Indian Space Research Organisation’s (ISRO) space mission Chandrayaan-2 is just hours away from making history. Vikram Lander’s final touchdown will begin in the early hours of Saturday. Vikram, with the Pragyan rover, placed inside is scheduled for a powered-descent between 1 am and 2 am on September 7, followed by its touchdown between 1.30 am and 2.30 am. While India’s space history began 50 years ago, it hit a major milestone with Chandrayaan-1, which was launched on October 22, 2008. More than a decade later, the space agency is all set to achieve another major milestone with Chandrayaan-2. If successful, India will be the fourth country after the US, Russia, and China, to complete a soft landing on the Moon.

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Key differences between Chandrayaan-1 and Chandrayaan-2

1. PSLV & GSLV: Chandrayaan-1 was launched by India's Polar Satellite Launch Vehicle -PSLV-C11 -on October 22, 2008, from the Satish Dhawan Space Centre, Sriharikota. On the other hand, Chandrayaan-2 was launched by the GSLV Mk-III on July 22, 2019, from the same space centre.

2. Lifespan: Chandrayaan-1 scripted history by making more than 3,400 orbits around the Moon and was operational for 312 days till August 29, 2009, after ISRO lost communication with it, almost after a year it was launched. Meanwhile, Chandrayaan-2’s orbiter will continue its mission for around a year. (Chandrayaan-1 was recently confirmed to still be orbiting the Moon, though it is no longer transmitting back to ISRO. Chandrayaan-2's eventual fate is as yet unknown)

3. Soft-Landing vs Orbiting: According to ISRO, India’s first Moon mission conclusively established traces of water on the Moon, making a path-breaking discovery. Chandrayaan-2 will be the first space mission to conduct a soft landing on the Moon’s South Polar region. This is also India’s first expedition to attempt a soft landing on the lunar surface with home-grown technology.

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4. Instruments: Chandrayaan-1 also discovered water ice in the North Polar region besides detecting magnesium, aluminium, and silicon on the lunar surface. Global imaging of the Moon was another achievement of the mission.

According to the ISRO, the mission objective of Chandrayaan-2 is to develop and demonstrate the key technologies for end-to-end lunar mission capability, including soft-landing and roving on the lunar surface. The space agency had also said it aims to further expand the knowledge about the moon through a detailed study of its topography, mineralogy, surface chemical composition, thermo-physical characteristics and atmosphere, leading to a better understanding of the origin and evolution of the moon.

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Chandrayaan-2 to continue the research started by Chandrayaan-1

Once India accomplishes soft landing on the moon, Pragyan rover will roam the south pole on the lunar surface to test the possibility of the presence of water. As explained by ISRO, Pragyan is a six-wheeled robotic vehicle. With a 50W power generation capacity, Pragyan can travel up to 500m before it loses power. Pragyan, which weighs 27kg can only communicate with the Lander - Vikram. After Chandrayaan-1 provided evidence of water molecules on the moon, Pragyan will study the extent of water molecule distribution on the surface, below the surface and in the exosphere using its two payloads - Alpha Particle X-ray Spectrometer (APXS) and Laser-Induced Breakdown Spectroscope (LIBS).

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