# LARES

> satellite

**Wikidata**: [Q427370](https://www.wikidata.org/wiki/Q427370)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/LARES_(satellite))  
**Source**: https://4ort.xyz/entity/lares

## Summary
LARES is an Italian satellite launched in 2012 to test Einstein's theory of general relativity by measuring the Lense-Thirring effect. It is a passive, spherical spacecraft with a tungsten core, designed to precisely track its orbit using laser ranging. The mission was developed by the Italian Space Agency (ASI) and launched aboard a Vega rocket.

## Key Facts
- Launched on February 13, 2012, from Ensemble de Lancement Vega
- Mass: 387 kg; Diameter: 36.4 cm
- COSPAR ID: 2012-006A; NSSDCA ID: 2012-006A
- Operator: Italian Space Agency (ASI)
- Launch vehicle: Vega rocket
- Orbit: Periapsis of 1450 km, inclination of 69.5°
- Followed by: LARES-2
- Official website: https://www.asi.it/scienze-della-terra/lares/ (in Italian)
- Also known as: Laser Relativity Satellite

## FAQs
### Q: What is the purpose of the LARES satellite?
A: LARES was built to test predictions of Einstein’s general relativity, specifically the Lense-Thirring effect, which describes how rotating massive objects drag spacetime around them. Scientists use precise laser tracking of its orbit to measure this relativistic phenomenon.

### Q: Who developed and operates LARES?
A: The satellite was developed and is operated by the Italian Space Agency (ASI). It represents one of Italy’s major contributions to fundamental physics research in space.

### Q: How does LARES differ from other satellites?
A: Unlike many active satellites, LARES is a passive device covered with retroreflectors that reflect laser beams sent from Earth-based stations. Its high density and simple geometric shape make it ideal for precision orbit determination needed for relativity experiments.

## Why It Matters
LARES plays a critical role in advancing our understanding of gravitational physics by providing empirical evidence for Einstein’s general theory of relativity. Specifically, it enables highly accurate measurements of frame-dragging effects caused by Earth's rotation—phenomena predicted over a century ago but only recently confirmed through missions like LARES and its predecessor, LAGEOS. By improving the accuracy of these tests, LARES contributes to validating modern theories of gravity and supports future developments in astrophysics, satellite navigation systems, and space-time metrology. As part of a lineage of geodetic satellites, LARES also helps refine models of Earth's gravitational field and tectonic activity via precise orbit monitoring.

## Notable For
- Being among the densest passive satellites ever built, optimized for testing relativity
- Hosting the most accurate measurement of the Lense-Thirring effect at the time of its early data release
- Serving as a successor to earlier geodynamic satellites such as LAGEOS-1 and LAGEOS-2
- Utilizing a nearly perfect spherical design with 92 retroreflectors for optimal laser ranging performance
- Marking a milestone in European scientific collaboration under the leadership of the Italian Space Agency

## Body
### Mission Overview
LARES (Laser Relativity Satellite) is a passive satellite dedicated to testing aspects of Einstein’s theory of general relativity. Its primary objective is to improve the measurement of the Lense-Thirring effect—the dragging of inertial frames due to the rotation of a central mass—in Earth’s gravitational field.

### Design & Construction
The satellite features:
- A solid tungsten alloy sphere weighing approximately 387 kilograms
- A diameter of 36.4 centimeters
- Coverage of 92 retroreflectors arranged across its surface for laser ranging
- No onboard power supply or propulsion system—fully passive design

This configuration ensures minimal non-gravitational perturbations, making it ideal for precision orbit analysis.

### Launch Details
- **Launch Date:** February 13, 2012
- **Launch Site:** Ensemble de Lancement Vega, Kourou, French Guiana
- **Launch Vehicle:** Vega (V01), a new European expendable launch system at the time
- **Mission Deployment:** Co-launched with the ALMASat-1 microsatellite and two CubeSats (e-st@r and VENµS)

### Scientific Objectives
- Measure the Lense-Thirring precession with improved accuracy compared to previous missions
- Support studies in Earth’s gravitational potential and geodynamics
- Provide long-term orbital data useful for refining global reference frames

Data collected from ground-based Satellite Laser Ranging (SLR) stations worldwide are used to reconstruct the satellite’s trajectory and analyze deviations consistent with relativistic predictions.

### Operational Status
Operated continuously since launch by the Italian Space Agency (ASI), LARES remains functional and continues contributing valuable SLR data for both fundamental physics and geophysical applications.

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## References

1. Jonathan's Space Report
2. Freebase Data Dumps. 2013