ASM
India Goes to the Moon
Chandrayaan-1 was launched towards the moon yesterday by a PSLV. This is the launcher’s 14th flight without incident. The spacecraft is carrying a comprehensive set of 11 instruments that will be able to remotely sense the lunar surface at all wavelengths between visible and X-ray frequencies.
The 1380 kg spacecraft will use a complex system of orbits to reach the moon using minimum thrust. The rocket delivered Chandrayaan-1 into an elliptical transfer orbit at an altitude of 255 km with an apogee of 22,860 km. Its liquid apogee motor will be used to progressively raise this apogee until a small increment will transfer it into an eliptical orbit about the moon. There, the reverse process will slowly reduce the apogee until the spacecraft is in a circular 100 km orbit above the lunar surface. This will take about 15 days.
Once on station, the craft’s instruments will be deployed. An impact probe will also be launched amd crashed into the surface.
Indian institutes developed four of the instruments. The Terrain Mapping Camera (TMC) is a visible pan sensor with five metre resolution. Its swath width is 20 km. The TMC was built by ISRO's Space Applications Centre in Ahmedabad.
The Hyperspectral Imager (HySI) is a CCD camera operating in the visible and near infrared region. It will image a strip of lunar surface that is 20 km wide with a resolution of 80 metre. Each of its 64 bands is 15 nanometer wide. HySI will help improve information on the mineral composition of the lunar surface. SAC also built HySI.
The Lunar Laser Ranging Instrument (LLRI) is based on an infrared Nd-YAG laser. LLRI is built by ISRO's Laboratory for Electro Optic Systems in Bangalore. It will be used to establish the instantaneous spacecraft-terrain distance.
The High Energy X-ray Spectrometer (HEX) is designed to identify polar regions covered by water-ice deposits, or other regions of high uranium and thorium concentration. It was built jointly by Physical Research Laboratory (PRL) of Ahmedabad and ISRO Satellite Centre of Bangalore.
Various overseas teams also contributed instruments. Rutherford Appleton Laboratory of England contributed the Chandrayaan-1 Imaging X-ray Spectrometer (C1XS): This instrument will map the moon using using X-ray fluorescence technique for measuring elemental abundance of magnesium, aluminium, silicon, iron and titanium.
The Max Plank Institute in Germany contributed the Smart Near Infrared Spectrometer (SIR-2), which aims to study the lunar surface to explore the mineral resources, the formation of its surface features, the way different layers of the moon's crust lie over one another and the way materials are altered in space. It has the ability to detect and record near infrared radiation. Since this is the radiation band through which various minerals and ices reveal their existence, SIR-2 is well suited for making an inventory of various minerals on the lunar surface. It can detect the radiation in the range of 0.93-2.4 micron.
The Swedish Institute of Space Physics developed the Sub keV Atom Reflecting Analyser (SARA). The aim of this instrument is to study the way in which the Moon's surface reacts with solar wind. SARA will be sensitive to neutral atoms that have escaped from the surface of the moon and have energy in the range of 10 eV—2 keV (kilo-electron-Volt).
The Bulgarian Academy of Sciences developed the Radiation Dose Monitor (RADOM). This instrument aims to qualitatively and quantitatively characterise the radiation environment in lunar space.
In addition, there are two US payloads. The Mini Syntheic Aperture Radar is from Johns Hopkins University's Applied Physics Laboratory and Naval Air Warfare Centre. MiniSAR has a spatial resolution of about 75 metres.
The Moon Mineralogy Mapper (M3) is an imaging spectrometer which is intended to assess and map lunar mineral resources at high spatial and spectral resolution. It was developed by Brown University and the Jet Propulsion Laboratory. The instrument has a spatial resolution of 70 metres.
The ultimate aim of these instruments is to develop a 3D chemical and mineralogical map of the entire lunar surface. Because Chandrayaan-1 will be placed in polar orbit, it will also be able to observe the polar regions of the moon. It will search for traces of water. Data from NASA's Clemetine probe offered a hint that water might exist in some of the polar craters.
