Chandrayaan 2 / Vikram

Chandrayaan 2 [ISRO]
(cruise configuration)

Chandrayaan 2 Orbiter [ISRO]

Chandrayaan 2 Lander (Vikram) [ISRO]

Chandrayaan 2 Rover (Pragyan) [ISRO]

Chandrayaan-2 is an Indian mission to the Moon, which will have an Orbiter, a Lander and a Rover. After reaching the 100 km lunar orbit, the Lander housing the Rover will separate from the Orbiter. After a controlled descent, the Lander will soft land on the lunar surface at a specified site and deploy a Rover.

The science goals of the mission are to further improve the understanding of the origin and evolution of the Moon using instruments onboard Orbiter and in-situ analysis of lunar samples using Lander and Rover.

Chandrayaan-2 will be launched on India’s GSLV-MkIIA in 2018, delayed from the original 2014 timeframe. In 2018, it was moved to a LVM3 (2) rocket due to mass gains and further delayed to 2019. Lift off mass has gone up from 3250 kg to 3850 kg. The lander weight went up from 1250 kg to about 1350 kg and the six-wheeled rover’s weight from 20 kg to 25 kg.

Orbiter Craft (OC)

Chandrayaan-2 Structure configuration has been changed from I2K to I3K configuration due to the revision of payload lift off capacity by GSLV. This change will enable accommodating larger propellant tanks. The mission strategy was revised to inject the satellite in a lower initial orbit (170 × 16980 km) with a higher lift-off mass of 3200 kg and the Propulsion System Configuration changed to increase fuel carrying capability of the satellite. The other activities completed are: finalisation of all electrical and mechanical interfaces including the payload interfaces; Preliminary Design Reviews (PDRs) of Bus Systems (Power, Attitude Orbit Control Electronics, Telemetry, Tracking and Command Baseband Systems, RF Systems, Data Handling System, Structure, Thermal Control System, Propulsion System); all systems accommodation studies and initial thermal analysis.

The following payloads are on board of the orbiter.

• Terrain Mapping Camera-2 (TMC-2) for preparing a three-dimensional map essential for studying the lunar mineralogy and geology.
• Orbiter High Resolution Camera to conduct high-res topography mapping
• Large Area Soft X-ray Spectrometer (CLASS) and Solar X-ray Monitor (XSM) for mapping the major elements present on the lunar surface.
• Imaging IR Spectrometer (IIRS) for mapping of lunar surface over a wide wavelength range for the study of minerals, water molecules and hydroxyl present.
• L- and S-band Synthetic Aperture Radar (SAR) for probing the first few tens of meters of lunar surface for the presence of different constituents including water ice. SAR is expected to provide further evidence confirming the presence of water ice below the shadowed regions of the moon.
• Chandra’s Atmospheric Composition Explorer-2 (ChACE-2), a Neutral Mass Spectrometer to carry out a detailed study of the lunar exosphere.
• Dual Frequency Radio Science Experiment to study the lunar ionosphere

Lander Craft (LC) (Vikram)

Chandrayaan 2’s lander is named Vikram after Dr Vikram A Sarabhai, the Father of the Indian Space Programme. It is designed to function for one lunar day, which is equivalent to about 14 Earth days. Vikram has the capability to communicate with IDSN at Byalalu near Bangalore, as well as with the Orbiter and Pragyan rover. The lander is designed to execute a soft landing on the lunar surface at a touchdown velocity of 2 m/s. The planned landing site is a high plain between two craters, Manzinus C and Simpelius N, at a latitude of about 70.9° South 22.7° East. An alternative site is 67.7° South 18.4° West.

The lander carries following instruments:

• Seismometer for studying Moon-quakes near the landing site
• Thermal probe for estimating the thermal properties of the lunar surface
• Langmuir probe for measuring the density and variation of lunar surface plasma
• Laser Retroreflector Array (LRA) for lunar laser ranging studies

On 6 September 2019, the lander lost contact shor before landing on the lunar surface. A few days later, it was discovered to have apparently landed, albeit possibly at an angle, which potentially prevents communications.

Rover (Pragyan)

Chandrayaan 2’s 27 kg rover is a 6-wheeled robotic vehicle named Pragyan, which translates to ‘wisdom’ in Sanskrit. It can travel up to 500 m at a speed of 1 cm per second, and leverages solar energy for its functioning. It communicates via the lander. The planned mission life is one lunar day.

Following scientific payloads selected for Indian Rover would carry out elemental analysis of the lunar surface near the landing site.

• Alpha Particle X-ray Spectrometer (APIXS) to determine the elemental composition near the landing site
• Laser Induced Breakdown Spectroscope (LIBS) to derive elemental abundance in the vicinity of the landing site