Key things to know about Chandrayaan 2: From mission aim to landing site

India will be the fourth nation apart from US, the former USSR and China to reach the moon.

India is all set to launch its most prestigious and complex space mission Chandrayaan-2. The mission will make India the fourth country to soft land on the lunar surface after Russia, the United States and China.

Chandrayaan-2 onboard its heavy-lift rocket GSLV-MkIII, nicknamed Baahubali, will be launched at 2.51 am from the Satish Dhawan Space Centre (SDSC) in Sriharikota.

Here are the key things to know about India's second unmanned mission to the moon:

Objectives of Chandrayaan-2

The primary objective of Chandrayaan-2 is to demonstrate the ability to soft-land on the lunar surface and operate a robotic rover on the surface. Scientific goals include studies of lunar topography, mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxyl and water ice.

Evidence for water molecules discovered by Chandrayaan-1, requires further studies on the extent of water molecule distribution on the surface, below the surface and in the tenuous lunar exosphere to address the origin of water on Moon.

The lunar South Pole is especially interesting because of the lunar surface area here that remains in shadow is much larger than that at the North Pole.

All you need to know about Chandyaan 2's orbitor, lander and rover

The orbiter will have a scientific payload comprising a visible terrain mapping camera, a neutral mass spectrometer, a synthetic aperture radar, a near infrared spectrometer, a radio occultation experiment, a soft X-ray spectrometer and solar X-ray monitor.

The lander, named Vikram, has a mass of 1471 kg (including the rover), and can generate 650 W of solar power. The lander can communicate directly to the Indian Deep Space Network, the orbiter, and the rover. The lander will carry a camera, seismometer, thermal profiler, Langmuir probe, and a NASA-supplied laser retroreflector.

The rover, Pragyan (also Pragyaan), is a 6-wheeled vehicle with a mass of 27 kg that runs on 50 W of solar power and can travel up to 500 m at a speed of 1 cm per second. The rover communicates directly with the lander. the rover will hold cameras, alpha-proton X-ray spectrometer, and a laser-induced ablation spectroscopy experiment.

Mission schedule

Chandrayaan 2 is scheduled to launch on 15 July at 02:51 am. The lander-orbiter pair will go into an initial elliptical lunar orbit on 5 or 6 August. After orbit insertion, the lander and orbiter separate. The orbiter evolves into a 100 km altitude circular polar orbit and the lander brakes from orbit and lands on the surface in the high latitude areas near the south pole, planned for 6 or 7 September. The orbiter portion of the mission is planned to last 1 year. The rover will be deployed using a ramp shortly after landing. The lander and rover portions of the mission are planned for 14-15 days, one period of lunar daylight.