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ISRO News & Discussions

Discussion in 'Education & Research' started by Varad, Apr 17, 2011.

  1. Blackjay

    Blackjay Developers Guild IDF NewBie

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    Thanks for answering....
    Hope we have some kind of weapon against enemy satellites soon.
    Those who have already got them are now all clamoring for ban on anymore testing of space weapons.We should have some tests ASAP.
     
  2. kurup

    kurup 2nd Lieutant IDF NewBie

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    Why not they transfer VSSC to Sriharikkotta ??

    This transportation of stages to Sriharikota from TVM is time consuming and risky as well .
     
  3. GSLV Mk III

    GSLV Mk III Captain FULL MEMBER

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    Dude !!!!
     
  4. kurup

    kurup 2nd Lieutant IDF NewBie

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    What ?? :)
     
  5. GSLV Mk III

    GSLV Mk III Captain FULL MEMBER

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    There was literally a riot at TVM when they started the satellite project (Today's ISAC) in Bangalore, skipping TVM. Also it is nearly impossible to move entire infra & facilities there, as well as the workforce, since Sriharikota is nearly an isolated island kilometers away from any Large city.
     
  6. kurup

    kurup 2nd Lieutant IDF NewBie

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    If not SHAR , then somewhere near SHAR should be selected and a township can be easily developed .

    There is no point making a stages and engines 1000km away from launch site and then transporting it by road for every launch.
     
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  7. GSLV Mk III

    GSLV Mk III Captain FULL MEMBER

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    Ahem, try telling that to common VSSC employees who view every new centre ISRO sets up with suspicion. ;)

    Actually as far as I understand, no LV presently have co-located launch pad & manufacturing facilities (even SpaceX don't). Actually transporting empty liquid fuel stages from LPSC to Sriharikota is far cheaper than setting up a unit like HAL ASD at Sriharikota.
     
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  8. kaku

    kaku Major REGISTERED

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    Its far more better to establish manufacturing facilities near port like Cochin, Chennai and transport stages via ship.
     
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  9. Agent_47

    Agent_47 Admin - Blog IDF NewBie

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    Vizhinjam port under construction is at TVM which will be bigger than Cochin or chennai.
     
  10. migflug

    migflug FULL MEMBER

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    India's 'Baahubali' GSLV MK III Lifts Less Luggage Than Lighter Rockets
    The GSLV Mk III rocket weighs 640 tonne with a capacity to carry four tonne satellite.
    All India | Indo-Asian News Service | Updated: June 17, 2017 01:02 IST

    2SHARES
    COMMENTS
    [​IMG]


    GSLV Mk III payload to GTO as compared to other rockets is less. (PTI Photo)

    CHENNAI: The "Baahubali" or "fat boy" of Indian rockets -- GSLV Mk III -- weighs several tonnes more than some of the other expendable rockets in the world but its carrying capacity is far less, say experts. On June 5, India successfully flight-tested its brand new rocket, the 640 tonne Geosynchronous Satellite Launch Vehicle-Mark III (GSLV Mk III) nick-named "Baahubali" by the Telugu media and "fat boy" by officials of Indian Space Research Organisation (ISRO).

    The rocket powered by its own cryogenic engine at the upper stage, placed communication satellite GSAT-19 weighing 3,136 kg or 3.1 tonne.

    "The GSLV Mk III rocket weighs 640 tonne with a capacity to carry four tonne satellite. But when one compares the ratio of the GSLV Mk III's weight to its carrying capacity to geo transfer orbit (GTO - where communication satellites will be placed) with rockets of other countries, the former ranks low," an industry expert told IANS on the condition of anonymity.


    For instance, Japan's H-IIB rocket weighs 531 tonne but can place an eight tonne rocket in GTO. Similarly, Soyuz, Russia (312 tonne, payload to GTO 3.2 tonne); Falcon, USA (549 tonne, payload to GTO 8.3 tonne) and Proton, Russia (693 tonne, payload to GTO 6.3 tonne); Long March, China (weight 879 tonne, payload to GTO 14 tonne) and Ariane 5, Europe (777 tonne, payload 10.9 tonne).

    Sriharikota in Andhra Pradesh is the second best rocket launch site in the world, the expert added.


    Agreeing that the GSLV Mk III payload to GTO as compared to other rockets is less, G Ayyappan, Project Director, GSLV Mk III, cited a couple of reasons for it.

    "From the rocket's propulsion point of view, in foreign rockets, the lower stages (engines at the lower part of the rocket that are fired first to lift the rocket and make it escape earth's gravitational force) are powered by semi-cryogenic or cryogenic engines," Ayyappan said.

    The thrust power of semi-cryogenic or cryogenic engines are higher than that of engines fired with solid fuel.

    The GSLV Mk III is a three stage/engine rocket. The core of first stage is fired with solid fuel and its two motors by liquid fuel. The second stage is liquid fuel and the third is the cryogenic engine.

    "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.

    ISRO officials said the mass of communication satellites is also coming down and hence India may not need a heavy-lift rocket.

    "Nearly 55-60 per cent of a satellite's weight consists of its chemical fuel. Now the idea is to shift to electric propulsion of satellites which would reduce their weight," Ayyappan pointed out.

    Somanath said: "ISRO started designing GSLV Mk III with four tonne carrying capacity when it was making two tonne satellites. At the global level also the weight of satellites are coming down. It is very difficult to predict the market trends."

    "Electric propulsion will not drastically reduce the weight of satellites to make much of a difference in the rocket's carrying capacity and it cannot replace chemical fuel. The chemical fuel will be used to take the satellite to its space slot and for managing it later electric propulsion would be used," the expert said.

    "The Chinese government approved the Long March 5 project sometime mid-2000 to have a rocket with a capacity of 14 tonne. The size of communication satellites will have to go up as there is limitation on the orbital slots. It all boils down to planning and also predicting the global trends," the expert added.

    Citing the example of Japanese H-IIB rocket, Ayyappan said the Japanese use lot of composite materials to make the rocket more efficient and light weight.

    "In future we will also be using more composites in the upper stages instead of metal. Half of the rocket's velocity is achieved only at the upper stage and composite will be the only choice in future," Ayyappan said.

    "The specific impulse of our cryogenic engine is also slightly less than that of others," Somanath added while listing out other reasons for GSLV Mk III's lower carrying capacity.

    "The aluminium used in some foreign rockets are less dense and their weight is less. We will also use such materials to reduce the weight of our cryogenic stage by 500-600 kg," he said.

    Somanath said there are plans to reduce the weight of the electronics by around 150 kg so that every kilogram of weight reduced increases the payload capacity.

    According to him, switching off and restarting of cryogenic stage in the space would also increase the rocket's capacity.

    Experts said India has to realise its semi-cryogenic stage faster and it cannot have the luxury of spending a decade or more in developing newer rocket technologies.

    "We are planning to realise the semi-cryogenic engine in 2019 and the entire stage by 2021," Somanath said.


    Some future enhancements to increase gslv mk3 payload. Its said that gslv mk3 can carry upto 4.5 tonnes with current weakass engines by incorporating various measures as listed above. Also we need to get the SCE asap, involve ukraine , russia whosoever and get it done quickly. Spacex is already getting ahead of us in low cost carrying capablity which is our strength. Their melin 1d engine has T/W of fcuking 200.While we cant compete with that , we atleast need to get SCE to remain competetive.
    https://www.google.co.in/url?sa=t&r...BQpT8yyXBPb4lXyvA&sig2=jXDoPRDVW6ITvCQVzEbY3w


    @GSLV Mk III
     
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  11. GSLV Mk III

    GSLV Mk III Captain FULL MEMBER

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    The main reason for the low mass fraction is the large SRBs as mentioned in the article. Actually I'm hoping for better payloads when they reduce the inert mass of C27 stage & increase it's propellent loading to above 30 tonnes. The current inert mass of 5 tonnes is a bit high when compared to equivalent stages like Delta Cryogenic Second Stage & ESC-B.
     
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  12. InfoWarrior

    InfoWarrior Lieutenant FULL MEMBER

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    Everyone seems to blame DRDO and praise ISRO, but does DRDO deserve this blame and ISRO this relative praise. Let's analyze with an open mind, clear vision and perception is most important. The idea is not to reduce achievement of ISRO but to see things in proper light.

    The Criterion for success in-case of DRDO is different compared to ISRO. To succeed, Isro has to achieve goals and avoid mistakes. But Isro does not have to compete with international players. DRDO has to achieve goals, avoid mistakes, but it has to compete at international levels.

    For example, ISRO has to research and create rockets to launch satellites, make satellites. If ISRO succeeds in placing a satellite in correct orbit and satellite functions properly, it is deemed a success. ISRO's operations are lower in cost due to lower currency exchange rate of India.

    In case of DRDO for example, ARJUN MBT has achieved every goal and function of a tank. But does it compare well with other foreign tanks. It is too heavy, too expensive, over sized, even after 30 years of research etc

    Let's put Isro through such a comparisons:
    ISRO 'Fat Boy' GSLV Mk-III Has Very Low Carrying Capacity: Experts
    "The GSLV Mk III rocket weighs 640 tonne with a capacity to carry a four-tonne satellite. But when one compares the ratio of the GSLV Mk III's weight to its carrying capacity to geo-transfer orbit (GTO - where communication satellites will be placed) with rockets of other countries, the former ranks low," an industry expert told IANS on the condition of anonymity.

    For instance, Japan's H-IIB rocket weighs 531 tonne but can place an eight-tonne rocket in GTO. Similarly, Soyuz, Russia (312 tonne, payload to GTO 3.2 tonne);
    Falcon, USA (549 tonne, payload to GTO 8.3 tonne) and
    Proton, Russia (693 tonne, payload to GTO 6.3 tonne);
    Long March, China (weight 879 tonne, payload to GTO 14 tonne) and
    Ariane 5, Europe (777 tonne, payload 10.9 tonne).

    ISRO Mars Orbiter Mission’s Methane Instrument Has a Glitch

    Isro has completed the engineering goal of sending a orbiter into correct orbit around Mars. But what about the scientific goals, like using Methane sensor to study Mars atmosphere.

    The orbiter was packed with six scientific instruments, altogether able to study the Martian atmosphere and surface characteristics. However, by January 2016, ISRO had been able to release only high-definition pictures taken by MOM – no scientific results seemed forthcoming. One ostensible reason provided for this was that MOM’s primary mission was as a technology demonstrator, and that scientific studies would follow after the mission was completed.
    https://thewire.in/23544/first-scientific-result-from-mars-orbiter-mission-published/
     
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  13. mugundhan

    mugundhan 2nd Lieutant FULL MEMBER

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    It's really stupid to compare isro and drdo.
    Both are doing good in their own way.

    ISRO cannot launch a rocket within 1 hour notice or can launch from any part of the country, but drdo need to design a missile for that.
     
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  14. zebra7

    zebra7 Captain FULL MEMBER

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    Those who critisize DRDO don't have the idea of the range of the technologies it works. They even didn't have the idea that the DRDO developed the special food processing material to be consumed by the soldiers on the Siachin Glacier, and the technology to grow vegetable of mamoth size in the harsh environment of the Ladakh, whose demand is so much in the local market and making India among the group of 2 nation together with the Norway to have such capability. Those people should see those 1.5 KG onions from the Leh fields.
     
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  15. Grevion

    Grevion Professional Think Troll IDF NewBie

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    Certainly more efficient in the way they deals with their job but DRDO aren't bad either.
     

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