Come November 8, India’s space programme could have its first ever date with the moon.

Five years after the Government cleared the project, ISRO announced on Thursday that it is all set to launch the country’s first unmanned mission to the moon and unveiled the spacecraft — Chandrayaan-1, fully loaded with its six Indian and five foreign scientific instruments— at its satellite centre.

The spacecraft is scheduled for launch on October 22 with a window fixed between October 19 and October 28. It will make an entry into the lunar atmosphere for a two-year mission. The window is, however, subject to Chandrayaan-1 clearing the vibration and acoustic tolerance tests over the next week before it is shipped to Sriharikota for integration with its launch vehicle the PSLV-XL. “The flesh and bone is ready,” said ISRO moon mission director M Annadurai. It has cleared a major hurdle in the form of extreme temperature tests (thermo vacuum test) over the past fortnight. Now its launch is dependent on weather factors, said Annadurai.

“Weather is a key issue. We are watching for forecasts closer to the tentative launch dates. On the east coast there are worries over weather at this time of the year,” Annadurai added. Chandrayaan-1 would take approximately eight days to course the nearly 3,86,000 km to get to its final orbit — 100 km from the moon.

LunarCraft would be launched using Polar Satellite Launch Vehicle (PSLV) from .The Satish Dhawan Space Centre (SDSC) is located in Sriharikota.

LunarCraft would weight 1304 kg at launch and 590 kg at lunar orbit.

The LunarCraft would be launched in a highly elliptical transfer orbit with perigee (Perigee is the point at which an object in orbit around the Earth makes its closest approach to the Earth) of about 240 km and an apogee (The point in the orbit of the moon or of an artificial satellite most distant from the center of the earth) of about 24,000 km.

After a quick estimate of the achieved LTT (Lunar Transfer Trajectory) a mid-course correction will be imparted at the earliest opportunity. The spacecraft coasts for about five and a half days in this trajectory prior to the lunar encounter. The major maneuver of the mission, called Lunar Orbit Insertion (LOI) that leads to lunar capture, would be carried out at the peri-selene (nearest point in lunar orbit) leading to successful lunar capture in a polar, near circular 1000 km-altitude orbit.

After successful capture and health checks, the altitude is planned to be lowered through a series of in-plane corrections to achieve the target altitude of 100 km circular polar orbit.

links:Indian Express

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