Chandrayaan 3: Launch and Discussions

[disha]

CNN (not IBN but the Amrikan wala channel) had this ex NASA astronaut and professor in their studios to talk about Indian moon landing and he was saying that no one attempted to land on the south pole so far because no body thought it was feasible. But in 2019 we almost did it and that should have made it clear it was possible but other than Russia nobody attempted to do it in 4 years.

China landed on the dark side of the moon. How difficult was it compared to ours and how did/do they communicate with it?
[/i]

Let's call it the far side of the moon, it is the near side which always faces us when we look at the moon, from Earth. The word "dark side" is due to the Apollo program when the apollo lander will go dark to communications. That is, once it reaches the far side of the moon, no communication is possible until it emerges out of the other side.

Yes, the ex-Nasa astronaut and professor are right, it was *not feasible* because the technology and engineering required was a quantum jump. Yes, a quantum jump even over the Change' 4.

Yes, the Change' 4 landing was complex. Still it landed on a relatively very very very flat lava flood plain formed within a crater. It landed in the Von Kamen impact crater of ~160km diameter https://en.wikipedia.org/wiki/Von_K%C3% ... graphy.jpg.

Chandrayaan 3 is an order more complex than Change' 4. Since landing at the S. Pole of moon requires a far more sophisticated autonomous navigation system. Its a generational shift in the nav system and integration with various input/output elements (for example cameras, laser altimeters) etc to achieve a landing precisely and at a safe spot.

It was C2 which thought us a lot and it is C3 which nailed it. The technology used in C3 is ultra-sophisticated state of the art technology. And ISRO has it in house.

I mentioned this earlier and mention it again, the inertial system used in Luna 25 is 10x heavier than what airbus sells for space mission. ISRO I believe has as sophisticated if not more sophisticated inertial system in C3 than what airbus/ESA has.

Again, the C2 camera taking fotos of the moon is the most advanced camera currently orbiting the moon. It was C2 that helped narrow down the precise spot for C3.

[disha]

Waiting for the video of the Rover, that is when I am going to lose it

Why wait saar! Pragyaan is like a baby taking its first tentative steps. It will look only cute when it walks on the moon.

The feeling of exhilaration on a tough mission accomplished successfully, yes 99.9% of the mission complexity has been solved phenomenally and in style, is now and do let it out!

[Cyrano]

Thank you for that wonderful post Amber ji, one in a long line. Keep them coming.

And in case anyone missed the Sci Am article someone posted earlier, here it is again:
https://www.scientificamerican.com/arti ... -the-moon/
Good reporting that by Jatan Mehta.

[Cyrano]

It was C2 which thought us a lot and it is C3 which nailed it. The technology used in C3 is ultra-sophisticated state of the art technology. And ISRO has it in house.

I mentioned this earlier and mention it again, the inertial system used in Luna 25 is 10x heavier than what airbus sells for space mission. ISRO I believe has as sophisticated if not more sophisticated inertial system in C3 than what airbus/ESA has.

Again, the C2 camera taking fotos of the moon is the most advanced camera currently orbiting the moon. It was C2 that helped narrow down the precise spot for C3.

Absolutely Disha ji !
BTW, who makes our camera optics ? ISRO? DRDO? Pvt Co? thanks.

[Najunamar]

Also, our autonomous landing capability will be even more crucial during the mars landing mission as the time delays then would be far exceeding the 3s latency in the case of moon. We’re blessed to be witnessing a lot of records from ISRO with more to come.

[nitzter]

Also, our autonomous landing capability will be even more crucial during the mars landing mission as the time delays then would be far exceeding the 3s latency in the case of moon. We’re blessed to be witnessing a lot of records from ISRO with more to come.

True, in a sense.

However, Mars landing is a wildly different monster as well -
1. It has just enough atmosphere to require good heat shielding, but not enough to generate good drag using droge chutes.
2. Gravity, on the other hand, is good enough to create high entry velocities upwards of 4 km/s, needing very high thrust to counter it.

ISRO won't focus on Mars landing anytime before 2027. Until then, the Gaganyaan mission, MOM2 and a second moon landing are a priority.

[hgupta]

We need to do a lunar sample return mission.

[bala]

For those wanting to re live the descent of Chandrayaan-3 to the South Pole of the moon..

[dnivas]

Ignore - if not interested in nerdy science - Trying to give some scientific insights in answering the questions:
(Comments are scientifically accurate -- figures etc are not 'official' etc)

....
(Hope this is useful)

Thanks for the illuminating post. Most of your mathematics post is way above my iq, but this way a great read.

[sanjaykumar]

Thanks Disha.

I thought Change e was a showcase of autonomous systems and communication relays.

I really wonder about the algorithms and data fusion of Vikram to steer the craft so wonderfully. I wonder if it is world class. In which case one can anticipate demand for collaborations.

[Amber G.]

Space.com:India on the moon! Chandrayaan-3 becomes 1st probe to land near lunar south pole

[Tanaji]

I think the coolest bit was it reselecting the target landing spot after the initial one was deemed not good enough.

Need more details on this, should be an interesting anecdote

[Vayutuvan]

I think the coolest bit was it reselecting the target landing spot after the initial one was deemed not good enough.
Need more details on this, should be an interesting anecdote

The decision was made by alorithms on board or were steered from mission control? Going by the @AmberG ji's post, I am assuming it is the former as the communication delay would be far too much to steer from mission control.

[Vayutuvan]

We need to do a lunar sample return mission.

The lander is going to return, right? or both the lander and rover are going to be abandoned?

[Tanaji]

I think the coolest bit was it reselecting the target landing spot after the initial one was deemed not good enough.
Need more details on this, should be an interesting anecdote

The decision was made by alorithms on board or were steered from mission control? Going by the @AmberG ji's post, I am assuming it is the former as the communication delay would be far too much to steer from mission control.

I assume it was automated as well, I meant the lander itself deemed its original target not good enough and chose a new one. That is the coolest bit for me. It shows expertise over algorithms on rapid pattern recognition and fast acting control systems to effect the same

[Atmavik]

We need to do a lunar sample return mission.

The lander is going to return, right? or both the lander and rover are going to be abandoned?

I don’t think so

[sanman]

Landing snapshot

https://twitter.com/santak/status/1694462676347519192

[Amber G.]

Meanwhile:
The next mission will launch on Friday, Aug. 26. JAXA's SLIM ( Smart Lander for Investigating Moon, from Japan’s space agency). SLIM aims to test the country’s lunar landing technologies; JAXA has yet to announce a landing date for the mission.

(There are Two American companies also vying to set down on the lunar surface later this year. )

All excited from success of CY3!

[sanman]

The lander is going to return, right? or both the lander and rover are going to be abandoned?

This is a one-way trip. Nothing comes back except the data being transmitted.

[ramana]

AmberG and team Kudos for high level discussions and explaining intricacies.
Ramana

[ramana]

For finance minded folks.
CY3 project cost Rs.615 crores
The rise in market valuation of companies in volved in CY3 today is Rs. 50000 crores.

[Amber G.]

We need to do a lunar sample return mission.

The lander is going to return, right? or both the lander and rover are going to be abandoned?

Short answer NO. CH3PM has much more fuel than expected ... so its useful life is in years (SHAPE payload).
Vikram (and Pragyan) is set for next 14 days to work..very small probability, if the electronics survive the night.. the batteries can start charging from sun and it go for another 14 days etc..

Lander has LRA -(requires no batteries and no maintenance, weighing only 20 gm ) will be there for a long time -- providing navigational reference points on lunar surface for future missions.

[AdityaM]

This is the representative image of the tire imprints from the rover that will stay for quite sometime on the windless surface of the moon.............

On CY3 rover, the isro & lion imprints are on separate left & right wheels, so that isro emblem is not seen to be above the national emblem.

[sanman]

Effort. Dedication. Victory.

[hanumadu]

Ignore - if not interested in nerdy science - Trying to give some scientific insights in answering the questions:
(Comments are scientifically accurate -- figures etc are not 'official' etc)

Thank you, Amber ji.

What the chinese did with chang'e 4 is impressive.
They also carried out a chang'e 5 where they brought back soil samples from the moon. They did not get much attention from the western press or Indian press.

[rahulm]

India's historic Chandrayaan-3 moon landing celebrated by ISS astronauts

[Najunamar]

Is the 140kg fuel in the PM sufficient to attempt a return to earth's atmosphere to validate the return path/fuel needs?

[Vayutuvan]

For finance minded folks.
CY3 project cost Rs.615 crores
The rise in market valuation of companies in volved in CY3 today is Rs. 50000 crores.

That is a great perspective. Faces of those who say "why space missions when people are starving?" should be rubbed in this facts. INR 50K cr is cna buy not only a lot of food but lift many many many poor out of poverty.

Confucius say "Money talk ... walk"

[sanman]

Is the 140kg fuel in the PM sufficient to attempt a return to earth's atmosphere to validate the return path/fuel needs?

Nah, and that won't happen anyway. ISRO already has enough experience with orbit changes, etc. Landing was something very different, since it's more complicated.

I hope India continues to build on this work, sending bigger and more robust landers to the lunar surface, transporting higher-mass payloads including bigger and more robust rovers, which can carry out more robust lunar surface exploration and discoveries.

[rahulm]

[Roop]

Jai Hind. Thank you and congratulations ISRO!!

Arre bhai sahab, Jai Hind is all very well and good, but I am sitting here chanting Jai Dilbu.

[rahulm]

Chandrayaan-3: India becomes fourth country to land on the moon

[disha]

I thought Change e was a showcase of autonomous systems and communication relays.

I really wonder about the algorithms and data fusion of Vikram to steer the craft so wonderfully. I wonder if it is world class. In which case one can anticipate demand for collaborations.

Here are my notes on the Autonomous system Chandrayan 3 vis-a-vis ChangE' 4:

1. ChangE''s 3/4 autonomous system/communication relay can be considered Gen II. Chandrayaan's 3 is Gen III. It is the latest
2. Yes, ChangE' 5 moon sample return is impressive. Very impressive.

With all of the prowess of China, it will have to go alone on lot of its missions.

JAXA and others will look to collaborate with ISRO for future moon missions. It is in their interest and in the interest of humanity.

Also this is a major boost for Indian space program. ISRO has a lunar bus that can take several partner agency payloads to Moon. To where it is needed.

I think the coolest bit was it reselecting the target landing spot after the initial one was deemed not good enough.
Need more details on this, should be an interesting anecdote

+72. Tanaji' thanks for catching that. I saw that too. I was trying to piece together the final sequence and the clueless cameraman panned out and in. So I will have to go back and piece together from several sources.

I assume it was automated as well, I meant the lander itself deemed its original target not good enough and chose a new one. That is the coolest bit for me. It shows expertise over algorithms on rapid pattern recognition and fast acting control systems to effect the same.

The entire C3 Landing sequence was autonomous from the time when command to de-orbit and land was given.

[Roop]

... to be first to land on South Pole of moon.

Is that true, though? I thought the Americans had a Viking lander there. Maybe I'm mistaken. Amber / SSS, any comments?

[Najunamar]

Viking 1 and 2 were Mars landers. Roopji was that sarcasm?

[disha]

I hope India continues to build on this work, sending bigger and more robust landers to the lunar surface, transporting higher-mass payloads including bigger and more robust rovers, which can carry out more robust lunar surface exploration and discoveries.

+72.

The lander is going to return, right? or both the lander and rover are going to be abandoned?

Yes Sir! Both Lander and Rover will be given a tata-bye-bye abandoned on the Lunar surface after 14 days. Or until its batteries last.

Just hope it finds lots of water and ice on moon. If it finds Ice, that will be basically a game changer for humanity. Since there is life on Moon!

--------

Again what C3 achieved is Epochal. And Modi's address right after the successful landing *and* from the BRICS summit makes a very huge statement! We need to hear it again, link it again here and analyze it*

*PS: More of it coming this weekend.

[disha]

Is that true, though? I thought the Americans had a Viking lander there. Maybe I'm mistaken. Amber / SSS, any comments?

Roop'ji, please do a simple google search.

[Najunamar]

Quick question to Gurus: Based on the lunar day duration and speed of Pragyan can it reach any of the craters which are in perpetual shadow and might have large quantum of ice? Or will it need to be only in vicinity of lander so still more exploration required if water isn't found or found in very small quantities?

[SivaR]

I've few questions popped in my mind after this landing.
1. With lunar gravity very low, returning to earth should consume much less thrust. What would be the ratio , is it 1:100?
2. Entering back to earth, how much thrust ratio needed compared to escaping the earth's gravity, my understanding is huge thrust is used for escaping the earth's gravity.
3. How easy it would be to launch rocket from moon to outer space compared to launching from earth, with moons low gravity advantage, provided we can generate rocket fuel from moon's water/gas/elements.
4. In case we make moon habitable, does building international space station become redundant?

[sanman]

Rover's solar panel is deployed and upright:



(that happened hours ago, but I was so busy surfing I forgot to post it)