NEW DELHI: A crucial manoeuvre, to be performed on Saturday, on Chandrayaan-1 will inject it into an orbit around the moon from its current highly elliptical orbit around the earth.
On November 4, the last of the earth-bound manoeuvres was carried out, which put the satellite into an orbit with an apogee (the farthest point in the orbit from the earth) of 3,84,000 km and a perigee (the nearest point) at 1,019 km. With this apogee, the satellite actually encircles the moon as well. However, this earth-bound orbit is actually at about an inclination of 18 degrees to the earth's Equator. Since the final designated lunar orbit is a circumpolar one, this orbit has also to turn around by almost 90 degrees.
As the satellite cruises along its present trajectory, the moon's gravity will begin to dominate when this orbit will be about 60,000 km from the moon, which is expected to happen around midnight on Friday. Under the gravitational pull, the satellite will also begin to gain velocity. The orbit plane will also begin to gradually tilt away from its present near-equatorial one. |