Eccentricity

TECHNICAL DEFINITION

Eccentricity (e) is a dimensionless orbital element quantifying the deviation of an elliptical orbit from a perfect circle, where e=0 signifies a circular orbit and 0 < e < 1 indicates an elliptical path.

BACKGROUND

The Moonlight programme or the Moonlight Lunar Communications and Navigation Services (LCNS) is an initiative by the European Space Agency (ESA) with the goal of creating uninterrupted telecommunications satellite coverage between Earth and the Moon, as well as lunar satellite navigation, facilitating future lunar projects. LCNS is a partnership between ESA and an industry consortium led by Telespazio, with support from the UK Space Agency and the Italian Space Agency. Moonlight is managed by ESA Connectivity and Secure Communications (CSC) directorate, alongside the ARTES and IRIS2 programmes.

SYNONYMS & ALIASES

• Orbital shape
• Ellipticity
• Ovalness
• Non-circularity

USAGE NOTE

Understanding an orbit's eccentricity is vital for predicting a satellite's varying altitude and speed throughout its revolution.

DEVELOPERS

Organizations developing technology related to Eccentricity.

• NASA (National Aeronautics and Space Administration)

  Designs and operates spacecraft missions that utilize a wide range of orbital eccentricities for various scientific, exploratory, and observational purposes, requiring precise astrodynamics and mission planning.

• European Space Agency (ESA)

  Develops and manages numerous space missions, including those in highly elliptical orbits for science or communication, where orbital eccentricity is a critical design and operational parameter.

• SpaceX

  As a leading launch service provider and satellite operator (Starlink), SpaceX precisely places payloads into target orbits and manages large constellations, with orbital eccentricity being a key parameter in trajectory design and constellation maintenance.

• Arianespace

  Provides launch services, frequently inserting satellites into geostationary transfer orbits (GTO) which are highly eccentric, requiring precise calculation and execution of orbital maneuvers.

• Lockheed Martin

  A major developer and manufacturer of satellites and spacecraft for various applications, where mission success relies on designing and maintaining orbits with specific eccentricities.

• Ansys (formerly AGI)

  Develops Systems Tool Kit (STK), a widely used software platform for space mission design, analysis, and operations, which deeply models and simulates orbital mechanics, including eccentricity.

• LeoLabs

  Provides space situational awareness services, tracking objects in orbit and characterizing their trajectories, where the precise measurement and prediction of orbital eccentricity is fundamental for collision avoidance and space traffic management.