Chandrayan-2 Mission

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UlanBatori
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Re: Chandrayan-2 Mission

Postby UlanBatori » 22 Jul 2019 20:43

How dare India solve glitch in 24 hours when there are sooo many stupid Generals in Pakistan?

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Re: Chandrayan-2 Mission

Postby Singha » 22 Jul 2019 20:55


srin
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Re: Chandrayan-2 Mission

Postby srin » 22 Jul 2019 21:15

A question probably a week late .... After the first attempt was scrubbed last week, I presume they'd have de-fueled the L110 and the cryo stages. Would the hypergolic fuels in the liquid apogee motor of the chandrayaan spacecraft also be defueled ?

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Re: Chandrayan-2 Mission

Postby Varoon Shekhar » 22 Jul 2019 21:17

Excellent, congrats ISRO! Looking now to see validation of new 800 N LAM as it performs manoeuvers over the next few weeks. Evidently, the 800 N LAM( as opposed to the 440N LAM used all these years) is not such a big deal for ISRO, for me it is though :) And for communication to be sustained.

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Re: Chandrayan-2 Mission

Postby ArjunPandit » 22 Jul 2019 21:18

i have started loving their burns..

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Re: Chandrayan-2 Mission

Postby Gagan » 22 Jul 2019 21:24

UlanBatori wrote:How dare India solve glitch in 24 hours when there are sooo many stupid Generals in Pakistan?

They only tightened two screws. That valve was leaky, and they tightened where it was.

All it took was a spanner, anyone could have done it in 10 mins. These guys took 10 days !!!

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Re: Chandrayan-2 Mission

Postby Gagan » 22 Jul 2019 21:24

Congrats to Team ISRO !!!!

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Re: Chandrayan-2 Mission

Postby Varoon Shekhar » 22 Jul 2019 21:25

Mort Walker wrote:
juvva wrote:
Just slightly. Let's see what happens when GSAT-20 is put up in Sep. The C-25 cryo engine performance will be an important step when going to the HLV.


Is that September launch more or less on course? Another Mark 3 launch within 2 months, awesome.

Wish there was no mention of 'underperformance' of a stage( even slightly :) ) at a time like this. Sours the mood a bit, but anyway, the vehicle itself as a whole performed or overperformed :) that's what is important.

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Re: Chandrayan-2 Mission

Postby Gagan » 22 Jul 2019 21:27

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.

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Re: Chandrayan-2 Mission

Postby sanjaykumar » 22 Jul 2019 21:28

There is no such thing as 'over performed' in engineering. Either it is to design parameters or it is not.

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Re: Chandrayan-2 Mission

Postby Gagan » 22 Jul 2019 21:31

Why can't Antrix / ISRO have 4K cameras of their own, including on the rocket itself?
The stage seperation, heat shield seperation, satellite deployment should be done with high bandwidth link, in real time.
All other space powers are doing it, only ISRO lags behind.

They are still "Inviting" news agencies to come and cover launches. They won't allow even a helicopter based camera to capture slick aerial shots. Their list of "Noes" is probably endless. Looks like only Chennai Doordarshan shows up, with their poorly maintained HD cameras.
Just look at how the camera was shaking up and down when the Rocket took off - shameful !!!

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Re: Chandrayan-2 Mission

Postby Gagan » 22 Jul 2019 21:34

Telemetery needs to be on the screen in the bottom or the top, real time, not shots of the DOS tele screen from time to time.

This can be improved by SO MUCH !!!

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Re: Chandrayan-2 Mission

Postby Rishi_Tri » 22 Jul 2019 21:46

chetak wrote:
sudhan wrote:
That's what the ISRO graphic showed, not able to make the tread marks out clearly in pics of the rover.. Will have to wait and see


maybe it wasn't the right angle


Saw it too. One track left imprint of 'Ashok Chinh' and other track left imprint of 'Rashtriya Dhwaj'. Hopefully shall be there on moon too.!!

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Re: Chandrayan-2 Mission

Postby juvva » 22 Jul 2019 21:58

Gagan wrote:Why can't Antrix / ISRO have 4K cameras of their own, including on the rocket itself?
The stage seperation, heat shield seperation, satellite deployment should be done with high bandwidth link, in real time.
All other space powers are doing it, only ISRO lags behind.

They are still "Inviting" news agencies to come and cover launches. They won't allow even a helicopter based camera to capture slick aerial shots. Their list of "Noes" is probably endless. Looks like only Chennai Doordarshan shows up, with their poorly maintained HD cameras.
Just look at how the camera was shaking up and down when the Rocket took off - shameful !!!


Bad as it is, I am willing to live with it , If only they can cut down on the awfull second by second continuos loud commentary , and allow us to hear the controllers call outs.
Last edited by juvva on 22 Jul 2019 21:58, edited 1 time in total.

chetak
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Re: Chandrayan-2 Mission

Postby chetak » 22 Jul 2019 21:58

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.




pay peanuts and get monkeys principle of govt service on display

So many smart lady hindi announcers for the voice over even in DD and yet they had some hack droning on and on, reading from some dreary prepared script.

need to smartly showcase our achievements with some degree of panache and sophistication.

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Re: Chandrayan-2 Mission

Postby Rishi_Tri » 22 Jul 2019 22:04

Of course we shall go to Moon and it shall be fantastic scientific achievement but think the most critical aspect of this launch (IMHO) has been further proving of C25 Cryogenic engine. We don't have to go to Arianespace for launching heavy satellites. GSLV MKIII has been proven for 4T as Dr Sivan said. Even some folks from Arianespace had said years ago: GSLV MKII/III shall be the one to watch.

Now have only faint remembrance of reading newspaper reports saying Glavkosmos backed out of deal to do TOT for cryogenic engine. It put us back by decade if not more. Led to scientists being compromised, arrested (Prof. Nambi Narayanan and others) in an attempt to prevent progress. But guess what, it took 25 years and we are Independent and Truly Independent.

Sashtang Dandavat to those toiled day in day out and brought True Independence.

Know it is OT here but:

Gaganyaan - 2021/2022
Manned Space Station - 2030
Landing on Moon - 2030??
Station on Moon - 2035??
Landing on Mars - 2040??
Station on Mars - 2045??

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Re: Chandrayan-2 Mission

Postby UlanBatori » 22 Jul 2019 22:07

They had a bit of trouble figuring out what time it was: the DDM countdown clock hit 0 a full 10 seconds before the real clock. And yes, they were doing a CNN-like parrotlike repetition, drowning out the precise call-outs as each system checked in.
But all that could not spoil the sheer awe at the size of the rocket and the support structures. Wow!!
Tell me again, why can't India build her own large airplanes, esp. supersonic airliners? Or big jet engines?
Last edited by UlanBatori on 22 Jul 2019 22:11, edited 1 time in total.

dinesh_kimar
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Re: Chandrayan-2 Mission

Postby dinesh_kimar » 22 Jul 2019 22:07

Aiyee.......... ye foolish yindoos...

You having flag on moon in 2019 is no big deal.

Pakistan has moon on flag since 1947.

India copied from us, Reparations are due !!

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Re: Chandrayan-2 Mission

Postby Mort Walker » 22 Jul 2019 22:37

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.

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Re: Chandrayan-2 Mission

Postby Mort Walker » 22 Jul 2019 22:39

Can we please stop talking about the shithole countries and keep discussion on this mission? There is a lot which can go wrong still. Let’s get into trans lunar injection before the next stage of celebrations.

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Re: Chandrayan-2 Mission

Postby Mort Walker » 22 Jul 2019 22:42

Rishi_Tri wrote:Of course we shall go to Moon and it shall be fantastic scientific achievement but think the most critical aspect of this launch (IMHO) has been further proving of C25 Cryogenic engine. We don't have to go to Arianespace for launching heavy satellites. GSLV MKIII has been proven for 4T as Dr Sivan said. Even some folks from Arianespace had said years ago: GSLV MKII/III shall be the one to watch.

Now have only faint remembrance of reading newspaper reports saying Glavkosmos backed out of deal to do TOT for cryogenic engine. It put us back by decade if not more. Led to scientists being compromised, arrested (Prof. Nambi Narayanan and others) in an attempt to prevent progress. But guess what, it took 25 years and we are Independent and Truly Independent.

Sashtang Dandavat to those toiled day in day out and brought True Independence.

Know it is OT here but:

Gaganyaan - 2021/2022
Manned Space Station - 2030
Landing on Moon - 2030??
Station on Moon - 2035??
Landing on Mars - 2040??
Station on Mars - 2045??


There is Gaganyaan next followed by Shukrayaan 1 to Venus in 2023. After that Aditya L1 (sun to earth Lagrange point), Managalyaan-2 and Chandrayaan 3. This should all happen by 2030.

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Re: Chandrayan-2 Mission

Postby Varoon Shekhar » 22 Jul 2019 23:04

Aditya is scheduled to be launched next year, before Shukrayaan, I'm pretty sure :)

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Re: Chandrayan-2 Mission

Postby prasannasimha » 22 Jul 2019 23:06

sanjaykumar wrote:There is no such thing as 'over performed' in engineering. Either it is to design parameters or it is not.

The burn was "burn to depletion" allowing a higher apogee.

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Re: Chandrayan-2 Mission

Postby Amber G. » 22 Jul 2019 23:20

Mort Walker wrote:
The amount of time for orbit raising could probably be trimmed as well as the time spent in lunar orbit. Moon perigee becomes an issue, but I think they could have planned a landing by Republic Day 2019. However, when this launch is nearly 10% of your annual budget, you naturally become more cautious.

You have mentioned "perigee" a few times in this reference.. what exactly do you mean, and how this is an issue. I ask because from what I think, the perigee (of moon) is not (or hardly) an important consideration for timing... TIA.

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Re: Chandrayan-2 Mission

Postby Kakarat » 22 Jul 2019 23:38

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

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Re: Chandrayan-2 Mission

Postby A Nandy » 22 Jul 2019 23:54

But what will our space station be named? That's going no where except round and round and round! Chakrayaan!
Last edited by A Nandy on 22 Jul 2019 23:56, edited 1 time in total.

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Re: Chandrayan-2 Mission

Postby Mort Walker » 22 Jul 2019 23:56

Amber G. wrote:
Mort Walker wrote:
The amount of time for orbit raising could probably be trimmed as well as the time spent in lunar orbit. Moon perigee becomes an issue, but I think they could have planned a landing by Republic Day 2019. However, when this launch is nearly 10% of your annual budget, you naturally become more cautious.

You have mentioned "perigee" a few times in this reference.. what exactly do you mean, and how this is an issue. I ask because from what I think, the perigee (of moon) is not (or hardly) an important consideration for timing... TIA.


Being about 360,000KM vs. 405,000KM from earth. Timing and burning of fuel are the concern.

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Re: Chandrayan-2 Mission

Postby krishGo » 23 Jul 2019 00:02

prasannasimha wrote:
sanjaykumar wrote:There is no such thing as 'over performed' in engineering. Either it is to design parameters or it is not.

The burn was "burn to depletion" allowing a higher apogee.


The commentators did a great job explaining this during the launch. Usually the close loop monitoring system will cut off the engine when the required orbital parameters have been achieved. But in this case the cryogenic engine kept running till the propellant pressure got really low (close to empty but not quite). This allowed the upper stage to impart some extra delta-V into Chandryaan thereby saving some onboard propellant which could come in handy.

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Re: Chandrayan-2 Mission

Postby nachiket » 23 Jul 2019 00:03

Mort Walker wrote:Can we please stop talking about the shithole countries and keep discussion on this mission? There is a lot which can go wrong still. Let’s get into trans lunar injection before the next stage of celebrations.

Yes, this thread is for serious discussion about the Chandrayaan-2 and tracking its progress. No more talk about pakis etc. Frivolous or off-topic posts will be summarily deleted.

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Re: Chandrayan-2 Mission

Postby Mort Walker » 23 Jul 2019 00:47

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


Please let us know. Thanks!!!!

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Re: Chandrayan-2 Mission

Postby Amber G. » 23 Jul 2019 00:53

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


To add a few comments - It would be nice to have powerful rockets to give flexibility but to keep the things in perspective:

- The time needed for each phase of the voyage is virtually the same. IOW time from TLI to lunar orbit is virtually same. Newton could have calculated it. (In fact Jules Verne calculated that 100 years before and was able to predict that time for Apollo 11 quite accurately). Same thing for, for example, time of flight for Eagle and Vikram.

- What was important then ,and now, is to "wait" - after complex calculation for the "right time" (aka 'launch window'), so that all the objects are at right place with the right orbital velocities for rockets to work accurately so the required path follows.

- The calculations of these "launch windows" is quite complex and depending on other restrictions these windows are quite narrow. For Apollo 11, it took months to actually calculate these Launch windows -, now computers are faster and we are smarter with more precise data so we can do the calculations faster. We can (and did) launch even when the window was only a minute or so. (For Apollo 11 they needed a few hours - and if they missed it there were only few other choices in next 12 months - and it would take lot of time, just to calculate those windows).

- The position of landing site for Vikram - near south pole - poses a special challenge. If the landing site is near equator of Moon, the orbit manipulation of the orbiter is easier (with given energy consideration bigger time windows for Vikram launch). All Apollo landings, for this reason, were selected near the Moon's equatorial region. This is because Moon's equatorial plane is tilted only a degree or so from ecliptic. The Moon's orbit is about 5-6 degree tilted from the ecliptic. For Vikram to land near south pole, the orbiter has to get a polar orbit around moon - (inclination changes in orbit requires relatively larger energy and timing has to be perfect). The polar orbit has to be "just right" and one may have to wait for the right time for Vikram to start its journey to the Moon's surface.

So yes, the power of rocket is a factor (Saturn V had MUCH more power than GSLV Mk3) but MUCH bigger factor is computer and navigation accuracy - we can calculate much more complex orbits and find the right time to execute critical operation with extreme accuracy. The waiting time ( a few weeks or few days) is not that much a concern. We want safe landing and we wait for the right time.
***
For scientists it is a BIG and really incredible achievement that we can put a Vikram/Pragyan on the Moon with much smaller rockets by being extremely smart.

Hope this helps in understanding why some of us are extremely impressed by and proud of Indian Scientists.

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Re: Chandrayan-2 Mission

Postby Mort Walker » 23 Jul 2019 01:13

Thanks for the explanation Buzz AmberG Aldrin. ;)

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Re: Chandrayan-2 Mission

Postby nachiket » 23 Jul 2019 01:17

Thanks Amber G.

Even today's giants like the Falcon Heavy and Delta IV Heavy pale in comparison to the absolute monster that was the Saturn V. It was built for only one mission - taking the Apollo missions to the moon as fast as possible. Complete overkill for any other kind of mission like satellite launches and hence unusable for that purpose. I don't think even NASA can afford a program like that in this day and age. It makes far more sense to have a multipurpose SLV that can be used for launching spacecraft to the moon and beyond like the ISRO (and everyone else) has done.

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Re: Chandrayan-2 Mission

Postby Amber G. » 23 Jul 2019 01:24

Mort Walker wrote:
Amber G. wrote:You have mentioned "perigee" a few times in this reference.. what exactly do you mean, and how this is an issue. I ask because from what I think, the perigee (of moon) is not (or hardly) an important consideration for timing... TIA.


Being about 360,000KM vs. 405,000KM from earth. Timing and burning of fuel are the concern.


One would think so, but practically speaking, for fuel requirements or accuracy, this is not as important as one may think. For example MUCH more energy will be needed to change inclination of an orbit (to consider where nodes of Moon orbits are) than increasing the apogee of an orbit in TLI phase. ..

The "perigee" is important, but normally here one talks about orbit of the space craft around earth. because at this point the burn would be most efficient.

To be clear - Let me "cut/paste" a part from a link I may have posted earlier.

In order to accomplish this 'rendezvous' with a minimum expenditure of propellant, the injection (TLI) must occur very close to the extension of the earth-moon line at the time of the spacecrafts lunar arrival. This is termed the negative of the unit vector of the moons position (the position on the opposite side of the earth from the sub-lunar point), which is called the moons antipode. The optimum trajectory is very similar to a Hohmann transfer.

This minimum energy transfer trajectory would have placed the earth parking orbit perigee (this is perigee of parking orbit) at the moons antipode if the moons mass did not perturb the trans lunar trajectory. However the moon does perturb the spacecrafts trans lunar trajectory and therefore the earth parking orbit perigee must lead the moons antipode by approximately 8 degrees to compensate. The apogee altitude of the osculating conic trans lunar trajectory was determined by the trans lunar flight time which defined the trajectory energy requirements at trans lunar injection (TLI).

To inject the spacecraft to the moon in the most efficient manner, an impulsive velocity (acceleration) would be added along the orbital velocity vector (direction), giving an injection at the perigee of the trans lunar conic.


Anyway for those who are interested I can post some more links.

****

Hope this helps.

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Re: Chandrayan-2 Mission

Postby krishGo » 23 Jul 2019 01:32

nachiket wrote:Thanks Amber G.

Even today's giants like the Falcon Heavy and Delta IV Heavy pale in comparison to the absolute monster that was the Saturn V. It was built for only one mission - taking the Apollo missions to the moon as fast as possible. Complete overkill for any other kind of mission like satellite launches and hence unusable for that purpose. I don't think even NASA can afford a program like that in this day and age. It makes far more sense to have a multipurpose SLV that can be used for launching spacecraft to the moon and beyond like the ISRO (and everyone else) has done.


There are missions designed considering a specific launcher as baseline and then there are launchers designed for a specific mission. Like you said, Apollo program and the Saturn V are in the later category.

The only launch of Saturn V beyond the Apollo Program was for the launch of SkyLab space station. Since the space station was destined for low earth orbit they really did not need a 3rd stage of Saturn V. So they actually converted the 3rd stage into a mini space station. Even in its Low Earth Orbit Avatar, Saturn V put the 80 ton SklyLab into orbit.

Apollo was also the hayday of American space program when they spent almost 4-5% of their annual budget on their space program. I believe it is 0.5% currently.

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Re: Chandrayan-2 Mission

Postby Bibhas » 23 Jul 2019 02:58

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.

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Re: Chandrayan-2 Mission

Postby Sridhar » 23 Jul 2019 03:29

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.

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Re: Chandrayan-2 Mission

Postby Mort Walker » 23 Jul 2019 03:39

Then it should be relayed to other channels besides DD. They could do a better job.

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Re: Chandrayan-2 Mission

Postby SaiK » 23 Jul 2019 04:06

Sridhar wrote: close T-1min, they should just shut up and let the R/T feed play itself out ...Instead we have two people giving us often repeats of what we hear on the R/T track.

No.. they can do whatever they want in protected mode broadcast.. just don't go public with it. We can hire private cinematographers and broadcasters to jazz up for the world.

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Re: Chandrayan-2 Mission

Postby ldev » 23 Jul 2019 04:18

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.


The Saturn V launched it's entire 3rd stage including unburnt fuel into LEO. That 3rd stage then fired up for ~6 minutes to get the required delta v for the Apollo spacecraft of 3.10-3.25 km/sec to escape from LEO. For Chandraayan 2 to achieve that, GSLV Mk 3 will have to insert the cryo 3rd stage which has a dry mass of ~5000 kgs into orbit + the Chandraayan spacecraft (moon orbiter + lander) which itself weights just under 4000 kg into orbit plus the fuel required for that combined mass of ~9000 kgs to achieve the required delta v by re-starting the 3rd stage engine in LEO. That means that the lower stages of GSLV Mk 3 need a capacity to loft about 20 tons to LEO. 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.


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