LAGEOS: Difference between revisions

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{{Short description|Scientific research satellites}}
{{Short description|NASA scientific research satellites}}
{{Infobox spaceflight
{{Infobox spaceflight
| name                  =  LAGEOS-1
| name                  =  LAGEOS-1
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{{Infobox spaceflight
{{Infobox spaceflight
| name              = LAGEOS-2
| name              = LAGEOS-2
| image              = STS-52 LAGEOS-II deployment.jpg
| image              = Sts052-80-030 lrg.jpg
| image_caption      = LAGEOS 2 during deployment on STS-52
| image_caption      = LAGEOS 2 during deployment on STS-52
| mission_type      = [[Geodesy]]
| mission_type      = [[Geodesy]]
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== Function and operation ==
== Function and operation ==
The spacecraft are [[aluminum]]-covered [[brass]] spheres with diameters of {{convert|60|cm}} and masses of {{convert|400|and|411|kg|lbs|abbr=off}}, covered with 426 cube-corner [[retroreflector]]s, giving them the appearance of [[disco ball]]s.<ref>{{cite web|url=https://science.nasa.gov/missions/lageos-1-2/ |title=Missions - LAGEOS 1&2 - NASA Science |website=Science.nasa.gov |date=1976-05-04 |accessdate=2016-02-22}}</ref><ref>Kramer, Herbert J. (2013) [https://books.google.com/books?id=U3v1CAAAQBAJ&pg=PA149 ''Observation of the Earth and its Environment: Survey of Missions and Sensors''] Springer {{ISBN|9783662090381}} p149</ref><ref>[https://history.nasa.gov/SP-4012/vol3/table4.166.htm LAGEOS Characteristics] ''NASA Historical Data Book'' Volume III Table 4-166 SP-4012</ref> Of these retroreflectors, 422 are made from fused silica glass while the remaining 4 are made from germanium to obtain measurements in the infrared for experimental studies of reflectivity and satellite orientation.<ref name="ILRSLageos"/> They have no on-board sensors or electronics, and are not [[Spacecraft attitude control|attitude-controlled]].
The spacecraft are [[aluminum]]-covered [[brass]] spheres with diameters of {{convert|60|cm}} and masses of {{convert|400|and|411|kg|lbs|abbr=off}}, covered with 426 cube-corner [[retroreflector]]s, giving them the appearance of [[disco ball]]s.<ref>{{cite web |url=https://science.nasa.gov/missions/lageos-1-2/ |title=Missions - LAGEOS 1&2 - NASA Science |website=Science.nasa.gov |date=1976-05-04 |accessdate=2016-02-22 |archive-date=2016-08-09 |archive-url=https://web.archive.org/web/20160809203950/http://science.nasa.gov/missions/lageos-1-2/ |url-status=dead }}</ref><ref>Kramer, Herbert J. (2013) [https://books.google.com/books?id=U3v1CAAAQBAJ&pg=PA149 ''Observation of the Earth and its Environment: Survey of Missions and Sensors''] Springer {{ISBN|9783662090381}} p149</ref><ref>[https://history.nasa.gov/SP-4012/vol3/table4.166.htm LAGEOS Characteristics] ''NASA Historical Data Book'' Volume III Table 4-166 SP-4012</ref> Of these retroreflectors, 422 are made from fused silica glass while the remaining 4 are made from germanium to obtain measurements in the infrared for experimental studies of reflectivity and satellite orientation.<ref name="ILRSLageos"/> They have no on-board sensors or electronics, and are not [[Spacecraft attitude control|attitude-controlled]].


They orbit at an altitude of {{convert|5900|km}},<ref name="LageosQL">{{cite web|url=http://space.jpl.nasa.gov/msl/QuickLooks/lageosQL.html |accessdate=March 31, 2011 |title=JPL Mission and Spacecraft Library, Lageos |website=space.jpl.nasa.gov|archiveurl=https://web.archive.org/web/20110721062751/http://space.jpl.nasa.gov/msl/QuickLooks/lageosQL.html|url-status=dead |archivedate=2011-07-21 }}</ref> well above [[low Earth orbit]] and well below [[geostationary orbit]], at orbital inclinations of 109.8 and 52.6 degrees.
They orbit at an altitude of {{convert|5900|km}},<ref name="LageosQL">{{cite web|url=http://space.jpl.nasa.gov/msl/QuickLooks/lageosQL.html |accessdate=March 31, 2011 |title=JPL Mission and Spacecraft Library, Lageos |website=space.jpl.nasa.gov|archiveurl=https://web.archive.org/web/20110721062751/http://space.jpl.nasa.gov/msl/QuickLooks/lageosQL.html|url-status=dead |archivedate=2011-07-21 }}</ref> well above [[low Earth orbit]] and well below [[geostationary orbit]], at orbital inclinations of 109.8 and 52.6 degrees.
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== Time capsule ==
== Time capsule ==
LAGEOS-1 (which is predicted to re-enter the atmosphere in 8.4 million years<ref name="ILRSLageos">{{cite web|url=http://ilrs.gsfc.nasa.gov/missions/satellite_missions/current_missions/lag1_general.html |title=International Laser Ranging Service |website=Ilrs.gsfc.nasa.gov |date= |accessdate=2016-02-22}}</ref>) also contains a 4&nbsp;in&nbsp;×&nbsp;7&nbsp;in plaque designed by [[Carl Sagan]]<ref>''[https://lageos.gsfc.nasa.gov/Design/Message_to_the_Future.html LAGEOS: LAser GEOdynamic Satellite : Design : Message to the Future]'', [[National Aeronautics and Space Administration]], [[Goddard Space Flight Center]]</ref> to indicate to future humanity when LAGEOS-1 was launched. The plaque includes the numbers 1 to 10 in binary. In the upper right is a diagram of the Earth orbiting the Sun, with a binary number 1 indicating one revolution, equaling one year. It then shows 268,435,456 years in the past (binary: 2<sup>28</sup>), indicated by a left arrow and the arrangement of the Earth's continents at that time (during the [[Permian]] period). The present arrangement of the Earth's continents is indicated with a 0 and both forward and backward arrows. Then the estimated arrangement of the continents in 8.4 million years with a right facing arrow and 8,388,608 in binary (2<sup>23</sup>). LAGEOS itself is shown at launch on the 0 year, and falling to the Earth in the 8.4 million year diagram.<ref>[https://historydms.hq.nasa.gov/sites/default/files/DMS/e000045273.pdf NASA Press Kit for Project Lageos] (1976) p14</ref><ref>{{Cite book|title = Science Newsfront - Message for the future|url = https://books.google.com/books?id=DgEAAAAAMBAJ|publisher = [[Bonnier Corporation]]|date = 1976-07-01|language = en|first = Popular Science|last = Magazine}}</ref>
LAGEOS-1 (which is predicted to re-enter the atmosphere in 8.4 million years<ref name="ILRSLageos">{{cite web|url=http://ilrs.gsfc.nasa.gov/missions/satellite_missions/current_missions/lag1_general.html |title=International Laser Ranging Service |website=Ilrs.gsfc.nasa.gov |date= |accessdate=2016-02-22}}</ref>) also contains a 4&nbsp;in&nbsp;×&nbsp;7&nbsp;in plaque designed by [[Carl Sagan]]<ref>''[https://lageos.gsfc.nasa.gov/Design/Message_to_the_Future.html LAGEOS: LAser GEOdynamic Satellite : Design : Message to the Future]'', [[National Aeronautics and Space Administration]], [[Goddard Space Flight Center]]</ref> to indicate to future humanity when LAGEOS-1 was launched. The plaque includes the numbers 1 to 10 in binary. In the upper right is a diagram of the Earth orbiting the Sun, with a binary number 1 indicating one revolution, equaling one year. It then shows 268,435,456 years in the past (binary: 2<sup>28</sup>), indicated by a left arrow and the arrangement of the Earth's continents at that time (during the [[Permian]] period). The present arrangement of the Earth's continents is indicated with a 0 and both forward and backward arrows. Then the estimated arrangement of the continents in 8.4 million years with a right facing arrow and 8,388,608 in binary (2<sup>23</sup>). LAGEOS itself is shown at launch on the 0 year, and falling to the Earth in the 8.4 million year diagram.<ref>[https://historydms.hq.nasa.gov/sites/default/files/DMS/e000045273.pdf NASA Press Kit for Project Lageos] {{Webarchive|url=https://web.archive.org/web/20170130223437/https://historydms.hq.nasa.gov/sites/default/files/DMS/e000045273.pdf |date=2017-01-30 }} (1976) p14</ref><ref>{{Cite book|title = Science Newsfront - Message for the future|url = https://books.google.com/books?id=DgEAAAAAMBAJ|publisher = [[Bonnier Corporation]]|date = 1976-07-01|language = en|first = Popular Science|last = Magazine}}</ref>


==Launch data==
==Launch data==

Latest revision as of 22:23, 10 October 2025

Template:Short description Template:Infobox spaceflight

Template:Infobox spaceflight

File:LAGEOS-FILE.jpg
The LAGEOS plaque, designed by Carl Sagan

LAGEOS (Script error: No such module "IPAc-en".), Laser Geodynamics Satellite or Laser Geometric Environmental Observation Survey, are a series of two scientific research satellites designed to provide an orbiting laser ranging benchmark for geodynamical studies of the Earth. Each satellite is a high-density passive laser reflector in a very stable medium Earth orbit (MEO).

Function and operation

The spacecraft are aluminum-covered brass spheres with diameters of Script error: No such module "convert". and masses of Script error: No such module "convert"., covered with 426 cube-corner retroreflectors, giving them the appearance of disco balls.[1][2][3] Of these retroreflectors, 422 are made from fused silica glass while the remaining 4 are made from germanium to obtain measurements in the infrared for experimental studies of reflectivity and satellite orientation.[4] They have no on-board sensors or electronics, and are not attitude-controlled.

They orbit at an altitude of Script error: No such module "convert".,[5] well above low Earth orbit and well below geostationary orbit, at orbital inclinations of 109.8 and 52.6 degrees.

Measurements are made by transmitting pulsed laser beams from Earth ground stations to the satellites. The laser beams then return to Earth after hitting the reflecting surfaces; the travel times are precisely measured, permitting ground stations in different parts of the Earth to measure their separations to better than one inch in thousands of miles.

The LAGEOS satellites make it possible to determine positions of points on the Earth with extremely high accuracy due to the stability of their orbits. The high mass-to-area ratio and the precise, stable (attitude-independent) geometry of the LAGEOS spacecraft, together with their extremely regular orbits, make these satellites the most precise position references available.

Mission goals

The LAGEOS mission consists of the following key goals:

  • Provide an accurate measurement of the satellite's position with respect to Earth.
  • Determine the planet's shape (geoid).
  • Determine tectonic plate movements associated with continental drift.

Ground tracking stations located in many countries (including the US, Mexico, France, Germany, Poland, Australia, Egypt, China, Peru, Italy, and Japan) have ranged to the satellites and data from these stations are available worldwide to investigators studying crustal dynamics.

There are two LAGEOS spacecraft, LAGEOS-1 launched in 1976, and LAGEOS-2 launched in 1992. As of 2024Script error: No such module "Check for unknown parameters"., both LAGEOS spacecraft are routinely tracked by the ILRS network.[6]

Time capsule

LAGEOS-1 (which is predicted to re-enter the atmosphere in 8.4 million years[4]) also contains a 4 in × 7 in plaque designed by Carl Sagan[7] to indicate to future humanity when LAGEOS-1 was launched. The plaque includes the numbers 1 to 10 in binary. In the upper right is a diagram of the Earth orbiting the Sun, with a binary number 1 indicating one revolution, equaling one year. It then shows 268,435,456 years in the past (binary: 228), indicated by a left arrow and the arrangement of the Earth's continents at that time (during the Permian period). The present arrangement of the Earth's continents is indicated with a 0 and both forward and backward arrows. Then the estimated arrangement of the continents in 8.4 million years with a right facing arrow and 8,388,608 in binary (223). LAGEOS itself is shown at launch on the 0 year, and falling to the Earth in the 8.4 million year diagram.[8][9]

Launch data

  • LAGEOS 1, launched 4 May 1976, NSSDC ID 1976-039A, NORAD number 8820
  • LAGEOS 2, deployed 23 October 1992 from STS-52, NSSDC ID 1992-070B, NORAD number 22195

See also

References

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  1. ↑ Script error: No such module "citation/CS1".
  2. ↑ Kramer, Herbert J. (2013) Observation of the Earth and its Environment: Survey of Missions and Sensors Springer Template:ISBN p149
  3. ↑ LAGEOS Characteristics NASA Historical Data Book Volume III Table 4-166 SP-4012
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ LAGEOS: LAser GEOdynamic Satellite : Design : Message to the Future, National Aeronautics and Space Administration, Goddard Space Flight Center
  8. ↑ NASA Press Kit for Project Lageos Script error: No such module "webarchive". (1976) p14
  9. ↑ Script error: No such module "citation/CS1".

Script error: No such module "Check for unknown parameters".

Further reading

  • Script error: No such module "citation/CS1".
  • The Conversation (May 3, 2017) Space bling: ‘jewelled’ LAGEOS satellites help us to measure the Earth, [1]

External links

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