Chandrayan-2 Mission

SwamyG · Post by **SwamyG** » 06 Sep 2019 14:24

Mort Walker wrote:From Nair's interview it appears there will be real-time pictures during the descent and landing. But would it be broadcast to the world soon?

If you look at the youtube video posted by juvva, there are at least 3 cameras in action. Maybe a couple more. They are being used by the lander for its operations during the descent. How many of those are for public consumption is not known.

SwamyG · Post by **SwamyG** » 06 Sep 2019 14:41

Courtesy Business Today: https://www.businesstoday.in/current/ec ... 77650.html

In less than 13 hours, the Chandrayaan-2 mission's lander Vikram is going to enter the most challenging phase of its journey as it attempts to soft land near the Moon's hitherto unexplored south pole. In fact, the Indian Space Research Organisation (ISRO) has described it as "15 minutes of terror". According to the space agency, the lander hopes to touch down in a high plain between two craters, Manzinus C and Simpelius N.

The 1,471 kg lander successfully separated from the orbiter on Monday and began revolving around the Moon, lowering its orbit over two manoeuvres and performing several pre-landing tests.

According to ISRO Chairman K. Sivan, the final descent is going to be terrifying as the agency has not done it before. "It is for the first time we are going to another body where there is no atmosphere and using the propulsion system we will have to break the velocity and bring the vehicle safely to soft land. To achieve this we will have to balance between the gravity and thrust. So we have to modulate the thrust of the engine," he said.

Moreover, of the 38 attempts of 'soft landing' on the lunar surface so far, only 20 have been successful. Just five months back, Israel's attempt crash-landed on the moon. If things go to plan on Saturday morning, India will become the fourth country after Russia, the US and China to achieve success.

So what will happen in the last 15 minutes before touchdown?

At 1:40 am on September 7, Vikram will begin its descent from a height of 35 km above the lunar surface and a velocity of around 6,000 kmph. In just over 10 minutes, the lander will drop to a height of 7.4 km above the Moon altitude and lower its speed to around 526 kmph.

At this point things will pick up pace and every second will matter. Over the next 38 seconds, the lander will further reduce its speed to 331.2 kmph and reach a height of 5 km above the lunar surface. As it drops to an altitude to 400 metres above the lunar surface in the course of the following 1.5 minutes, Vikram will have to lose more velocity and reach a speed of approximately 100 kmph. At this point it will briefly suspend its descent and hover for about 12 seconds to collect data of the lunar surface.

Touchdown is less than three minutes away at this point. When Vikram resumes its descent, it will drop 300 mts in the span of 66 seconds and once again hover at the height of 100 mts above the lunar surface. This pause of about 25 seconds is to give the lander a chance to make a final choice between two pre-determined landing sites. The onboard instruments will give it the necessary data to make this decision - the lander carries three scientific payloads to conduct surface and subsurface science experiments.

If Vikram chooses the first site, the lander will make a vertical descent to a height of 10 mts above the lunar surface over 65 seconds while significantly reducing its velocity. On the other hand, if it opts for the second site, it will first descend to a height of 60 mts over 40 seconds, and then drop down to 10 metres in the next 25 seconds. Either way, from the height of 10 mts, Vikram will take just 13 seconds to hopefully make history and soft land on the moon. Fifteen minutes after the touchdown, Vikram will send in the first pictures. Keep in mind, that the data mentioned above are approximations and reality may not match the plan on paper.

The primary objective of the fully indigenous Chandrayaan-2 mission is to demonstrate the ability to operate a robotic rover on the lunar surface. So four hours after landing, between 5.30 am and 6.30 am, the Pragyaan rover will be unloaded from the Vikram lander. The six-wheeled robotic vehicle with a mass of 27 kg will then carry out surface and sub-surface experiments for one lunar day, which is equal to around 14 Earth days. It can travel at a speed of 1 cm per second and leverages solar energy for its functioning. It will cover 500 metres in its lifetime.

Apart from studying the presence of water on the Moon, Chandrayaan-2 will also perform experiments that will hopefully shed light on the origins of the Solar System and, by extension, life.

A Nandy · Post by **A Nandy** » 06 Sep 2019 15:00

What kind of soil is expected around the lunar South Pole? Loose sandy type? Given the frigid temperatures and possibility of water can the surface be icy?

From what I last read, I don't think its that icy. All water locked up in regolith.

Supratik · Post by **Supratik** » 06 Sep 2019 15:25

Is this operation going to be shown live on any Indian TV channels?

Ashokk · Post by **Ashokk** » 06 Sep 2019 15:32

Everything going according to plan, ISRO chief

"We are eagerly waiting for the event. Everything is going according to the plan," Isro chairman K Sivan said. The touch-down of 'Vikram' lander is scheduled between 1.30 am and 2.30 am on Saturday, followed by the rollout of rover 'Pragyan' between 5.30 a.m and 6.30 a.m. "Certainly there is lot of anxiety in the minds of the entire (Chandrayaan-2) team because it's a very complex operation and we are doing it for the first time," a senior official associated with the mission, said on condition of anonymity. "Everything... sensors, computers, command systems... has to work perfectly. But we are confident in the sense we have conducted a large number of simulations on the ground; it gives us the confidence it would go alright," the official said. He described the soft-landing as "almost like placing a baby on the cradle", and said, "there is certain amount of anxiety but there is no fear."

Gagan · Post by **Gagan** » 06 Sep 2019 16:11

Is there a youtube link to the landing? What about the Nat-Geo plan to Telecast Live?
Is Nat Geo, going to take over the live transmission itself?
Or should we once again put our faith in the hands of Dukh-darshan.

<rant>
You never know with Dukh-darshan, just as the lander is about to touchdown, they might decide to switch over to Krishi Darshan and start showing us how to make good fertilizer from a mix of goat and buffalo manure, or how to tackle the darned "Kharpatwar" in the fields

Oh so the PM will be present! maybe we will escape DD's urges to show us Krishi-Darshan in between then. But then they will keep changing the shots to show the PM's face at the most critical juncture, because these guys are CHAMCHA's of the first order
</rant>

SwamyG · Post by **SwamyG** » 06 Sep 2019 16:30

The concept of "Live" seems debatable. All channels and news outlet are using the words - live, watch etc. BRF gurus feel it won't be instantaneous, and only telemetry data will be live. On top of it there will be 15mns of no communication. We at BRF are speculating there might be deferred pictures or video.

Hope ISRO clarifies. If there is a live video then I would hope and expect DD to be the preferred video feed provider.

BTW, Sooraj posted DD National link above.

Dilbu · Post by **Dilbu** » 06 Sep 2019 16:31

Vikram lander will fail onlee.

sooraj · Post by **sooraj** » 06 Sep 2019 16:59

Meet Vikram — Chandrayaan 2’s Lander!

Mort Walker · Post by **Mort Walker** » 06 Sep 2019 17:45

Supratik wrote:Is this operation going to be shown live on any Indian TV channels?

The PM and dignitaries will be at ISTRAC at Bengaluru for this landing attempt. Of course Vikram has multiple cameras, but sending pictures or video back live is limited by bandwidth. Telemetry data will be coming live, delayed by a little over 1 second due to distance. Former ISRO chairman in an interview implies that pictures will be coming back live, and I suspect some will provided bandwidth isn’t too taxed, in case there is a failure and it would allow ISRO to see what happened before failure.

Arnab Goswami will be covering it live on Republic TV and I’m sure he’ll find someone to shout at. Regardless of failure or success, that will still be fun to watch.

Mort Walker · Post by **Mort Walker** » 06 Sep 2019 17:56

From India Today

15:31 PM IST Posted by Dev Goswami
Will you get to see Chandrayaan-2 landing live?
Sadly, no. The Indian Space Research Organisation's mission control will have a graph splashed across a big screen that will mainly show beeps. What we're hearing from Bengaluru is that there will no real time video or visuals during the night. A still picture shot by Chandrayaan-2's Vikram lander is likely to be released tomorrow morning.

Amber G. · Post by **Amber G.** » 06 Sep 2019 18:21

Arjun wrote:What kind of soil is expected around the lunar South Pole? Loose sandy type? Given the frigid temperatures and possibility of water can the surface be icy?

Read all about it, for example here:
GEOLOGICAL INSIGHTS INTO CHANDRAYAAN-2 LANDING SITE IN THE SOUTHERN HIGH LATITUDES OF THE MOON.
You have detailed description of soil/minerals etc around the area:

: The landing ellipse is generally flat in the LRO WAC DTM (‘GLD100’ at 100 m/pixel) and is confined by craters of varying diameter. The center of the landing ellipse (i.e., PLS) is devoid of craters with significant depth. The estimated age of the landing ellipse reveals that it is younger than the age of impact craters present to the north (e.g. Manzinus)`. Ejecta of the crater Schomberger in the south superimpose the landing ellipse region. Therefore, it is possible that these craters could have significantly changed the stratigraphy of the landing region. The 1:5,000,000lunar geologic renovation (2013) map I-703 shows that the geologic unit within the landing ellipse corresponds to unit Ntp (Nectarian plains) [15-16]. Ntp is defined as ‘terra mantling and plains material’ and is proposed to be sourced by primary and secondary ejecta deposits
of Nectarian basins and large craters on the Moon [15].
Therefore, it is likely that the landing ellipse may host
primary crustal materials.
Our spectral analysis suggests the presence of weak
absorption bands centered at ~900-950 nm and ~2000
nm at two locations within the landing ellipse. This
indicates the presence of low-calcium pyroxene. The
landing ellipse is mainly dominated by highland-type
featureless spectra indicative of FAN lithologies. Our
spectral and chemical composition analyses suggest
that the surface composition corresponds to FAN materials mixed with Mg-suite rocks. We hypothesize that
such a lithology could be a result of mixing of ejecta
from the SPA basin impact that may have excavated
and redistributed lower crustal or upper mantle materials.
Ityadi ityadi ..

SwamyG · Post by **SwamyG** » 06 Sep 2019 18:23

Mort Walker wrote: Arnab Goswami will be covering it live on Republic TV and I’m sure he’ll find someone to shout at. Regardless of failure or success, that will still be fun to watch.

OT: I heard the rumor that both Vikram and Pragyan can hear Arnab. So that communication channel is definitely open.

Ashokk · Post by **Ashokk** » 06 Sep 2019 18:41

Meet Pragyan — Chandrayaan 2’s Rover!

Amber G. · Post by **Amber G.** » 06 Sep 2019 19:06

SwamyG wrote:
Mort Walker wrote: Arnab Goswami will be covering it live on Republic TV and I’m sure he’ll find someone to shout at. Regardless of failure or success, that will still be fun to watch.
OT: I heard the rumor that both Vikram and Pragyan can hear Arnab. So that communication channel is definitely open.

Okay stating the obvious, as there is lot of messages about broadcasts of "live" landing . and communication channels.

- Not sure if Vikram/Pragyan even want to hear Arnab .. but seriously ..

Forget about watching and quickly posting cool high-definition videos here in brf or on YouTube .. data transmission rate from Vikram (or any space probe/rover etc to Deep space Network back at home) is painfully slow ..may be about half a megabit/sec in best of times. (Live audio requires very little band-width so if there were Vyomyatris one can hear them live).

Apart from all the telemetry data and may be a photo or two will be live or near live..It just doesn't work that way.
(There are plans for NASA which may boost speeds of these kind of networks but that is years in future)

Photos *may* (I don't know but ISRO/Newspapers may have details) come, and posted within an hour or earlier but for cool video's one may have to wait a bit longer. (These will be stored/cashed in Vikram's storage, compressed and sent over efficiently as their priority but it will be slower than many desire here).

(Apollo 11 and other landings did broadcast "live" but it was B/W - very low definition etc. (And that only of moon walks after setting up good transmitter etc). For really stunning photographs one waited till people came back and developed their film back on earth).

SwamyG · Post by **SwamyG** » 06 Sep 2019 19:27

Some of the private companies involved with CY2: https://economictimes.indiatimes.com/ma ... 005762.cms

Mort Walker · Post by **Mort Walker** » 06 Sep 2019 19:32

AmberG,

There is some good documentary about Apollo 11 video engineering. In the 1960s-80s It was analog RCA subset of NTSC at around 441 horizontal lines of resolution interlaced (meaning every other line would update per frame) that is updated around 30 frames per second. Westinghouse engineers devised a camera that would transmit at half rate, that is 15 frames a second. This reduced the bandwidth load.

That said, the Chinese did eventually release video of Chang-e 4 as it landed. It was impressive.

Mort Walker · Post by **Mort Walker** » 06 Sep 2019 19:36

My biggest concern right now is that Vikram’s 4 engine braking works well and then fine braking using 2 engines work well at 400m altitude. The electromechanical relays and actuators makes me worry, as these things do fail regularly.

SwamyG · Post by **SwamyG** » 06 Sep 2019 19:57

Almost everyone in my circle, based on Nat Geo, YouTube and other channel descriptions.....all are waiting for a live video. I had to disappoint them...however I asked to wake/stay up and watch. Even my sister was going to watch live. I think media has wiped up the frenzy today......good thing.

suryag · Post by **suryag** » 06 Sep 2019 20:55

Aaj mere paas Saturn hai Apollo hai ion propulsion hai ... mere paas dilbu hai

Nerve wracking few hours

Mort Walker · Post by **Mort Walker** » 06 Sep 2019 21:12

Whatever happens we learn from and next time will be an even bigger success. CY2 orbiter will still map the moon in great detail for a year and Vikram is in a successful 35 Km orbit scanning the South Pole. That data is coming back. Success has happened for a great investment of Rs. 1000 crore.

sooraj · Post by **sooraj** » 06 Sep 2019 21:33

Timeline in UTC:

20:08 "Rough" braking burn (30 km altitude)
20:18 "Fine" braking burn (7.4 km altitude)
20:20 Start of terminal guidance navigation
20:22 First picture from descent camera
20:23 Touchdown
22:23 Deployment of rover ramp
22:53 Rover power up
23:33 Rover solar panel deployment
23:49 Start of rover roll off
23:59 Rover roll down onto lunar surface
00:15 Rover takes picture of lander

Arjun · Post by **Arjun** » 06 Sep 2019 21:57

Amber G. wrote:Read all about it, for example here:
GEOLOGICAL INSIGHTS INTO CHANDRAYAAN-2 LANDING SITE IN THE SOUTHERN HIGH LATITUDES OF THE MOON.
You have detailed description of soil/minerals etc around the area:
: The landing ellipse is generally flat in the LRO WAC DTM (‘GLD100’ at 100 m/pixel) and is confined by craters of varying diameter. The center of the landing ellipse (i.e., PLS) is devoid of craters with significant depth. The estimated age of the landing ellipse reveals that it is younger than the age of impact craters present to the north (e.g. Manzinus)`. Ejecta of the crater Schomberger in the south superimpose the landing ellipse region. Therefore, it is possible that these craters could have significantly changed the stratigraphy of the landing region. The 1:5,000,000lunar geologic renovation (2013) map I-703 shows that the geologic unit within the landing ellipse corresponds to unit Ntp (Nectarian plains) [15-16]. Ntp is defined as ‘terra mantling and plains material’ and is proposed to be sourced by primary and secondary ejecta deposits
of Nectarian basins and large craters on the Moon [15].
Therefore, it is likely that the landing ellipse may host
primary crustal materials.
Our spectral analysis suggests the presence of weak
absorption bands centered at ~900-950 nm and ~2000
nm at two locations within the landing ellipse. This
indicates the presence of low-calcium pyroxene. The
landing ellipse is mainly dominated by highland-type
featureless spectra indicative of FAN lithologies. Our
spectral and chemical composition analyses suggest
that the surface composition corresponds to FAN materials mixed with Mg-suite rocks. We hypothesize that
such a lithology could be a result of mixing of ejecta
from the SPA basin impact that may have excavated
and redistributed lower crustal or upper mantle materials.
Ityadi ityadi ..

That is detailed....Thanks!

Mort Walker · Post by **Mort Walker** » 06 Sep 2019 22:08

Thank you Sooraj and Dilbu of course.

A Nandy · Post by **A Nandy** » 06 Sep 2019 22:18

https://timesofindia.indiatimes.com/ind ... 013702.cms

Landing & Rover Deployment

Post midnight, Vikram will begin the 15-minute final descent between 1am and 2am. As per Isro’s plan, about 10 minutes later, it would have dropped to reach a height of 7.4km from the lunar surface.

In the next 38 seconds, it will reach a height of 5km and another 89 seconds later Vikram's altitude will be 400m.
At 400m, Vikram will hover for about 12 seconds to collect some data from the lunar surface and then further reduce its altitude in the next 66 seconds, to reach a height of 100m.

At this height (100m), Vikram will hover again to decide if it must land on the first preferred site or the second one. Its onboard
instruments will tell Vikram what to do.

If it can land on the first site, Vikram will, in 65 seconds, reach a height of 10m directly. In case it has to pick the second landing site, it will use 40 seconds to first descend to a height of 60m, then, further drop down to 10m in the next 25 seconds. From the height of 10m, it will take Vikram 13 seconds to touchdown on Moon.

williams · Post by **williams** » 06 Sep 2019 22:34

Live cast link

https://www.youtube.com/watch?v=lqQe7WsFVQg

Amber G. · Post by **Amber G.** » 06 Sep 2019 22:47

sooraj wrote:

Timeline in UTC:

20:08 "Rough" braking burn (30 km altitude)
20:18 "Fine" braking burn (7.4 km altitude)
20:20 Start of terminal guidance navigation
20:22 First picture from descent camera
20:23 Touchdown
22:23 Deployment of rover ramp
22:53 Rover power up
23:33 Rover solar panel deployment
23:49 Start of rover roll off
23:59 Rover roll down onto lunar surface
00:15 Rover takes picture of lander

All from available data and best I can do: (Vikram Landing planned for 6th September, 20:08)
(I am using 2-D projection not as nice-looking with 3D rendering but just wanted to understand the orbits)
(Vikram's orbit in blue, CY2's current and some of the older ones in yellow - Looking from the reference of the Moon)
(Red triangle is when first "braking" starts - Disclaimer: It is not from ISRO and no one else other than me is responsible if there is an error)

Ashokk · Post by **Ashokk** » 06 Sep 2019 23:09

Chandrayaan-2 landing live updates: Everything going according to plan, Isro chief on proposed soft landing of 'Vikram' module

22:17 (IST), Sep 06
Visuals from Isro Monitoring Centre in Bengaluru.

The final descent of #Chandrayaan2 to take place on the Lunar South Pole, tonight. #Visuals from ISRO Monitoring Ce… https://t.co/o2LYsRztRL
— ANI (@ANI) 1567787815000

21:53 (IST), Sep 06
PM Modi received by Karnataka CM BS Yeddiyurappa at Bengaluru Airport

PM Modi arrives at Bengaluru airport, to head to Isro monitoring centre

21:09 (IST), Sep 06
Jerry Michael Linengar, former Nasa astronaut is in India to do a special show at 11.30pm on Friday night on Chandrayaan-2 moon landing that will be live telecast on National Geographic.

21:08 (IST), Sep 06
Over 300 journalists from across the country, including some from the foreign media, have congregated at ISTRAC to cover the moon landing in the south pole.

williams · Post by **williams** » 06 Sep 2019 23:13

https://www.youtube.com/watch?v=7iqNTeZAq-c

ISRO official live telecast

Amber G. · Post by **Amber G.** » 07 Sep 2019 00:07

One more orbit to go!!!

Mort Walker · Post by **Mort Walker** » 07 Sep 2019 00:11

Maybe AmberG on a BRF podcast would have been better than TV newsreaders.

Amber G. · Post by **Amber G.** » 07 Sep 2019 00:17

At Present (10:40 AM, California Time - 17:40 UTC, 23:10 IST) View from Vikram:
(I am looking towards earth (hidden behind moon at present) - North is straight up, (Yellow thin line on the right) Can't see CY2)

Looks Good! (Photo *not* real but view created from current data - best to my knowledge).. (The view is about 45 degrees wide)

Amber G. · Post by **Amber G.** » 07 Sep 2019 00:54

So Vikram lander went to the far side at 18:30 UTC. From this complete orbit any one can see the current orbital period of the lander: 1h 54min 56s. . Watching world can see the data independently and see what a perfect orbit ... Looks like ISRO knows how to make things stick to their schedule

.. Well done. Next orbit will be the last one for Vikram anyway.

*** This is from an amateur astronomer's observation of Vikram from DSN Madrid DSS54 antenna ****

UlanBatori · Post by **UlanBatori** » 07 Sep 2019 00:58

I am on the "Live Telecast link" but all I see live is a countdown clock. Where is the Situation Naarmal voice please?
Plus an accelerating inflow of garbage comments (like mine). Am I at the right place?

darshan · Post by **darshan** » 07 Sep 2019 01:05

Has anyone seen Hindi version of this video? https://youtu.be/V9LFnEycVcg

UlanBatori · Post by **UlanBatori** » 07 Sep 2019 01:08

Oh! FOUND the motormouth site.
https://www.youtube.com/watch?v=d6VmPU6Us00

UlanBatori · Post by **UlanBatori** » 07 Sep 2019 01:09

What's with the 1 hour addition? Moving to second site? I thought that was seconds, not many minutes? O I c, that is until the START of the landing window, when DoorDarshan wakes up?

Amber G. · Post by **Amber G.** » 07 Sep 2019 01:11

Slightly OT but in the meanwhile Chinese Media is claiming that the country’s Yutu-2 lunar rover stumbled upon a unique “gel-like” substance of unknown origin sitting inside a small crater.

The only real details China has released so far is that the material is “gel-like,” and that is exhibits an “unusual color.”

UlanBatori · Post by **UlanBatori** » 07 Sep 2019 01:13

Pakis have been there already? Vaseline?

Dilbu · Post by **Dilbu** » 07 Sep 2019 01:19

Vikram lander will fail onlee