Mission 100

PSLV C-21 on its wayto put the French SPOT-6 and the Japanese PROITERES, both earth observation satellites, into orbit on September 9.-S.R. RAGHUNATHAN

With the experience of a century of missions, ISRO aims at sending a spacecraft to Mars.

Its hundredth mission, the launch of PSLV-C-21 on September 9, an unalloyed success, the Indian Space Research Organisation (ISRO) now has its eyes set on sending a spacecraft to Mars in November 2013 using its rugged workhorse, the Polar Satellite Launch Vehicle (PSLV).

Indias space journey began on April 19, 1975, when the indigenously built Aryabhatta satellite was put into orbit by the Soviet Intercosmos vehicle from the Volgograd launch station at Kapustin-Yar (now in Russia). India has since orbited 62 satellites of its own, has had 37 launch missions, and has brought back from orbit the satellite called Space Capsule Recovery Experiment, said ISRO Chairman K. Radhakrishnan.

The PSLV-C-21 mission was to put the 712-kilogramme French SPOT-6 and the 15-kg Japanese PROITERES, both earth observation satellites, into orbit. It was the PSLVs 22nd flight and 21st success in a row. P.S. Veeraraghavan, Director, Vikram Sarabhai Space Centre, Thiruvananthapuram, summed it up thus: The French SPOT-6 was exactly on the spot. If SPOT-6 and PROITERES were to be put into a polar orbit at a height of 655 kilometres, the accuracy achieved was so good that the dispersion was within 7 km.

S. Ramakrishnan, Director, Liquid Propulsion Systems Centre, ISRO, said: This time, the conditions of the vehicles systems were perfect and there were no anomalies to be debated. So it was a smooth 51-hour countdown. Mission Director P. Kunhikrishnan said the four stages of PSLV-C-21 had performed exceedingly well.

Prime Minister Manmohan Singh, who was present at the Mission Control Centre at the spaceport in Sriharikota in Andhra Pradesh, called the mission a spectacular success and said the fact that PSLV-C-21 put two satellites into orbit was a testimony to the commercial competitiveness of the Indian space industry.

The PSLV-C-21 carried an improved inertial navigation system (INS) with a sophisticated accelerometer, which helped the rocket to catapult the two satellites accurately into orbit. This INS was lighter by 15 kg than those previous missions used. This meant that PSLV-C-21 could carry a heavier payload. This is the heaviest customer-built spacecraft put into orbit by the PSLV, Radhakrishnan said.

He declined to reveal how much Antrix Corporation, the commercial arm of the Department of Space, had charged from the builders of SPOT-6 and PROITERES. The cost of PSLV-C-21, Rs.90 crore, has been recovered, the ISRO Chairman said. PSLV-C-21 is a core-alone rocket without the standard strap-on booster motors.

PROITERES is an experimental satellite built by students and teachers of the Osaka Institute of Technology (OIT) and has a novel electric propulsion. It will observe the Kansai district in Japan with a high-resolution camera. PROITERES stands for Project of the OIT Electric Rocket Engine Onboard Small Space Ship.

Although ISRO has lined up several PSLV missions from December this year, the focus will be on the lift-off of Indias own Mars Orbiter aboard PSLV-XL in November 2013. PSLV-XL, which has more than normal powerful strap-ons, will put Indias Mars Orbiter into an orbit of 500 km by 80,000 km around the planet. The spacecraft will carry about 25 kg of scientific payloads. They will focus on weather, geology, and the origin, evolution and sustainability of life on Mars. The Mars Orbiter has to be launched when the planet comes closest to the earth, and such slots are available only in 2013, 2016 and 2018. The lift-off should take place by November 27, 2013. The voyage to Mars will take about 300 days. For the first time, we are doing a voyage for such a long time, said Radhakrishnan. For this journey, ISRO has to develop the on-board autonomy for the Mars Orbiter to handle itself and there should be constant communication with it from the ground. This is one of the challenges. Mars is important because we will be developing several critical technologies needed for the future, he said.

ISROs confidence about the Mars mission is high after its PSLV-XL put Chandrayaan-I into orbit in October 2008. It is collaborating with Russia to orbit Chandrayaan-II, which will feature a lander from Russia and a rover on the moon from India.

Astrosat will be Indias first dedicated astronomy mission, which will enable observations of celestial bodies. A standard PSLV will put the 1,500-kg Astrosat into orbit at an altitude of 650 km. These are ISROs science missions apart from its application satellites.