LARES (satellite)

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]

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.^{[citation needed]}

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][clarification needed]}

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]

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]

• LAGEOS similar satellites launched in 1976
• List of laser ranging satellites
• List of passive satellites
• PAGEOS
• Project Echo
• Vega flight VV01

• LARES Mission: official Web Site of LARES Mission.
• LARES - Testing of General Relativity on ASI's page.
• LARES - Pronto al via! article with images of LARES on ASI's site (in Italian).
• LARES Satellite Information LARES page on the ILRS Web Site.