ISRO scores a centum

A Polar Satellite Launch Vehicle (PSLV-C21) blasted off from Sriharikota on September 9 and placed two foreign satellites in orbit, accomplishing the Indian Space Research Organisation’s 100th mission, a milestone in the country’s space journey.

After a 51-hour countdown, the PSLV lifted off at 9.53 a.m., two minutes behind schedule, to avoid any collision with space debris.

In the textbook launch, it carried SPOT-6, a 712-kg French earth observation satellite and injected it into an orbit of 655-km altitude, inclined at 98.23 degrees to the equator. Proiteres, a 15-kg Japanese microsatellite, was put into orbit as an additional payload. Prime Minister Manmohan Singh and a host of dignitaries watched the flight path on electronic screens, as the 44-metre tall PSLV accomplished its task, reinforcing the fact that it is the ISRO’s workhorse, with 21 successful missions in a row.

The four-stage ignition and the injection of the satellites into the orbit took 18 minutes and 37 seconds. As Proiteres separated at the final moment, the scientists erupted into joyous applause.

SPOT-6, an optical remote-sensing satellite capable of imaging the earth with a 1.5-metre resolution, is built by Astrium SAS, a European space technology company.

Proiteres is meant to study the powered-flight of a small satellite by an electric thruster and to observe Japan’s Kansai district with a high-resolution camera.

With Sunday’s mission, the ISRO has launched 62 satellites and 38 rockets. It has so far injected 28 foreign satellites into orbit, beginning with Germany’s 45-kg DLR-TUBSAT aboard the PSLV-C2 in 1999. SPOT-6 is the the PSLV’s biggest commercial lift so far. At a press conference, Dr. Radhakrishnan said the financial matters relating to the launch could not be disclosed, but the cost of the vehicle was recovered. The ISRO also sent its own payload, ‘Mini Resins,’ for demonstration of an instrument called Redundant Strap down Inertial Navigation System.
Manmohan Singh watched the historic 100th mission of the Indian space agency and scientists at Indian Space Research Organisation's (ISRO) rocket's mission control room kept an eye on the rocket that escaped the earth's gravitational pull.

ISRO officials are hoping that the agency's 100th space mission will turn out to be a grand success.
The PSLV-C21 rocket is expected to deliver SPOT 6 and Proiteres into a 655 km polar orbit.
Remote sensing satellites send back pictures and other data. The SPOT and Indian remote sensing satellites are the two leading earth observation satellite series.
Interestingly SPOT 6 is the heaviest foreign satellite to be carried by a PSLV rocket since 1999 when ISRO started launching satellites owned by foreign agencies.
ISRO has been carrying foreign satellites since 1999 initially as an add-on luggage to its own satellite.
It was with Agile, a 350 kg Italian satellite, that ISRO started flying a full commercial rocket. Till date ISRO has launched 27 foreign satellites successfully and the Sunday mission would take the tally to 29.
The successful launch of SPOT 6 would make ISRO's PSLV rocket a strong contender to carry SPOT 7 planned by French company Astrium SAS soon.
According to ISRO, the satellite launch agreement between Antrix and Astrium is part of the long-term agreement signed between the two agencies in September 2008.
The space agency has also jointly built two heavy satellites - 3,453 kg W2M and 2,541 kg Hylas - for the French agency.
India has the largest constellation of remote sensing satellites in the world providing imagery in a variety of spatial resolutions, from more than a metre ranging up to 500 metres, and is a major player in vending such data in the global market.
With 12 remote sensing/earth observation satellites orbiting in the space, India is a world leader in the remote sensing data market. The 12 satellites are TES, Resourcesat 1, Cartosat 1, 2, 2A and 2B, IMS 1, Risat-2, Oceansat 2, Resourcesat-2, Megha-Tropiques and Risat-1.