Bangalore, January 5, 2014
India's Geosynchronous Satellite Launch Vehicle, which will flight test the indigenous cryogenic upper stage again after a failure nearly three years ago, is slated to lift off on Sunday from the Sriharikota spaceport with the aim of injecting the 1982 kg communication satellite GSAT-14 into a geosynchronous transfer orbit.
ISRO begins countdown for launch of GSLV-D5
India's Geosynchronous Satellite Launch Vehicle (GSLV-D5), which will flight test the indigenous cryogenic upper stage (CUS) again after a failure nearly three years ago, is slated to lift off this afternoon from the Sriharikota spaceport in Andhra Pradesh with the aim of injecting the 1982 kg communication satellite GSAT-14 into a geosynchronous transfer orbit (GTO).
The cryogenic engine, developed after 20 years of work by scientists and engineers of ISRO on this complex technology, is crucial for putting communication satellites heavier than two tonnes into GTO.
The 29-hour countdown began at 1118 hours yesterday and the launch is scheduled at 1618 hours today.
Preparations for GSLV-D5 Second Stage (GS2) propellant filling operation commenced at 1148 hours yesterday and completed in about six hours, Indian Space Research Organisation (ISRO) sources said.
Propellant filling operations of GSLV-D5 strap-ons began yesterday and were completed this morning. Preparations for propellant filling operations of the cryogenic stage were in progress, they said.
The Mission Readiness Review (MRR) team and the Launch Authorisation Board (LAB) had, on December 28, cleared the GSLV-D5/GSAT-14 launch.
The vehicle was moved from the vehicle assembly building to the umbilical tower (the launch pad) that morning.
The launch was earlier scheduled for August 19 but was called off on that day due to a technical probem.
A press release from ISRO on that date had said the launch was called off because a leak was observed in the UH25 fuel system of the liquid second stage during the pre-launch pressurisation phase on the vehicle, just two hours before the scheduled lift-off.
This will be the eighth flight of GSLV and its fourth developmental flight.
The first flight test of the indigenous CUS on GSLV-D3 had ended up as a failure on April 15, 2010 when it deviated from its path and splashed into the sea.
GSLV-D3 would have put the 2200 kg GSAT-4, an experimental advanced technology communication satellite that carried communication and navigation payloads, into GTO.
On December 25, 2010, India's space programme suffered yet another setback when the launch of GSLV-FO6, meant to place its heaviest communication satellite GSAT-5P in orbit, failed when the rocket exploded within a minute after lift-off from Sriharikota.
Less than a minute after lift-off, the launch vehicle developed a snag in its first stage and, as scientists at the Satish Dhawan Space Centre (SDSC) watched in disbelief, exploded into flames.
The launch vehicle was meant to inject the 2310 kg GSAT-5P into GTO.
On May 12 last year, ISRO successfully conducted the acceptance test of the indigenous cryogenic engine for the GSLV-D5 flight for 200 seconds. The test was conducted at the Liquid Propulsion Systems Centre (LPSC) test facilities at Mahendragiri. The performance of the engine was as predicted, an ISRO press release had said at that time.
ISRO sources said that, after reaching GTO, GSAT-14 will use its own propulsion system to reach its geostationary orbital home and will be stationed at 74º East longitude. GSAT-14 will help provide many satellite-based communication services to the country including tele-education and telemedicine.
The mission will be launched from the second launch pad at the Satish Dhawan Space Centre at Sriharikota (SDSC SHAR). The flight duration of GSLV-D5 is 17 min 8 sec.
The 49.13 metre GSLV-D5 will have a lift-off mass of 414.75 tonnes and a lift-off thrust of 6773 kilo Newton. It will target an orbit with perigee of 180 ± 5 km and apogee of 35975 ± 675 km with an inclination of 19.3 ± 0.1 deg.
According to ISRO, GSLV is a three-stage launch vehicle with solid, liquid and cryogenic stages. It is designed to inject 2 Ton class of communication satellites into GTO. The four liquid L40 strap-ons as well as the second stage of GSLV use storable liquid propellants.
GSLV-D5 vehicle is configured with its first and second stages similar to the ones flown during earlier GSLV missions. The third stage is the indigenous cryogenic stage. The metallic payload fairing with a diameter of 3.4 metre is adopted for GSLV-D5.
ISRO sources explained that a cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse (a measure of the efficiency) achievable with cryogenic propellants (liquid hydrogen and liquid oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage.
However, cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and the associated thermal and structural problems.
According to them, oxygen liquefies 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 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. The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum.
During the flight, CUS fires for a nominal duration of 720 seconds. Liquid oxygen (LOX) and liquid hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbopump to ensure a high flow rate of propellants into the combustion chamber. Thrust control and mixture ratio control are achieved by two independent regulators. Two gimbaled steering engines provide for control of the stage during its thrusting phase.
The sources said that, based on its performance during the earlier missions, end-to-end design of GSLV as well as indigenous cryogenic stage systems have been re-examined and some new features introduced. In addition, indigenisation of many critical systems has been accomplished, they said.
GSAT-14 is the 23rd geostationary communication satellite of India built by ISRO. Four of GSAT-14’s predecessors were launched by GSLV during 2001, 2003, 2004 and 2007, respectively. After its commissioning, GSAT-14 will join the group of India’s nine operational geostationary satellites.
The main objectives of GSAT-14 mission are to augment the in-orbit capacity of extended C and Ku-band transponders and to provide a platform for new experiments.
Some of the new experiments that will be flown on GSAT-14 are: Fiber Optic Gyro, Active Pixel Sun Sensor, Ka band beacon propagation studies and Thermal control coating experiments.
GSAT-14 will be positioned at 74 deg East longitude and co-located with INSAT-3C, INSAT-4CR and KALPANA-1 satellites. The 12 communication transponders onboard GSAT-14 will further augment the capacity in the INSAT/GSAT system, ISRO added.
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