// ORBITAL LOGISTICS AND PROPULSION TERM
Highly Elliptical Orbit
A highly elliptical orbit (HEO) is an orbit shaped like a very stretched-out ellipse, meaning the satellite's distance from Earth varies greatly between its closest and farthest points.
TECHNICAL DEFINITION
A Highly Elliptical Orbit (HEO) is a type of Earth orbit characterized by a high eccentricity (e > 0.5), resulting in a significant difference between its periapsis and apoapsis altitudes, often used for communications or observation over high latitudes.
BACKGROUND
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, peaking in number at an altitude around 800 km (500 mi), while the farthest in LEO, before medium Earth orbit (MEO), have an altitude of 2,000 kilometers, about one-third of the radius of Earth and near the beginning of the inner Van Allen radiation belt.
READ MORE ON WIKIPEDIASYNONYMS & ALIASES
- HEO
- Molniya orbit
- Tundra orbit
- eccentric orbit
USAGE NOTE
HEOs are used for communications satellites serving polar regions where geostationary satellites have poor coverage.
DEVELOPERS
Organizations developing technology related to Highly Elliptical Orbit.
Operates critical national security assets in HEO, such as the Space-Based Infrared System (SBIRS) satellites, which provide missile warning and detection with persistent coverage over the polar regions.
As the prime contractor for the U.S. Space Force's SBIRS program, Lockheed Martin designs and builds the satellites that operate in highly elliptical orbits to provide persistent overhead surveillance.
Develops and integrates the sophisticated sensor payloads for the SBIRS HEO satellites, which are essential for detecting and tracking missile launches from high-latitude regions.
A commercial operator that utilizes a constellation of satellites in a highly elliptical, tundra-like geosynchronous orbit to provide uninterrupted satellite radio broadcasting services across North America.
A leading Russian satellite manufacturer responsible for developing and building numerous spacecraft designed for HEO, including the Meridian communications satellites and the historical Molniya series.
The Russian state space corporation that oversees launches and operations of satellite systems in HEO, continuing a long history of utilizing these orbits for national communication (Meridian) and early warning (Tundra) purposes.
A Canadian satellite communications company developing the Telesat Lightspeed network. They have actively explored multi-orbit architectures, including HEO, to provide continuous, high-speed connectivity to Canada's northern and arctic regions.
Conducts research and funds technology development programs studying the use of HEO for various applications, including future satellite communication systems and navigation services for high-latitude users.