It’s ready and gift-wrapped in a gold hued foil, but Indian space scientists who are toiling for Chandrayaan-I’s rendezvous with the Moon seem to have their hearts in their mouth. For, they have to steer India’s first orbiter to the Earth's nearest astral neighbour through a 3,86,000-km voyage over five-and-a-half days.
And one little glitch could jeopardise the Indian Space Research Organisation’s (ISRO) venture to find answers to a surfeit of questions: from the origin and evolution of the Moon – which, in turn, will help unravel the origin of the Earth and other celestial bodies – to the possibility of the presence of water and minerals on the Moon’s surface.
As D-day draws nearer (October 19-26), the scientists are pouring over tonnes of mathematical calculations on the orbits of various planets and reviewing the results of simulations performed on high-speed computers to fine-tune the orbiter’s trajectory and to make sure that it “captures the moving target (the Moon)”, says M. Annadurai, project director, Chandrayaan-I.
“Of course, it is not a trivial thing. We have taken it as a big challenge and will use our experience of launching satellites to get it right the first time,” he told reporters at ISRO’s Satellite Centre here.
The big challenge will be on how to guide and control the spacecraft over the 3,86,000-km journey because it will mean a quantum jump from the 36,000 km reached so far by the scientists through the INSAT communication satellites. The scientists have been tracking foreign satellites about 400,000 km away with the help of two gigantic antennae at the Deep Space Network (DSN) station on the outskirts of the city, says Dr Sreekumar, chief scientist, Chandrayaan-I.
On Thursday, the media got a glimpse of Chandrayaan-I at the Satellite Centre's ground-check laboratory. Wrapped in a multi-layer insulation blanket, it has endured a test for a month that subjected it to extreme heat and extreme cold conditions that it is likely to face during its cruise.
Next, it will be rocked with a blast of sound – up to 153 decibels or many times the sound produced by an aircraft – and intense jolts likely during its ride onboard the modified PSLV (polar satellite launch vehicle). It will next be shipped to the Satish Dhawan Space Centre at the Sriharikota range, about 120 km from Chennai, for integration with the rocket.
Annadurai said on reaching its orbit, about 100 Km from the Moon, the spacecraft would sweep over the surface 24 times during its two-year mission. “We will then have enough data on what the Moon contains,” he said.
The project slipped behind schedule by a couple of months because two instruments, which are part of the experiments planned by the European Space Agency, arrived late from Rutherford Appleton Laboratory in the UK and Swedish Institute of Space Physics. Originally, Chandrayaan-I, was scheduled for launch on April 9, but will now start its journey next month or in November.
ISRO has earmarked Rs 386 crore for Chandrayaan-I. The orbiter will be hoisted into space by the homegrown PSLV from the Sriharikota range. It will take the spacecraft six to seven days to reach its orbit — a distance of 100 km from the Moon. Midway through the mission, a 50-kg impactor will be released to crash onto the lunar surface, with a set of gadgets tuned to peer through the cloud set off by the collision.