Chandrayan I :-

Chandrayaan I, the Indian spacecraft, successfully reached the lunar surface at 20:31 hrs on November 14, 2008. It is actually the first Indian-built object to reach the surface of the Moon.

It was weighed 34 kg at the time of its on-board launch and carried a video imaging system, a radar altimeter, and a mass spectrometer. The video imaging system was designed to take pictures of the Moon's surface as MIP approached the lunar surface. Whereas, the radar altimeter measured the rate of descent of the probe while the mass spectrometer made a detailed study of the extremely thin lunar atmosphere.

With the launch of the mission, India joined a select band of countries who have undertaken lunar missions by launching the first unmanned mission to the Moon.

The flight was conducted from the Satish Dhawan Space Centre (SDSC), Sriharikota on October 22, 2008. The Polar Satellite Launch Vehicle, PSLV-C11, successfully launched the 1380 kg Chandrayaan I spacecraft into a transfer orbit with a perigee of 255 km and an apogee of 22,860 km, inclined at an angle of 17.9 degree to the equator.

• Journey of Chandrayan I :-  Chandrayaan was first made to circle the Earth in its transfer orbit, and then was put into elliptical "extended transfer orbits" by repeatedly firing its liquid engine in a pre-determined sequence. Consequently, the liquid engine was once more fired to make the spacecraft travel to the vicinity of the Moon by following a path called the "Lunar Transfer Trajectory (LTT)."

When it reached near the Moon and passed at a few hundred kilometers from it, its liquid engine was fired again so that the spacecraft slowed down sufficiently to enable the gravity of the Moon to capture it into an elliptical orbit with the consequence that the engine firing the height of the spacecraft's orbit around the Moon was reduced in steps. After cautious and detailed observation of the orbit perturbations, the orbital height of Chandrayaan I was finally lowered to its intended 100 km height from the lunar surface.

• Finding of Chandrayan I :- The cameras on board Chandrayaan I, which were named the terrain mapping camera (TMC) and hyper-spectral imager (HySI), were switched on and excellent quality pictures of the lunar surface were taken. All the payloads resulted in a satisfactory operation. Chandrayaan I has successfully demonstrated India's capability and proficiency in carrying out highly complex space missions.

It should be noted that the successful launch of Chandrayaan I has paved the way for undertaking missions to the Moon and beyond.

Chandrayaan II :-

Chandrayaan-2 is India’s most challenging and India’s second mission to Moon.It is advanced version of previous Chandrayaan-1 mission (launched in 2008) which only involved orbiting around moon, Chandrayaan-2 is much complicated mission as it involves an orbiter, lander and rover. The mission components have been completely developed indigenously by ISRO and consists of Orbiter, Lander and Rover configuration. Chandrayaan-2 will be ISRO’s first time attempt to land a rover on the moon. The rover of India’s second lunar mission, costing nearly Rs. 800 crore, will be made to land near the yet-unexplored south pole.

Initially, ISRO planned to partner with Russia to perform Chandrayaan-2. The two agencies signed an agreement in 2007 to launch the orbiter and lander in 2013. Russia later pulled out of the agreement, however, according to a news report from The Hindu. The Russian lander's construction was delayed after the December 2011 failure of Roscosmos' Phobos-Grunt mission to the Martian moon of Phobos, the report stated.

Russia subsequently pulled out of Chandrayaan-2 altogether, citing financial issues. Some reports stated that NASA and the European Space Agency were interested in participating, but ISRO proceeded with the mission on its own.

Features of the mission :- 

• In this mission, ISRO will for first time attempt to land rover on moon’s south-pole.The mission involves soft-landing on lunar surface and rover that will walk and analysis content on moon’s surface.Chandrayaan 2 will be launched on board of Geosynchronous Satellite Launch Vehicle Mk III (GSLV-F10).It will be ISRO’s first inter-planetary mission to land rover on any celestial body.
• The spacecraft (orbiter) weighs around 3,290 kg and it will orbit around moon and perform objectives of remote sensing moon.Once GSLV-F10 put spacecraft in 170 km x 20,000 km elliptical orbit, orbiter will be manoeuvred towards 100-km lunar orbit by firing thrusters and the rover will separate from orbiter. 
• The six wheeled rover will move on unexplored lunar surface and collect soil or rock samples for on-site chemical analysis to gather scientificinformation on lunar topography, mineralogy, elemental abundance, lunar exosphere and signatures of hydroxyl and water-ice.

Delay and timeline :- 

Chandrayaan 2's journey has been rather slow so far. Although the mission was envisioned way back in November 2007, as a joint mission between India and Russia, it had faced a series of setbacks.

There has been delay and postponment of the date of launch of the satelite.As of now, there will be a further delay in the launch of India’s second mission to the moon, Chandrayaan-2 and it may be no sooner than January 2019. The postponement of the ambitious mission from October comes in the wake of the Indian Space Research Organisation (ISRO) facing two setbacks in less than a year. The launch of the mission was first planned in April. 

Earlier this year, the ISRO had launched GSAT-6A, a military communication satellite, but lost communication with it. Following this, the ISRO also recalled the launch of GSAT-11 from from Kourou, French Guiana, for additional technical checks. Last September, the PSLV- C39 mission, carrying the IRNSS-1H navigation satellite, failed after the heat shield refused to open and release the satellite.

Earlier this year, the ISRO had launched GSAT-6A, a military communication satellite, but lost communication with it. Following this, the ISRO also recalled the launch of GSAT-11 from from Kourou, French Guiana, for additional technical checks. Last September, the PSLV- C39 mission, carrying the IRNSS-1H navigation satellite, failed after the heat shield refused to open and release the satellite.