks for confirming.

Yes I did see all the posts you mention above. I only wanted to confirm this was still true after the actual orbit is known. Indeed I was a little loose with my term 'equatorial' plane. i meant it for the moon (while knowing its axis is inclined by 1.5 degrees to the ecliptic). I looked at sankara.net's orbital paths and the LOI trajectory in the XY plane and one sees that:
1. The lander was placed 'ahead' of the moon i.e. it 'intersected' lunar orbit around earth and got there before the moon did, and 2. appears to come to a stop (almost) because the approaching moon pulls it towards itself, and 3. then retraces its path towards the approaching moon a bit before going into orbit, but is now in a polar plane.
Quite interesting....I was wondering how it went from an essentially an 'equatorial' plane to a polar plane without significant thrusters. The LOI trajectory shows it clearly.

Of course, ISRO achieved this in 2008 (as I understand it, it orbited the poles .....inferring from the fact that it detected water at the poles), so I guess no surprise that they did it a third time in 2023.

I read your post carefully but sorry, but this 'equatorial plane to 'polar' plane which scientifically makes little sense to me in the context .. perhaps some some confusion on mine (or your) part .. ... Let me explain --

Equatorial/Polar orbits make clear sense for earth's orbit (or moon's orbit) but not for the part of the orbit from TLI to LOI --

--- Let us consider this part of the orbit (which is still quite far from closest approach to the moon) -- an ellipse whose focus is approximately at barycenter of earth-moon system.

-- You require, three dimensional (or spherical trigonometry) to calculate how any such plane is inclined with equatorial plane of earth or the moon,

-- This part of the orbit is (more or less) in one plane -- this plane is tilted about 5 degrees from X-Y plane of the coordinate system. The angle between 'equatorial' plane (of earth) and a typical LOI orbit is typically between 18 degrees to 28 degrees. ( Angle depends on the many factors -- (where we are in 18.6 year cycle we are etc).. but typically it is as close to the plane in which moon rotates wrt to earth.

--- When the CY3 on that part of the orbit reaches near the moon, moon's gravity perturbs it -- the point of closest approach could be ahead-behind or left-right or up or down from the center of the moon... and the surface part nearest of the moon need *not* be a point on moon's equator.
(See - S^3 orbit, he once posted of the actual approach ...)

---- Things would be much simpler is moon' N-S pole, Earth N-S Pole and earth's equator/ ecliptic, and earth-moon orbital plane were all alighted but they are not. (You need three dimensional analysis and clear understanding of geometry involved).
(In short - the orbits are quite complex and getting all the timing right is crucial to save the fuel...here at the point of closest approach CY3 was just right amount of 'up' that first LOI burn, almost put it in an orbit which was inclined to >80 degrees from moon's equator....

Hope this helps ... (You may also contact Sankara -- or check out JPL/Horizon -- those ephemerides are there and you can see what the inclinations actually were etc)

Let me leave with this figure which may make some of the geometry involved a little clearer:

1- is path (orbit) coming from earth (after TLI) --- (Earth in the meanwhile has moved and you can see it in lower left- in background - at the time of the snap shot)
2 - is path after LOI ( the ellipse is quite big - will not fit but you can see the return part on top - also marked 2)
3 - After LBN2 the orbit is almost polar.

In the picture, you can see the poles of the Moon)

(The positions are on August 6 at 2:30 PM EDT - day/night line and position of CY3 changes with time... etc)



Added later: One of the reason, people are extremely impressed with ISRO is selection of orbit(s) (including the fine-tuning of inclination right from the beginning). Normally people just go in the neighborhood than do LOI (ending up in desire orbits which -- somewhat equatorial to the moon)...

[Amber G.]

Atcually Giordano Bruno was burnt at the stake for proposing SOlar centered universe and stars being distant suns.

Galileo Galilei and Giordano Bruno were both prominent figures in the history of science and astronomy, ..Both Italian Scientists lived around the same time..

Galileo was convicted by the Roman Catholic Inquisition of heresy for promoting heliocentrism.
His sentence included abjuring his views and spending the rest of his life under house arrest, during which he continued his scientific work.
(It's worth noting that in 1992, over three centuries after his trial, the Catholic Church officially acknowledged its error in condemning Galileo)
In summary, Giordano Bruno was executed by burning at the stake for his heretical beliefs, while Galileo Galilei faced house arrest and censorship but was not put to death.
(In BRF if he would have been banned or not, is everybody's guess )

[Amber G.]

I like this tweet from Canberra DSN (Part of NASA's Deep Space Network. Managed in Australia by CSIRO.):

जिन्हें सपने देखना अच्छा लगता है, उन्हें रात छोटी लगती है और जिन्हें सपने पूरे करना अच्छा लगता है, उन्हें दिन छोटा लगता है।

Those who like to dream, the night seems short to them and those who like to fulfill their dreams, the day seems short to them.
#Chandrayaan3 #PragyanRover

[Amber G.]

Per my calculations, sun is going to set at 18:09 (UTC) - in about 6 hours of this posting...


BTW: This answers Q2 of my questions -- see if it agrees with your answer..

Seems that calculation was correct..

[Vayutuvan]

@disha ji, and @AmberG ji

I came across Giordano Bruno in this book

https://www.amazon.com/History-Pi-Petr- ... 880294183/

A History of Pi Hardcover – January 1, 1993
by Petr Beckmann (Author)

It is an excellent short book and doesn't shy away from getting into Mathematics as well. I found it to be a great read.

FYI

[Amber G.]

^^^ Thanks. ... Agree, it's a great read ...

“Do not touch my circles!” said the thinker to the thug. Thereupon the thug became enraged, drew his sword and slew the thinker.
The name of the thug is forgotten.
The name of the thinker was Archimedes.

Slightly OT, but I will recommend "Galileo's Daughter" - a book I enjoyed about historical aspect of that time.

[Amber G.]

Here we go! A picture of the lander taken by the rover -- at last!

https://twitter.com/isro/status/1696792992718442558

Looking at this picture which was released/taken on 8/30 -- This is "noon" there at the Shakti point.
When I look at the picture it confirms how the lander was orientated on the moon. The rover ramp deployed south to ensure the three power generating surfaces were best orientated for power generation.

Not only softly landing on the moon but the ability to land at the exact orientation ISRO desired to maximize power generation. Impressed!

[SriKumar]

Sideview (YZ plane) of the 2D view from sankara.net (no issues here)




Following three 2D images in the XY plane show CY3 approaching the moon, or rather, the moon approaching CY3.

CY3 is poised at (what I believe to be) the beginning of the Lunar orbit insertion phase. There is a drastic change in the direction of the trajectory as it transitions from a long arc (about earth orbit) on the left (TLI trajectory?) and poised to enter into a lunar trajectory in the first picture below. This rapid change in direction, and actually, change in the plane of the trajectory is quite extreme; and was interesting to me- that it seemed to be done entirely by gravitational pull of the moon and presumably no thrusters were used in this phase other than for minor re-orientation.

CY3 reverses its direction (this is clearer in the video rather than still pictures), and the kinetic energy of CY3 in the process of reversing, it appears, was bled off entirely by lunar gravity pull.

[Amber G.]

Japan launches rocket carrying moon lander SLIM.

[sanman]