November 9, 2008
By Syed Akbar
Hyderabad, Nov 8: India on Saturday joined the select club of four Moon-faring nations when its first-ever lunarcraft, Chandrayaan-1, successfully entered the elliptical orbit of the Moon after a series of complex manoeuvres by a team of ISRO scientists based in Bengaluru.
Though India sent its unmanned mission to the Moon on October 22, the Chandrayaan-1 spacecraft had been orbiting the Earth all along and only on Saturday evening, it successfully came off the gravitational pull of the human planet to enter the unknown realms of the lunar world. It is now orbiting at a distance of 500 km from the Moon when it is nearest, and 7,500 km when it is farthest, from the Earth's natural satellite.
"We will put the Chandrayaan-1 spacecraft in the designated orbit of about 100 km away from the Moon in a couple of days. This is the first time that an Indian built spacecraft has broken away from the Earth’s gravitational field and reached the moon," ISRO's director (PR) S Satish told this correspondent from Bengaluru.
Only the United States of America, the erstwhile USSR, Japan and China have thus far sent their missions to the Moon. With Saturday's crucial manoeuvring of the orbit of the Chandrayaan-1, India enters the select Moon Club. When the Chandrayaan-1 is put in the designated orbit of 100 km away from the Moon, ISRO scientists back home
in Bengaluru will order the spacecraft to eject a probe onto the lunar soil. The probe carries the Indian national flag, a brainchild of former President APJ Abdul Kalam.
According to Mr Satish, the motor on the spacecraft was fired for about 805 seconds at around 4.51 pm to put Chandrayaan-1 into an elliptical orbit with 7,502 km aposelene (farthest from moon) and 500 km pericelene (nearest to moon).
Putting the spacecraft in the lunar orbit is a critical task and any minor mistake in ground command would have sent it farther deep into the Space, far away from the lunar world."Our scientific prowess is on the rise. We are proud of Chandrayaan-I. The very fact that it has been a success so far is a great achievement. The lunar mission will take a closer look at the north and the south poles, something which
has not been attempted before," Kapil Sibal, Union Minister for Science and Technology, who is in Hyderabad to release his book, told this correspondent.
An ISRO official statement later said Chandrayaan-1’s liquid engine was fired when the spacecraft passed at a distance of about 500 km from the Moon to reduce its velocity to enable lunar gravity to capture it into an orbit around the Moon.
The spacecraft is now orbiting the moon in an elliptical orbit that passes over the polar regions of the moon. Chandrayaan-1 takes about 11 hours to go round the moon once in this orbit. "The performance of all the systems onboard Chandrayaan-1 is normal. In the coming days, the height of Chandrayaan-1 spacecraft’s orbit around the moon will be carefully reduced in steps to achieve a final polar orbit of
about 100 km height from the moon’s surface. Following this, the Moon Impact Probe (MIP) of the spacecraft will be released to hit the lunar surface. Later, the other scientific instruments will be turned on sequentially leading to the normal phase of the mission," it said.
Since its launch, the liquid engine of Chandrayaan-1 has been successfully fired five times at opportune moments to increase the apogee (farthest distance from earth) height, first to 37,900 km, then to 74,715 km, later to 164,600 km, after that to 267,000 km and finally to 380,000 km. During this period, the Terrain Mapping Camera, one of the 11 scientific instruments of the spacecraft, was successfully operated twice to take the pictures, first of the Earth, and
then moon.
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