CHANDRAYAAN 1 MISSION PROFILE

Mission Sequence

Chandrayaan-1 spacecraft would be launched from the Satish Dhawan Space Centre, SHAR, Sriharikota by PSLV-XL (PSLV-C11) in an highly elliptical initial orbit (IO) with perigee (nearest point to the Earth) of about 257 km and an apogee (farthest point from the Earth) of about 22,858 km. After a few revolutions in the initial orbit, the spacecraft's Liquid Apogee Motor (LAM) firing would be done, when the spacecraft is near perigee, to raise the apogees to 37,421 km and 73,925 km respectively. Subsequently, the LAM is fired to take the Chandrayaan-1 spacecraft to extremely high elliptical orbit with apogees 199,277 km and 269,201 km. Later the spacecraft would be raised to an orbit with 1,019 km perigee and 386,194 km apogee. Once the Chandrayaan-1 spacecraft reaches the vicinity of the Moon, the spacecraft is slowed down sufficiently so as to enable the gravity of the moon capture it into an elliptical orbit (LC). After a careful and detailed observation the height of the spacecraft's orbit will be finally lowered to its intended 100 km circular polar orbit. Following this, the Moon Impact Probe (MIP) would be ejected from Chandrayaan-1 to impact on the lunar surface. Afterwards, all the scientific instruments/payloads are commissioned sequentially and Chandrayaan-1 spacecraft explores the Moon with its array of instruments for two years.

CHANDRAYAAN 1 -SCIENTIFIC OBJECTIVES AND MISSION OBJECTIVES

Scientific Objectives

The Chandrayaan-1 mission is aimed at high-resolution remote sensing of the moon in visible, near infrared (NIR), low energy X-rays and high-energy X-ray regions. Specifically the objectives are

To prepare a three-dimensional atlas (with high spatial and altitude resolution of 5-10 m) of both near and far side of the moon. To conduct chemical and mineralogical mapping of the entire lunar surface for distribution of mineral and chemical elements such as Magnesium, Aluminum, Silicon, Calcium, Iron and Titanium as well as high atomic number elements such as Radon, Uranium & Thorium with high spatial resolution.

The Simultaneous photo geological, mineralogical and chemical mapping through Chandrayaan-1 mission will enable identification of different geological units to infer the early evolutionary history of the Moon. The chemical mapping will enable to determine the stratigraphy and nature of the Moon's crust and thereby test certain aspects of magma ocean hypothesis. This may allow to determine the compositions of impactors that bombarded the Moon during its early evolution which is also relevant to the formation of the Earth.

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Radiation Environment of the Moon

Radiation environment of the Moon produced by solar radiation and solar and galactic cosmic rays: The reflectance spectrum is useful for mineral identification, the fluorescent X-ray spectrum and solar and galactic cosmic-ray produced gamma radiation for chemical mapping, and radiogenic gamma and alpha particle spectrum for mapping of radioactive nuclides (U, Th, K, etc.) and in understanding the leakage of radon from the lunar interior and its transport on the lunar surface. The uranium decay chain, which produces 222Rn and its daughters, forming a thin 'paint' on the lunar surface, are shown on the right. The temperature regimes on the sunlit and night side of the Moon and the permanently shadowed cold Polar Regions are shown schematically. (Ref: Current Science, Bhandari 2004)

Mission Objectives

To realise the mission goal of harnessing the science payloads, lunar craft and the launch vehicle with suitable ground support systems including Deep Space Network (DSN) station. To realise the integration and testing, launching and achieving lunar polar orbit of about 100 km, in-orbit operation of experiments, communication/ telecommand, telemetry data reception, quick look data and archival for scientific utilisation by scientists.

CHANDRAYAAN MISSION OBJECTIVES

Mission Objectives

• 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 unraveling mysteries about the origin and evolution of solar system in general and that of the moon in particular.
• Realize the mission goal of harnessing the science payloads, lunar craft and the launch vehicle with suitable ground support system including DSN station, integration and testing, launching and achieving lunar orbit of ~100 km, in-orbit operation of experiments, communication/telecommand, telemetry data reception, quick look data and archival for scientific utilization by identified group of scientists.