GSAT-4+GAGAN=GSLV-D3(Mk.2)- 15.04.10 14:57 ЛМВ -авария

[Salo]

http://beta.thehindu.com/news/national/article321187.ece

GSLV to be launched on April 15

For the first time GSLV will be powered by home-made cryogenice engine. PSLV will take off on May 5

India's GSLV rocket, powered by home-made cryogenic engine for the first time, would be launched on April 15 from Sriharikota to place into orbit GSAT-4 experimental satellite. Previous GSLV flights were fitted with Russian engines.

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http://www.hindu.com/2010/04/10/stories/2010041068741900.htm

GSLV-D3 ready for launch on April 15

T.S. Subramanian

India is flying its own cryogenic stage for the first time


HIGH HOPES:GSLV-D3 on the launch pad at Sriharikota on Friday.

CHENNAI: There is an air of expectancy at Sriharikota even as the Geo-synchronous Satellite Launch Vehicle (GSLV-D3) stands gleaming in off-white and grey on the beachside launch pad of the island. It was fitted together at the towering Vehicle Assembly Building and moved to the pad on April 7. The vehicle, 49 metres tall and weighing 419 tonnes, was married up with the satellite GSAT-4 earlier. When the vehicle lifts off at 4.27 p.m. on April 15, it will be a major riposte to the United States' technology denial tactics.

"Crucial mission"

"The vehicle has been assembled and is ready for the launch," Mission Director G. Ravindranath told journalists at the spaceport on Friday. He called it "a crucial mission because we are flying our own cryogenic stage for the first time in this flight." It was "the most reviewed vehicle" and the result of "our efforts of the last 19 years. We started in 1991 and we have reached this stage despite technology denials."

The entire flight from lift-off will last 1,022 seconds. Of this duration, the indigenous cryogenic engine alone will fire for 720 seconds. At the end of 1,022 seconds, the cryogenic engine will catapult the communication satellite GSAT-4 into the orbit at a velocity of 10.2 km a second. It will be a geo-synchronous transfer orbit (GTO) with a perigee of 170 km and an apogee of 36,000 km.

The cryogenic stage was built at the Liquid Propulsion Systems Centre (LPSC), Mahendragiri, Tamil Nadu. Cryogenic engines are crucial for putting communication satellites weighing more than two tonnes into a GTO. Cryogenic technology involves the use of liquid oxygen at minus 183 degrees Celsius and liquid hydrogen at minus 253 degrees Celsius.

Mohammed Muslim, Project Director, Cryogenic Upper Stage Project (CUSP), said the cryogenic technology was the most complex one to be developed by the Indian Space Research Organisation (ISRO). "It has taken us 15 years to achieve this. It is normal time for any country and we are the sixth country to acquire this technology [after the U.S., Russia, Europe, Japan and China]. This is a highly guarded technology." The ISRO had not taken chances with this mission and "the vehicle has been reviewed and checked point by point any number of times," he said.

The ISRO built the cryogenic engine from scratch after the U.S. pressured Russia in April 1992 and July 1993 into agreeing not to sell cryogenic technology to India. In January 1991, India and the erstwhile Soviet Union had reached an agreement, under which the Soviet space agency, Glavkosmos, would sell cryogenic stages and transfer the cryogenic technology to India.

Goes back on pact

Under U.S. pressure, Russia in July 1993 went back on its agreement to transfer the cryogenic technology. In lieu of the technology, it agreed to sell two additional cryogenic stages to India. The last five flights of the GSLV from Sriharikota were powered by the Russian cryogenic stages. A cryogenic stage includes the engine, propellant tanks, motor casing and wiring.

Mr. Ravindranath said it took the ISRO all these years to develop the cryogenic technology because it had to develop special materials.

(At very low temperatures of liquid hydrogen and liquid oxygen, metals become brittle. The ISRO, therefore, had to develop new alloys, new welding techniques and new types of lubricants).

7-year mission life

Satellite Director M. Nageswara Rao said GSAT-4 would have a mission life of seven years. One of the payloads would help passenger aircraft land accurately despite poor visibility.

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http://isro.org/news/pdf/GSLV-D3.pdf

GSLV-D3 / GSAT-4 MISSION
 
Background  
 
GSLV-D3 is the third developmental mission of India's Geosynchronous Satellite Launch Vehicle during which ISRO's indigenously developed Cryogenic Upper Stage (CUS) will be flight tested. In this flight, GSLV is scheduled to launch 2220 kg GSAT-4, an experimental advanced technology communication satellite that carries communication and navigation payloads, into Geosynchronous Transfer Orbit (GTO). GSLV, carrying the indigenous CUS, is designated as GSLV MkII.  Envisaged mainly as a technology demonstrator for advanced satellite communications, GSAT-4 will enable the testing of many future communication satellite technologies.  After reaching GTO, GSAT-4 will use its own propulsion system to reach its geostationary orbital home  and will be stationed at 82 deg East longitude there.
 
GSLV-D3 Mission
 
GSLV-D3 is the sixth flight of ISRO's Geosynchronous Satellite Launch Vehicle (GSLV) as well as its third developmental flight. Major changes incorported in GSLV-D3 compared to its previous flight (GSLV-F04) include:

•  Indigenous Cryogenic Upper Stage
•  Advanced Telemetry System and Advanced Mission Computers
•  Larger Composite Payload Fairing  
 
GSLV-D3 is the maiden flight of GSLV in which the indigenous Cryogenic Upper Stage (CUS) is used. In the past five flights of GSLV, Cryogenic Stages (CS) procured from Russia were used.  GSLV, with the Russian CS, was designated as GSLV MkI, whereas the present GSLV carrying the indigenous CUS is designated as GSLV MkII.  
 
GSLV was designed to inject 2 ton class of communication satellites to Geosynchronous Transfer Orbit (GTO). Usually, geostationary satellites are first injected into the elliptical GTO by launch vehicles. Later, the satellites are taken to the circular Geostationary Orbit using their own propulsion system. Geostationary Orbit lies at a height of 36,000 km over the equator.
 
The 50 m tall GSLV, with a lift-off mass of 416 ton, is a three-stage vehicle with solid, liquid and cryogenic stages. The solid core motor of the first stage of GSLV is one of the largest rocket motors in the world and uses 138 tons of Hydroxyl Terminated Poly-Butadiene (HTPB) based propellant (fuel-oxidiser combination). The second stage (carrying 38.5 tons of   propellant ) as well as the four strap-on motors of the first stage
(each carrying 42 tons of propellant) use liquid propellant 'Vikas' engine burning UH25 and Nitrogen Tetroxide. The third stage of GSLV carrying 12.5 tons of propellants is a cryogenic stage that uses liquid Hydrogen as fuel and liquid Oxygen as oxidiser.  
 
GSLV employs S-band telemetry and C-band transponders for enabling vehicle performance monitoring, tracking, range safety/flight safety and Preliminary Orbit Determination (POD).  
 
The Composite Carbon Fibre-Reinforced Plastic Payload Fairing (PLF), which is 8.657 m long and 4 m in diameter, protects the satellite and the vehicle electronics during its ascent through the atmosphere. It is jettisoned when the vehicle has reached an altitude of about 115 km.  In the earlier flights of GSLV, a metallic PLF of 3.4 m diameter was used.
 
The Redundant Strap Down Inertial Navigation System (RESINS MkIV) / Inertial Guidance System (IGS), housed in the equipment bay of GLSV, guides the vehicle from lift-off to satellite injection. The digital auto-pilot and closed-loop guidance scheme ensure the required attitude manoeuvre and guided injection of the satellite to the specified orbit.

GSLV employs various separation systems such as Flexible Linear Shaped Charge (FLSC) for the first stage, pyro actuated collet release mechanism for the second stage and Merman band bolt cutter separation mechanism for the PLF.  Spacecraft separation is by spring thusters mounted at the separation interface.    
 
Besides having the indigenous Cryogenic Upper Stage for the first time, in another  major change, GSLV-D3 is carrying  Advanced Mission Computer (AMC) and Advanced Telemetry System (ATS) packages.    
 
GSLV-D3 will be launched from the Second Launch Pad (SLP) at Satish Dhawan Space Centre SHAR, Sriharikota.
 
Indigenous Cryogenic Upper Stage
 
GSLV-D3 flight is significant since the indigenously developed Cryogenic Upper Stage (CUS) is flight tested in this mission.  This is the first time GSLV is carrying the indigenous CUS as its third stage instead of the Russian supplied Cryogenic Stage (CS), which was carried during its earlier flights.

Cryogenic Stage is a rocket stage that is much more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant stages. Specific impulse (a measure of the efficiency) achievable with cryo fluids (liquid Hydrogen and liquid Oxygen) is of the order of 450 sec compared to 300 sec for earth storable and solid fuels, giving a substantial payload advantage; for an upper stage, with every one second increase in the specific impulse, the payload gain is of the order of 15 kg.  
 
However, cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to the use of propellants at extremely low temperatures and the associated thermal and structural problems. Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C.  The propellants, at these low temperatures, are to be  pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of the cryo fluids and related safety aspects.  
 
ISRO's Cryogenic Upper Stage Project (CUSP) envisaged the design and development of the indigenous Cryogenic Upper Stage to replace the stage procured from Russia and used in GSLV flights.  CUSP was intended to develop a cryogenic stage with regenerative cooled engine, producing a thrust of 69.5 kilo Newton (kN) in vacuum. As part of this effort, cryogenic engines were realised and tested earlier for a cumulative duration of 7760 sec. In the stage level hot test, apart from cryogenic engine, all other stage elements worked in unison as per flight standards.  
 
In December 2008, a major milestone was achieved with the flight acceptance hot test of the indigenous Cryogenic engine. This hot test was an importance step in acquiring a coveted status for the country among space faring nations which have successfully mastered this critical and most complex technology. With this, India came a step closer to becoming totally self reliant in all aspects of launch vehicle technology.
 
The indigenous Cryogenic Upper Stage (CUS) is powered by a regeneratively cooled cryogenic engine, which works on staged combustion cycle.  This main engine, and two smaller (cryogenic) steering engines together develop a nominal thrust of 73.55 kN in vacuum.   The main engine of CUS achieves a specific impulse of 452 seconds.  During the flight, CUS fires for a nominal duration of 720 seconds.  
 
Along with the main engine and the two steering engines, the other stage systems of CUS 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 16.6 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 during initial stages.
 
Apart from the complexities in the fabrication of stage tanks, structures, engine and its subsystems and control components, CUS employs special materials like Aluminum, Titanium, Nickel and their alloys, bi-metallic materials and polyimides. Stringent quality control and elaborate safety measures have to be ensured during assembly and integration.
 
GSAT-4: The Satellite
 
GSAT-4 is the nineteenth geostationary satellite of India built by ISRO and fourth in the GSAT series. Its three GSAT predecessors were launched by GSLV during 2001, 2003 and 2004 respectively.  After its commissioning, GSAT-4 will join the group of India's eleven operational
geostationary satellites.
 
Some of the new Technologies being tested in GSAT-4 include:
 
•  Electric Propulsion System  
•  Bus Management Unit  
•  1553 Bus for Data Communication
•  Miniaturised Dynamically Tuned Gyros
•  36 AH Lithium Ion Battery  
•  70 V Bus for Ka band TWTAs
 
Besides, the Technology Experiments carried onboard GSAT-4 are:
 
On-board Structural Dynamics Experiment to monitor on-orbit structural dynamic behavior of the satellite during various phases of the mission corresponding to various flight/mission and satellite configurations
 
Velocity Measurement Package to measure the incremental velocity imparted to GSAT-4 during LAM firings and station keeping manoeuvres Thermal Control Coating Experiment to study the degradation characteristics of thermal control materials in space environment with time
 
The cuboid shaped GSAT-4 has a lift-off weight of 2220 kg of which propellants weigh 1155 kg and the dry mass of the satellite is 1063 kg. GSAT-4 structure is based on ISRO's standard I-2000 bus.  The two solar arrays (each with two panels) of GSAT-4 together generate about 2800 W of power.
 
GSAT-4 is the first geostationary satellite of ISRO to employ integrated Bus Management Unit (BMU) which combines the functions of Telemetry, Telecommand, Sensor Electronics and Control Electronics.  BMU acts as the brain of GSAT-4.  
 
Like its INSAT and GSAT predecessors, GSAT-4 has a conventional chemical propulsion system for orbit raising and station keeping manoeuvres.  Besides, GSAT-4 is the first ISRO satellite having Electric Propulsion Sytem (EPS) to perform North South Station Keeping.  The satellite will demonstrate the capabilities and advantages (very high Isp, meaning efficiency) of EPS employing state-of-the-art stationary plasma thrusters.  
 
 
GSAT-4 at a glance:
 
Structure      : I-2000
Overall Size (m)        :  2.4 X 1.6 X 1.5  
Liftoff mass  (kg)        :  2220  
Generated Power (W)   :  2760
Payload Power (W)       :  1785
Propulsion (Chemical)  : MMH as fuel and MON-3 as Oxidiser
Propulsion (Electric)     : Xenon based stationary plasma thrusters (four)
Mission Life          : > 7 years
Orbital Location         : 82 deg E longitude in GSO
 
 
GSAT-4 Payloads:
 
GSAT-4 carries communication as well as navigation payloads.  They are:
 
•  Ka - band bent pipe and regenerative transponder
•  GAGAN payload operating in C, L1 and L5 bands  
 
Of these, Ka-band Transponder operates on 30 GHz uplink and 20 GHz downlink. This payload provides 8 spot beams covering entire India. Spot beams allow frequency reuse through geographical separation.  The payload also comprises beacon transmitters in 30 GHz and 20 GHz to facilitate propagation studies. Ka band payload also has the facility of RF tracking and antenna pointing.    
 
New technologies incorporated in Ka-Band Payload include Multiple Spot Beams (eight) with Frequency Reuse, Double Frequency Conversion, Very
High Stability Local Oscillator and Onboard Base band Processing and Switching.
 
The advantages of using a regenerative transponder are many.  It allows the use of smaller ground terminals at the user end by incorporating efficient processing on-board the satellite.  Regenerative transponder also increases system flexibility by facilitating network interconnection on-
board satellite without the use of a hub, which in turn results in increased capacity, reduced errors and greater throughput.
 
Each of the 8 beams will have 8 narrow band channels of 64 Kbps and one wide band channel of 2048 Kbps.  Interconnectivity between  the narrow band channels within the same beam or with any of the other beams is possible.  
 
Similarly,  interconnectivity is possible with wide band channels between any of the beams or all beams can be used together in broadcast mode. Another objective of this payload is to develop advanced Digital Signal Processor based subsystems, implement various interface protocols and verify interconnectivity of terminals between multiple beams.  
 
The intended applications for Ka band include Wide band Multimedia Services, Mobile Information System, SPACE LAN, e-Commerce and High Bandwidth Internet.
 
The second payload carried by GSAT-4 is GAGAN, which is a navigational payload operating in C, L1 and L5 bands. Essentially, the GAGAN payload of GSAT-4 forms the space segment of GAGAN Satellite Based Augmentation System (SBAS) developed by India.  GAGAN stands for GPS Aided Geo Augmented Navigation.  Through SBAS, the positional information from the GPS satellites is improved by a network of ground based receivers and the same is made available to any user through geostationary satellites.
 
GAGAN is a Wide Area Differential Global Positioning System (WADGPS) employing a geostationary satellite overlay system.  It was conceived to provide a position accuracy of better than 7.6 metre needed for the precision landing of civilian aircraft.  The GAGAN system consists of the Space Segment, the Ground Segment and the User Segment.  The GPS and Geostationary overlay system form the Space Segment while the Ground Segment comprises Indian Reference Stations (INRES), Indian Master Control Centre (INMCC) and Indian Land Uplink Stations (INLUS).  The User Segment consists of SBAS receivers capable of receiving GPS signals and corrections from the Geostationary satellite.    
 
In the GAGAN architecture, Data from INRES is transmitted to INMCC. This data is processed by INMCC and sent to INLUS. INLUS transmits the corrected GPS information and time synchronisation signal to a geostationary satellite. The satellite then transmits a GPS like signal on L-band  frequency.  Accuracy  of  the  order  of  3  meter  horizontal and 4 meter vertical is feasible in such a system.
 
Thus, GAGAN navigation payload of GSAT-4 receives the correction signals sent by Indian Land Uplink Stations in C-band and translates these into GPS L1 and L5 band signals and transmits these navigation signals.  These signals can be received by GPS SBAS receivers, thus enabling them to get a highly accurate and reliable navigational fix.
 
The Technology Demonstration Phase(TDS) of GAGAN was successfully completed in August 2007. As  part of the TDS, eight Indian  Reference Stations (INRES) were installed at eight Indian airports. They are linked to the Indian Master Control Centre (INMCC) located at Kundanhalli near Bangalore. In June 2009, the final operational phase (FOP) of  GAGAN was initiated.
 
Geostationary Satellites of India : Ushering in a Revolution
 
GSAT-4 is the nineteenth Indian geostationary satellite built by ISRO. In the past two and a half decades, India's geostationary satellites have revolutionised the country's telecommunications, TV broadcasting and Weather Monitoring sectors. More recently, ISRO's INSAT and GSAT series of satellites circling the Earth in the 36,000 km high geostationary orbit have brought in a revolution in India's healthcare and educational sectors.  Besides, they have been instrumental in taking the benefits of space technology directly to the doorsteps of rural India through Village Resource Centres (VRCs).  Today, geostationary satellites are an integral part  of  India's  national  infrastructure. The country has about 200 communication transponders in geostationary orbit that operate in S, C, Extended C and Ku bands.
 
INSAT system has become a major catalyst for the expansion of television coverage in India. Satellite television (DTH) now covers 100% area and 100% population. The terrestrial coverage is over 65 percent of the Indian  landmass  and  over  90  percent  of  the  population.  Around 30 million of TV Receive Only (TVRO) terminals were distributed and operational all over India by various DTH service providers.  
 
Similarly, a total of about 650 Earth stations and nearly 120,000 VSAT terminals are operating in INSAT telecommunications network providing 9600 two-way speech circuits. Besides, Mobile Communication Services are also offered by the INSAT system.
 
Two of India's geostationary satellites - INSAT-3A and KALPANA-1 - are also providing meteorlogical services by sending weather imagery and relaying meteorological data collected by automatic Data Collection Platforms established in various parts of the country. At the same time, the Search and Rescue Transponder onboard INSAT-3A has picked up many distress signals and thus has enabled the saving of many lives through timely search and rescue operations.
 
India has a dedicated geostationary communication satellite called EDUSAT for educational field.  Currently , about 52,000 classrooms from primary to university level as well as those in the non formal educational sector are in the EDUSAT network facilitating the extension of quality education to students in semi urban and rural areas.
 
Additionally,  India's geostationary satellites have facilitated the extension of quality healthcare services to rural India. Presently, 306 remote/rural/district/medical college hospitals and 16 Mobile Telemedicine units are connected to 60 specialty hospitals in the ISRO telemedicine network.
 
This apart, as per the relatively recent Village Resource Centre (VRC) initiative, India's geostationary satellites have been instrumental in taking the benefits of space technology directly to the Indian villages by providing the much needed connectivity.
 
In this context, coupled with the growing demand for geostationary communication transponders, the launch of GSAT-4, which is a technology demonstrator for advanced satellite communications, acquires added significance.

[Salo]

http://isro.org/gslv-d3/Imagegallery/launchvehicle.aspx#2


First stage of GSLV-D3 .  


Hoisting of GSLV-D3 Second Stage. Second stage of GSLV-D3.


Indigenous Cryogenic Upper Stage being lifted at Vehicle Assembly Building. Staking of GSLV-D3 Indigenous Cryogenic Upper Stage


GSLV-D3 Payload fairing containing GSAT-4


GSLV-D3 being transported to second launch pad with the vehicle assembly building in the background. GSLV-D3 at the second
launch pad at SDSC SHAR Sriharikota - Ready for Launch

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http://www.youtube.com/watch?v=nd8GwjWOsp4&feature=player_embedded
http://www.youtube.com/watch?v=wlTYKuuY0Nc&feature=player_embedded

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http://www.spaceflightnow.com/tracking/index.html

April 15     GSLV  •  GSAT 4
Launch time: 1057 GMT (6:57 a.m. EDT)
Launch site: Satish Dhawan Space Center, Sriharikota, India

India's Geosynchronous Satellite Launch Vehicle (GSLV) will launch the GSAT 4 experimental communications satellite for the Indian Space Research Organization. Codenamed GSLV D3, the launch will be the first GSLV to use an indigenous third stage cryogenic engine. [April 14]

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http://beta.thehindu.com/opinion/lead/article397441.ece?homepage=true

The long road to cryogenic technology
N. Gopal Raj

The immediate challenge for ISRO in the GSLV launch is to demonstrate that it has indeed mastered the intricacies of cryogenic technology.

The forthcoming launch of the Geosynchronous Satellite Launch Vehicle (GSLV) will be a watershed for the Indian Space Research Organisation, marking the culmination of the quest for cryogenic technology that dates back to over 25 years and has seen many twists and turns.

Cryogenic technology involves the use of rocket propellants at extremely low temperatures. The combination of liquid oxygen and liquid hydrogen offers the highest energy efficiency for rocket engines that need to produce large amounts of thrust. But oxygen remains a liquid only at temperatures below minus 1830 Celsius and hydrogen at below minus 2530 Celsius. Building a rocket stage with an engine that runs on such propellants means overcoming engineering challenges.

The United States was the first country to develop cryogenic rocket engines. The Centaur upper stage, with RL-10 engines, registered its first successful flight in 1963 and is still used on the Atlas V rocket. America's early mastery of the technology paved the way for the J-2 engine, which powered the upper stages of the immensely powerful Saturn V rocket that sent humans to the Moon.

Other spacefaring nations followed. The Japanese LE-5 engine flew in 1977, the French HM-7 in 1979 and the Chinese YF-73 in 1984. The Soviet Union, first country to put a satellite and later a human in space, successfully launched a rocket with a cryogenic engine only in 1987.

ISRO recognised the importance of cryogenic technology fairly early. A rocket stage based on a cryogenic engine offered the simplest way of transforming the Polar Satellite Launch Vehicle (PSLV), intended to carry one-tonne earth-viewing satellites, into the far more powerful GSLV that could put communications satellites into the orbit.

In December 1982, six months after the PSLV project was cleared, a Cryogenic Study Team was set up. A year later, it submitted a report recommending the development of a cryogenic engine that could generate about 10 tonnes of thrust. The 15-volume report went into every aspect of developing the engine and rocket stage indigenously.

Then, strangely, ISRO went through a long period of indecision, dithering on whether to buy the technology or develop it on its own. Acquiring the technology from abroad would greatly reduce the time that would otherwise be needed, it argued.

But the U.S., Japan and France would either not provide the technology or do so only at an exorbitant price. Finally in January 1991, a deal was signed with the Soviet company Glavkosmos to buy two cryogenic flight stages as well as the technology to make them in India.

The 11D56 cryogenic engine had been developed for one of the upper stages of the mammoth N1 rocket, the Soviet equivalent of Saturn V. But after four successive launch failures, the N1 project was scrapped and its engines were mothballed. Under the Indo-Soviet deal, ISRO would get a stage built around the 11D56 cryogenic engine that could produce 7.5 tonnes of thrust. The stage would carry 12 tonnes of propellant.

But the deal violated the Missile Technology Control Regime, which was intended to prevent the spread of missile-related technology, and fell foul of the U.S. laws meant to enforce its provisions. Despite warnings from within the organisation, ISRO opted to go ahead with the import. In May 1992, the U.S. imposed sanctions on ISRO and Glavkosmos. A year later, Russia, which inherited the contract after the break-up of the Soviet Union, backed out of the deal.

ISRO then had no option but to develop the technology on its own. The Cryogenic Upper Stage project was launched in April 1994. Its aim was to develop a cryogenic engine and stage closely modelled on the Russian design.

At the time, ISRO gave the impression that much of the technology had already been acquired and further development would be quick. A GSLV with an indigenous cryogenic engine would be ready to fly in about four years, Chairman U.R. Rao told The Hindu in July 1993. The space agency's engineers were privately saying then that a flightworthy cryogenic stage was 10 years away. Instead, it has taken 16 years.

The Russian design involves a complicated 'staged combustion cycle' to increase the engine efficiency. Hydrogen is partially burnt with a little oxygen in a gas generator. The hot gases drive a turbopump and are then injected at high pressure into the thrust chamber where the rest of oxygen is introduced and full combustion takes place. Before going to the gas generator, the incredibly chilly liquid hydrogen is used to cool the thrust chamber where temperatures rise to over 3,0000 Celsius when the engine is fired.

Reproducing the Russian design meant ISRO engineers also learning to deal with new materials and manufacturing methods. A process, known as vacuum brazing needed to make the engine's thrust chamber, for instance, took considerable time to master. Then there was the challenge posed by the powerful turbopump that rotates at a tremendous speed in order to send up to 18 kg of propellants every second into the thrust chamber. It must do so in the face of a sharp temperature gradient, with hot gases at over 5000 Celsius driving the turbine, which then spins the pumps for freezing-cold propellants.

Steps were also taken so that materials required for the engine and stage could be made within the country.

The Indian cryogenic engine is produced by Godrej and the Hyderabad-based MTAR Technologies working together as a consortium. Instead of ISRO first mastering the technology and transferring it to industry, the two companies were involved from the start and even the early prototypes were built by them. Failure on their part was not an option and the space agency had to make sure that these companies succeeded.

Finally, in February 2000, the first indigenous cryogenic engine began to be test-fired on the ground. According to one source, things went wrong in one test and an engine ended up badly damaged. However, by December 2003, three engines had been ground-tested for a cumulative duration of over an hour and half. One of those engines was fired continuously for more than 16 minutes, four minutes longer than it would operate in actual flight. More tests with the engine integrated into the full stage followed. The cryogenic engine that will fly in the forthcoming GSLV launch was tested on the ground for a little over three minutes in December 2008.

Meanwhile, the Russians had supplied ISRO with seven ready-to-fly stages. But their 11D56 cryogenic engine had not flown before and the Indians faced some unpleasant surprises.

The first was that the Russian-supplied stages turned out to be heavier than expected. In order to carry the extra load, it is learnt, the Russians increased the maximum thrust that the 11D56 engine was capable of — from 7.5 tonnes to a little over eight tonnes. The engine operates at the higher thrust for only part of the duration of its flight. The Indian engine too had to be tested and made to work at the higher thrust level. Moreover, the Indian stage is lighter than the Russian one.

When the GSLV was first launched in April 2001, the Russian cryogenic engine was found to be less efficient than predicted, based on a measure that rocket engineers call specific impulse. The increase in stage weight and decrease in efficiency together reduced the rocket's payload capacity significantly.

Where the GSLV with the cryogenic stage was intended to put 2.5 tonnes into the orbit, the rocket carried a satellite weighing just 1.5 tonnes in its first flight. With further optimisation of the Russian cryogenic stage and other parts of the rocket, the GSLV could successfully launch the 2,140-kg Insat-4CR in its fifth launch in 2007.

Sources told this correspondent that the last two stages supplied by the Russians carry an engine with a maximum thrust of over nine tonnes and are capable of accommodating an additional three tonnes of propellant. The GSLV with this stage would be capable of delivering a payload of 2.5 tonnes into the orbit. With further ground testing, the Indian engine too would be upgraded to a similar thrust level.

But the immediate challenge for ISRO and its engineers is to demonstrate in the GSLV launch that they have indeed mastered the intricacies of cryogenic technology.


All SET: The advanced communication satellite GSAT-4 undergoes tests at Sriharikota, in this April 13 photo. India's Geo-synchronous Satellite Launch Vehicle (GSLV-D3), which is powered by a totally indigenous cryogenic engine, will put the GSAT-4 into the orbit.

[Salo]

http://www.thehindubusinessline.com/2010/04/15/stories/2010041556400800.htm

Bandwidth to improve as GSat-4 heralds Ka band

ISRO's latest satellite to be launched today.



Ready for lift-off:The two portions of the payload fairing on either side of the communication satellite GSat-4 at Sriharikota prior to the satellite's launch on Thursday.

Madhumathi D.S.

Bangalore, April 14

The new Ka band that ISRO is heralding in the country on its latest satellite GSat-4 will improve the bandwidth for the Net user and also drive down the price noticeably.

But not immediately. The customer has to wait for three more years to feel the effect of its real operation, according to Mr K.R. Sridhara Murthi, Managing Director of ISRO's commercial arm, Antrix Corporation. GSat-4 is an experimental satellite with a multi-beam Ka-band transponder.

The Ku band has got crowded and it is believed that Ka, which can support higher data transmission by at least two or three fold, will be preferred for non-broadcasting applications.

The biggest advantages of Ka band are the higher bandwidth it offers, a 20-30-cm antenna that is almost half the diameter of the present Ku band dishes; and transmission over small areas at higher power. The C-band antenna was 2 metres wide.

On the flip side, Ka transmission is vulnerable to outages during rain. "One big issue with the Ka band for our country is attentuation or rain-fade, which is worse than with Ku band. Communication can be impaired during rain," Mr Murthi told Business Line. He was speaking ahead of the launch of the advanced communications satellite slated for Thursday evening from Sriharikota.

With Ka, the entire country can be covered much more efficiently in 20-50 spot beams instead of using one big beam. The same frequency can be re-used for different users without interference. "You can use this more amenably for Internet broadband services. It may not be preferred for DTH or broadcasting which needs very big beams," Mr Murthi said. The multiple beams have been tried out with another experimental service, the Edusat.

Potential users are VSAT operators, rural Internet connectivity where cables will not go; for video conferencing and certain user groups.

Ka services may cost more in the beginning because of new equipment that the service provider has to install. But as with Ku band equipment, over time and number of sales, it can get cheaper than Ku. The price of terminals is ruling at $200-$300, which should not be a big constraint for operators, Mr Murthi said.

GLOBAL TREND

By 2013, ISRO plans to have a fully operational Ka-band satellite, the GSat-14. "I'm sure Ka will click technologically. It is very much part of future technology. While you may enjoy new recipes, you also cherish the older ones. Ka, when it gets operational, will complement C and Ku bands that we have used so far."

Reports say the world is certainly moving towards Ka, and for new and lucrative applications. Of the 75-plus communications satellites going into service between now and 2014, some 30-35 will have Ka band transponders.

ISRO is building Hylas-1 with Ka transponders for UK operator Avanti. The other large Ka projects include Hylas-2, DirecTV, EutelSat Ka-Sat, Yahsat 1A and 1B; and ABS-2.

Meanwhile, Mr Murthi said, "We have to measure the extent of fading. With C and Ku bands, the quality of service was 99.9 per cent. We don't know yet how good this would be for DTH operations." In the West, impaired communication has been managed with some technical solutions, he said.

The Space Applications Centre, Ahmedabad, which developed the payload, is also understood to be working on solutions for the industry on how to beat the rain fade problem

[Salo]

http://beta.thehindu.com/sci-tech/science/article396898.ece

The 29-hour countdown for GSLV-D3 begins
T. S. Subramanian

The 29-hour countdown for the lift-off of India's Geo-synchronous Satellite Launch Vehicle (GSLV-D3) is proceeding satisfactorily for the launch to take place from Sriharikota on April 15 at 4.27 p.m. The countdown began at 11.27 a.m. on Wednesday, April 14. The GSLV-D3 will put an advanced communication satellite named GSAT-4 into orbit. The importance of the launch lies in that the vehicle is being powered by a totally indigenous cryogenic engine for the first time. "A successful flight will give India a coveted status among the space-faring nations in the world and total self-reliance in all areas of launch vehicle technology," said S. Satish, spokesman, the Indian Space Research Organisation (ISRO).

The GSLV-D3 vehicle is 49 metres tall and weighs 419 tonnes. It is a three-stage rocket. The core first stage is powered by solid propellants. Around this core stage are four strap-on motors that are powered by liquid propellants. The second stage again uses liquid propellants. The third upper stage is propelled by the indigenously made cryogenic engine.

Filling of the second stage and the four strap-on booster motors with liquid propellants will be completed during the 29-hour countdown. "The filling of the cryogenic engine with liquid hydrogen and liquid oxygen will continue till almost the end of the countdown. This is to prevent loss of cryogenic fluids due to evaporation," said Mr. Satish. Certain mandatory checks of the vehicle and charging of the batteries in both the rocket and the satellite would be done during this countdown.

This mission was crucial for India because India, for the first time, was flying its own cryogenic stage in the rocket, the ISRO spokesman said. Only five other countries had developed this complex technology. They were the U.S., Russia, Europe, Japan and China. Cryogenic technology was a must to put heavy communication satellites, weighing more than two tonnes, into elliptical geo-synchronous orbit of 170 km by 36,000 km.

The GSAT-4 weighs 2,220 kg. It carries communication and navigation payloads. They are Ka-band transponder and the GPS-Aided Geo-Augmented Navigation (GAGAN). The applications of Ka-band include wide-band multimedia services, e-commerce, high band-with internet, mobile information system etc. The GAGAN payload will help commercial aircraft to land accurately in runways during poor visibility.

[Salo]

http://www.thaindian.com/newsportal/sci-tech/countdown-on-for-rocket-launch-with-indian-cyro-engine-lead_100348156.html

Countdown on for rocket launch with Indian cryo engine (Lead)
April 15th, 2010

ISRO Chennai, April 14 (IANS) The countdown to the launch of a 50-metre, tall, 416-tonne rocket with an Indian cryogenic engine to inject an advanced communication satellite in the geo-synchronous orbit has started at the Sriharikota spaceport in Andhra Pradesh, a space agency official said Wednesday.
"Filling of liquid propellants in the four strap-on motors (42 tonnes each) that will be hugging the rocket is set to begin soon. Fuel filling of the second stage (40 tonnes) got over recently," Indian Space Research Organisation (ISRO) director S.Satish told IANS from Sriharikota.

The countdown for the blast off for the Rs.330 crore mission (rocket Rs.180 crore, GSAT-4 satellite Rs.150 crore) started Wednesday morning at 11.27 a.m.

The propellant filling for the Indian designed cryogenic stage (12.5 tonne) will start five hours before the rocket launch and will get over minutes before the actual blast off.

The first stage with 138 tonnes solid fuel is all ready to be fired up.

"All activities are progressing smoothly without any hitch," he added.

The rocket is expected to blast off at 4.27 p.m. Thursday to deliver the 2.2-tonne GSAT-4 satellite into the geosynchronous transfer orbit (GTO).

The notable aspect of this launch is that the rocket will be powered by ISRO designed and built cryogenic engine (development cost around Rs.350 crore). If the cryogenic engine performs as expected, India will become the sixth country in the world to design and develop the cryogenic technology.

The two other unique features of the rocket are its larger composite payload fairing or heat shield and the advanced telemetry systems and mission computers.

After a gap of several decades, the Indian space agency has reverted to fibre reinforced plastic (FRP) heat shield for its rocket.

The GSLV-D3 rocket has a bigger heat shield - four metre diameter - as compared to the earlier rocket versions whose heat shield were of 3.4 metre diameter and were made of aluminium alloy metal.

"In order to reduce the rocket weight with a bigger heat shield, ISRO has decided to use a FRP heat shield. A bigger heat shield will provide more space for carrying a bigger payload," an ISRO official told IANS on the condition of anonymity.

According to him, a bigger equipment bay will not constrict ISRO's satellite building team in their ventures.

Heat shield made of FRP is not new to ISRO as it was used in its satellite launch vehicles (SLV) earlier.

However, the space agency changed to metallic heat shield when it designed its workhorse rocket polar satellite launch vehicle (PSLV) and also in GSLV.

"The increase in heat shield size is made with future launches in mind. While the heat shield of SLV was just one metre diameter, here it is four metres. The challenge was to make the mould," the ISRO official said.

[Salo]

http://timesofindia.indiatimes.com/india/Countdown-begins-as-GSLV-D3-looks-skyward/articleshow/5806596.cms

Countdown begins as GSLV-D3 looks skyward
Arun Ram, TNN, Apr 15, 2010, 04.04am IST

CHENNAI: The Geosynchronous Satellite Launch Vehicle GSLV-D3, the first Indian rocket to be powered by a totally indigenous cryogenic engine, will blast off from the Satish Dhawan Space Centre at Sriharikota at 4.27pm on Thursday. The 416-tonne vehicle will carry GSAT-4, a 2,218-kg communication satellite, to be put in an orbit 36,000km from earth. The countdown for the launch began at 11.27am.

So far only the US, Russia, European Space Agency, China and Japan have developed cryogenic engines. The successful launch of GSLV-D3 will place India in the elite league of masters of cryogenics, the science of very low temperatures. The cryogenic engine gives higher thrust than conventional liquid and solid propellants to launch satellites weighing more than 4,000kg in geosynchronous orbit.

"All parameters of the vehicle are normal and we are proceeding with the pre-launch tests. So far the weather conditions are favourable. We are looking forward to a historic launch," M Nageswara Rao, project director of GSAT4 spacecraft, said.

The fueling of second stage that started on Wednesday will go on till 6am on Thursday, after which the vehicle will be powered. The cryogenic upper stage will be fueled only four hours before the launch. "We are repeatedly checking all systems and everything looks fine. Drifts of the gyroscope will now be corrected every hour till a few minutes before the launch. The rocket will be ignited 4.8 seconds before the lift-off," Rao said.

[Salo]

А это ссылки на возможную трансляцию:

http://forum.nasaspaceflight.com/index.php?topic=18858.msg574150#msg574150

Look out for the live coverage on IBN, and NDTV

http://www.ndtv.com/news/videos/video_live.php?id=LIVE_BG24x7&live=tv
http://ibnlive.in.com/

I will try to update the list closer to launch time....

edit: + http://timesnow.live.indiatimes.com/

[Frontm]

http://www.ndtv.com/news/videos/video_live.php?id=LIVE_BG24x7&live=tv

[us2-star]

2 минуты до старта..

[us2-star]

Пошла!

[Frontm]

Пишут что
problems in GSLV

[Sharicoff]

Водородник...

[Чебурашка]

Телеметрия прекратилась. Пуск аварийный.

[Sharicoff]

Орбитальной скорости не набрали. Всё на корм рыбам...

[Старый]

О всех, кого помню и люблю...
Говорите индийский был водородник?