A nice shot of the CE-20 engine (an exhibit) with all the 'messy' plumbings visible.. Source
Quote from: vineethgk on 06/22/2017 04:19 pmA nice shot of the CE-20 engine (an exhibit) with all the 'messy' plumbings visible.. SourceWhy it is so messy? Is it because the propellant?
Because its a gas generator cycle rather than expander or staged combustion cycle but most are this way.
On the lower PMF of GSLV-III compared to other rockets of its class and ISRO's plans to address it...The solid-vs-liquid debateQuote"We use solid fuel in the lower stages as it is cheaper than cryogenic fuel. Even other space agencies are looking to use solid fuel to cut costs," ISRO`s Liquid Propulsion Systems Centre Director S. Somanath told IANS."But other space agencies are looking at solid fuel to reduce cost only after their rockets carry far much heavier satellites than Indian rockets," the space industry expert pointed out.
"We use solid fuel in the lower stages as it is cheaper than cryogenic fuel. Even other space agencies are looking to use solid fuel to cut costs," ISRO`s Liquid Propulsion Systems Centre Director S. Somanath told IANS."But other space agencies are looking at solid fuel to reduce cost only after their rockets carry far much heavier satellites than Indian rockets," the space industry expert pointed out.
Quote from: vineethgk on 06/16/2017 05:29 pmOn the lower PMF of GSLV-III compared to other rockets of its class and ISRO's plans to address it...The solid-vs-liquid debateQuote"We use solid fuel in the lower stages as it is cheaper than cryogenic fuel. Even other space agencies are looking to use solid fuel to cut costs," ISRO`s Liquid Propulsion Systems Centre Director S. Somanath told IANS."But other space agencies are looking at solid fuel to reduce cost only after their rockets carry far much heavier satellites than Indian rockets," the space industry expert pointed out.That's an interesting claim to make... Solids being cheaper. It is not one that seems to have much real life support, with the possible exception of small boosters, perhaps. But the industry as a whole is moving away from them. All who use them in new designs (Ariane 6 and H-III) do so because they have the existing capability, so why not use it? Or because they have an existing military need for solids where they are trying to share costs somehow.And as far as only being able to choose between solids and cryogenic (HydroLox). That's a false dilemma. What about KeroLox and MethaLox? Both are likely cheaper than either extreme option, and can outperform HydroLox upper stages. (the all-kerolox F9 is lighter than the GSLV-MK-III and yet lifts more)My big issue with the GLSV-Mk III is how ISRO seems to be behind the curve. There is clearly so much technical capability, so why do they keep trying to re-create vehicles that are 20-30 years old (GSLV-Mk III being the child of Titan IV and Ariane 5) instead seeing where current industry trends, or even better - chart their own course completely?(Doing reusability through fly-back boosters seems to be another example of this... People have talked about them for over 40 years, yet none have surfaced. But despite the recent successes of vertical landing boosters, ISRO appears to have made up their minds that fly-back boosters are the way forward)
As mentioned in PSLV-C38 post-launch briefing - ISRO is working on increasing the thrust of L110 stage Vikas engines in order to improve GSLV Mk III efficiency.
Quote from: vyoma on 06/23/2017 06:04 pmAs mentioned in PSLV-C38 post-launch briefing - ISRO is working on increasing the thrust of L110 stage Vikas engines in order to improve GSLV Mk III efficiency.To add to that, they mentioned increasing the performance of CE-20 as well towards the same objective.
Locational constraintAn area of major concern was the launch constraint imposed by the location of Sriharikota, India’s space port. The launch had to take place eastward from the island to put a communication satellite into the GTO. This did not offer “full freedom” because after the vehicle cleared the Bay of Bengal, the Indonesian land mass appeared on the scene. The launch vehicle debris—from the jettisoned stages—should not be allowed to fall over Indonesia.Sivan said: “We had seen that when the vehicle reached a velocity of more than 5 km a second, the Indonesian land mass came in. So we had a requirement of designing a launch vehicle that will have a capacity of reaching [a velocity of] 5 km a second. But it is the lower stages that should produce that velocity of 5 km a second. We then needed one more stage which will produce another 5 km a second of velocity. There cannot, however, be an intermediary stage. [A total of 10.2 km a second velocity is required to put a four-tonne satellite into the GTO.] After the vehicle crosses the land mass, its stages should not come down. They should continuously burn and go into orbit. That means we should have a stage that should give another 5 km a second after the vehicle crosses the land mass. So we had to necessarily go in for a cryogenic stage that will give 5 km a second at a stretch and carry the four-tonne satellite into orbit. To put a 2.2-tonne satellite into orbit, we had a cryo stage with 12 tonnes of liquid oxygen and liquid hydrogen. But to put a four-tonne satellite into orbit, we needed a cryogenic stage which will use 25 tonnes of propellants. That is how the C-25 stage came into the picture.”
Hi, let me please quote from the following:http://www.frontline.in/science-and-technology/in-the-big-league/article9731133.ece?homepage=true#testQuoteLocational constraintAn area of major concern was the launch constraint imposed by the location of Sriharikota, India’s space port. The launch had to take place eastward from the island to put a communication satellite into the GTO. This did not offer “full freedom” because after the vehicle cleared the Bay of Bengal, the Indonesian land mass appeared on the scene. The launch vehicle debris—from the jettisoned stages—should not be allowed to fall over Indonesia.Sivan said: “We had seen that when the vehicle reached a velocity of more than 5 km a second, the Indonesian land mass came in. So we had a requirement of designing a launch vehicle that will have a capacity of reaching [a velocity of] 5 km a second. But it is the lower stages that should produce that velocity of 5 km a second. We then needed one more stage which will produce another 5 km a second of velocity. There cannot, however, be an intermediary stage. [A total of 10.2 km a second velocity is required to put a four-tonne satellite into the GTO.] After the vehicle crosses the land mass, its stages should not come down. They should continuously burn and go into orbit. That means we should have a stage that should give another 5 km a second after the vehicle crosses the land mass. So we had to necessarily go in for a cryogenic stage that will give 5 km a second at a stretch and carry the four-tonne satellite into orbit. To put a 2.2-tonne satellite into orbit, we had a cryo stage with 12 tonnes of liquid oxygen and liquid hydrogen. But to put a four-tonne satellite into orbit, we needed a cryogenic stage which will use 25 tonnes of propellants. That is how the C-25 stage came into the picture.”Launch site geography was a key constraint here.
Yes, it is a constraint, but an not as important as it might seem. An upper stage with 5km/s delta-v is not that unusual and does not require hydrogen. For example, the F9 upper stage (again KeroLox) provides 7.5-8 km/s of delta-V.It does bug me when the Sriharikota location is used an excuse like that. Most countries would LOVE to have that location. It may be the 2nd best located launch complex on earth after French Guyana, and many two-stage launch vehicles could operate out of there without making any changes.
On GSLV Mark III, Dr. Sivan said attempts would be made to increase the launch vehicle’s payload carrying capacity – four tonnes at the moment – with each forthcoming flight. “We are adding an additional 600 kg payload with each of its flights.”
QuoteOn GSLV Mark III, Dr. Sivan said attempts would be made to increase the launch vehicle’s payload carrying capacity – four tonnes at the moment – with each forthcoming flight. “We are adding an additional 600 kg payload with each of its flights.”SourceWith a max upper limit of around 4.4-4.5 tonnes I guess.
Quote from: vineethgk on 02/25/2018 12:23 pm....So, can we expect a payload of 3700-3800 kg for the forthcoming GSLV MK-III D2 launch ? That will be a phonomenal achievement for GSLV MK III which could have had a potential of launching over 6 Ton payload, had ISRO clustered 4 Vikas Engines instead of two. What puzzles me is why they chose to cluster only 2 Vikas 2 Engines. With a diameter of 4.0 Meter, they could have easilyclustered 2 or even 3 more ( putting the 5th clustererd engine at the center ). If SpaceX can cluster 9 Marlin Engines for the the Falcon 9's First Stage with a diameter of 3.66 meter ( less than the GSLV MK-III L-110 stage ), ISRO could have accomodated 2 to 3 more Vikas 2 Engines. Instead of 1600 kN thrust, L-110 stage could have generated thrust of 3200 kN or 4000 kN withtout the engines being uprated.--- [ --- ]
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Quote from: vineethgk on 02/25/2018 12:23 pmQuoteOn GSLV Mark III, Dr. Sivan said attempts would be made to increase the launch vehicle’s payload carrying capacity – four tonnes at the moment – with each forthcoming flight. “We are adding an additional 600 kg payload with each of its flights.”SourceWith a max upper limit of around 4.4-4.5 tonnes I guess.So, can we expect a payload of 3700-3800 kg for the forthcoming GSLV MK-III D2 launch ? That will be a phonomenal achievement for GSLV MK III which could have had a potential of launching over 6 Ton payload, had ISRO clustered 4 Vikas Engines instead of two. What puzzles me is why they chose to cluster only 2 Vikas 2 Engines. With a diameter of 4.0 Meter, they could have easilyclustered 2 or even 3 more ( putting the 5th clustererd engine at the center ). If SpaceX can cluster 9 Marlin Engines for the the Falcon 9's First Stage with a diameter of 3.66 meter ( less than the GSLV MK-III L-110 stage ), ISRO could have accomodated 2 to 3 more Vikas 2 Engines. Instead of 1600 kN thrust, L-110 stage could have generated thrust of 3200 kN or 4000 kN withtout the engines being uprated.--- [ --- ]
With the implementation of HTVE's on GSLV-Mk II and later PSLV (PS2 / HPS2), will ISRO also upgrade GSLV-Mk III with HTVE on the interim L-110 stage (GS1??) until the new GS1 stage with SCE takes over??
So, can we expect a payload of 3700-3800 kg for the forthcoming GSLV MK-III D2 launch ? That will be a phonomenal achievement for GSLV MK III which could have had a potential of launching over 6 Ton payload, had ISRO clustered 4 Vikas Engines instead of two. What puzzles me is why they chose to cluster only 2 Vikas 2 Engines. With a diameter of 4.0 Meter, they could have easilyclustered 2 or even 3 more ( putting the 5th clustererd engine at the center ). If SpaceX can cluster 9 Marlin Engines for the the Falcon 9's First Stage with a diameter of 3.66 meter ( less than the GSLV MK-III L-110 stage ), ISRO could have accomodated 2 to 3 more Vikas 2 Engines. Instead of 1600 kN thrust, L-110 stage could have generated thrust of 3200 kN or 4000 kN withtout the engines being uprated.
Quote from: --- on 02/26/2018 07:52 amSo, can we expect a payload of 3700-3800 kg for the forthcoming GSLV MK-III D2 launch ? That will be a phonomenal achievement for GSLV MK III which could have had a potential of launching over 6 Ton payload, had ISRO clustered 4 Vikas Engines instead of two. What puzzles me is why they chose to cluster only 2 Vikas 2 Engines. With a diameter of 4.0 Meter, they could have easilyclustered 2 or even 3 more ( putting the 5th clustererd engine at the center ). If SpaceX can cluster 9 Marlin Engines for the the Falcon 9's First Stage with a diameter of 3.66 meter ( less than the GSLV MK-III L-110 stage ), ISRO could have accomodated 2 to 3 more Vikas 2 Engines. Instead of 1600 kN thrust, L-110 stage could have generated thrust of 3200 kN or 4000 kN withtout the engines being uprated.It would totally change the vehicle. They wouldn't be able to use the same solid boosters, they would have to be smaller due to limitations on maximum dynamic pressures. So, in the end, it's not clear that with the constraints of keeping the lower stages to =<5km/s (in order to not drop hardware on Indonesia/Malaysia) whether clustering 4 Vikas/HTVEs on the core stage would actually provide any improvement. In addition, they had already set their sights on switching the core to the SCE-200 in which case clustering on the L-110 would likely end up a wasted or dead-end effort.
Quote from: Lars-J on 06/26/2017 10:39 pmYes, it is a constraint, but an not as important as it might seem. An upper stage with 5km/s delta-v is not that unusual and does not require hydrogen. For example, the F9 upper stage (again KeroLox) provides 7.5-8 km/s of delta-V.It does bug me when the Sriharikota location is used an excuse like that. Most countries would LOVE to have that location. It may be the 2nd best located launch complex on earth after French Guyana, and many two-stage launch vehicles could operate out of there without making any changes.Well, I'd prefer a precedent from a pre-Falcon rocket, because GSLV was conceived long before it. Besides, ISRO was looking to scale past what individual expendable Falcon9 can do....