Chandrayaan-2 expected to reach Moon on Aug 20, landing on Sept 7: Isro

Chandrayaan-2 will be orbiting the Earth for 23 days and on August 14, Isro will conduct the Trans Lunar Injection

India's second mission to the Moon, Chandrayaan-2, is expected to reach the orbit of Earth's satellite on August 20. 

Isro officials said that the Earth-bound manoeuvers for Chandrayaan-2 spacecraft are being executed from today onwards.

The first earth-bound orbit-raising manoeuver of the Chandrayaan-2 spacecraft was performed successfully on this afternoon at 1452 hrs (IST) as planned, they added.

Four Earth-bound manoeuvers are planned between July 26 and August 8, culminating into a trans-lunar insertion on August 14, which will send Chandrayaan-2 to the Moon.

The Geosynchronous Satellite Launch Vehicle-Mk III (GSLV-Mk III), carrying the 3.8-tonne Chandrayaan-2 spacecraft, lifted off from its launchpad on July 22, at 2.43 p.m. 

After a technical snag aborted the takeoff on July 15, the space agency succeeded in putting the satellite in the desired orbit, as the first step of its 48-day journey to the Moon’s unexplored south pole, about 384,000 km away.

Following a week-long delay in its journey due to a serious technical snag that compelled the Isro to postpone the launch on July 15, the space agency reworked its schedule to enable its landing on the south pole on the previously fixed date.

For this, Isro has had to adjust the travel time by tweaking the earth-bound and lunar-bound phases, officials explained. As per the new timeline, the Earth-bound phase has gone up by six days to 23 days, from 17 days earlier. The Lunar Orbit Insertion (LOI) now stands reduced to 13 days, from 28 days earlier.

With this, the Earth-bound phase has risen by six days, while the Lunar-bound phase stands reduced by 15 days. Thus, in total, there has been a nine-day reduction, while only seven days have been lost due to the postponement on July 15, said experts.

Isro chairman K Sivan told Business Standard that the Space Agency has 45 days to complete the mission and can always adjust the journey. "To go to the Moon, it will take only five days. During the remaining days, the satellite will be orbiting around Earth or Moon, so we can adjust during the period," he said.

According to the new schedule, Chandrayaan-2 will be orbiting the Earth for 23 days before Isro conducts the Trans Lunar Injection on August 14. The satellite would be in the Lunar Transfer Trajectory from the Day 23 to Day 30. On August 20, it will be inserted into the Lunar Orbit and will be there till September 1. On September 2, the lander and orbiter will be separated from the orbiter and Isro will conduct a deboosting on September 3. The Moon landing will take place as per the earlier plan, on September 7, the 48th day since launch.

According to experts, the distance to the orbit has risen by 6,000 kilometers due to the delay, so more time on the Earth orbit and less on the Moon orbit is based on the positioning the Moon (as the Earth's natural satellite). This has been achieved by a 15 per cent increase in the efficiency of the GSLV Mk 3, in order to make up for the delay.