Friday, August 26, 2011


News continues to be slow and my workload high, so I will post (with permission) another abstract from the recent Low Cost Planetary Mission conference.  The entry of India and China into the group of planetary faring nations will expand the roster of missions we'll be seeing the next decades.  Our moon is a complex world, and exploring a new region by this joint Indian-Russian mission of the surface along with orbital observations is likely to bring new discoveries.

CHANDRAYAAN-2 MISSION. J. N. Goswami1 and M. Annadurai2, 1Physical Research Laboratory, Ahmedabad-380009, India, 2ISRO Satellite Center, Bangalore-560017, India.

The first Indian planetary mission to moon, Chandrayaan-1 [1], with a suite of Indian and International payloads on board, collected very significant data over its mission duration of close to one year. The success of this mission provided the impetus to implement the second approved Indian mission to moon, Chandrayaan-2, with an Orbiter-Lander-Rover configuration [2]. This will be a collaborative mission between the Indian Space Research Organization (ISRO) and the Federal Space Agency of Russia. ISRO will be responsible for the Launch Vehicle, the Orbiter and the Rover while the Lander will be provided by Russia.

The orbiter for the Chandrayaan-2 mission is similar to that in Chandrayaan-1 from structural and propulsion aspects. The indigenously developed Geostationary Satellite Launch Vehicle, GSLV(Mk-II), will place the Orbiter-Lander-Rover in GTO (180km-36,000km), following which the Orbiter will boost the orbit to LTT. Separation of Orbiter and the Lander-Rover modules will take place in LTT and they will reach lunar polar orbit independently. The orbiter will be placed in an elliptical (5000km-200km) polar orbit prior to the descent of the Lander-Rover module to the lunar surface. Multiple communication links involving Rover-Lander-Orbiter-Earth, direct Lander-Earth and Rover-Orbiter will be implemented.

Althouh the exact landing location is yet to be finalized, a high latitude location is preferred from
scientific interest. The orbiter will be finally placed in a 200 km circular orbit and the instruments on board will have a close up view of the moon. The scientific payloads on the orbiter include a Terrain Mapping Camera (TMC-2), an Imaging Infra-red Spectrometer (IIRS), a Synthetic Aperture Radar (SAR), a Collimated Large Area Soft X-ray Spectrometer (CLASS), and a Neutral Mass Spectrometer (ChASE-2). TMC will provide 3D imaging and DEM, while the IIRS will cover the 0.8-5 micron region and collect information on mineralogy, detect OH and H2O on lunar surface and measure thermal emission from the moon. CLASS is an improved version of C1XS flown on Chandrayaan-1 for inferring chemical composition based on detection of X-rays emitted from lunar surface during solar flares. ChASE-2 is a modified version of ChASE on the Moon Impact Probe (MIP) on Chandrayaan-1 that provided hints for the presence of water molecule and CO2 in the lunar exosphere. The Synthetic Aperture Radar will include both L (1.25 GHz) and S (2-2.2 GHz) bands with selectable (few meter) resolution.

There will be two payloads on the Rover: an Alpha Particle induced X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscopy (LIBS) for studies of chemical composition and volatiles present in lunar surface near the landing site. The Lander will have a suite of Russian instruments to study physical and chemical properties of the lunar surface and sub-surface material, lunar environment and siesmic activity [3]. The lander will have direct communication link to Earth Stations as well as via Orbiter and act as the hub for communication with the Rover. The design and development of the various mission elements as well as of the scientific payloads are currently in progress both in India and in Russia.

References: [1] Goswami J. N. & Annadurai M. (2009) Current Science 96, 486-491. [2] Goswami J. N. & Annadurai M. (2011) LPS 42 #2042,. [3] Mitrofanov I. G. et al. (2011) LPS 42, #1798.

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