Chandrayaan 1

Chardrayaan-1 is the first Indian Mission to the Moon devoted to high-resolution remote sensing of the lunar surface features in visible, near infrared, X-ray and low energy gamma ray regions. This will be accomplished using several payloads already selected for the mission. In addition a total of about 10 kg payload weight and 10 W power are earmarked for proposals, which are now solicited. The mission is proposed to be a lunar polar orbiter at an altitude of about 100 km and is planned to be launched by 2007-2008 using indigenous spacecraft and launch vehicle of ISRO. The mission is expected to have an operational life of about 2 years.

Mission Objectives are to carry out high resolution mapping of topographic features in 3D, distribution of various minerals and elemental chemical species including radioactive nuclides covering the entire lunar surface using a set of remote sensing payloads. The new set of data would help in unravelling mysteries about the origin and evolution of solar system in general and that of the moon in particular.

Indian on-board instruments are:

• Terrain Mapping stereo Camera (TMC) in the panchromatic band having 5m spatial resolution and 40 km swath, to prepare a high resolution atlas of moon
• A Hyper Spectral Imager (HySI) operating in 400-900nm band with a spectral resolution of 15nm and spatial resolution of 80 m with a swath of 40 km, for mineralogical mapping. The hyper spectral camera has 64 channels.
• A Lunar Laser Ranging Instrument (LLRI), for determining accurate altitude of the spacecraft above the lunar surface for topographical mapping with height resolution of about 10 m.
• A collimated Low Energy (0.5-10 keV) X-ray spectrometer (LEX) for measuring the fluorescent X-rays emanating from the lunar surface having ground spatial resolution of about 10 km, for elemental mapping of Si, Al, Mg,Ca, Fe,Ti
• A Solar X-ray Monitor (SXM) in 2-10 keV energy range, for solar X-ray flux monitoring
• A High Energy (10-200keV) X-ray/g-ray spectrometer (HEX) having a ground spatial resolution of approximately 20 km, for measuring 210Pb, 222Rn degassing, U, Th etc.
• Also a moon impact probe (MIP), which is conceived as a technology forerunner for future lunar landing mission is also being incorporated.

In addition six such payloads have been selected out of the proposals received from the international scientific community in response to the announcement of opportunity made earlier. The payloads selected are:

• Low energy (0.5-10 keV) X-ray spectrometer called Chandrayaan Imaging X-Ray Spectrometer from Rutherford Appleton Laboratory, UK, to measure elemental abundance distributed over the lunar surface using X-ray fluorescence technique. It will also include X-ray solar monitor to record the incident solar X-ray flux.
• Near Infra-Red (IR) Spectrometer from Max Planck Institute of Aeronomie, Germany, to detect and measure lunar mineral abundances.
• Sub keV Atom Reflecting Analyser from Swedish Institute of Space Physics, developed in collaboration with India, to measure volatiles generated due to solar wind impacting on lunar surface and determine the surface magnetic field anomalies.
• Radiation Dose Monitor from the Bulgarian Space Laboratory
• Mini Synthetic Aperture Radar (Mini SAR from Applied Physics Laboratory (APL)
• Moon Mineralogy Mapper (M3) from JPL/NASA

MIP

The Moon Impact Probe (MIP) weighing 29 kg will ride piggyback on the top deck of the main orbiter and will be released at a predetermined time after the orbiter reaches the final 100 km orbit to impact at a pre-selected location. During the descent phase it is in spin-stabilized configuration. The total flight time from release to impact on Moon will be close to twenty minutes. The dimension of the impact probe is 375 mm x 375 mm x 470 mm

There will be three major payloads in the Moon Impact Probe:

• Radar Altimeter - for measurement of altitude of the Moon Impact Probe above the lunar surface and qualify technologies for future landing missions. The operating frequency band is 4.3 GHz ± 100 MHz
• Video Imaging System - for acquiring images of the surface of moon from the descending probe. The video imaging system consists of analog CCD camera along with a video decoder
• Mass Spectrometer - A state-of-the-art Quadrupole mass spectrometer with a mass resolution of 0.5 amu and sensitive to partial pressure of the order of 10-15 torr for measuring the constituents of tenuous lunar atmosphere during descent.

Source: ISRO Website

Last update: 27.09.2009
Contact: gunter.krebs@skyrocket.de
© Gunter Dirk Krebs