An Indian rocket carrying two satellites blasted off from the first launch pad at the Satish Dhawan Space Centre in Andhra Pradesh Sunday, with the launch being witnessed by Prime Minister Manmohan Singh.

The rocket carried two foreign satellites - SPOT 6, a French satellite and a Japanese micro satellite called Proiteres.

Manmohan Singh along with Minister in Prime Minister Office, V. Narayanasamy, were present to witness the launch at the Indian Space Research Organisation (ISRO). Sriharikota is around 80 km north of Chennai.

Exactly at 9.51 a.m., the rocket - Polar Satellite Launch Vehicle-C21 (PSLV-C21), standing around 44 metres tall and weighing around 230 tonne, with a one way ticket - hurtled towards the skies ferrying the two foreign satellites - SPOT 6, a French earth observation satellite weighing 712 kg and 15 kg micro satellite Proiteres of Japan.

The cost of the rocket is around Rs.75 crores.

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

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.