What they talk about when they talk about the GSLV?

The GSLV-F10/EOS-03 mission failed on August 12, 2021. The vehicle faced an issue in it’s third cryogenic stage.

What does ISRO mean when they say GSLV? There is a lot of confusion between the GSLV Mk I and the GSLV Mk II. The YouTuber Gareeb Scientist raised this question in a video he posted on August 8, 2021. He provides the reasons for this confusion.

I believed the first version of the story shared in Gareeb Scientist’s video. I believed that the Mk I was a reference to the GSLVs which flew with the Russian cryogenic engine, KVD-1. And, thought that the Mk II referred to the GSLV which flew with the Indian cryogenic engine, CE-7.5.

This version was shared by ISRO in the brochure of the GSLV-D3 which flew on April 15, 2010. ISRO has removed this brochure from it’s website. But, there is an archived version online as well as on the VSSC website [PDF]. Page two of this brochure carries this explanation.

The Wikipedia page for GSLV still references this explanation and describes variants in this manner. I think that this has contributed to this confusion.

ISRO seems to have changed this version of the story in 2015 in an e-book published on its website, Fishing Hamlet to Red Planet. You need an epub reader to read the book. In an essay by R V Perumal titled, Evolution of the Geosynchronous Satellite Launch Vehicle, he mentions that the GSLV Mk I was actually a modified version of the PSLV with a cryogenic upper stage. However, since the Cryogenic Stage did not work out for the PSLV, hence the idea of the GSLV Mk I was dropped. Perumal was the Project Director for the PSLV and GSLV and later the Director, Liquid Propulsion Systems Center (LPSC). I think I would trust this version.

Since there is no Mk I and all the flights of the GSLV are what ISRO called the Mk II project, it seems ISRO just dropped the Mk II and began calling the launch vehicle GSLV in 2017. This change is also seen on the ISRO website on the GSLV page from 2017.

The GSLV Mk III is a totally different project. I think the GSLV tag got attached to it only because it primarily delivers its payload to a geostationary transfer orbit.

Addendum – August 17, 2021

In response to this blog post @zingaroo replied on Twitter stating that ISRO had always called the GSLVs with the Russian cryogenic engines as the Mk-I and the ones with the Indian cryogenic engines as the Mk-II. He provided two examples of the same from the past.

He presents evidence from the magazine, SPACE-India April-June 2003, Page 11. Also from Gopal Raj’s book Reach for the Stars published in 2000.

It seems ISRO is also re-writing history in a way. It seems that the project started somewhere after 2010.

GSLV on Wikipedia

Note: I wrote this on my earlier blog hosted as http://parallelspirals.wordpress.com/. I recovered the text from the WayBack Machine. This post appeared on December 13, 2013 as per the permalink. I’m trying to collect here again all my old writings spread on various blogs.

I began contributing to Wikipedia in 2007 with the idea of improving coverage of Indian space sciences on Wikipedia. I began working on the articles related to the astronomical observatories. This also fell in line with the space popularization work I was involved in at Students for the Exploration and Development of Space (SEDS) India chapter. In 2009, I also began editing general interest articles on Wikipedia.

It was only yesterday, after a break of nearly a year or more, that I got back to editing on Wikipedia. I worked on the article of India’s Geosynchronous Satellite Launch Vehicle or GSLV. The upcoming launch has me nervous and had me interested in the history of the GSLV. I looked to Wikipedia as my first port of call and was frankly, disappointed at the shape in which I found the article. So, I rolled up my sleeves and began working on the article, in true Wikipedian style.

The history of the GSLV is as interesting as the vehicle itself. It was designed specifically to carry the INSAT class of satellites which weighed in at 2 to 2.5 tons. The Project was started in 1990 as the PSLV took shape and was beginning to move towards a development flight in 1993 to reduce reliance on the US’ Delta and European Ariane launch vehicles which are expensive options. Reading up, there seems to have been confusion on how to proceed with the tricky cryogenic third stage of the vehicle. Both US and Europe refused to share the technology and India had to go to the crumbling Soviet Union for help. US and Europe refused help pointing to the fact that India had not signed the Missile Technology Control Regime. I guess they also tried to offer the technology if India became part of the regime. The Soviet Glavkosmos offered to transfer technology to India in 1991. Following the fall of the Soviet Union, Russia could not stand up to US pressure on falling in line with the MTCR. It finally have India just 7 cryogenic stages and 1 ground mock up instead of 5 stages and transfer of technology. I am happy that India did not become part of MTCR despite immense pressure and need for cryogenic technology. Scientists at ISRO began work on India’s own cryogenic technology in 1994 called the Cryogenic Upper Stage Project.

Even the 7 cryogenic stages Russia supplied to ISRO held surprise for ISRO. The stage was heavier and there were interface problems. The engine was also not proven on any flight. It took ISRO about 6-7 years to get the stage to fly at all. Hence you see the first flight of the GSLV in 2001.

Scientists working on the Cryogenic Project were also part of what is now called the ISRO Spy Case. The scientist has alleged that the Case was put together at the behest of foreign interests that were trying to scuttle Indian efforts at building a cryogenic engine.

Although the learning curve on the GSLV has been huge, I think it will help India build a vehicle that is as versatile as the PSLV is today.

Madhavan Nair on the GSLV Failure

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 31, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

Madhavan Nair made a comment to IANS that was carried to many news carriers about the GSLV failure. He made some interesting remarks:

‘On the day of the failure it was announced the connectors relaying the command led to the rocket’s failure. We have revisited and have confirmed that the connectors located between the cryogenic engine and the lower stage (engine) snapped. We have to find why the snapping happened,’ Nair said.

‘As per the data there are no indications of any control command from the onboard computers to the rocket engines,’ he said.

He said simulated experiments will have to be carried out to find out why the connectors got disconnected from the rocket.

‘Whether vibrations or external forces led to the snapping of connectors has to be found out. We will have to conduct simulation experiments to find that out,’ Nair said.

To a query as to why the ISRO was taking a long time to come out with a preliminary report, he said: ‘The preliminary data runs into more than 100 pages even though the flight is of around 50 seconds.’

As written yesterday, the Russians did come out with a report pretty quickly and did another launch after fixing the faulty system on the Proton rocket to give it 12 launches this year – it’s record/year since 2000. If India intends to capture the commercial satellite launch market, its system must also be as flexible. On the question of dummy payloads to test launches, Madhavan Nair responds:

On a suggestion of using a dummy payload instead of a real satellite costing around Rs.150 crore till the ISRO stabilises its heavier rocket, Nair said: ‘The efforts required for both are more or less the same. However, if the satellite is slung into the orbit then it throws up an opportunity to earn higher revenue.’

I am guessing he is merely being optimistic here. He has spoken about what would happen if the satellite/dummy successfully orbits but there is a loss if it does not.

Preliminary Findings of the GSLV Failure

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 31, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

ISRO has just posted the preliminary findings of the GSLV Failure. This is what it has to say on what happened:

The performance of the GSLV-F06 flight of December 25, 2010 (with GSAT-5P Satellite onboard) was normal up to 47.5 seconds from lift-off. The events leading to the failure got initiated at 47.8 seconds after lift-off. Soon, the vehicle started developing larger errors in its orientation leading to build-up of higher angle of attack and higher structural loads and consequently vehicle broke up at 53.8 seconds from lift-off (as seen visually as well as from the Radars).

As per the Range safety norms, a destruct command was issued from the ground at 64 seconds after lift-off. The flight was hence terminated in the regime of the First Stage itself.

After this ISRO constituted a preliminary failure committee which has found this:

The finding of the Preliminary Failure Analysis Team is that the primary cause of the failure is the untimely and inadvertent snapping of a group of 10 connectors located at the bottom portion of the Russian Cryogenic Stage. Some of these connectors carry command signals from the onboard computer residing in the Equipment Bay (located near the top of the vehicle) to the control electronics of the four L40 Strap-ons of the First Stage. These connectors are intended to be separated only on issue of a separation command at 292 seconds after lift-off. The premature snapping of these connectors has led to stoppage of continuous flow of control commands to the First Stage control electronics, consequently leading to loss of control and break-up of the vehicle. The exact cause of snapping of the set of connectors, whether due to external forces like vibration, dynamic pressure is to be analysed further and pin-pointed.

The full Failure Analysis Committee has also been constituted under the chairmanship of former ISRO Chairman Madhavan Nair to not only to analyse not only to go into the problems of the GSLV’s current flight but also of the six previous flights and the corrective actions for both the GSLV and the use of the remaining one Russian cryogenic engine. The committee has 11 members from both inside and outside ISRO. This is definitely a positive outcome and also the fact that it has been given a timeline of up to January 2011 to present their report.

Although seemingly late, they have also constituted a Programme Review and Strategy Committee. This will look into the broader implications for the GSLV Programme, assured launches of INSAT-3D and Chandrayaan-II, operationalisation of the indigenous cryogenic stage and meeting the immediate shortage of transponders being faced by the nation. This seven member Committee will be chaired by another former ISRO Chairperson, K Kasturirangan.

These reports will submit their reports in January 2011 to a National Experts Panel that will study the report. Although, what the output of this panel will be is not sure. They hope to complete the whole process by February 2011.

In parallel, a Panel has been setup under Dr. S C Gupta, a former member of the Space Commission to solicit views from within ISRO for gearing up for the upcoming space missions. These will be submitted to Chairman, ISRO.

In all, an exhaustive review of all matters pertaining to or related to the GSLV Programme will be carried out. We hope this will help ISRO emerge stronger and hope a re-invented GSLV programme follows. There is still no idea on whether these reports will be made available to the scientific community at large in India and abroad as done by NASA and ESA. The Preliminary Findings have come out in 5 days. This is certainly going to be a strenuous New Year but it will ensure many more happier New Years in the future!

Post GSLV Failure comments

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 29, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

I have refrained from commenting too much about the GSLV failure after the initial reaction, which was also emotional on my part. This is mainly because there has been a lot of speculation already in various newspapers. This has been caused by the sudden springing up of subject experts by TV and newspapers when they found that they did not get through to any ISRO official on time. They did this only to break the story. I have presented these suggestions to aerospace friends and they say it is too premature to tell the cause of failure.

These are the news stories and videos of the GSLV failure that I read and collected from the web:

    1. This report by Stephen Clark for Spaceflight Now is the sanest report to read.
    2. Hindustan Times has posted this IANS report first on speculation that the heavier payload mass caused the failure. There are mirrors of this report in Economic Times and DNA.
    3. This report by Nirad Mudur of DNA speculates whether this was an ISRO goof up i.e. oversight error.
    4. This report by Charu Sudan Kasthuri of the Hindustan Times on ISRO’s clarification that they will use the GSLV Mk-II vehicle for Chandrayaan-II.
    5. This report by T S Subramanium of The Hindu suggests that the failure of connectors is a very trivial problem.
    6. Pathri Rajashekhar of The Asian Age reports suggest that it is the workers fault that the accident occured.
    7. Another report by T S Subramanium of The Hindu. I give kudos to him to have the presence of mind to question the VSSC Director. VSSC is the centre which builds India’s launch vehicles.

In short, these so called “space experts” have criticised everything that was new on this spacecraft. I think the best way for ISRO to correct its mistake is to follow the engineering creed and not bow down to immediate needs of media houses, political party or a short-memoried public. I hope ISRO officials can thrash down the problems.

I would also apologise for my own speculation in the previous post. But, I still think ISRO should nonetheless put the launch stack through re-qualification and test them again. It does not hurt.

GSLV-F06 flight unsuccessful

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 26, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

The seventh flight of the Geosynchronous Satellite Launch Vehicle (GSLV) designated F06 ended when the launch vehicle was destroyed by a manual self-destruct button activated by the Range Safety Officer. The destruct button was used when the first stage suffered a “technical glitch” and the vehicle started veering off its designated path.

At a press conference, ISRO Chairman Dr. Radhakrishnan explained:

Its performance was normal for 50 seconds after the lift-off. “Soon afterwards, the vehicle’s attitude was increasing, leading to heavier structural loads, higher angle of attack and breaking up of the vehicle.” The Range Safety Officer in the Mission Control Centre gave the ‘destruct’ command to the vehicle 63 seconds after the lift-off from its second launch pad and it was destroyed.

Although I told Srinivas Laxman and am quoted as saying that I would want the whole vehicle to undergo testing again, VSSC Director P S Veeraraghavan said that the fundamental vehicle design was good and it was possibly the connector snapping that caused the mission failure.  I would say such a comment is still premature. We should still wait for the Analysis Report to come out before making comments. Radhakrishnan is quoted as saying in the same article that the entire GSLV programme will be reviewed.

Prof U R Rao, former ISRO Chairman commented in the Times of India that the programmes such as Chandrayaan-II and Human Spaceflight will not be affected since they are different vehicles, perhaps alluding to the fact that GSLV Mk-III may be used for these.

I believe that ISRO must work on a different stack for the 2 – 6 tonne class satellite launch vehicles. Perhaps, a downgraded version of GSLV Mk-III architecture can be used or a 4-stage GSLV are can be used for this class of launch vehicles. Two failures in six months does not provide sufficient confidence in trusting the vehicle with precious cargoes such as Chandrayaan-II or humans. That, or the whole configuration must be tested again. This may cost more money but it is much better than loosing payloads to accidents.

I am really confident with the scientists and their work in ISRO but this should also encourage them to encourage budding rocketeers in the country. Fields like amateur rocketry will give them a large and experienced talent pool of do-ers who can then easily be upgraded to scientists working on Indian launch vehicles programme. ISRO has done service by encouraging the next generation of satellite engineers through work at nano and cube satellites.

Spaceflight Now cleared some of the doubts I had about how a 12.5 tonne engine could be made to accomodate 15.3 tonnes of cryogenic fuel in the third cryogenic stage:

GSAT 5P’s weight forced Russian and Indian engineers to modify parts of the rocket to lift the satellite, which is the heaviest spacecraft ever orbited by ISRO. The Russian third stage was lengthened 3.6 feet to fit an extra 6,000 pounds of propellant inside. The additional cryogenic hydrogen and oxygen was designed to permit the upper stage engine to burn about two minutes longer than on previous flights.

It is this sort of attention-to-detail that was missing in Indian media. They also continually said that the Indian satellite exploded, referred to the weight of the GSAT-5P as 2130 kg instead of 2310 kg and repeatedly called “scientists” space experts. Many of the said space experts were also forced to comment on a situation without much data being made available and were then sensationalized as banner and news ticker stories.

It is also now clear that the helium gas leak was fixed rather than found to be within acceptable risk limits. It is also wrong to claim that it was the Russian cryogenic engine which caused trouble and that ISRO should have checked it as was ripe in the initial minutes after the scenes of disaster played itself out on television screens. It is easier to blame and much difficult to fix. As Prof. Rao says there is a huge amount of data needs to be checked to identify all the various points that seem to/could or have failed.

GSLV-F06 Launch on Dec 25, 2010

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 24, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

On Christmas Day, India will launch its GSLV-F06 with GSAT-5P satellite on board. Since December 20, 2010 when the delay in the launch was announced, ISRO has been working with Russian engineers by conducting several tests on the leaked valve in the Russian cryogenic engine.

It has now been ascertained that the launch could go on. It is still not sure if the leak was fixed or whether it was found whether the leak was within acceptable limits.  ISRO has just posted a note on its website saying the launch has started.

There have been several mis-leading reports in Western blogs stating that this is the Indian cryogenic engine. This is wrong. This is one of the two spare engines that ISRO obtained from Russia.

The 2310 kg GSAT-5P is the heaviest satellite that an Indian launch vehicle will carry. Hence the cryogenic engine has been uprated. It now carries 15.3 tonnes of fuel as against 12.5 tonnes and has a payload fairing diameter of 4 metres instead of 2.8 metres. This uprating enables the GSLV Mk-I to carry 2310 kg instead of the 1900 kg capability. GSAT-5P itself is to replace INSAT-2E’s services and upgrade television, tele-medicene, tele-education and telephony services.

GSLV-F06 Launch Postponed

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 20, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

I only got around to writing this now after a day of BlogCamp:

The launch of GSLV-F06 with  GSAT-5P Satellite onboard, scheduled for December 20, 2010 has been postponed due to a minor leak in one of the valves of the Russian Cryogenic stage, observed during the pre-countdown checks.
The 29-hours countdown sequence planned to commence at 1100 hrs today (Dec 19th ) has not been authorized by the Launch Authorisation Board that met this forenoon to review the results of pre-countdown checks.
The revised schedule for launch will be firmed up after ascertaining the cause for the leak, remedial actions and due verifications.
Well, hope they get to fix the problem as soon as they can. Checks  are carried out before the launch to ensure that all systems work perfectly. Minor defects are not tolerated since its failure can lead to the failure of the whole system. Will keep you posted on the developments of this GSLV flight.

GSLV-F06 launching the GSAT-5P on December 20

Note: I wrote this on my earlier blog hosted as http://parallelspirals.blogspot.com. I recovered the text from the WayBack Machine. This post appeared on December 16, 2010 as per the time stamp. I’m trying to collect here again all my old writings spread on various blogs.

I had earlier written about the possible launch date of GSAT-5P as being December 20. This is now confirmed. Yesterday, ISRO posted photos and descriptions [PDF] about the GSLV-F06 and the GSAT-5P.

A little bit on the satellite. Unlike the satellite it is replacing, the GSAT-5P is a pure communications satellite. It does not have the meteorological payload that INSAT-2E had. The 2310 kg satellite will be placed in a geosynchronous transfer orbit by the GSLV-F06. The satellite with its C-band transponders will provide continuity of telecommunication services.

The importance of this launch is not because of its payload but rather because of its launch vehicle. The Geosynchronous Satellite Launch Vehicle (GSLV) is a completely new launch vehicle unlike the PSLV, which has now been tried and tested over the years. It is tasked with launching 2-4 tonne class satellites that the PSLV is not designed to handle. The problems facing the programme have been faced by other rockets in its class and are not un-precedented. However, it has been worrying ISRO because it has impacted ISRO’s strive for self-reliant systems. The delay will cause India to fall back on support on Astrium’s Ariane launch vehicles.

For the technical personnel, such times are uncomfortable. Questions are raised on the personnel’s capability by the management and it is a difficult time for all concerned. However, this is how people learn in rocketry and science. In a recent interview, I was informed that the way the Sriharikota spaceport works right now it is capable of doing only 3-4 launches per year. ISRO has been working to improve this launch rate with its Chairman making the claim in early 2010 that they hoped to do 10launches this year. The same claims have been carried forward to 2011. I wonder if this has impacted ISRO’s ability to test the rocket without a payload or with dummy payloads like SpaceX did. I had raised this question earlier as well when ISRO’s GSLV with indigenous cryogenic engine failed and fell into the Bay with its payload.

GSLV is a machine with contributions from many people each one providing critical components. The failure of even one component amongst the bunch can lead to the catastrophic results. Before this launch, I have depressed myself a little. I hope and pray for the team of GSLV-F06. Godspeed!

India successfully tests its cryogenic upper stage

Note: I wrote this on my earlier blog hosted as https://blogs.seds.org/pradeep. I recovered the text from the WayBack Machine. This post appeared on November 19, 2007 as per the timestamp. I’m trying to collect here again all my old writings spread on various blogs.

The third stage of India’s latest satellite launch vehicle, the GSLV is cryogenic. On November 15, 2007, ISRO successfully tested the indigenously built cryogenic rocket engine that will power the GSLV third stage. Till now, India depended on Russia for its cryogenic third stage but the test now allows India to use its own.

Developed by the Liquid Propulsion Systems Centre and supported by ISRO centres, public and private companies, it’s a milestone worth taking note of.

The press release describes the rocket as:

The indigenous Cryogenic Upper Stage (CUS) is powered by a regeneratively cooled cryogenic engine, which works on staged combustion cycle developing a thrust of 69.5 kN in vacuum. The other stage systems include insulated propellant tanks, booster pumps, inter-stage structures, fill and drain systems, pressurisation systems, gas bottles, command block, igniters, pyro valves and cold gas orientation and stabilisation system. Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbo-pump, which rotates at 39,000 rpm to ensure a high flow rate of 16.5 kg/sec of propellants into the combustion chamber. The main turbine is driven by the hot gas produced in a pre-burner. Thrust control and mixture ratio control are achieved by two independent regulators. LOX and Gaseous Hydrogen (GH2) are ignited by pyrogen type igniters in the pre-burner as well as in the main and steering engines.

Congragulations to ISRO for a successful test firing.