Chandrayan-2 Mission

VenkataS · Post by **VenkataS** » 23 Jul 2019 04:47

Bibhas wrote:Very very naive and stupid question, but its constantly bothering me, and I never knew any other place other than BRF to ask this.
I know that the rover is planned for 14 earth days as this is the time its going to get enough sunlight. Is it possible that after another 15 days, its battery starts charging again and it can work again. I mean is there even 1% possibility of that happening. After all, if everything runs on battery, isn't there a thin possibility that everything else except a clock and a trigger is safely shutdown and then kicked up (like Wake-on-LAN type, just a simple example onlee) through a remote signal when the battery re-charges.

I think this is possible. According to wiki on Pragyan "The expected operating time of Pragyan rover is one lunar day or around 14 Earth days but its power system has a solar-powered sleep/wake-up cycle implemented, which could result in longer service time than planned"

If it can operate for one full lunar day, it will be great achievement. Lander landing without any glitches and Pragyan operating for one full lunar day would mean that this mission is a great success.

nachiket · Post by **nachiket** » 23 Jul 2019 05:14

Chetak, this is not the place for political posts. I have deleted yours. You can post it in the politics thread if you wish.

SSSalvi · Post by **SSSalvi** » 23 Jul 2019 07:21

VenkataS wrote:
Bibhas wrote:Very very naive and stupid question, but its constantly bothering me, and I never knew any other place other than BRF to ask this.
I know that the rover is planned for 14 earth days as this is the time its going to get enough sunlight. Is it possible that after another 15 days, its battery starts charging again and it can work again. I mean is there even 1% possibility of that happening. After all, if everything runs on battery, isn't there a thin possibility that everything else except a clock and a trigger is safely shutdown and then kicked up (like Wake-on-LAN type, just a simple example onlee) through a remote signal when the battery re-charges.
I think this is possible. According to wiki on Pragyan "The expected operating time of Pragyan rover is one lunar day or around 14 Earth days but its power system has a solar-powered sleep/wake-up cycle implemented, which could result in longer service time than planned"

If it can operate for one full lunar day, it will be great achievement. Lander landing without any glitches and Pragyan operating for one full lunar day would mean that this mission is a great success.

At least before the original scheduled launch ( which was aborted ) it was mentioned that there is a dim chance that 2nd session is possible if batteries survive.
But in current scenario that chance seems to be very very weak because of longer 'night' at lunar south pole this time.

NRao · Post by **NRao** » 23 Jul 2019 07:38

Gagan wrote:Yet another VERY DISAPPOINTING coverage by Doordarshan.
Can't believe they allow the wonderful folks at Chennai Doordarshan to drag the country's image down with substandard coverage, unimaginative shots, poor camera angles.

This doordarshan is the same bunch of morons who still play the Top Gun movie theme music everytime they capture a military aircraft in their frames.

FYI:

SSridhar · Post by **SSridhar** » 23 Jul 2019 07:46

Kakarat wrote:Just settled down in front of my pc and copying the photos from camera to pc. Will post the first batch tonight if possible
For the first time we had hired a professional camcorder and have shot UHD video, which we are yet to watch. Hoping to upload a Low res version by today or tomorrow and HD version by next week in our new YouTube channel to be announced shortly

Excellent work Kakarat. Awaiting all that.

juvva · Post by **juvva** » 23 Jul 2019 08:37

when is the first orbit raising burn?

Did isro publish the burn schedules ( in earth/moon orbits), any link?

UlanBatori · Post by **UlanBatori** » 23 Jul 2019 10:02

Extending that, could the experts pls post the following: ALL TIMES FROM T=0, ignition, pls:
1. Time from t=0 to solid booster burnout (my estimate is 110 seconds this time)
2. Time of liquid stage burnout (I mean total time since t=0). Started at round 110 seconds, but when did it end?
3. Time of cryo engine burnout (which means by-bye, off into deep Space). Total burn time of cryo was estimated at around 500-600 seconds. What time was it when that ended?
IOW, how long does it take, total, to get into GTO or whatever its called: ending in perigee burn at what altitude? What was that "6000km extra" that the Director mentioned? Increase in apogee beyond the design?
I also gather that the apogee is raised in 3 or 4 steps, each time using a perigee burn of the spacecraft engines: 48,000km, 72000km, 154,000 km or something like that.

sanjaykumar · Post by **sanjaykumar** » 23 Jul 2019 10:11

sanjaykumar · Post by **sanjaykumar** » 23 Jul 2019 10:13

Some time ago I had mentioned search for 'slow life' dependent on chemical reactions occurring at cold temperatures.

Apparently one mission objective is the search for quantum tunneling driven reactions on the moon. I would like to learn more about how they intend to probe for these. This is heady stuff. Congratulations for the sheer ambition.

https://youtu.be/OOlrhjs672s?t=1239

UlanBatori · Post by **UlanBatori** » 23 Jul 2019 10:25

Seems a pretty interesting place to stick up a telescope and let it scan the universe around as well as across the sky as the Moon goes around Earth.Just point it away from the Earth side, and shield it as the Sun approaches. After the dust of landing settles, the sky should be pretty clear.

disha · Post by **disha** » 23 Jul 2019 10:46

ldev wrote: Which in turn means that it needs a more efficient 1st and 2nd stage probably pure cryo or a combination of semi and pure cryo. Anything with a higher ISP than the present engines.

These are my very rough numbers/estimates.

Not just ISP, but thrust as well is required - like a big truck boosting the upper stages higher up in atmosphere. Currently the boosters together supply some 10 MN of thrust or some approx. 90% of total thrust. Atleast a cluster of Fifty (50) current CE 200 engines will be required to provide that thrust. It will look like N1 rocket.

Instead of replacing lower stages, add the CUS (CE7.5) upper stage from GSLV MkII on top of the current CE25 GSLV MkIII stage. In fact, if it can be clustered, one can have two of such clustered CE7.5 providing some 150 KN of thrust. And that should take it to 8 tonne to GTO.

Mort Walker · Post by **Mort Walker** » 23 Jul 2019 10:52

Chandrayaan 3 discussions are on to bring back lunar soil and rock samples from the south pole.

https://www.thehindu.com/news/national/ ... 655993.ece

Amber G. · Post by **Amber G.** » 23 Jul 2019 10:55

VenkataS wrote:
Bibhas wrote:Very very naive and stupid question, but its constantly bothering me, and I never knew any other place other than BRF to ask this.
I know that the rover is planned for 14 earth days as this is the time its going to get enough sunlight. Is it possible that after another 15 days, its battery starts charging again and it can work again. I mean is there even 1% possibility of that happening. After all, if everything runs on battery, isn't there a thin possibility that everything else except a clock and a trigger is safely shutdown and then kicked up (like Wake-on-LAN type, just a simple example onlee) through a remote signal when the battery re-charges.
I think this is possible. According to wiki on Pragyan "The expected operating time of Pragyan rover is one lunar day or around 14 Earth days but its power system has a solar-powered sleep/wake-up cycle implemented, which could result in longer service time than planned"<snip>

Wiki is basically correct but the question is not "stupid" at all, in fact it is a very good question. There is lot of work went in in designing it. Mostly developed by Indians -

The problem here, among other things but the most difficult to solve, is the low temperature on the moon - which at Vikram's landing reaches up to -200 C. Many systems designed for moon carried RTG (nuclear - generally Pu238) even when not for power itself but to thermally heat the batteries./ critical circuits.
Pragyaan/Vikram's power systems do not contain radio-isotopes. But lot has gone in the design so that there is temperature sensing cycles to 'shutdown' (thermally isolate critical parts etc.

From what I know, some of the previous system failed - mainly because electrolyte in batteries will "freeze" at such a low temperature and once frozen those batteries/power-system becomes useless. We will see how this new systems perform but the system is quite complex - without adding too much weight and keeping the things simple. People are quite optimistic that it will survive the lunar cold and will be able to "wake up". But as this is not the *main* criteria for design no one will go into this in too much details. (If there is interest, I can post a link - a little too technical - unless someone finds a good other resource and posts it here.).

The main design criteria for the power-system is that it has minimum drain in the batteries while in transit and work most reliably for at least 14 days when it is not cold.

But as Wiki says, the present power system has wake-up/sleep cycle, designed to likely survive the cold night. (Many things like batteries charging circuits switches off when temperature falls below -4C etc and other systems start going in hibernation mode).

This may be one of the most remarkable system without passive radioisotope heating - The design complexity is kept minimum and operationally address many of the possible failure scenarios imposed by lunar environment and unknown terrain. The built in reconfigurability feature of the power bus, - we hope - will improve the effective operational life.

I am optimistic - not so much if Pragyan wakes up - but things we will learn in this kind of design.

(Just BTW - Mars's Curiosity is still chugging along even after MANY years of its designed life. - True it carried radio-isotope but still..)

sivab · Post by **sivab** » 23 Jul 2019 12:04

^^^Here are links to some technical papers on this subject from ISRO.

1. Design framework of a Configurable Electrical Power System for Lunar Rover
https://www.researchgate.net/profile/Sa ... -rover.pdf

2. Study on survivability of 18650 Lithium-ion cells at cryogenic temperatures
https://archive.org/details/StudyOnSurv ... es/page/n5

3. Estimation of Thermodynamic Equilibrium Temperature of Chandrayaan-2 Rover Solar Panel during Long Lunar Nights
http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf

The temperatures are so extreme, its a very low probability that the system (solar panels, battery and electronics) will come back up. Think of solder joints on pcb, contacts of dissimilar materials inside electronic components not cracking up at such low temp due to dissimilar thermal shrinkage/expansion during warm up. I am sure they tested all of that, but it will be very low probability to actually work.

Amber G. · Post by **Amber G.** » 23 Jul 2019 12:32

^^^ Thanks Sivab.

My "optimism" was mainly about the things we will learn. I think we are the only one who - without using RHU have designed a system which *may* survive the lunar night. We will see.

I did some simple checking and found that from what I can see only a few (3 I could see) missions to the moon with this kind of situation have survived the lunar night - US and USSR's (70's) and China’s Yutu (2013, 2019) .. But all of these used radioisotopes to keep warm in the cold lunar night.

India, at least so far, has decided not to use nuclear-powered systems in its space missions.

Meanwhile I am pretty sure that one thing will survive and be operative of long time with Vikram - Laser Retroreflector arrays - we can shine laser and see the reflection coming back..

pankajs · Post by **pankajs** » 23 Jul 2019 13:40

Was this posted

Chandrayaan-2: This is how people witnessed successful launch of the Moon mission

Singha · Post by **Singha** » 23 Jul 2019 14:30

any station on the moon should best be highly autonomous robots of different types - wheels, tracks, legs.... no point going to time and expense of creating a human rated lab on such a hostile environment.

A Nandy · Post by **A Nandy** » 23 Jul 2019 14:52

I wonder what happened to the radioisotope thermoelectric generator being 'mulled' back in 2015. That would have kept things warm and comfy!

https://hardware.slashdot.org/story/15/ ... o-the-moon

The moon would actually be an excellent place to develop autonomous resource extraction swarms for future extraction at the asteroid belt.

Even co-ordinated construction by robots underground of habitable structures. Given the low gravity, large structures can be built on the moon and accelerated into orbit through a lunar launch loop

Kakarat · Post by **Kakarat** » 23 Jul 2019 15:38

Can some one suggest me a free video editing software to edit the launch video for posting online

Rahulsidhu · Post by **Rahulsidhu** » 23 Jul 2019 16:02

A Nandy wrote:I wonder what happened to the radioisotope thermoelectric generator being 'mulled' back in 2015. That would have kept things warm and comfy!

https://hardware.slashdot.org/story/15/ ... o-the-moon

The moon would actually be an excellent place to develop autonomous resource extraction swarms for future extraction at the asteroid belt.

Even co-ordinated construction by robots underground of habitable structures. Given the low gravity, large structures can be built on the moon and accelerated into orbit through a lunar launch loop

IIRC they were planning a RHU, not RTG. But even that didn't come to fruition.

akashganga · Post by **akashganga** » 23 Jul 2019 17:36

Now that chandrayaan-2 is successfully in orbit is there any news about the health of the chanyaan-2 spacecraft circling earth.

SSSalvi · Post by **SSSalvi** » 23 Jul 2019 18:07

Kakarat wrote:Can some one suggest me a free video editing software to edit the launch video for posting online

You Tube's own editor is good ... You can cut/move and give textual highlights.
Not very cumbersome to grasp the nitty gritties.

jaysimha · Post by **jaysimha** » 23 Jul 2019 18:18

Congrats to Isro.

But I felt there was a "CAP" on the success speech by Isro Chairam. May be dilli sultanate do not want anybody to give great success/victory speech lest they become more popular.. JMT.

Remember earlier launches, head of each group were called by person and called to dias to share his/her views. This time they could have glorified those who identified/ rectified the glitch.

I am sure every one here will remember when Dr. Sivan ( Director - VSSC ) when he said " I am proud to be Indian Today" and Shri Tapan mishra ( Director - SAC) calling " bahubali" when the first time indigenous cryo launched our GSAT

pandyan · Post by **pandyan** » 23 Jul 2019 18:42

Kakarat wrote:Can some one suggest me a free video editing software to edit the launch video for posting online

Saar...try shotcut. it is free and opensource with support for linux, windows and mac

https://shotcut.org/

If you want to try paid ones, powerdirector is pretty good. Also, some prefer adobe.

Kakarat · Post by **Kakarat** » 23 Jul 2019 18:50

SSSalvi wrote:
Kakarat wrote:Can some one suggest me a free video editing software to edit the launch video for posting online
You Tube's own editor is good ... You can cut/move and give textual highlights.
Not very cumbersome to grasp the nitty gritties.

My mistake should have been specific, the video is 4GB in size. Its 4K video shot with a professional camcorder.
The size makes it difficult for me to upload and edit it online

VikramA · Post by **VikramA** » 23 Jul 2019 19:04

jaysimha wrote:Congrats to Isro.

But I felt there was a "CAP" on the success speech by Isro Chairam. May be dilli sultanate do not want anybody to give great success/victory speech lest they become more popular.. JMT.

Remember earlier launches, head of each group were called by person and called to dias to share his/her views. This time they could have glorified those who identified/ rectified the glitch.

I am sure every one here will remember when Dr. Sivan ( Director - VSSC ) when he said " I am proud to be Indian Today" and Shri Tapan mishra ( Director - SAC) calling " bahubali" when the first time indigenous cryo launched our GSAT

The mission is not a success yet. Until the rover actually deploys on moon any self patting by isro should be limited to successful working of GSLV. Until then let's be optimistically cautious.after soft landing let the celebrations and speeches begin

Kakarat · Post by **Kakarat** » 23 Jul 2019 19:33

https://twitter.com/kakarat2001/status/ ... 1155718146

GSLV MKIII M1 with Chandrayaan2 Launch from Second Launch Pad as seen from Launch Viewing Gallery at Satish Dhawan Space Centre SHAR, Sriharikota

more to follow

prasannasimha · Post by **prasannasimha** » 23 Jul 2019 19:36

Sridhar wrote:
Mort Walker wrote:TV coverage was awful because only DD is allowed to live telecast from launch control facility and launch pad. At least 2 private TV channels must be granted access proving they have state of the art 4K HDR television cameras. Let some competition come in and even DD will improve. The private TV channels can hire some astrophysicist as their broadcast specialist for ISRO space launches.
The feed is from ISRO. ISRO cameras, ISRO commentators. Doordarshan merely relays it.

That said, the coverage has lots of scope for improvement. For one, the commentators need to learn that close T-1min, they should just shut up and let the R/T feed play itself out (perhaps only clarifying things that are hard to understand or need context). There are enough sharp people within ISRO and outside who can do this well. Instead we have two people giving us often repeats of what we hear on the R/T track.

Not all of ISROP's data collection is fed top DD. For eg see the cl;arity of the launch photographs that ISRO posts much later .

prasannasimha · Post by **prasannasimha** » 23 Jul 2019 19:36

Kakarat wrote:
SSSalvi wrote: You Tube's own editor is good ... You can cut/move and give textual highlights.
Not very cumbersome to grasp the nitty gritties.
My mistake should have been specific, the video is 4GB in size. Its 4K video shot with a professional camcorder.
The size makes it difficult for me to upload and edit it online

Use lightworks

Vips · Post by **Vips** » 23 Jul 2019 20:22

akashganga wrote:Now that chandrayaan-2 is successfully in orbit is there any news about the health of the chanyaan-2 spacecraft circling earth.

Chandrayaan-2 moving in right direction: ISRO.

A day after launching the country's second moon mission, the Indian Space Research Organisation (Isro) on Tuesday said the Chandrayaan-2 spacecraft is in "good health" and moving in the "right direction".

India had on Monday launched Chandrayaan-2 on-board its powerful rocket GSLV-MkIII-M1 from the spaceport of Sriharikota in Andhra Pradesh
with the aim of landing a rover in the unexplored lunar south pole.

The 3,850 kg Chandrayaan-2, a three-module spacecraft comprising orbiter, lander and rover, has been injected into the earth's orbit. It will be
subjected to a series of orbit manoeuvres in the coming weeks to take it to the vicinity of moon, with the rover soft landing planned on September 7.

"The Chandrayaan-2 is in good health. There is no doubt about it. It is moving in the right direction," an official of the Bengaluruheadquartered Isro told PTI here. He said at present, no updates on the mission have been made because there is no need for it at this juncture.

"However, there is a little milestone which we will not reveal now, but will update when the right time comes," the official said.

In a giant leap for the country's ambitious low-cost space programme, Isro has undertaken the most complex and its prestigious mission ever aiming to land the rover on the moon.If successful, it will make India the fourth country after Russia, the US and China to pull off a soft landing on the moon.

The Isro is aiming for a soft landing of the lander (spacecraft) in the South Pole region of the moon where no country has gone so far.

Immediately after Chandrayaan-2's separation from the rocket, the solar array of the spacecraft automatically got deployed and the Isro Telemetry, Tracking and Command Network at Bengaluru successfully took control of the spacecraft, the Isro has said.

Kakarat · Post by **Kakarat** » 23 Jul 2019 20:43

https://twitter.com/kakarat2001/status/ ... 9386207232

GSLV MKIII M1 in flight as seen from Launch Viewing Gallery at Satish Dhawan Space Centre SHAR, Sriharikota

disha · Post by **disha** » 23 Jul 2019 21:46

^How was the vibrations felt at the gallery? Can you describe your experiences at the gallery? We will be happy to know.

juvva · Post by **juvva** » 23 Jul 2019 23:51

Kakarat wrote:https://twitter.com/kakarat2001/status/ ... 9386207232

GSLV MKIII M1 in flight as seen from Launch Viewing Gallery at Satish Dhawan Space Centre SHAR, Sriharikota

Are these pics taken with optical zooming? Other launch pics/videos shot from the gallery do not show this much detail.

krishGo · Post by **krishGo** » 24 Jul 2019 00:01

Rishi_Tri wrote:A question on today's launch:

In previous launches I have seen ignition before t-0 and actual liftoff at t-0. In today's launch ignition was at t-0 and liftoff about 2 seconds later. Any reason behind that or just some adjustment of the clock!!

A rocket "lifts off" when its Thrust to Weight ratio is greater than 1. When exactly this happens is slightly different for different launchers.

For the GSLV, the liquid boosters ignite at T-4 seconds. This is because the solid core cannot be cutoff after ignition and the fact that solids are in general more dependable in the Indian context. So, when the core is ignited at T0, there is already 3 MN of thrust available from the liquid boosters and the vehicle lifts off comparatively quickly.

For the Mk3, the solid boosters are solely responsible for the liftoff. When ignited at T0, they take slightly longer to build up enough thrust to lift the vehicle of the pad.

So, we see 2 vehicles, both have their solid stages ignited at T0, but one lifts off almost instantaneously while the other takes a wee bit longer.

Kakarat · Post by **Kakarat** » 24 Jul 2019 00:49

juvva wrote:
Kakarat wrote:https://twitter.com/kakarat2001/status/ ... 9386207232

Image
Are these pics taken with optical zooming? Other launch pics/videos shot from the gallery do not show this much detail.

The photos were taken in a DSLR with Canon 100-400 + 1.4 Extender

SSSalvi · Post by **SSSalvi** » 24 Jul 2019 08:28

Created 3 views of current orbit of Chandrayaan 2 .

Whole orbit around Earth for comparing the relative sizes of Earth and Orbit ellipse.

Orbit and also the Moon depicting the distance to be covered in the last maneuver to place Chandrayaan-2 complex around Moon.

Shows the Inclination of orbit wrt Equator

SSridhar · Post by **SSridhar** » 24 Jul 2019 09:50

krishGo wrote:For the GSLV, the liquid boosters ignite at T-4 seconds.

The Mk 1 & Mk 2 versions of GSLV have Vikas as the GS0 stage. Their firing slightly ahead of time ensures also that sufficient and uniform thrust is built up by the strap-ons before the solid-propellant GS1 stage is ignited. I recall one flight, GSLV-D1, aborted because sufficient thrust was not built by the Vikas. That was a dramatic event to see on telecast.

Kakarat · Post by **Kakarat** » 24 Jul 2019 12:01

disha wrote:^How was the vibrations felt at the gallery? Can you describe your experiences at the gallery? We will be happy to know.

It hast to be experience and difficult to describe
For almost 30 seconds its only visual and no audio, the pad is almost 7Km away then you will start to hear the music. This time the roar was louder after the rocket disappeared into the cloud
we have tried our beast to capture it with a 4K camera with a external mic, kindly request all to be a bit patient and we will definitely release a SD version minimum by weekend and a professionally edited HD version with noise removed by next weekend

Haridas · Post by **Haridas** » 24 Jul 2019 12:08

prasannasimha wrote:
Singha wrote:Apollo11 got to the moon and back in 8 days.

so why is our chandrayaan only getting to the moon in 48 days in early september.

was it because they used the huge Saturn5 rocket to make a direct beeline for the moon instead of slowly doing orbit raising manouvers ?
48 days would have needed a lot of food and o2 for the astronauts which was not feasible.
Apollo 11 could directly lift 100 tons to GTO ! Moon lander was 13 tons ! Totally different specs.
We can do TLI to moon directly but weight woild be less

Apollo rocket weighed 3000 tonne, Chandrayaan 2 rocket weighed 640 ton (almost 5 times smaller)

Haridas · Post by **Haridas** » 24 Jul 2019 12:32

UlanBatori wrote:This geeessellvee looks positively mota, not sdre at all. Amazing. As I mentioned, strap a couple more S200 boosters, increase the central tank diameter a bit, and one could lift 16T to GEO. Or stack a series of satellites in a longer tube. Is it limited by G now I wonder, from doing that.

When I put that config on BR's Space section page some 14 years ago, some folks accused me of flights of fancy. You & me can have the last laugh.