SV Krishna Chaitanya By

Express News Service

CHENNAI: The anxious wait is over. Indian Space Research Organisation (ISRO) has rescheduled Chandrayaan-2 launch on July 22 at 2:43 pm and the best part is there won't be any change in landing date. Though a week's travel time to Moon is lost, scientists are confident of soft landing on the lunar surface on September 6 as originally planned.

This was confirmed to Express by ISRO Chairman K Sivan.

"The integrity of the mission is intact. Lander Vikram will touch down on Moon's surface as originally planned on September 6, which is crucial since the mission life of Vikram and rover Pragyan is only one Lunar Day (14 Earth days). So, the travel time to Moon will be brought down from 54 days to 47 days. The mission has enough scope to make such an adjustment."

Officials said the moon mission has nine phases starting from Earth-bound phase to landing. After lift-off, 3,850 kg spacecraft will be injected into an earth parking 170 x 40400 km orbit and for 17 days a phased manoeuvre of five Earth Burns will be carried out to 1,05,292 kms and put the spacecraft on Lunar Transfer Trajectory.approximately on the 19th day. Sivan said: "Few lost days will be covered during the orbit raising."

From here, the Chandrayaan will take a few days to arrive in the proximity of the Moon. The spacecraft's Liquid Apogee Motor will be retrofitted to insert it into a lunar orbit. Gradually over a few days, the spacecraft will be brought closer to the Moon in 100x100 km circular obit through five Lunar Burns, which takes about 28 days. Officials say here again there is abundant scope to make necessary adjustments to match the targeted landing date.

Just five days before landing, Vikram will separate and de-boost to 100x30 kms lunar orbit where it will remain for four days. On the fourth day, Optical High-Resolution Camera payload onboard orbiter will be turned on to scout for a suitable landing site in the lunar South Pole region. The images taken will be transmitted to Earth and processed after which the landing site map will be uploaded in Vikram prior to its powered descent phase.

Lander will hover at 100 meters above the lunar surface and gradually begin its descent. Once Vikram lands, the Rover-Pragyan will deploy. The payloads of Pragyan and Vikram will then be turned on and start collecting information on lunar topography, mineralogy, elemental abundance, lunar exosphere and signatures of hydroxyl ions and water-ice.

Online registrations open on July 19

ISRO announced that online registrations for witnessing the launch of Chandrayaan-2 mission onboard GSLV-MkIII from viewer's gallery will commence from 6 pm on July 19.

Earlier in the day, in an official statement, ISRO said: "An expert committee was constituted to analyse the issue and suggest remedial action. The committee identified the root cause of the technical snag and all corrective actions are implemented. Thereafter, the system performance is normal."

Original plan:

Phase Period

Earth-bound Phase Day 1 to Day 17 (17 days)

Trans Lunar Injection (TLI) Day 17

Lunar Transfer Trajectory (LTT) Day 17 to Day 22

Lunar Orbit Insertion (LOI) Day 22

Lunar Bound Phase (LBN) Day 22 to Day 49 (28 days)

Lander-Orbiter Separation Day 50

Deboosting Day 51

Powered Descent Starts Day 54

Landing Day 54

(This will be brought down to 47 days)