| definition
| - The LAGEOS satellites are passive vehicles covered with
retroreflectors designed to reflect laser beams transmitted from
ground stations. By measuring the time between transmission of
the beam and reception of the reflected signal from the
satellite, stations can precisely measure the distance between
themselves and the satellite. These distances can be used to
calculate station positions to within 1-3 cm. Long term data
sets can be used to monitor the motion of the Earth's tectonic
plates, measure the Earth's gravitational field, measure the
"wobble" in the Earth's axis of rotation, and better determine
the length of an Earth day.
LAGEOS 2 was a joint program between NASA and the Italian space
agency (ASI), which built the satellite using LAGEOS 1 drawings
and specifications, handling fixtures, and other materials
provided by NASA.
LAGEOS 2's orbit was selected to provide more coverage of
seismically active areas, such as the Mediterranean Basin and
California, and may help scientists understand irregularities
noted in the motion of LAGEOS 1. Ground tracking stations are
located in many countries (including the US, Mexico, France,
Germany, Poland, Australia, Egypt, China, Peru, Italy, and
Japan) and data from these stations is available world-wide to
investigators studying crustal dynamics. LAGEOS 1 also
contains a message plaque addressed to human and other beings
of the far distant future with maps of the Earth from 3
different eras - 268 million years in the past, present day,
and 8 million years in the future (the satellite's estimated
decay date). Spacecraft: Both satellites are spherical bodies
with an aluminum shell wrapped around a brass core. The design
was a compromise between numerous factors including the need
to be as heavy as possible to minimise the effects of
non-gravitational forces vs. being light enough to be placed
in a high orbit and the need to accommodate as many
retroreflectors as possible vs. the need to minimise surface
area to minimise the effects of solar pressure. The materials
were chosen to reduce the effects of the Earth's magnetic
field on the satellite's orbit.426 cube-corner retroreflectors
are imbedded in the satellites' surface.422 of these are made
of fused silica glass while the other 4 are made of
germanium. The vehicles have no onboard sensors or
electronics, and are not attitude controlled. Payload: Science
is performed by reflecting laser light from the vehicle's 426
retroreflectors.
Additional characteristics:
-50 years design life
-0.6m total length
-0.6m maximum diameter
-405 kg total mass
Additional information available at
"http://www.astronautix.com/craft/lageos.htm"
[Summary provided by SpaceBank.com]
Group: Platform_Details
Entry_ID: LAGEOS-2
Group: Platform_Identification
Platform_Category: Earth Observation Satellites
Platform_Series_or_Entity: LAGEOS (Laser Geodetic Satellite)
Short_Name: LAGEOS-2
Long_Name: Laser Geodetic Satellite-2
End_Group
Group: Synonymous_Platform_Names
Short_Name: LAGEOS-2
End_Group
Group: Platform_Associated_Instruments
Short_Name: LASER TRACKING REFLECTOR
End_Group
Group: Orbit
Orbit_Inclination: 52.70 deg
Period: 222.50 min
Perigee: 5,616 km
Apogee: 5,952 km
End_Group
Creation_Date: 2007-10-10
Online_Resource: http://www.astronautix.com/craft/lageos.htm
Online_Resource: http://ilrs.gsfc.nasa.gov/satellite_missions/list_of_satellites/lag1_general.html
Online_Resource: http://nasascience.nasa.gov/missions/lageos-1-2
Sample_Image: http://msl.jpl.nasa.gov/QuickLooks/pictures/lageos.gif
Group: Platform_Logistics
Launch_Date: 1992-10-22
Launch_Site: Cape Canaveral/Kennedy Space Center, USA
Design_Life: 50 year
Primary_Sponsor: USA/NASA
End_Group
End_Group (en)
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