Unique instruments

Among the 68 spacecraft that have been sent to study the moon so far, Chandrayaan-1 has the largest number of instruments on board, 11. The instruments are also unique for their spectrum of coverage and the wealth of scientific data they will generate.

M. Annadurai, project director, Chandrayaan-1, said: We are carrying with us a spectrum of instruments that have not been sent to the moon earlier and the experiments they perform will be unparalleled.

This is the first time any spacecraft sent to the moon will prepare a three-dimensional atlas of the entire surface of the moon. Almost everything on the moon will come under the ken of these 11 instruments: minerals such as thorium, uranium, magnesium, iron, aluminium and titanium and chemicals in the lunar soil; the hills, valleys and craters; the thin atmosphere and the moons radiation field.

The instruments will provide confirmation on the reported presence of water-ice and whether helium-3, which will be used in the fusion reactors of the future, is available abundantly on the moon.

Of the 11 instruments, five are from India, three from the European Space Agency (or the ESA, whose members are the United Kingdom, Germany and Sweden), two from the National Aeronautics and Space Administration (NASA) of the United States and one is from Bulgaria.

The five Indian payloads:

Terrain Mapping Camera, built by ISROs Space Applications Centre (SAC), Ahmedabad. It will map the entire topography of the moon.

Hyper Spectral Imager (HySI). A camera built by the SAC, which will provide information on minerals such as thorium and uranium. These images will help scientists understand the changes in the mineralogy in the deep-crater regions.

Lunar Laser Ranging Instrument (LLRI). This is a laser radar that will generate data on the height or depth of hills, mountains, valleys and craters. Developed by ISROs Laboratory for Electro-Optics Systems (LEOS) in Bangalore, its high-energy lasers sent to the moons surface will be reflected back to the spacecraft. If the laser returns late, it signifies the presence of a crater or a valley. If it comes back early, it means there is a mountain or a hill.

High Energy X-ray Spectrometer (HEX). It will explore the moons polar regions for thick deposits of water-ice and also locate regions of high uranium and thorium concentration. HEX has been built by the Physical Research Laboratory, Ahmedabad, and ISRO Satellite Centre (ISAC), Bangalore.

Moon Impact Probe. Built by the Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, it will demonstrate the technologies required for landing a rover at a desired location on the moon. Thus, it will be a technological forerunner to Chandrayaan-2, which will deposit a lander-cum-rover on the moon.

The three ESA payloads:

Chandrayaan-1 Imaging X-ray Spectrometer (CIXS). Developed jointly by the Rutherford Appleton Laboratory of England and ISAC, it will carry out high-quality mapping of magnesium, aluminium, silicon, iron and titanium distributed on the lunar surface. This will help provide clues to the moons origin and evolution, which itself may throw light on the earths evolution.

Smart Near-Infrared Spectrometer. Developed by the Max Planck Institute, Germany, it will prospect the lunar surface for minerals, analyse the formation of its surface features, study the way different layers of the moons crust lie one over the other and the way materials are altered on the lunar surface. It can also detect the near-infrared radiation coming from the moon.

Sub keV Atom Reflecting Analyser (SARA). A product of the Swedish Institute of Space Physics and the Space Physics Laboratory (SPL) of the VSSC, it will study the moons surface composition, how its surface reacts with the solar wind and how materials are altered in space.

The Bulgarian payload:

Radiation Dose Monitor (RADOM). Developed by the Bulgarian Academy of Sciences, it will investigate the moons radiation environment and help prepare a radiation-dose map of space near the moon at various latitudes and altitudes. It will help investigate whether the moon is shielded by the space around it from cosmic rays emanating from the sun and distant celestial bodies. Data on this can help determine the shielding requirements of manned missions to the moon.

The two NASA payloads:

Moon Mineralogy Mapper (M3). From Brown University of the U.S. and the Jet Propulsion Laboratory of NASA, this is an imaging spectrometer to help locate thr moons minerals and provide clues about the moons early geological evolution. It will also identify water-ice in the lunar poles.

Mini Synthetic Aperture Radar (MiniSAR). This will perform the important task of detecting water-ice to a depth of a few metres in the permanently shadowed regions of the moons poles. It can distinguish water-ice from the dry lunar surface. MiniSAR is from Johns Hopkins Universitys Applied Physics Laboratory and the Naval Air Warfare Centre, U.S., through NASA.

Source: B.R. Guruprasad of ISRO.