February 12, 2009 Debris Spews Into Space After Satellites Collide By WILLIAM J. BROAD For decades, space experts have warned of orbits around the planet growing so crowded that two satellites might one day slam into one another, producing swarms of treacherous debris. It happened Tuesday. And the whirling fragments could pose a threat to the International Space Station, orbiting 215 miles up with three astronauts on board, though officials said the risk was now small. “This is a first, unfortunately,” Nicholas L. Johnson, chief scientist for orbital debris at the National Aeronautics and Space Administration Iridium'Coverage'Space'Surveillance'Network'• USSPACECOM'tracks'about'8,000'man‐made'space'objects,'baseball‐size'and'larger,'orbiEng'Earth.''– Through'the'SSN,'the'command'tracks'and'catalogs'all'space'objects'orbiEng'Earth'which'are'10'cenEmeters'or'larger.''• About'seven'percent'are'operaEonal'satellites,'15'percent'are'rocket'bodies,'and'about'78'percent'are'fragmentaEon'and'inacEve'satellites.'• Most'debris'(about'84'percent)'is'out'approximately'800'kilometers'‐'roughly'twice'the'normal'alEtude'of'the'space'shuRle'which'orbits'at'about'300'kilometers.''– normally'only'three'or'four'items'in'an'area'roughly'equivalent'to'the'airspace'over'the'conEnental'U.S.'up'to'an'alEtude'of'30,000'feet.''• The'likelihood'of'a'significant'collision'between'a'piece'of'debris'(10'cenEmeters'or'larger)'and'the'shuRle'is'extremely'remote.'The'staEsEcal'esEmate'is'one'chance'in'10,000'years,'in'the'worst'case.''– The'probability'is'higher'for'objects'smaller‐than‐baseball'size'which'currently'cannot'be'tracked'with'available'sensors.'• During'shuRle'missions,'the'center'computes'possible'close'approaches'of'other'orbiEng'objects'with'the'shuRle's'flight'path.'NASA'is'also'advised'of'space'objects'which'come'within'a'safety'box'that'measures'10'by'10'by'50'kilometers'of'the'orbiter.'The Corona Program* • In'1955,'with'Cold'War'anxiety'skyrockeEng,'Eisenhower'made'a'remarkable'proposal'to'his'Russian'counterpart,'Premier'Nikita'Khrushchev.'He'suggested'that'each'country'allow'the'other'to'conduct'reconnaissance'flights'in'the'air'and'from'space'over'the'other'country,'and'that'the'imagery'obtained'be'given'to'the'United'NaEons.'• Khrushchev'declined,'and'both'countries'proceeded'to'develop'surveillance'programs'in'secret'• In'1958,'the'Air'Force'abruptly'canceled'a'planned'satellite'system'that'was'classified'but'had'been'publicly'acknowledged,and'reconsEtuted'it'as'the'supersecret'Corona'reconnaissance'satellite'program.'It'was'organized'under'the'new'Keyhole'security'protocols,'the'most'secret'security'orders'in'American'history.'*'hRp://www.geog.ucsb.edu/~kclarke/Corona/story.htm'Corona'featured'an'evolving'series'of'extremely'sophisEcated'cameras'that'used'a'special'polyester'film'base'designed'just'for'the'program'‐'though'we'all'use'it'now,'under'its'later'name'"mylar".''The Corona ProgramAder'the'cameras'photographed'the'world'from'polar'orbit,'the'exposed'film'was'jeesoned'back'to'earth'near'Hawaii,'in'a'capsule'fiRed'with'a'parachute'designed'to'be'snagged'by'special'planes.'The Corona ProgramThe'capsules'were'designed'to'float,'so'that'if'the'plane'missed,'Navy'boats'could'retrieve'them.'In'case'the'boats'missed,'the'capsules'were'fiRed'with'salt'plugs'that'would'dissolve'ader'two'days'in'the'ocean,'causing'the'capsule'to'sink'beneath'the'waves,'so'the'film'could'never'fall'into'enemy'hands.'The Corona ProgramThe Corona Program'• After the launch on August 18, 1960 of Discover 14, a film bucket was successfully retrieved 2 days later by a C-119. • This was the first successful return of photographic film from orbit. • In comparison, Sputnik 5 launched into orbit on August 19, 1960, one day after Discoverer 14. Sputnik 5 took into orbit and safely returned two soviet space dogs.The Corona Program Corona'image'of'the'Pentagon,'1967'Ater'the'first'successful'launch'in'1960,'government'agencies'realized'there'were'massive'civilian'applicaEons'reaching'far'beyond'its'original'mission.'The'systems'worked'so'well'that'in'short'order'the'CIA'was'using'Corona'to'map'the'world,'remap'the'U.S.,'and'to'evaluate'all'1:24,000'topographic'maps'for'revision.'The Corona ProgramArcheological'sites'found'‐'ruins'of'a'Roman'fort.'The Corona ProgramFirst'high'resoluEon'image'of'Africa'‐'a'photomosaic'of'recEfied'ARGON'photographs'assembled'around'1966.'The'original'photomosaic'was'80'feet'by'60'feet.'The Corona Program• The Corona Program continued until 1972, when it was replaced by more advanced systems, such as Big Bird, which use digital imagery. It was not until late 1995 that the U.S. government finally acknowledged the existence of Corona. • Corona was a very successful program. It produced over 800,000 images taken from space, and 2.1 million feet of film, delivered in 39,000 cans. Individual images on average covered approximately 10 miles by 120 miles. • All 800,000 Corona images are now declassified and can be ordered through the U.S. Geological Survey. The Corona ProgramSpectral'Bands'of'AVHRR'AVHRR Swath!+"Gits'+"Humboldt'+"Tunu‐N'+"NASA‐U'+"ETH/CU'+"Crawford"1,2"+"JAR1'+"Summit'+"Dye‐2'+"S"Dome'+Saddle'+"NGrip'PARCA"Climate"Network"+"NASA‐E'+"NASA‐SE'+"Tunu‐S'+"Kulu'Ice'Albedo'Feedback'• The'paper'described'the'AVHRR'Pathfinder'Atmosphere'(PATMOS)'processing'system'and'some'of'its'atmospheric''parameters'for'the'period'1981‐1999.'• The'parameters'are:'total'cloud'amount,'aerosol'opEcal'thickness'over'oceans,'outgoing'long‐wave'radiaEon,'and'absorbed'or'reflected''radiaEon'at'the'top'of'the'atmosphere.'• To'determine'the'accuracy,'results'were'compared'to'ground'data'or'to'result'of'other'satellite'data'• Comparison'indicated'that'the'data'are'of'sufficient'accuracy'for'studies'of'climate'phenomena'with'large'signals,'such'as'ENSO,'major'volcanic'erupEons,'and'monsoons.'Time'series'analysis'of'cloud'amount'is'useful'for'invesEgaEng'climate'change,'however,'PATMOS'data'affected'by'orbital'drid.'This'complicates'the'detecEon'of'long'term'trend.'Tropical"(20"N"–"20"S)"day/night"average"monthly"mean"cloud"cover"(%)"Defense Meteorological Satellite Program (DMSP) • The Defense Meteorological Satellite Program (DMSP) provides global visible and infrared cloud data and other specialized meteorological, oceanographic
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