Chandrayan-2 Mission

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Mort Walker
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Re: Chandrayan-2 Mission

Post by Mort Walker »

CRamS wrote:Call me a conspiracy buff, but I can bet you, CIA and Chinncoms have all put their best assets on monitoring Chandrayan-2 Mission. And of course, no dearth of 5th columnist in India for hire (green cards and $s). With the rise of BJP/ModiJi, there is so much hatred against India and there are those within and outside happy and more sinister, collude to see India fail. I mean even in kirket, judging by tweets, starting with Kashmiri Muslim traitors, there was jubilation when India lost to NZ.
Go away! We're trying to discuss the technical merits of the launch. If you want to talk about conspiracy theories and kricket, go somewhere else.
Kakarat
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Re: Chandrayan-2 Mission

Post by Kakarat »

Katare wrote:
krishGo wrote:
There have been several launches by ISRO in the night. I believe one of the recent PSLV launches was in the night.
If you could post a source, it would be very helpful
Go and check the ISRO website, I my self have attended one night and one early morning launch in the last 1 year
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Re: Chandrayan-2 Mission

Post by Kakarat »

Singha wrote:one of pslv launches was during a heavy rain. these things can work fine in rain.
Rain was not an issue yesterday as the sky was clear and also there was no threat of lightning also
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Re: Chandrayan-2 Mission

Post by Pratyush »

Thank god for launch scrub. Or if it had been a failure. The DDM and the amateur rocket scientists I. India would be calling for the lynching of ISRO guys.

So good for ISRO to have detected this issue. They will fix it and launch when the window presents itself.
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Re: Chandrayan-2 Mission

Post by ramana »

CRS called it Conspiracy right?
We had enough censorship in last 5 years.
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Re: Chandrayan-2 Mission

Post by Indranil »

CRamS wrote:Call me a conspiracy buff, but I can bet you, CIA and Chinncoms have all put their best assets on monitoring Chandrayan-2 Mission. And of course, no dearth of 5th columnist in India for hire (green cards and $s). With the rise of BJP/ModiJi, there is so much hatred against India and there are those within and outside happy and more sinister, collude to see India fail. I mean even in kirket, judging by tweets, starting with Kashmiri Muslim traitors, there was jubilation when India lost to NZ.
It looks like you feel let down by this postponement. The whole purpose of a countdown is to do elaborate prelaunch tests and quit if a critical test fails. A launch abort is actually a success of a countdown. So, there is no need to go look for a conspiracy/sabotage story!
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Re: Chandrayan-2 Mission

Post by Gautam_2 »

don't quote me for it but I heard from a source at ISRO that there was fuel leak in the rocket. Good thing it was detected otherwise who knows, it could have ended in a ball of fire.

also - first post :D
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Re: Chandrayan-2 Mission

Post by SSSalvi »

^^^
AS far as launches are concerned ISRO has mastered the Launch process ( evolved through SLV,PSLV, GSLV and so on) and the softwares have been foolproof in detecting glitches and reporting those during countdown period.
Anyway there is no human involvement in the process so there can't be any 'to be or not to be' situation. System will follow blindly the protocol without human sentiments.
So there is nothing special if it raised the red flag to abort launch.
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Re: Chandrayan-2 Mission

Post by prasannasimha »

Please stick to discussion. The very nature of a countdown is for actual system checks and has happned in many space launches. In the last year itself multiple launches of various countries had to be scrubbed.
The probable cause here is the helium or main tank pressurization issue as per reports. Involved tank will have to have leak check etc which will take time.
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Re: Chandrayan-2 Mission

Post by thammu »

Second Chandrayaan 2 Launch Attempt Likely This Month: https://www.ndtv.com/india-news/second- ... ome-livetv
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Re: Chandrayan-2 Mission

Post by SSSalvi »

^^^
Care! Better rely only on ISRO updates ... otherwise conclusions drawn from half sentences create chaos.

No such update from ISRO.

One news source gives it more clearly

“We will have to dismantle the rocket to get to the root of the problem… we have window till month end to launch the mission,” the source added.

There were four suitable window periods for the launch in the month of July – July 15 and 16 and then again during new moon on July 29 and 30.
Last edited by SSSalvi on 15 Jul 2019 15:51, edited 1 time in total.
ArjunPandit
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Re: Chandrayan-2 Mission

Post by ArjunPandit »

to all respected posters, may i request the CTs not to be posted on this threat. While we dont want to be ostrich, dont fan fire. The good thing is our controls are robust to detect this thing. WIth the kind of budgets ISRO has got, it's better to be late than fail. Pessimism carreerists would have had a field day shouting, not to forget the Independent and dailymail. I am sure you all wish our ISRO guys the best.
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Re: Chandrayan-2 Mission

Post by Gagan »

So they can tell if adequate pressure is not being maintained in the tanks during fueling
The tanks and piping are checked during assembly for leaks

So this process will involve
1. Defueling
2. Some outward physical investigation
Unfortunately, also
3. Returning the launch vehicle back to the assembly bay, which might be happening today
4. Removing the payload section
5. Removing the cryo engine

They might replace the entire cryo section if this is where the fuel leak was - unless it was L110 itself. Then they probably will need a whole new launcher !
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Re: Chandrayan-2 Mission

Post by UlanBatori »

Can't be anything that bad, I hope. Items 1-3 seem reasonable precautions IFF the "dismantle the rocket" part is true (leak in cryogenic system).
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Re: Chandrayan-2 Mission

Post by Katare »

I guess there really is no need to rush it i.e. no commercial/security interests involved. Besides holding up a launchpad i see no reason why they should take any risk.
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Re: Chandrayan-2 Mission

Post by Amber G. »

Kakarat wrote:
Katare wrote: If you could post a source, it would be very helpful
Go and check the ISRO website, I my self have attended one night and one early morning launch in the last 1 year
IIRC .. Chandrayaan I launch was around mid-night.
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Re: Chandrayan-2 Mission

Post by Mort Walker »

From Telugu press:

https://www.sakshi.com/news/andhra-prad ... stopped...
The third stage, the most important stage in the rocket, seems to be a technical flaw as the batteries for the cryogenic engine are not charged. The addition of cryogenic gas bottle leakage has also been identified as another technical flaw. ISRO officials have announced that the launch has been postponed. This type of technical error has never been filed in the past. This is why ISRO scientists are criticizing the cause of this error. It is believed that the Chandrayaan-2 experiment is likely to be conducted on September 9.
https://www.ap7am.com/flash-news-656452-telugu.html
ISRO has also announced that it will refuel with liquid hydrogen an hour before the launch. And in the final minutes, ISRO decided to postpone the experiment, since the computer was showing that there was some vacuum, refueling in the tank, and that the batteries were not fully charged at the same time.
From Malayalam press:

https://www.deshabhimani.com/news/natio ... ned/810923
The unexpected change was caused by the fuel leak in the launch vehicle GSLV Mark-3. Preliminary information said the leak occurred in the most complex part. The malfunction occurred about half an hour after the liquid hydrogen was filled. Following the discovery of the leak, the mission director proposed postponing the launch.
From Hindustan Times:

https://www.hindustantimes.com/india-ne ... es-say-...
“The rocket functioning was not according to laid down parameters... we are extremely lucky to detect the anomaly just before the launch, we are in control, the rocket and satellite are safe,” the source added, hours after the moon mission was called off.
A committee of experts will now examine what went wrong and suggest ways to remove the glitches, it will take about a week to determine what exactly went wrong, the source added.

“We will have to dismantle the rocket to get to the root of the problem… we have window till month end to launch the mission,” the source added.

There were four suitable window periods for the launch in the month of July – July 15 and 16 and then again during new moon on July 29 and 30.
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Re: Chandrayan-2 Mission

Post by Mort Walker »

So it was the C25 cryogenic engine. If a launch would have happened, a failure at 172 Km altitude would occur when the 3rd stage ignited. Roughly 3 minutes after launch.
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Re: Chandrayan-2 Mission

Post by Singha »

probably in 2 months they will launch. no rush, the moon is mostly always there and close by. this is not a comet we are trying to catch.

only issue is the huge VAB needs to be cleared for next GSLV missions , so they will surely not waste time and keep it parked for too long once things are fixed.
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Re: Chandrayan-2 Mission

Post by Mort Walker »

Singha wrote:probably in 6 months they will launch. no rush, the moon is mostly always there and close by. this is not a comet we are trying to catch.
Over delay will cause other launches to slip. Fiscal year funding becomes a constraint too.
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Re: Chandrayan-2 Mission

Post by Singha »

i amended my prediction to 2 months for that reason. it will take about 10 days to move the beast , take things apart and even look deeply into it.
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Re: Chandrayan-2 Mission

Post by chetak »

the opposition to India's space program continues even today, driven by commercial jealousy and fear of loss of business.

The prospect of India sitting at the high table for formulating rules for the exploitation of space resources and conduct of stellar explorations is unnerving many whites and also the hans.

India may yet be able to pay them back for her thus far and malicious exclusion from the NSG and the SC.

Nambi Narayanan: A victim of India’s greatest politico-bureaucratic nexus, costing us huge accomplishments

Nambi Narayanan: A victim of India’s greatest politico-bureaucratic nexus, costing us huge accomplishments

The Union government led by Narendra Modi has finally awarded prestigious Padma Bhushan to Nambi Narayanan on the occasion of 70th Republic Day in 2019. Nonetheless, questions still remain on the need for accountability and justice for decades-long physical and mental agony suffered by Narayanan.

SHASHANK BHARADWAJ
JANUARY 27, 2019



Declining a prestigious job in the United States, a 28-year old prodigy graduating from one of the Ivy Leagues, Princeton, chooses to return back to the motherland at a time when her future prospects looked bleak. Two decades later, the young man had not only pioneered the science of building India’s most celebrated space vehicles PSLV and GSLV but also raised to be the country’s topmost cryogenic scientist.

This is the story of one of India’s greatest space scientists, Nambi Narayanan. An exemplary achiever, instrumental in India’s space accomplishments but only to be falsely implicated by a political-bureaucratic nexus in a bid to not only prevent country’s technological progress but also to use it to further an evil political outcome.

Nambi Narayanan perhaps had never thought that the factionalism between two groups of the Kerala Congress would end his distinguished career of being a premier space scientist. It all started with factionalism within the Kerala unit of the Congress when two sides tried to out-manoeuvre each other despite knowing the fact they were putting longtime security interest of the country at a huge risk. A quintessential Congress mindset?

In the late ’70s, Kerala Congress was amidst huge chaos as there was an open revolt against the then Chief Minister K Karunakaran. The Kerala Congress was divided into two groups, the first being Karunakaran group and another faction led by the then blue-eyed boy of the Congress, 37-year-old AK Anthony. Antony finally replaced Karunakaran as the Chief Minister of the state in 1977 for a brief period of time. Later, Karunakaran came back to power in 1991, which had caused severe heartburn for AK Antony faction, who eventually tried undermining Karunakaran at every opportunity presented.

How did Scientist Nambi Narayanan got caught in all this?
It is an interesting question. After completing his masters at Princeton in a record 10-months time, Nambi Narayanan returned back to India in 1969 to work on a new project at ISRO under the guidance of the Vikram Sarabhai. Narayanan, a chemical rocket propulsion expert soon began to work on liquid propulsion engines at a time when ISRO was solely dependent on solid propellants. The liquid propellant engines designed by the team led by Narayanan later came to be known as “VIKAS Engines”.

If you are wondering regarding the difference between the two, let me help you here. In liquid propellant rockets, fuel flow to the engine can be controlled, the amount of thrust produced can be regulated and the engine can be turned off or on as needed. In solid propellant engines, the ignition of the fuel cannot be regulated or turned off, which makes the system simpler, safer, and cheaper but less efficient than that of a liquid-fuel rocket.

Narayanan envisioned the need for liquid fuelled engines for ISRO’s future civilian space programmes while another team headed by APJ Abdul Kalam was working on mastering the science of building solid propellants motors. Decades later, India envisioned a cryogenic engine project at ISRO and signed an agreement with Russia for transfer of technology to develop cryogenic fuel-based engines. However, the deal did not materialise as the United States put pressure on the Russians not to transfer such critical technologies to India.

Nevertheless, India signed a new agreement with Russia to design four cryogenic engines and ISRO chose its finest man, Nambi Narayanan to head the indigenous cryogenic programme. At a time when everything was going at an ease, a fabricated spy scandal surfaced in late 1994 which shut the doors for one of India’s greatest rocket scientists, Nambi Narayanan.

Earlier in 1991, a coalition government headed by Congress leader PV Narasimha Rao was ruling the Centre, while K Karunakaran was the Chief Minister of Kerala. AK Antony along with the future Chief Minister of the state, Oommen Chandy was waiting for an opportunity to undermine the K Karunakaran government. However, they got an opportunity when Mariam Rashida was arrested in October 1994, on the charges of overstaying her visa. Reportedly, S Vijayan, a Kerala Police Inspector had arrested Rashida on false espionage charges after she had rejected Vijayan’s offer to indulge in sexual activities.

In the meantime, a plot was designed to embarrass K Karunakaran, AK Antony and Oommen Chandy, along with few aspirational police officers used the opportunity of Rashida’s arrest to target the senior police officer Raman Srivastava, who was close to the Chief Minister Karunakaran then. Within a month of Rashida’s arrest, the case was given a sinister twist by the few senior officers, when Nambi Narayanan’s deputy D. Sasikumaran and three others were arrested. Two weeks later, on November 30, 1994, Narayanan was also arrested.

Initially, the police had come up with a theory stating that the two ISRO scientists, Narayanan and Sasikumaran had been trapped in a sex racket involving the Maldivians and had shared the secrets pertaining to highly confidential “flight test data” from experiments with rocket and satellite launches. A team of Intelligence Bureau (IB) officers had allegedly played a controversial role in the whole case to frame two top ISRO scientists who were incidentally working on a secret project to build cryogenic engines. The case got murkier when RB Shrikumar, an officer close to Congress ecosystem was posted as the Deputy Director of the State Intelligence Bureau (SIB) at Trivandrum in 1994.

Shrikumar and other officials of the IB, along with the politically charged Kerala Police allegedly acted with a malafide intent not only destroy the career of Nambi Narayanan but also by compromising national security by preventing ISRO from succeeding in its mission to master the art of cryogenic engines. Yes, you heard it right. Years later, Nambi Narayanan goes on to plead with successive governments to investigate, expose the role of the CIA and politicians, police officers, media who had acted at CIA’s behest.

After 15 days of investigation by a Special Investigation Team (SIT) of the Kerala Police, the case was transferred to the CBI which after 18 months of the investigation in April 1996 concluded that the case against Nambi Narayanan and others was fabricated. The CBI had reportedly submitted two confidential reports to the Union and Kerala governments listing respectively serious lapses by IB officials and SIT members.

The CBI in its report had observed, “The aforesaid IB officials comprising the team enquiring into ISRO case acted in an unprofessional manner and were privy to the arrest of six innocent persons, thereby causing them immense mental and physical agony.” The CBI had also clearly indicted Srikumar for “failing in their duty to conduct the inquiry in an objective and fair manner.”

Interestingly, five top most scientists of the country, Sathish Dhawan, UR Rao, Yashpal Rodham Narasimha, K Chandrasekhar and TN Seshan had also written a joint statement in 1997 stating how America is posing hurdles to block India’s cryogenic engines programme. The statement by the top scientists had subtly hinted regarding the outside interference in the cryogenic developmental programme by fabricating fake espionage cases against its top scientists like Nambi Narayanan. It has been alleged that CIA to safeguard the US commercial interests, had planted a fabricated case through its moles in the Intelligence Bureau, using the politically inclined Kerala police as a conduit.

It leads to a very disturbing question on why did the Intelligence Bureau officers like RB Srikumar with the help of Kerala Police try to undermine the cryogenic programme by planting a fake espionage case against Nambi Narayanan and other scientists? The Congress leaders of Kerala to sustain its agenda towards K Karunakaran had allegedly utilised the services of the Kerala police to implicate Nambi Narayanan and other scientists in a fabricated case despite knowing that he was involved in one of the country’s significant developmental programmes.


However, the Supreme Court in 1996 had upheld the findings of the CBI and had asked the Kerala government to pay Rs 1 lakh in compensation to Narayanan and others. However, Dr Narayanan had approached the National Human Rights Commission (NHRC)seeking justice for the harassment and agony meted out to him. In 2001, the NHRC had awarded a compensation of Rs 10 lakhs to him.

The Supreme Court also awarded former ISRO scientist Nambi Narayanan a compensation of Rs 50 lakhs for his wrongful arrest and harassment by the Kerala Police in the 1994 ISRO spy case. The apex court had also ordered a probe into the role of the police officers involved in Narayanan’s arrest and alleged harassment in custody. The three-member probe panel is to be headed by former judge DK Jain.

The Union government led by Narendra Modi has finally awarded prestigious Padma Bhushan to Nambi Narayanan on the occasion of 70th Republic Day in 2019. Nonetheless, questions still remain on the need for accountability and justice for decades-long physical and mental agony suffered by the Narayanan. The compensation money along with the prestigious Padma award may bring him half-closure but will not clearly quantify his sufferings and leave alone the delay in mastering the art of cryogenics by the Indian space scientists without Nambi Narayanan.
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Re: Chandrayan-2 Mission

Post by rajsunder »

^^^^
When did we ever use American launch systems that US felt a need to sabotage our cryogenic engine building efforts? If ever there was a need to do so, it should have been from French/European space agency whose services we use to launch our satellites.
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Re: Chandrayan-2 Mission

Post by ArjunPandit »

rajsunder wrote:^^^^
When did we ever use American launch systems that US felt a need to sabotage our cryogenic engine building efforts? If ever there was a need to do so, it should have been from French/European space agency whose services we use to launch our satellites.
please read chetakji's commentary before the post..
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Re: Chandrayan-2 Mission

Post by Mort Walker »

Let’s try to keep politics out of this thread and discuss the technical aspects of the Chandrayaan-2 launch. If necessary another thread for ISRO or space program should be used.

This is a hard problem both scientifically and from an engineering point of view. There’s lots to discuss here without cluttering the thread with international and national politics.
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Re: Chandrayan-2 Mission

Post by Mort Walker »

Singha wrote:i amended my prediction to 2 months for that reason. it will take about 10 days to move the beast , take things apart and even look deeply into it.
In the 2nd stage, L110 motor, uses hydrazine based fuel. I wonder what sort of issues come up loading and unloading f it full of fuel?
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Re: Chandrayan-2 Mission

Post by UlanBatori »

What is the battery discussed here? The news reports seem as garbled as usual. battery, leak, charge, hydrogen, H2-LOX engine, all mixed. Sounds like a leak at some fitting.
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Re: Chandrayan-2 Mission

Post by Mort Walker »

UlanBatori wrote:What is the battery discussed here? The news reports seem as garbled as usual. battery, leak, charge, hydrogen, H2-LOX engine, all mixed. Sounds like a leak at some fitting.
Some of it is translation from vernacular press. I agree this is a fitting as the C-25 tank is checked out in production and assembly to ensure there is no leak. I think the C-25 has only been used 3 times before, so some of this may be teething issues. I’m so glad they caught it before hand.

The battery issue, if true, maybe the Chandrayaan-2, Viram or Pragayan not charging or holding a charge. I haven’t heard anything more. That would be a much more serious problem if true.
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Re: Chandrayan-2 Mission

Post by ArjunPandit »

UlanBatori wrote:What is the battery discussed here? The news reports seem as garbled as usual. battery, leak, charge, hydrogen, H2-LOX engine, all mixed. Sounds like a leak at some fitting.
Agni 5 had some battery issues many years back..that delayed its testing. Just curious if there could be some connection remotely..
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Re: Chandrayan-2 Mission

Post by juvva »

https://www.reddit.com/r/ISRO/comments/ ... =post_body

A new Notam : 17-31 July 2019 !!!!!!

Appended later:

A1550/19 NOTAMN
Q) VOMF/QWMLW/IV/BO/W/000/999/
A) VOMF B) 1907172100 C) 1907311000
D) BTN 2100-2200 ON 17 JUL AND BTN 0830-1000 ON 18-31 JUL
E) GSLV- MKIII- M1 CHANDRAYAAN-2 ROCKET LAUNCH FM SHAR RANGE,
SHRIHARIKOTA WILL TAKE PLACE AS PER FLW DETAILS. THE LAUNCH WILL BE
ON ANY ONE OF THE DAY DRG THIS PERIOD.ACTUAL DATE OF LAUNCH WILL BE
INTIMATED 24 HR IN ADVANCE THROUGH A SEPARATE NOTAM.
LAUNCH PAD COORDINATES : 134312.00N 0801348.00E
NO FLT IS PERMITTED OVER THE DNG ZONES

DANGER ZONE -1: IS A CIRCLE OF 10 NAUTICAL MILES AROUND THE LAUNCH
PAD.

DANGER ZONE -2:
I. 1230N 08240
II. 1315N 08250
III. 1245N 08410
IV. 1200N 08400

DANGER ZONE -3
I. 1135N 08500
II. 1225N 08510
III. 1145N 08715
IV. 1055N 08705

DANGER ZONE 4
I. 0810N 09420
II. 0900N 09440E
III. 0825N 09615
IV. 0735N 09555
Last edited by juvva on 15 Jul 2019 23:08, edited 1 time in total.
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Re: Chandrayan-2 Mission

Post by Amber G. »

I will not speculate as there is enough speculating (some times silly by some ddm's) is going on, but for historic perspective such "glitches" as some in isro said "not uncommon".

Chandrayaan I also had a similar glitch. IIRC there was leakage in propellant which was discovered about 2 hrs before launch but this was corrected and the the launch took place the same day.

Chandrayaan I went up and it is still orbiting the moon.

From what they say, the leak for Chandrayaan II was detected while pressuring .. as details are found (exact nature of the leak etc) and rectified, hopefully we can make the window in this month's launch window ... we just have to wait till our our experts makes decision based on all the factors.

As someone said early detection prevents catastrophe if we did not discover it and worst happened.

****
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Re: Chandrayan-2 Mission

Post by Amber G. »

There were four suitable window periods for the launch in the month of July – July 15 and 16 and then again during new moon on July 29 and 30.
The launch window for July 15/16 will be about 10 minutes duration while the later in July will be very short (about 1 minute).
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Re: Chandrayan-2 Mission

Post by SaiK »

yes Amber g, what is important here is that we are able to take corrective and appropriate measures on health checks. process and system maturity combo is the method here. hang tight folks! keep the right speculations based on valid information.
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Re: Chandrayan-2 Mission

Post by disha »

SSridhar wrote:
disha wrote: . . . Of course the SITVC will come into play and correct the veer.
Correction. Not SITVC but flex nozzles with mechanical actuators.
Right, thanks for correction.

GSLV MkIII does have SITVCs attached on the SRB. Since the flex nozzles with mechanical actuators is to control in pitch and yaw plane, I am assuming that the SITVCs are for roll control on GSLV Mk III.

A question remains, is S-139 not improved with flex nozzles? PSLV 3rd stage already has flex nozzle system for pitch and yaw.

Page 10-15 has interesting read, the above information is on page 12 -> https://www.isro.gov.in/sites/default/f ... cation.pdf
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Re: Chandrayan-2 Mission

Post by disha »

I do not understand the disappointment on launch delay of Chandrayan-2.

When I heard of news of launch delay (was driving), my first reaction was that this could be due to fuel leak during fuel filling operation. Such leaks happen. We are transferring several tonnes of cryo- fuel and it is not like take a hose out of a gas pump and put the fuel in car.

Such delays are common and if there are sensors that caught such leaks and raised the flag for launch abort, that is a successful thing!
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Re: Chandrayan-2 Mission

Post by Vips »

Key decision on new Chandrayaan-2 launch date likely Wednesday.

The Indian Space Research Organisation (Isro) may announce its decision on the next launch date for Chandrayaan-2 on Wednesday, after it “implements corrective action”, sources privy to the developments, said.

“If all goes well, we may probably see the launch happen as early as next Monday (July 22),” said a source. However, Isro is yet to officially make a statement.

Monday’s aborted bid was among the last of a series of launch windows Chandrayaan-2 mission missed since last year.

Every launch has an optimal window to achieve the desired results. While Monday (July 15) had the longest window of 10 minutes — between 2.51am and 3.01am — Isro will have a window of one minute a day for the rest of the month.

The present window closes by this month-end, and if Isro misses it, Chandrayaan-2 may have to wait at least till September. Some scientists said it may not happen this year.

A source from Isro Telemetry, Tracking and Command Network (Istrac), said: “The satellite side has done an analysis. According to this, if we miss the July 31 window, there will be an impact on the mission profile.”

The source, while stating that mission planning, will need re-worked if the present window is missed, and there are estimations that a new plan may need more fuel. “This will affect operations of payloads. If we miss the deadline, the orbiter’s life may be reduced to six months from the present one year, as it would have used up some of its fuel,” the source said.

Also, in an indication of Isro's urgency to launch in the July window, a fresh NOTAM (notice to airmen) — an alert issued ahead of every launch — has been issued Monday evening. The alert is effective on July 17 between 2.30am and 3.30am, and for July 18 to 31 between 2pm and 3.30pm.
Mort Walker
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Re: Chandrayan-2 Mission

Post by Mort Walker »

^^^I don’t see the rush. Why not wait until end of August or October when moon perigee is the best and the launch pad isn’t being used for other launches? Either that or the leak was so small they know exactly where it is as opposed to actually being in the C25 3rd stage.

Does anyone know if the 2nd stage has already been unloaded and if the rocket has been rolled back to the integration building?
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Re: Chandrayan-2 Mission

Post by krishGo »

Mort Walker wrote:^^^I don’t see the rush. Why not wait until end of August or October when moon perigee is the best and the launch pad isn’t being used for other launches? Either that or the leak was so small they know exactly where it is as opposed to actually being in the C25 3rd stage.

Does anyone know if the 2nd stage has already been unloaded and if the rocket has been rolled back to the integration building?
Trust ISRO to not give the go ahead unless they are fully sure that cause of the snag has been addressed and the launch can go ahead.

If the issue is indeed a propellant leak, then it is not the first. A bit of history. ISRO has dealt with similar problems before.

1) GSLV-D5 - August 2013 - A leak was detected some 70 minutes before launch in the 2nd stage (Hypergolic stage using Vikas engines). The leak was detected as propellants were being filled into the C15 cryogenic stage. The launch was called off. The actual launch took place in January 2014, and was a success.

Why so much of time? It was the second launch using the indigenous crygenic engine after the first flight had failed (plus the other failed flight with the Russian cryogenic engine). ISRO really made sure they did everything in their power to ensure the launch was successful.

2) GSLV F06 - December 2010 - Propellant leakage was detected in the Russian cryogenic stage. The leak was detected in the tests before the start of the countdown iself. This was 20th of December. They rectified the issue and launched on 25th (5 days). The launch failed for a completely differnt reason (one of the liquid boosters failed)
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Re: Chandrayan-2 Mission

Post by krishGo »

disha wrote:
SSridhar wrote: Correction. Not SITVC but flex nozzles with mechanical actuators.
Right, thanks for correction.

GSLV MkIII does have SITVCs attached on the SRB. Since the flex nozzles with mechanical actuators is to control in pitch and yaw plane, I am assuming that the SITVCs are for roll control on GSLV Mk III.

A question remains, is S-139 not improved with flex nozzles? PSLV 3rd stage already has flex nozzle system for pitch and yaw.

Page 10-15 has interesting read, the above information is on page 12 -> https://www.isro.gov.in/sites/default/f ... cation.pdf
I remember reading somewhere that Mk III does not have SITVC. What looks like SITVCs are actually tanks carrying oil. The oil/liquid must be for hydraulics or something on the flex nozzle.

https://www.isro.gov.in/sites/default/f ... ochure.pdf
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Re: Chandrayan-2 Mission

Post by Rishi_Tri »

As almost all of you said, ISRO through sources in media is saying this was leak - in Helium bottles. Similar leak was detected on June 22 test in oxygen bottles.

https://timesofindia.indiatimes.com/ind ... 236163.cms

Question though - what tolerance could be there for pressure loss with minimal impact on performance for launch to go ahead?
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