Σάββατο, 8 Νοεμβρίου 2008

Chandrayaan-1 in lunar orbit - Ο Ινδικός δορυφόρος σε τροχιά - οι πρώτες φωτο!

Bangalore, November 8: India's maiden moon mission -- Chandrayaan-I —
on Saturday entered the tricky lunar orbit after scientists successfully carried out a most critical manoeuvre, 18 days after it was fired into outer space. Space scientists at the Indian Space Research Organisation (ISRO) carried out the lunar orbit insertion by firing the liquid engines on board the spacecraft for 817 seconds. "The lunar orbit insertion (LOI) began at 4:50 p.m. and lasted for 817 seconds (14 minutes)," ISRO spokesperson S Satish said. The satellite has been placed in a 7,502 km X 500 km elliptical orbit around the moon, he said. Heaving a sigh of relief, ISRO chief G Madhavan Nair said Saturday's operation was the ‘most critical moment’ in the mission. "We have done it," a visibly happy Nair declared. "For the last 20 minutes, almost all our hearts were at a standStill," Nair said from a ground centre near Bangalore. The spacecraft, launched on October 22, had been placed in the Lunar Transfer Trajectory on November 4. The mission, orbiting the earth at a distance of 3,86,000 km, was commandeered from ISRO's Telemetry, Tracking and Command Network (ISTRAC) at Peenya on the outskirts of the city with aid from the Indian Deep Space Network (IDSN) at Byalalu. Chandrayaan-I would now be lowered gradually and placed in a circular orbit at a distance of 100 km from the lunar surface. The successful lunar orbit insertion (LOI) was an important milestone for the Rs 386 crore moon mission whose success depended on Saturday's hit or miss manoeuvre. According to space experts, the challenging LOI was not without danger because it meant traversing through an area in which the gravitational forces of the earth and moon nearly cancel each other out.
Consequently, even a small deviation could send the spacecraft into a frash course towards the moon or earth—or on a path leading into deep space. Experts recall that about 30 per cent of unmanned moon missions of the US and former Soviet Union failed during LOI phase. Prime Minister Manmohan Singh,who is now in Muscat on an official visit, congratulated the Indian space scientists for the singular achievement. "This (today's achievement) will be etched in the history of Indian space in golden letters", Nair said. In the coming days, the height of Chandrayaan-1's orbit around the moon would be carefully reduced in steps to achieve a final polar orbit of about 100 kms height from the moon's surface. The spacecraft, launched on October 22, had been placed in the Lunar Transfer Trajectory on November 4. The mission, orbiting the earth at a distance of 3,86,000 km, was commandeered from ISRO's Telemetry, Tracking and Command Network (ISTRAC) at Peenya on the outskirts of the city with aid from the Indian Deep Space Network (IDSN) at Byalalu. Chandrayaan-I would now be lowered gradually and placed in a circular orbit at a distance of 100 km from the lunar surface. The successful lunar orbit insertion (LOI) was an important milestone for the Rs 386 crore moon mission whose success depended on Saturday's manoeuvre. According to space experts, the challenging LOI was not without danger because it meant traversing through an area in which the gravitational forces of the earth and moon nearly cancel each other out. Consequently, even a small deviation could send the spacecraft into a fresh course towards the moon or earth—or on a path leading into deep space. Experts recall that about 30 per cent of unmanned moon missions of the US and former Soviet Union failed during LOI phase. The lunar orbit manoeuvre was performed from Chandrayaan-1 Spacecraft Control Centre of ISRO Telemetry, Tracking and Command Network here, while Indian Deep Space Network (IDSN) at Byalalu on the city outskirts supported the crucial task of transmitting commands and continuously monitoring this vital event with two dish antennas, one measuring 18 metres and the other 32 metres. Expressing happiness that the accuracy that ISRO got in regard to Saturday's lunar orbit is really remarkable, Nair said nobody (space agency) would have secured such a precise orbit in the first attempt. The achievement goes to the credit of ISRO, which has demonstrated its knowledge base in carrying out long trajectories under the influence of multiple bodies. "We (India) now have a big leadership as far as space is concerned", he said. ISRO said the performance of all the systems on board Chandrayaan-1 is normal. Nair said the Moon Impact Probe (MIP) on board Chandrayaan-1 would be released to hit the lunar surface around November 15. "Thereafter, systems (on board Chandrayaan-1) would be switched on one-by-one". ISRO officials said the primary objective of 29-kg MIP is to demonstrate the technologies required for landing a probe at the desired location on the moon. Through this probe, it is also intended to qualify some of technologies related to future soft-landing
missions. This apart, scientific exploration of the moon at close distance is also intended using MIP.

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