The SIR-2 instrument is a redesigned, highly compact, monolithic grating, near infrared spectrometer chosen to be a payload on the Indian Chandrayaan-1 satellite. It is an ESA project, and is built by Max Planck Institute for Solar System Research

Max Planck Institute for Solar System Research

The Max Planck Institute for Solar System Research is a research institute in Astronomy/Astrophysics, located in Lindau , Germany; 20 km north east of Göttingen. The exploration of our solar system is the central theme for the scientific research done at this Institute...

, Polish Academy of Science and University of Bergen

University of Bergen

The University of Bergen is located in Bergen, Norway. Although founded as late as 1946, academic activity had taken place at Bergen Museum as far back as 1825. The university today serves more than 14,500 students...

.

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

System-on-a-chip

A system on a chip or system on chip is an integrated circuit that integrates all components of a computer or other electronic system into a single chip. It may contain digital, analog, mixed-signal, and often radio-frequency functions—all on a single chip substrate...

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

LEON

LEON is a 32-bit CPU microprocessor core, based on the SPARC-V8 RISC architecture and instruction set. It was originally designed by the European Space Research and Technology Centre , part of the European Space Agency , and after that by Gaisler Research. It is described in synthesizable VHDL...

 (LEON3FT) SPARC

SPARC

SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....

 compliant CPU, communications interface Intellectual property

Intellectual property

Intellectual property is a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law...

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