The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is a visible-infrared spectrometer aboard the Mars Reconnaissance Orbiter that will search for mineralogic indications of past water on Mars. NASA 's Mars Reconnaissance Orbiter ( MRO) is a multipurpose Spacecraft designed to conduct Reconnaissance and exploration of Mars The CRISM instrument team comprises scientists from over ten universities and led by principal investigator Scott Murchie. A principal investigator ( PI) is the lead Scientist for a particular well-defined science (or other academic project such as an astronomical observing CRISM was designed, built, and tested by the Johns Hopkins University Applied Physics Laboratory. The Johns Hopkins University Applied Physics Laboratory (APL located in Laurel Maryland, is a not-for-profit university-affiliated research center employing
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Objectives
CRISM will be used to identify locations on Mars that have hosted water,[1] a chemical considered important in the search for past or present extraterrestrial life. Water is a common Chemical substance that is essential for the survival of all known forms of Life. Extraterrestrial life is Life originating outside of the Earth. In order to do this, CRISM will map the presence of minerals and chemicals that may indicate past interaction with water - low-temperature or hydrothermal. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat [2] These materials include iron and oxides, which can be chemically altered by water, and phyllosilicates and carbonates, which form in the presence of water. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element The silicate minerals make up the largest and most important class of rock-forming Minerals They are classified based on the structure of their silicate Ion group In Chemistry, a carbonate is a salt or Ester of Carbonic acid. All of these materials have characteristic patterns in their visible-infrared energy and may be readily seen by CRISM. In addition, CRISM will monitor ice and dust particulates in the Martian atmosphere to learn more about its climate and seasons. Particulates, alternatively referred to as particulate matter (PM or fine particles, are tiny particles of solid or liquid suspended in a gas Structure Mars' atmosphere is composed of the following major divisions Lower Atmosphere This is a warm region affected by heat from airborne Dust and
Investigation description
CRISM measures visible and infrared electromagnetic radiation from 370 to 3920 nanometers in 6. Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. A nanometre ( American spelling: nanometer, symbol nm) ( Greek: νάνος nanos dwarf; μετρώ metrό count) is a 55 nanometer increments. The instrument has two modes, a multispectral untargeted mode and a hyperspectral targeted mode. Multi-spectral imaging is a technology originally developed for space-based imaging Hyperspectral imaging collects and processes information from across the Electromagnetic spectrum. In the untargeted mode, CRISM reconnoiters Mars, recording approximately 50 of its 544 measurable wavelengths at a resolution of 100 to 200 meters per pixel. In this mode CRISM will map half of Mars within a few months after aerobraking and most of the planet after one year. [3] The objective of this mode is to identify new scientifically interesting locations that could be further investigated. [3] In targeted mode, the spectrometer measures energy in all 544 wavelengths. When the MRO spacecraft is at an altitude of 300 km, CRISM detects a narrow but long strip on the Martian surface about 18 meters across and 10,800 meters long. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International The instrument sweeps this strip across the surface as MRO orbits Mars to image the surface. [4]
Instrument design
The data collecting part of CRISM is called the Optical Sensor Unit (OSU) and consists of two spectrographs, one that detects visible light from 400 to 830 nm and one that detects infrared light from 830 to 4050 nm. The infrared detector is cooled to –173° Celsius (–280° Fahrenheit) by a radiator plate and three cryogenic coolers. The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 [5] While in targeted mode, the instrument gimbals in order to continue pointing at one area even though the MRO spacecraft is moving. A gimbal is a pivoted support that allows the rotation of an object about a single axis The extra time collecting data over a targeted area increases the signal to noise ratio as well as the spatial and spectral resolution of the image. Signal-to-noise ratio (often abbreviated SNR or S/N) is an Electrical engineering concept also used in other fields (such as scientific Measurements This scanning ability also allows the instrument to perform emission phase functions, viewing the same surface through variable amounts of atmosphere, which can be used to determine atmospheric properties. The Data Processing Unit (DPU) of CRISM performs in-flight data processing including compressing the data before transmission.
Notes
- ^ Johns Hopkins University (2006-03-11). Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1425 BC - Thutmose III, Pharaoh of Egypt, dies (according to the Low Chronology of the 18th Dynasty "CRISM Reaches the Red Planet". Press release. A news release, media release, press release or press statement is a written or recorded Communication directed at members of the News Retrieved on 2006-06-16. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1487 - Battle of Stoke Field, the last dying breath of the Wars of the Roses.
- ^ CRISM Joins Mars' Water Detectives. Astrobiology Magazine. Retrieved on 2006-06-16. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1487 - Battle of Stoke Field, the last dying breath of the Wars of the Roses.
- ^ a b Disappearing with a Trace. APL CRISM website. Retrieved on 2006-06-16. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1487 - Battle of Stoke Field, the last dying breath of the Wars of the Roses.
- ^ Instrument Development. APL CRISM website. Retrieved on 2006-06-16. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1487 - Battle of Stoke Field, the last dying breath of the Wars of the Roses.
- ^ CRISM FactSheet. APL CRISM website. Retrieved on 2006-06-16. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1487 - Battle of Stoke Field, the last dying breath of the Wars of the Roses.
References
Murchie, S. et al. (2002) CRISM: Compact Reconnaissance Imaging Spectrometer for Mars on the Mars Reconnaissance Orbiter. LPSC XXXIII, abstract #1697.
McGuire, P. et al. (2006) Retrieval of surface lambert albedos from the Mars Reconnaissance Orbiter CRISM data. LPSC XXXVII, abstract #1529.