Chandrayaan-2 is an Indian mission to send an orbiter, lander, and rover to the Moon. The 3 vehicles will launch as 1 combined spacecraft to lunar orbit, where the lander, carrying the rover, will touch down in the Moon's southern hemisphere. The orbiter will then continue studying the Moon from above. A successful mission would make India just the fourth country to soft-land on the lunar surface.
The mission builds on ISRO's Chandrayaan-1 orbiter, which launched in October 2008 and operated for 10 months. Chandrayaan-2 features improved instruments and new technologies intended for future planetary missions. The orbiter is planned to operate for one year (previously reported as 2 years), while the lander and rover are expected to survive one lunar daytime period—14 Earth days—their mission ending when night falls.
2007: India and Russia sign agreement for Chandrayaan-2 mission, with Russia to provide lander. Launch date scheduled for 2013.
ISRO's Chandrayaan 2 website says the landing will take place in a high plain between craters Manzinus C and Simpelius N, at a latitude of about 70° south. This matches the prime site identified in Amitabh et. al (2018), which reported two sites:
Prime site (designated SLS54): 70.90267 S 22.78110 E Alternate site (designated ALS01): 67.874064 S, 18.46947 W
These coordinates were cited again in Sinha et. al (2019), which describes the landing ellipse is 15 x 8 kilometers.
NASA/GSFC/Arizona State University / Edited by Jason Davis
Chandrayaan-2 candidate landing sites (wide)
This wide-angle Moon view shows the prime (right blue dot) and alternate (left blue dot) Chandrayaan-2 landing sites. The sites were mapped using LROC Quickmap and are only for estimation purposes.
NASA/GSFC/Arizona State University / Edited by Jason Davis
Chandrayaan-2 candidate landing sites (zoom)
This zoomed view of the Moon's south polar region, as seen from Earth, shows the prime (right blue dot) and alternate (left blue dot) Chandrayaan-2 landing sites. The landing sites were mapped using LROC Quickmap and are only for estimation purposes.
Beyond the technical achievement of placing a lander on the Moon and deploying a rover, ISRO hopes to build on the data collected during the Chandrayaan-1 mission using improved instruments. Science goals include mapping the Moon’s topography, investigating surface mineralogy and elemental abundances, studying the lunar exosphere, and looking for signatures of hydroxyl and water ice.
The Chandrayaan-2 orbiter, as shown in a 2017 UN COPUOS presentation.
In addition to collecting science data with its onboard instruments, the orbiter serves as a relay between the Vikram lander and the IDSN, or Indian Deep Space Network. (The lander can also communicate directly with the IDSN.) Its solar panels generate 1 kilowatt of power.
Mass: 2,379 kilograms. We believe this is wet mass and had previously derived a figure of 2,294 kilograms using known masses from other components.
Terrain Mapping Camera 2 (TMC 2): Used to create a 3D map of the lunar surface, TMC 2 is a miniature version of the Terrain Mapping Camera used onboard the Chandrayaan 1 mission. Its primary objective is mapping the lunar surface in the panchromatic spectral band (0.5-0.8 microns) with a high spatial resolution of 5 meters, on 20-kilometer swaths from orbit.
Chandrayaan 2 Large Area Soft X-ray Spectrometer (CLASS): UCLASS measures the Moon's X-ray Fluorescence (XRF) spectra to examine the presence of rock-forming elements such as Magnesium, Aluminium, Silicon, Calcium, Titanium, Iron, and Sodium. The XRF technique will detect these elements by measuring the characteristic X-rays they emit when excited by the Sun's rays.
Solar X-ray Monitor (XSM): Supports CLASS by observing the X-rays emitted by the Sun and its corona, and measuring the intensity of solar radiation in those rays. Measures the full solar X-ray spectrum every second in the 1-15 keV energy range.
Orbiter High Resolution Camera (OHRC): Captures images of the landing site from two look angles to generating DEMs (Digital Elevation Models) that will be used to search for potential hazards. Post-landing, they will be used for further scientific survey. OHRC images cover an area of 12 x 3 kilometers, and have a resolution of 0.32 meters.
Synthetic Aperture Radar (SAR): An L- and S-band radar system used to detect water ice inside permanently shadowed craters, and globally map the thickness and electrical conductivity of the lunar regolith. This will be the first L-band radar mapper to orbit the Moon.
Imaging Infrared Spectrometer (IIRS): Characterizes and maps the abundance of hydroxyl (OH) and molecular water in the Moon's polar regions. Sensitive to light with wavelengths between 0.8 and 5 microns.
Chandra Atmospheric Composition Explorer 2 (ChACE-2): A neutral mass spectrometer to sample atoms in the tenuous atmosphere above the Moon’s polar regions. CHACE 2 builds on the CHACE experiment from Chandrayaan 2.
Dual Frequency Radio Science (DFRS) experiment: Studies the temporal evolution of electron density in the lunar ionosphere using X-band (8496 MHz) and S-band (2240 MHz) signals transmitted to Earth-based receivers.
Chandrayaan-2 Vikram lander deploying rover
This screenshot from an ISRO video shows the Chandrayaan-2 Vikram lander deploying the Pragyan rover on the lunar surface.
The lander is named Vikram, after Vikram Sarabhai, the founder of India's space program. It is equipped with 4, 800N engines and a series of 50N attitude control thrusters. Its solar panels can generate 650 watts of power. It can communicate with both the orbiter or directly with the IDSN.
Mass: 1,471 kilograms. We believe this is wet mass and had previously estimated a figure of 1,571 kilograms by adding 100 kilograms of mass growth to an original NASA amount.
Instrument for Lunar Seismic Activity (ILSA): A seismometer to record moonquakes to study lunar core; may offer new insights due to location in the lunar southern hemisphere.
Thermal probe (ChaSTE): Measures temperature and electrical conductivity 100 millimeters beneath surface.
Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA-Langmuir Probe): A Langmuir probe to study plasma density in the thin atmosphere near the Moon's surface.
Radio occultation experiment: Used to study how lunar tides affect Earth's atmosphere.
Chandrayaan-2's Pragyan rover explores the Moon in this screenshot from an ISRO video.
The rover, which is named Pragyan (wisdom), has 6 wheels and uses a radio antenna to communicate with the lander, which relays data to Earth. It can travel up to 500 meters and its solar panels generate 50 watts of power.
Chandrayaan-2 will launch aboard a GSLV Mark III rocket into an initial elliptical Earth parking orbit. Through a series of engine burns, the spacecraft will raise its orbit until it can be captured by the Moon's gravity with a lunar insertion burn.
Reported numbers for the initial Earth parking orbit vary widely (see here, here, here, and here). ISRO's website lists the initial orbit as 170 x 40400 kilometers, but that is likely incorrect because the apogee, or high point of the orbit, would already reach out to the vicinity of the Moon.
Chandrayaan-2's initial lunar orbit will be elliptical, until the spacecraft lowers itself to a circular, 100-kilometer-high orbit. There, the lander will separate and descend to the surface on the same day, according to ISRO.