Chandraayan countdown started

October 20th, 2008 - 11:42 am ICT by IANS  

Sriharikota (Andhra Pradesh), Oct 20 (IANS) As the countdown for the Wednesday launch of lunar mission Chandrayaan-1 on board the polar satellite launch vehicle (PSLV-C11) started early Monday, this spaceport off the Bay of Bengal coast was bustling with activity, excitement and a bit of anxiety.With the countdown starting at 5.22 a.m., about 1,000 top scientists and technologists are working round-the-clock to send India’s first spacecraft mission beyond earth orbit from the picturesque spaceport, located on an island about 80 km from Chennai.

Housing the Satish Dhawan Space Centre of the state-run Indian Space Research Organisation (ISRO), the spaceport is popularly known as SHAR (Sriharikota Range). The rocket-launch station was built in 1971 over an area of 43,360 acres (175 sq km) along a 50-km coastline between Pulicat lake and the blue lagoon.

“Sriharikota was chosen as India’s spaceport because of its strategic location, topography, good launch azimuth corridor for space missions, advantages of earth rotation for eastward launches, nearer to the equator and an uninhabited area for safety,” SHAR spokesman N. Ravindranath told IANS.

With the state-of-the-art technology for producing solid propellant, processing heavier class solid rocket boosters, the facilities are equipped for testing their flight worthiness.

The first launch pad and the second launch pad are equipped with propellant storage and servicing, integration and launch facilities to meet the requirements of PSLV and GSLV (geo-synchronous satellite launch vehicle). A host of facilities for tracking and real-time flight data processing include range instrumentation.

“The spaceport has best-in-class infrastructure for launching satellites into low earth orbit, polar orbit and geo-stationary transfer orbit. The complex provides complete support for vehicle assembly, fuelling, checkout and launch operations,” Ravindranath said.

The various stages of PSLV and GSLV, their sub-systems and the spacecraft are prepared and tested in separate facilities before they are moved to the launch pad for integration. A 76-metre tall mobile service tower (MST) facilitates the vertical integration.

The foldable working platforms of MST provide access to the vehicle for elevations. A massive launch pedestal, made up of steel plates, acts as the base on which the vehicle is integrated. The umbilical tower houses the feed lines for liquid propellants and high-pressure gases, checkout cables and chilled air duct for supplying cool air to the satellite and equipment bay.

“A few hours before the launch of any mission to polar or geo-synchronous orbit, the MST is withdrawn and the vehicle remains on the launch pedestal. The 3,200-tonne MST moves at snail’s pace to its parking slot on 32 wheels, eight in each corner, on a twin rail track,” Ravindranath explained.

The second launch pad provides redundant facilities for launching operational PSLVs and GSLVs and to have quick turnaround time for more launches. It is being augmented for future launch vehicle configurations such as GSLV-MkIII.

“The launch vehicle is assembled and checked out on a mobile pedestal in the vehicle assembly building and then moved in vertical position to the launch pad on a rail track. The second launch pad is being used for the Chandrayaan mission to reduce pad occupancy and move the vehicle back to the VHB for protection in the event of cyclone warning,” Ravindranath pointed out.

Besides launch pads, the spaceport boasts of a high-tech range instrumentation facility comprising tracking, telemetry and tele-command systems. High precision radars track the launch vehicle.

“The tele-command system is used to transmit command to the vehicle. If the vehicle malfunctions and deviates from the trajectory beyond the acceptable limits, the range safety officer terminates the flight using the telecommand,” the official affirmed.

As the heart of the spaceport, the mission control centre (MCC), situated about six km from the launch complex, coordinates and conducts the launch operations during the countdown phase and till the injection of the satellite into its designated orbit.

The MCC is linked to all the ground stations through communication links for voice and data transmission. The launch preparations on the vehicle are monitored from the MCC using a multi-channel closed-circuit television system,” Ravindranath noted.

Of the 2,600-plus people employed to operate the spaceport, about 700 are scientists and technologists. A township has been built on the island, surrounded by the sea on the east and backwaters on the other three sides.

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