The SIR-2 instrument is a redesigned, highly compact, monolithic grating, near infrared spectrometer chosen to be a payload on the Indian

Chandrayaan-1 Chandrayaan-1 (, ) was the first Indian lunar probe under the Chandrayaan program. It was launched by the Indian Space Research Organisation in October 2008, and operated until August 2009. The mission included a lunar orbiter and an impacto ...

satellite. It is an

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project, and is built by

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Polish Academy of Science The Polish Academy of Sciences ( pl, Polska Akademia Nauk, PAN) is a Polish state-sponsored institution of higher learning. Headquartered in Warsaw, it is responsible for spearheading the development of science across the country by a society of ...

and

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Mission

The mission of the instrument is to map the lunar surface in the near infrared spectrum from 0.9 - 2.4 μm with an unprecedented resolution of 6 nm. The purpose of this is to obtain information on the mineral composition of the moon, which in turn will help getting insight into a number of questions: * What is the cause of the global asymmetry of the moon, which on the far side has a thicker crust and lacks the Mare structures which are characteristic for the near side? * What was the early thermal evolution of the moon? * What is the vertical and lateral structure of the lunar crust and how did it develop? * What is the composition and structure of the lunar mantle? * Why is the moon different from other planets and how do planets work in terms of surface processes, heat transfer, and geologic evolution? * Are the Apollo geophysical measurements representative of the moon, or are they only valid for the small regions around the Apollo landing sites?

Similar missions

The instrument is a redesigned version of SIR, which was flown on board the SMART-1 technology satellite. SIR performed the same mission, but had a problem with dark current induced noise due to varying temperatures caused by differences in heat flux from the light and dark side of the Moon. SIR-2 will attempt to improve this, mainly by using a detector with an embedded thermoelectric cooler and a digital controller to keep the detector temperature stable. This will stabilize the dark current noise, making it simple to subtract it since it will have an almost constant level.

Electronics

The control unit of SIR-2 is based on a

System-on-a-chip A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory ...

design, minimizing the size and power consumption of the unit. A central component is the radiation hardened RTAX2000S Axcelerator

FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware de ...

, containing a

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(LEON3FT)

SPARC SPARC (Scalable Processor Architecture) is a reduced instruction set computer (RISC) instruction set architecture originally developed by Sun Microsystems. Its design was strongly influenced by the experimental Berkeley RISC system developed ...

compliant

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...

, communications interface

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cores, and custom interfaces to the rest of the instrument.

References

SIR-2 on Chandrayaan-1 - First resultsAn in-depth look at the lunar crater Copernicus: Exposed mineralogy by high-resolution near-infrared spectroscopyStudy of Spectral Characteristics of the Central Peak Region of Tycho Crater Using the SIR-2 Data On-Board Chandrayaan-1SIR-2 as an important geological investigative toolData from the SIR-2 Experiment on Chandrayaan-1A Near-Infrared Reflectance Survey Across Lunar Crater AristotelesStudy of Spectral Characteristics of the Central Peak Region of Tycho Crater Using the SIR-2 Data On-Board Chandrayaan-1

External links

Official website
Indian lunar exploration programme Spacecraft instruments