LARES (satellite)

LARES (Laser Relativity Satellite) is a passive satellite system of the Italian Space Agency.[4]

LARES
LARES satellite
Mission typeLaser ranging satellite
Tests of general relativity[1][2]
OperatorItalian Space Agency (ASI)
COSPAR ID2012-006A
SATCAT no.38077
Websitehttp://www.lares-mission.com/
Mission durationLARES 1: 11 years, 8 months and 12 days (elapsed)
LARES 2: 1 year, 3 months and 11 days (elasped)
Spacecraft properties
ManufacturerCarlo Gavazzi Space
Launch mass386.8 kg
Dimensions36.4 cm (diameter)
Start of mission
Launch date13 February 2012, 10:00:00 UTC 14 July 2022, 13:13:43 UTC
RocketVega VV01 Vega-C VV21
Launch siteKourou, ELA-1
ContractorArianespace
Orbital parameters
Reference systemGeocentric orbit[3]
RegimeLow Earth orbit
Perigee altitude1437 km
Apogee altitude1451 km
Inclination69.49°
Period114.75 minutes
 

Mission

LARES 1

LARES 1 was launched into orbit on 13 February 2012 at 10:00:00 UTC. It was launched on the first Vega rocket from the ESA Centre Spatial Guyanais in Kourou, French Guiana.[5]

Composition

The satellite is made of THA-18N, a tungsten alloy,[6] and houses 92 cube-corner retroreflectors, which are used to track the satellite via laser from stations on Earth. LARES's body has a diameter of about 36.4 centimetres (14.3 in) and a mass of about 387 kilograms (853 lb).[1][7] LARES was inserted in a nearly circular orbit near 1,451 kilometres (902 mi) and an inclination of 69.49 degrees. The satellite is tracked by the International Laser Ranging Service stations.[8]

The LARES satellite is the densest object known orbiting the Earth.[1] The high density helps reduce disturbances from environmental factors such as solar radiation pressure.

Scientific goals

The main scientific target of the LARES mission is the measurement of the Lense–Thirring effect with an accuracy of about 1%, according to principal investigator Ignazio Ciufolini and the LARES scientific team,[9] but the reliability of that estimate is contested.[10]

In contrast, a recent analysis of 3.5 years of laser-ranging data reported a claimed accuracy of about 4%.[11] Critical remarks appeared later in the literature.[12]

Beyond the project's key mission, the LARES satellite may be used for other tests of general relativity as well as measurements in the fields of geodynamics and satellite geodesy.[13]

LARES 2

A second satellite, LARES 2, was launched into orbit on 13 July 2022 at 13:13:43 UTC on a Vega-C.[14] It was originally due to launch in mid-2021.[15][16] The launch was delayed to mid-2022 due to continuing impacts from the COVID-19 pandemic.[17][18]

LARES 2 may improve the accuracy of the frame-dragging effect measurement to 0.2%.[19] Concerns about the actual possibility of reaching this goal were raised.[20] LARES 2 is made of a nickel alloy instead of a tungsten alloy.[21]

See also

References
  1. "The LAser RElativity Satellite". The LARES Team. Archived from the original on 31 December 2012. Retrieved 28 February 2013.
  2. "LARES". International Laser Ranging Service. Retrieved 28 February 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  3. Peat, Chris (29 July 2013). "LARES - Orbit". Heavens-Above. Retrieved 29 July 2013.
  4. "LARES: Satellite per misure relativistiche" (in Italian). Agenzia Spaziale Italiana. Archived from the original on 15 October 2009. Retrieved 12 March 2009.
  6. Proceedings of "9th YSESM "Youth Symposium on Experimental Solid Mechanics". Gruppo Italiano Frattura. p. 97. ISBN 9788895940304.
  7. Peroni, I.; et al. (2007). "The Design of LARES: A satellite for testing General Relativity". Proceedings of the 58th International Astronautical Congress. IAC-07-B4.2.07.
    • Ciufolini, I.; Paolozzi A.; Pavlis E. C.; Ries J. C.; Koenig R.; Matzner R. A.; Sindoni G. & Neumayer H. (2010). "Gravitomagnetism and Its Measurement with Laser Ranging to the LAGEOS Satellites and GRACE Earth Gravity Models". General Relativity and John Archibald Wheeler. Astrophysics and Space Science Library. Vol. 367. SpringerLink. pp. 371–434. doi:10.1007/978-90-481-3735-0_17. ISBN 978-90-481-3734-3.
    • Ciufolini, I.; V. G. Gurzadyan; R. Penrose; A. Paolozzi (2012). Geodesic motion in general relativity: LARES in Earth's gravity. pp. i–xv. doi:10.1142/9789814440349_fmatter. ISBN 978-981-4440-33-2. {{cite book}}: |journal= ignored (help)
  10. Iorio, L. (2009). "Towards a 1% measurement of the Lense-Thirring effect with LARES?". Advances in Space Research. 43 (7): 1148–1157. arXiv:0802.2031. Bibcode:2009AdSpR..43.1148I. doi:10.1016/j.asr.2008.10.016. S2CID 14946573.
  11. Ciufolini, I.; A. Paolozzi; E. C. Pavlis; R. Koenig; J. Ries; V. Gurzadyan; R. Matzner; R. Penrose; G. Sindoni; C. Paris; H. Khachatryan; S. Mirzoyan (March 2016). "A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model. Measurement of Earth's dragging of inertial frames". The European Physical Journal C. 76 (3): 120. arXiv:1603.09674. Bibcode:2016EPJC...76..120C. doi:10.1140/epjc/s10052-016-3961-8. PMC 4946852. PMID 27471430.
  12. Iorio, L. (February 2017). "A comment on " A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model. Measurement of Earth's dragging of inertial frames", by I. Ciufolini et al". The European Physical Journal C. 77 (2): 73. arXiv:1701.06474. Bibcode:2017EPJC...77...73I. doi:10.1140/epjc/s10052-017-4607-1. S2CID 118945777.
  13. Paolozzi, A.; Ciufolini, I. (2013). "LARES successfully launched in orbit: Satellite and mission description". Acta Astronautica. 91: 313–321. arXiv:1305.6823. Bibcode:2013AcAau..91..313P. doi:10.1016/j.actaastro.2013.05.011. S2CID 111380211.
  14. European Space Agency, ed. (13 July 2022). "Vega-C successfully completes inaugural flight". www.esa.int. Retrieved 14 July 2022.
  15. Henry, Caleb (14 September 2020). "Vega C debut slips to mid-2021". SpaceNews. Retrieved 14 September 2020.
  16. "Launch Schedule – Spaceflight Now". 15 September 2020. Archived from the original on 15 September 2020. Retrieved 22 November 2021.
  17. Kanayama, Lee (29 October 2021). "Ariane 6 undergoing preparations for its 2022 debut". NASASpaceFlight.com. Retrieved 22 November 2021.
  18. "Launch Schedule – Spaceflight Now". Retrieved 22 November 2021.
  19. A new laser-ranged satellite for General Relativity and space geodesy: I. An introduction to the LARES2 space experiment arXiv:1910.13818
  20. Iorio, L. (2023). "Limitations in Testing the Lense–Thirring Effect with LAGEOS and the Newly Launched Geodetic Satellite LARES 2". Universe. 9 (5): 211. arXiv:2304.14649. Bibcode:2023Univ....9..211I. doi:10.3390/universe9050211.
  21. "Mission Lares 2". Retrieved 13 July 2022.
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