Author Topic: Chandrayaan-2 GSLV MkIII NET January 30 2019  (Read 165421 times)

Offline baldusi

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #140 on: 10/18/2014 01:01 PM »
Ok, the source appears to be a diplomatic cable that's on WikiLeaks. And its from 2008. At that time NASA was trying to get ASRG qualified. Or at least the division in charge of development. The divisions actually selecting missions kept selecting the ones that didn't use Pu238. Among other issues, restart of Pu238 production was still a distant hope.

Offline sanman

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #141 on: 10/18/2014 03:50 PM »
I'm curious  -- when these radiothermal generators are used on rovers, are they merely meant to keep delicate electronics from freezing and breaking at night?

If so, then it seems like an awful lot of complexity would be removed by inventing electronics that can withstand extreme temperature swings.


However, a Stirling engine component sounds like its meant to generate electrical power, if not locomotive.


Offline Steven Pietrobon

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #142 on: 10/22/2014 09:23 AM »
There are military grade electronics parts that work at -55 C, but Lunar night can go down to -150 C. I'm not sure of parts that can work that low. There are also reliability aspects as high temperature swings cause thermal contraction and expansion, which can break wires, parts and boards. RTGs can provide both heat and electrical power for the rover.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline baldusi

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #143 on: 10/22/2014 10:43 AM »
To expand on what Steven said. Lunar night goes to -150C, while day might go to 400C. That's a 550C variance. That's quite a problem mechanically. Even the solders have to be special. And when you have features measured in nanometers, any differential in thermal expansion can disrupt an electronic contact. NVidia had a notebook chipset that simply broke due to this problem a few years back. The root cause was a selection of a pin bonding method that was too sensitive to thermal swings. And those are usually 10C to 75C parts.
Btw, a new chip factory is around 5B. But I believe that bonding (i.e putting the actual chip in the square support and connecting it to the pins) is done separately. Thus, developing such a chip would be mighty expensive. It is actually cheaper to put a cooling system and an RHU.
Incidentally, electronics that worked at around 800K would enable Venus surface missions for very cheap.

Offline abhishek

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #144 on: 10/29/2014 05:47 PM »
BREAKING NEWS  ;D

GSLV MK3 instead of MK2 will be used for chandrayaan 2 mission

http://ibnlive.in.com/news/india-plans-second-mars-mission-in-2018/509390-11.html
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 vineethgk

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #145 on: 10/30/2014 01:03 PM »
BREAKING NEWS  ;D

GSLV MK3 instead of MK2 will be used for chandrayaan 2 mission

http://ibnlive.in.com/news/india-plans-second-mars-mission-in-2018/509390-11.html

Seems to me more like a case of misreporting here and there.
Quote
"We will be able to take the Mars-2 mission after launching the second mission to the moon (Chandrayaan-2) in 2016 with our own lander and rover, which will help us develop a separate lander and rover for the red planet," Kumar said
Quote
The space agency has developed the geo-synchronous satellite launch vehicle (GSLV-Mark I-III) with indigenous cryogenic engine to launch heavier satellites weighing more than two tonnes and three tonnes into the geo-orbit at 36,000 km above Earth.
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"GSLV-Mark I-III will be used for Chandrayaan-2, which will have heavier payload than its predecessor (Chandrayaan-1) and later for Mars-2 mission, as both will have a lander and rover in addition to scientific experiments," he said.

What does he mean by GSLV-Mark I-III? Either the reporter was referring to both GSLV-II & GSLV-III in general, or he was confused between the two. If ISRO plans to launch Mangalyaan-2 with lander/rover after Chandrayaan-2, they will have to stick with a 2017 launch schedule for the latter. It is highly unlikely GSLV-III will be ready for operational flights by then.

I would put my bets on ISRO sticking to GSLV-II as the launcher.  ;)



Offline ss1_3

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #146 on: 10/30/2014 06:24 PM »
Going by the timelines for operationalization, Mk-III launch can be ruled out.

Quote
The first development flight (GSLV Mk-III D1) with an operational cryogenic stage is planned between 2016 to 2017. The second development flight (GSLV Mk-III D2) is planned after one year of GSLV Mk-III D1 flight in 2017 to 2018.

http://www.dnaindia.com/scitech/report-gslv-mk-iii-expected-to-be-launched-in-first-half-of-december-2030711

Offline sanman

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #147 on: 10/31/2014 12:58 AM »
Note that good payloads have been launched on developmental flights for GSLV-Mk2. Some have been successful, some have been lost, but there were no dummy payloads. The same may be possible for GSLV-Mk3.


Offline vineethgk

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #148 on: 10/31/2014 10:26 AM »
I feel Chandrayaan-II would be too prestigious a payload to risk in a development flight. If the launch were to fail, it will be a PR disaster for ISRO and the agency would be bashed left and right for using an untested launcher. The case of Mangalyaan-II might be a bit different though, as GSLV-II may not be able to launch a good orbiter, lander and rover to Mars on a single flight.

Offline sanman

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #149 on: 11/11/2014 11:45 PM »
After Mars, ISRO chief Radhakrishnan aims for the moon


http://economictimes.indiatimes.com/tech/after-mars-isro-chief-radhakrishnan-aims-for-the-moon/articleshow/45112373.cms

Quote
Buoyed by the success, Indian Space Research Organisation (ISRO) chairman K.S Radhakrishnan said the agency was forging ahead with plans to land an unnamed craft on the moon, along with a satellite to study the sun.

"The aim is three years from now, an Indian lander and Indian rover will land on the moon," he told AFP.

Offline antriksh

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #150 on: 11/19/2014 03:03 AM »
Landing Stages

Nasadiya Sukta:
Srishti se pehle sat nahin thaa, asat bhi nahin | Antariksh bhi nahin, aakaash bhi nahin thaa | chhipaa thaa kyaa, kahaan, kisne dhakaa thaa | us pal to agam, atal jal bhi kahaan thaa ||

From: 1st verse of 129th Hymn of the 10th Book of Rig Veda

Offline sanman

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #151 on: 11/24/2014 10:17 PM »
Preparations for the unmanned crew module are on track for a December launch:

http://www.thehindu.com/sci-tech/science/all-set-to-put-unmanned-crew-module-into-orbit/article6631187.ece

Offline vineethgk

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #152 on: 11/25/2014 04:35 AM »
Preparations for the unmanned crew module are on track for a December launch:

http://www.thehindu.com/sci-tech/science/all-set-to-put-unmanned-crew-module-into-orbit/article6631187.ece

@sanman, just wondering.. does this news item have relevance in the Chandrayaan-II thread? Maybe you meant to post in a different thread?  ;)

Offline sanman

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #153 on: 11/27/2014 07:37 PM »
Yeah, sorry, meant to post it in the GSLV-Mk3 thread -- but Antriksh has done that anyway

Offline JH

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #154 on: 11/28/2014 05:10 AM »
Can anyone comment on why they aren't pushing the mission back a year rather than flying on the GSLV Mk II? I had thought that MOM was crammed onto a PSLV because the GSLV Mk III wasn't ready yet and planetary missions are considered too important to entrust to the (as I understand it) unreliable GSLV Mk II. Surely the same logic would preclude launching Chandrayaan 2 on a GSLV Mk II.

Offline abhishek

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #155 on: 11/28/2014 09:15 AM »
Can anyone comment on why they aren't pushing the mission back a year rather than flying on the GSLV Mk II? I had thought that MOM was crammed onto a PSLV because the GSLV Mk III wasn't ready yet and planetary missions are considered too important to entrust to the (as I understand it) unreliable GSLV Mk II. Surely the same logic would preclude launching Chandrayaan 2 on a GSLV Mk II.

The Chandrayaan 2 cannot fly on GSLV MK 3 because GSLV 3 would still be in developmental stage and a mission like Chandrayaan2 is just too critical to be sent on a rocket thats still on developmental flight.

Where as GSLV 2 needs just one more developmental flight to get commissioned into regular service.
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 JH

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #156 on: 11/29/2014 03:04 AM »
I understand that the GSLV Mk III is under development. I was asking why the mission isn't delayed until the Mk III is finished with development. The GSLV Mk II is just a Mk I with an indigenous CE-7.5 cryogenic engine rather than a Russian KVD-1 cryogenic engine for the third stage. The GSLV Mk I has a bad launch record, therefore most of the components of the Mk II have a bad launch record. Why is an important mission being placed on a launcher with questionable heritage? Is it that they believe all of the issues with the Mk II have been resolved?

Offline abhishek

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #157 on: 11/29/2014 04:04 AM »
I understand that the GSLV Mk III is under development. I was asking why the mission isn't delayed until the Mk III is finished with development. The GSLV Mk II is just a Mk I with an indigenous CE-7.5 cryogenic engine rather than a Russian KVD-1 cryogenic engine for the third stage. The GSLV Mk I has a bad launch record, therefore most of the components of the Mk II have a bad launch record. Why is an important mission being placed on a launcher with questionable heritage? Is it that they believe all of the issues with the Mk II have been resolved?

The project has already been delayed by 3 years,any further delay would adversely affect other critical programs.

The project is already gone beyond design board and is under fabrication stage.So for sending it on GSLV 3 would require redesigning and incur additional cost and time.

The issue with GSLV  largely lies with it's Upper stage which seems to have been resolved.We need just one more successful launch to press it into regular service.
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 savuporo

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #158 on: 11/29/2014 04:50 AM »
Landing Stages

That pic seems to indicate as the lander is now planned have autonomous hazard avoidance and final landing site selection ( retargeting ) , just like Change-3 did ? Earlier graphics did not seem to indicate that.

BTW, relatively comprehensive tracking page on all C-2 developments:
http://isp.justthe80.com/moon-exploration/chandrayaan---2
« Last Edit: 11/29/2014 04:54 AM by savuporo »
Orion - the first and only manned not-too-deep-space craft

Offline JH

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Re: GSLV-MkII, Chandrayaan-2, NET 2018-Q1
« Reply #159 on: 11/29/2014 06:26 AM »
Gotcha. Thanks!