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Collection:
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NASA Mars Collecton
Collection
NASA Mars Collecton
Collection
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title:
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North Polar Cap in Summer
title
North Polar Cap in Summer
title
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Description:
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In the middle of January 2001, Mars Global Surveyor (MGS) completed one Mars year in its ~380 km-high (236 mi) mapping orbit. The mapping orbit was originally achieved in late February 1999. In March of that year, MGS conducted a series of operations in preparation for full-up mapping, first calibrating its scientific instruments and then operating in a mode in which the high gain antenna was held fixed against the body of the spacecraft. During this Fixed High Gain Antenna period, 'contingency science' observations were made in case the high gain antenna failed to properly deploy. The wide angle view of the martian north polar cap shown on the left was acquired on March 13, 1999, during early northern summer. The image on the right was acquired almost exactly one Mars year later, on January 26, 2001. The light-toned surfaces are residual water ice that remains through the summer season. The nearly circular band of dark material surrounding the cap consists mainly of sand dunes formed and shaped by wind. The north polar cap is roughly 1100 kilometers (680 miles) across. Close inspection will show that there are differences in the frost cover between the two images (for example, in the upper center of each image, and on the left edge center). Although these changes appear small, they are in fact quite large--the change in frost covering is equivalent to the amount of frost that would be evaporated (in the case of areas that are darker) or deposited (in areas where frost is still on the ground) in almost 5 months. What gives rise to such large changes in the heat budget for the polar caps from one year to the next is not known. Changes in the coloration and brightness of the polar cap suggest dust, deposited perhaps by dust storms during critical periods of the year, may play an important role.
Photo Credit: NASA/JPL/Malin Space Science Systems
Description
In the middle of January 2001, Mars Global Surveyor (MGS) completed one Mars year in its ~380 km-high (236 mi) mapping orbit. The mapping orbit was originally achieved in late February 1999. In March of that year, MGS conducted a series of operations in preparation for full-up mapping, first calibrating its scientific instruments and then operating in a mode in which the high gain antenna was held fixed against the body of the spacecraft. During this Fixed High Gain Antenna period, 'contingency science' observations were made in case the high gain antenna failed to properly deploy. The wide angle view of the martian north polar cap shown on the left was acquired on March 13, 1999, during early northern summer. The image on the right was acquired almost exactly one Mars year later, on January 26, 2001. The light-toned surfaces are residual water ice that remains through the summer season. The nearly circular band of dark material surrounding the cap consists mainly of sand dunes formed and shaped by wind. The north polar cap is roughly 1100 kilometers (680 miles) across. Close inspection will show that there are differences in the frost cover between the two images (for example, in the upper center of each image, and on the left edge center). Although these changes appear small, they are in fact quite large--the change in frost covering is equivalent to the amount of frost that would be evaporated (in the case of areas that are darker) or deposited (in areas where frost is still on the ground) in almost 5 months. What gives rise to such large changes in the heat budget for the polar caps from one year to the next is not known. Changes in the coloration and brightness of the polar cap suggest dust, deposited perhaps by dust storms during critical periods of the year, may play an important role.
Photo Credit: NASA/JPL/Malin Space Science Systems
Description
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section:
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Polar Ice Caps
section
Polar Ice Caps
section
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facet_what:
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Mars
facet_what
Mars
facet_what
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facet_what:
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Surveyor
facet_what
Surveyor
facet_what
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facet_what:
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Polar
facet_what
Polar
facet_what
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facet_what:
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Mars Global Surveyor Orbiter (MGS)
facet_what
Mars Global Surveyor Orbiter (MGS)
facet_what
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facet_what:
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polar ice cap
facet_what
polar ice cap
facet_what
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facet_where:
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Mars
facet_where
Mars
facet_where
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facet_where:
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Jet Propulsion Laboratory (JPL)
facet_where
Jet Propulsion Laboratory (JPL)
facet_where
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facet_when:
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January 26, 2001
facet_when
January 26, 2001
facet_when
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facet_when:
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January 2001
facet_when
January 2001
facet_when
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facet_when:
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February 1999
facet_when
February 1999
facet_when
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facet_when:
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March 13, 1999
facet_when
March 13, 1999
facet_when
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facet_when_year:
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2001
facet_when_year
2001
facet_when_year
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facet_when_year:
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1999
facet_when_year
1999
facet_when_year
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UID:
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SPD-MARS-gallery/pol aricecaps/PIA03204.h tml
UID
SPD-MARS-gallery/pol aricecaps/PIA03204.h tml
UID
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original url:
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original_url
original url
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