Mars: History of Exploration IIMars: History of Mars ExplorationSlide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Mars: Remote Sensing BasicsC.M. Rodrigue, 2007Geography, CSULBMars: History of Exploration IIGeography 494-01S/07Dr. Christine M. RodrigueC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationThe Spectral Analysis era: A New MarsSpectral analysis in this context is the study of absorbed, emitted, and scattered radiationA radiant object can emit wavelengths along the EMS at varying intensities: hot or dense objects emit across a continuous spectrumSubstances in the radiant object or between it and the sensor can absorb certain wavelengthsThe wavelengths absorbed are diagnostic of particular minerals or elements or compoundSubstances and surfaces also reflect particular wavelengthsC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationThe Spectral Analysis era: Martian air pressuresIn 1862, William Higgins tried out the new technology to get at Martian atmospheric pressures: All he got was that sunlight reflected off Mars and the planet didn’t glowIn 1908, Percival Lowell tried:Mars’ air pressure looked like 87% of Earth’sHis method was sound but he didn’t correct for dustErroneous as his results were, the method was a significant contribution to launching the use of spectral analysis on Mars and other planetsC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationThe Spectral Analysis era: Martian temperaturesAny object that absorbs radiation re-emits it at a longer wavelength, because it is necessarily cooler than the original radiant bodyWien’s Displacement Law (L = 2,897 / TK ) allows you to calculate temperatures (TK = 2,897 / L )In the 1920s, Lowell Observatory established that Mars was very cold, -40 C on average (Earth averages 15 C)The poles got down around -70 C, and the equatorial areas got as warm as 10 CIn 1954, equatorial highs got as high as 25 CC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationThe Spectral Analysis era: Life on Mars?Mars shows seasonally shifting patterns of spring darkening Some folks inferred that this could be a wave of vegetation greening up for springIn 1938, Peter Millman compares the spectra from the dark areas with spectra that had been collected for various kinds of vegetation here on Earth and said they did not resemble one another at allIn 1954, W.M. Sinton said these spectra did resemble organic compounds, later retracting thisAudoin Dofus and Thomas McCord showed that the dark areas were not greenish: That was an optical illusionC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationTelescope observation from near-Earth Hubble Telescope was designed in 1973, since the Shuttle had been recently approved as a way of schlepping it outCongress funded it in 1977 and it launched in 1990It’s a reflecting mirror type of telescopeThe main (2.4 m) mirror turned out to have an optical flaw, enough to give it astigmatismCorrective optics applied in 1993Angular resolution is 0.05 arcsecond"If you could see as well as Hubble, you could stand in New York City and distinguish two fireflies, 1 m (3.3 feet) apart, in San Francisco."C.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationTelescope observation from near-Earth: HubbleBoth infrared and visible light imaging of MarsBest resolution: 19 kmGot best images in August 2003, the best opposition in 59,619 yearsC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of Earth-based Mars explorationTelescope observation from near-Earth -- Hubble has:Monitored weather (very useful when Mars Global Surveyor was ærobraking into Martian orbit in 1997!)Caught a 1996 spring dust stormDocumented cloudiness in 1997Caught a polar cyclone in 1999Identified water-bearing minerals on MarsC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationC.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of the Robotic Missions to MarsHugely dangerous: Most missions have failed (about 60%)"Great Galactic Ghoul," Mars as the "Bermuda Triangle," the "Mars Curse" There have been launch failuresUSSR Mars 1960A failed at liftoffRussian Space Agency Mars 96 orbiter/lander/penetratorNASA Mariner 8 1971Communications failuresUSSR Mars 1 (aka Sputnik 23) 1963NASA Mars Observer lost contact at arrival in 1993Orbit insertion failuresJapan ISAS Nozomi 1999 *and* 2003Crashes on the Martian surfaceNASA Mars Climate Observer 1999NASA Mars Polar Lander/Deep Space 2 1999ESA Beagle lander 2003C.M. Rodrigue, 2007Geography, CSULBMars: History of Mars ExplorationHistory of the Robotic Missions to MarsSpacecraft typesFlyby missions (Cassini-Huygens gravity-assists by Earth and Venus)Orbiters (Earth’s Landsat, IKONOS, SPOT)Probes (Huygens probe at Titan, NEAR at asteroid EROS)Landers (USSR Venera, NASA Surveyor on Moon)Rovers (Spirit and Opportunity, Earth portable spectrometers)Penetrators (USSR Mars 96 had two)Balloon probes (USSR Vega 1 at Venus)Sample return landers (MSRL, Genesis from L1, Stardust from Comet Wild 2)C.M. Rodrigue, 2007Geography, CSULBMars: Remote Sensing BasicsResolutionSpatial Varying, as in a descending probe (e.g, Huygens descending to Titan)Fine resolution, 0.5 – 5.0 m (e.g., IKONOS, OrbView-3)Coarse resolution, 1 km (e.g., MODIS) to 8 m (e.g., GEOS)VerticalGenerally worse than horizontal spatial resolutionGenerated by laser altimeters, InSAR, stereo pairingTemporalOne time (e.g., flyby) Intermittant (e.g., AVIRIS) Repetitive (stationary orbits, e.g., GEOS, or regular overflights, e.g., Landsat) SpectralPanchromatic (all bands within a large range, often fine resolution) Multispectral (3-100 or so bands, at discrete intervals along the spectrum) Hyperspectral (16-220 narrow bands contiguous to one another over a spectral
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