Author Topic: Chandrayaan-2 Mission - Launch and Landing Coverage  (Read 673920 times)

Offline Phil Stooke

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Re: Chandrayaan-2 GSLV-MkII NET April 2018
« Reply #280 on: 02/26/2018 05:08 am »
You're right, of course, that the Moon's always there and we could launch towards it in any month.  But once the trajectory is defined - trans-lunar coast, lunar orbit injection, lunar orbit all in a specific geometry leading to periapsis over the landing site, the question is: when does that periapsis, when landing would occur, coincide with sunrise at the landing site?  To get the longest possible rover mission the landing needs to be shortly after sunrise, since it may die after sunset.  The trajectory can be flown any month but the combination of trajectory and illumination is more restrictive and repeats at 6 month intervals.  They could go in another month if they accept a different landing site, and they do have one alternative site.  This limitation is much less severe near the equator, so it applied far less to Surveyor and the early Apollo landings.

Offline Steven Pietrobon

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Re: Chandrayaan-2 GSLV-MkII NET April 2018
« Reply #281 on: 02/27/2018 07:32 am »
The trajectory can be flown any month but the combination of trajectory and illumination is more restrictive and repeats at 6 month intervals.

That's right, but the Moon has the same illumination every month. However, the inclination of the launch site will change relative to the Moon and if you are performance limited, that restricts you to launch at the optimum month.

Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline vineethgk

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Re: Chandrayaan-2 GSLV-MkII NET April 2018
« Reply #282 on: 03/02/2018 11:24 pm »
Chandrayaan-II likely delayed to October

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India’s second mission to the moon, Chandrayaan-2, is likely to be launched only in October. Further delays cannot be ruled out if systems are not yet in place by then.
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An Isro official told TOIseveral tests have to be done and arrangements need to be made.
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The original plan envisaged the launch between April and November with the real target focussed for April. Top Isro officials had expressed confidence that the takeoff will happen in April.
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But on Friday, it was stated the lunar mission was not yet ready for an April lift-off and much still needs to be done.

Source

Offline worldtimedate

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Re: Chandrayaan-2 GSLV-MkII NET April 2018
« Reply #283 on: 03/03/2018 05:16 am »
Chandrayaan-II likely delayed to October

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India’s second mission to the moon, Chandrayaan-2, is likely to be launched only in October. Further delays cannot be ruled out if systems are not yet in place by then.
Quote
An Isro official told TOIseveral tests have to be done and arrangements need to be made.
Quote
The original plan envisaged the launch between April and November with the real target focussed for April. Top Isro officials had expressed confidence that the takeoff will happen in April.
Quote
But on Friday, it was stated the lunar mission was not yet ready for an April lift-off and much still needs to be done.

Source

I expected the delay and waited without making comments so that I might prove wrong. But my assumption has come true. Who knows whether the lift-off can take place in October, because of one thing. ISRO's preoccupation with PSLV launch every month has put paid to the development of more powerful launch vehicles. ISRO seems to be content with the launch of PSLV only. GSLV MK-II needs to be uprated to launch at least 2.5 Ton payload to GTO. At least two GSLV MK-II launches need to take place before the launch of Chandrayaan-II. The performance of the uprated Cryogenic Engine which is supposed to generate 90 kN thrust needs to be verified with the launch of at least two GSLV MK-II. Then what to speak of the testing of the rover and landers. Frankly speaking, since former ISRO Chairman G. Madhavan Nair retired, Chandrayaan-II Mission faltered with his immediate successor busy in doing pilgrimage when ISRO was seriously working on the launch of GSLV MK-II with the indigeneous cryogenic engine. Then what happened is known to all of us. Two successive GSL MK-II launches failed, resulting in the GSLV MK-II getting the sobriquet of naughty boy. It was not until the former ISRO chairman A. S. Kiran Kumar that both GSLV MK-II and GSLV MK-III wer back into contention.

Can anyone tell me if the uprated cryogenic engine of GSLV MK-II is re-startable ? Any cryogenic engine propelled upper stage that is NOT RE-STARTABLE is simply of no vital use. This may sound harsh to many of us, but that is the reality. GSLV MK-II's cryogenic engine will not be able to do TLI maneuver. Can it do this ? Chandrayan-II has to reach the moon through the spacecraft's gradual orbit raising, thus taking it almost two months to get to the moon. ISRO seems to have its task cut out.

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Offline srikanthr124

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« Last Edit: 03/13/2018 06:53 am by srikanthr124 »

Offline vineethgk

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Re: Chandrayaan-2 GSLV-MkII NET April 2018
« Reply #285 on: 03/23/2018 01:26 pm »
Finally, official confirmation from ISRO that Chandrayaan-II has been delayed to October (though that was long expected)..

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The launch of India's second lunar mission 'Chandrayaan-2', slated for next month, has been postponed to October as the experts have suggested some tests, the ISRO said today.

Source

Offline vineethgk

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Re: Chandrayaan-2 GSLV October 2018
« Reply #286 on: 03/25/2018 02:14 am »
New targeted date for Chandrayaan-II launch is in the first week of October - ISRO Chairman
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Dr Sivan said, “The original targeted date for the launch was kept on April 23. However, as the ongoing tests for the lunar mission will take 20 more days, the April 23rd date could not be met. Therefore the panel decided to defer the launch. Unlike, other satellite launches where Isro could easily defer the launch by a day or two to get a perfect mission, Isro can’t do the same in this mission. This is because the ideal date for the moon launch comes only once in a month. If we skip that date of the month, we have to plan the launch next month. After April, if Isro launches the mission from May to September, we won’t be able to utilise the full lunar day (14 Earth days) for experiments on the moon because of eclipses. Therefore, Isro will launch the mission in the first week of October.”

Offline Steven Pietrobon

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Re: Chandrayaan-2 GSLV October 2018
« Reply #287 on: 03/25/2018 04:20 am »
The article also mentions that they could launch every month, but the six month delay is caused by "eclipses" so as to get the required landing light condition. Not sure if the eclipses refer to that in LEO or in LLO.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline vineethgk

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Re: Chandrayaan-2 GSLV October 2018
« Reply #288 on: 03/27/2018 11:58 pm »
Planned vehicle upgrades for GSLV for the Chandrayaan-II mission

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“All these new things are being done keeping lunar mission in the mind and ISRO’s bigger game plan to increase GSLV payload capability. For Chandrayaan-2, we are formulating a perfect combination. The four strap-ons and second stage will be boosted with high-thrust Vikas engines; cryogenic upper stage will be loaded with enhanced propellants of 15 tonnes instead of current 12.8 tonnes and will be operated with 9.5 tonne thrust compared to the present 7.5.”

Source

Offline chota

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Re: Chandrayaan-2 GSLV October 2018
« Reply #289 on: 07/05/2018 06:06 pm »
Some old tests conduction earlier as part of lander experiments
https://www.youtube.com/watch?v=r6SrZ_pYHpM&feature=youtu.be&start=14&end=20
« Last Edit: 07/05/2018 06:06 pm by chota »

Offline Steven Pietrobon

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Re: Chandrayaan-2 GSLV October 2018
« Reply #290 on: 07/06/2018 04:06 am »
Man, I can't stand those YouTube videos with robot voices. This is where the news came from for that video.

https://www.indiatimes.com/news/india/ahead-of-launch-chandrayaan-2-to-undergo-bungee-jump-like-simulation-test-in-mahendragiri-337615.html
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline chota

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Re: Chandrayaan-2 GSLV October 2018
« Reply #291 on: 07/16/2018 04:14 pm »

Offline TheVarun

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Re: Chandrayaan-2 GSLV October 2018
« Reply #292 on: 07/16/2018 04:25 pm »

^
 That can't be right, at least it shouldn't be!  ISRO has repeatedly stated that October would be an ideal month to launch Chandrayaan-2, because of the earth-moon distance at the time.   Must be a major oversight by NDTV-one is hoping anyway!

Offline worldtimedate

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Re: Chandrayaan-2 GSLV October 2018
« Reply #293 on: 07/17/2018 11:23 pm »

^
 That can't be right, at least it shouldn't be!  ISRO has repeatedly stated that October would be an ideal month to launch Chandrayaan-2, because of the earth-moon distance at the time.   Must be a major oversight by NDTV-one is hoping anyway!

According to this this Economic Times report also, the launch of Chandrayaan - 2 is not on cards this year. This makes me believe that Chandrayaan - 2 will NOT be launched until the launch of GSAT-7A by GSLV-II. I think, ISRO does NOT want to take risk without testing the capability of high thrust Vikas engine.

Offline TheVarun

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Re: Chandrayaan-2 GSLV October 2018
« Reply #294 on: 07/18/2018 01:55 pm »
[

According to this this Economic Times report also, the launch of Chandrayaan - 2 is not on cards this year. This makes me believe that Chandrayaan - 2 will NOT be launched until the launch of GSAT-7A by GSLV-II. I think, ISRO does NOT want to take risk without testing the capability of high thrust Vikas engine.

  Makes sense!  Any idea what would be the next most optimised launch date for a moon mission? One hopes its not Oct 2019!  True though, that caution is a sound policy. The Economic Times article does not emphatically say that "there will be no Chandrayaan mission in October". Perhaps what is happening is that they are conducting rigorous tests of a bunch of things, and if all those turn out well, they will launch Chandrayaan. But they don't want to build up hopes, considering the very high profile nature of the venture.

Being optimistic :)

Offline abhishek

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Re: Chandrayaan-2 GSLV NET end 2018
« Reply #295 on: 08/04/2018 12:47 pm »
Chandrayaan 2 Delayed, Israel Could Beat India In Race To Moon's Surface

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Dr M Annadurai, Director of U R Rao Satellite Centre confirmed to NDTV  that the launch date for Chandryaan-2 "is slipping to 2019" from the initially planned launch in October this year.

Dr Annadurai said that India's moon mission now aims to land in February and the rocket launch will take place in January next year.

Moreover, since the weight of the Chandrayaan-2 satellite has increased, Dr Annadurai said that now instead of GSLV MK-II, GSLV MK-III will be used

https://www.ndtv.com/india-news/chandrayaan-2-delayed-israel-could-beat-india-in-race-to-moons-surface-1895221
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Dont want to indulge in a political debate but i find news articles of Mr Bagla to be quite irritating in nature as it's more on nationalism and jingoism rather than on science....3rd country to do this,4th country to do that,gslv the bahubali rocket etc etc....

« Last Edit: 08/04/2018 01:06 pm by abhishek »
10, 9, ignition sequence start 6, 5, 4, 3, 2, 1, 0, all engines running Lift off, we have a lift off, lift off

Offline TheVarun

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Re: Chandrayaan-2 GSLV MkIII NET January 2019
« Reply #296 on: 08/04/2018 01:55 pm »
 ^
Agree. There's a little too much of that nationalism and jingoism in Bagla's reports- and he's supposed to be a science writer!  It's okay to mention it, but it shouldn't be the centrepiece or the dominant theme. I don't like Frontline magazine( way too left politically!) but they have excellent science and technology articles by T.S Subramanian and R. Ramachandran, particularly in the area of aerospace. The first, second, 5th, 6th et al are certainly brought up, as they should be, but the accent is on the actual science and technology, and the challenges therein.

Offline TheVarun

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Re: Chandrayaan-2 GSLV NET end 2018
« Reply #297 on: 08/04/2018 02:02 pm »
Chandrayaan 2 Delayed, Israel Could Beat India In Race To Moon's Surface

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Dr M Annadurai, Director of U R Rao Satellite Centre confirmed to NDTV  that the launch date for Chandryaan-2 "is slipping to 2019" from the initially planned launch in October this year.

Dr Annadurai said that India's moon mission now aims to land in February and the rocket launch will take place in January next year.

   
   A little disappointing, of course, but January 2019 isn't bad. For something as complex as a moon mission, better not to take chances.  But the news of GSLV Mark 3 being used for the launch, is startling. That was never spoken of before by ISRO, now it's pretty concrete!  All this time, only GSLV Mark 2 was spoken of.

Online sanman

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Re: Chandrayaan-2 GSLV MkIII NET January 2019
« Reply #298 on: 08/05/2018 12:23 am »
Dont want to indulge in a political debate but i find news articles of Mr Bagla to be quite irritating in nature as it's more on nationalism and jingoism rather than on science....3rd country to do this,4th country to do that,gslv the bahubali rocket etc etc....

^
Agree. There's a little too much of that nationalism and jingoism in Bagla's reports- and he's supposed to be a science writer!  It's okay to mention it, but it shouldn't be the centrepiece or the dominant theme. I don't like Frontline magazine( way too left politically!) but they have excellent science and technology articles by T.S Subramanian and R. Ramachandran, particularly in the area of aerospace. The first, second, 5th, 6th et al are certainly brought up, as they should be, but the accent is on the actual science and technology, and the challenges therein.

I don't feel that it's fair to single out Mr Bagla for that - to be fair, all members of the Indian media do that - he's a passionate science communicator. It's also about drumming up enthusiasm among the public for India's space program.


Online sanman

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Re: Chandrayaan-2 GSLV NET end 2018
« Reply #299 on: 08/05/2018 12:27 am »
Chandrayaan 2 Delayed, Israel Could Beat India In Race To Moon's Surface

Quote
Dr M Annadurai, Director of U R Rao Satellite Centre confirmed to NDTV  that the launch date for Chandryaan-2 "is slipping to 2019" from the initially planned launch in October this year.

Dr Annadurai said that India's moon mission now aims to land in February and the rocket launch will take place in January next year.
   
   A little disappointing, of course, but January 2019 isn't bad. For something as complex as a moon mission, better not to take chances.  But the news of GSLV Mark 3 being used for the launch, is startling. That was never spoken of before by ISRO, now it's pretty concrete!  All this time, only GSLV Mark 2 was spoken of.

With GSLV-Mk3 being used, it would have been nice if its higher payload margin could have allowed the use of a heavier and more robust rover & lander. The current lunar rover is looking a little minimalist and barebones - Oh well, can't revise things now.
« Last Edit: 08/05/2018 12:29 am by sanman »

 

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