Integral

Researchers at the University of La Rioja in Spain have created a new technique for disposing of artificial satellites from highly elliptical orbits (HEO) after they complete their mission.

Developed by the university’s Scientific Computing Group (GRUCACI), the method uses a biological evolution-based algorithm, and orbit propagator software that can depict the evolution of an orbiter over 100 years.

Through the depiction of a satellite’s development during its lifetime, researchers could analyse the best conditions for it to re-enter into the Earth’s atmosphere, and disintegrate without posing any risk to other satellites.

HEO orbits are said to be eccentric and inclined by 60° or more, with respect to the equator.

The satellites placed in HEO can cross low Earth orbits (LEO) and geostationary orbits (GEO), with a risk of collision with other existing satellites, and an uncontrolled re-entry into the lower layers of the Earth’s atmosphere.

"Our research has focused on taking advantage of the same gravitational effects that affect HEO orbits so as to reduce the cost of eliminating the satellites."

Study co-author Roberto Armellin told Sinc: "Our research has focused on taking advantage of the same gravitational effects that affect HEO orbits so as to reduce the cost of eliminating the satellites, which operate in them once they have reached retirement."

"Some propellant needs to be reserved in order to perform the satellite disposal manoeuvres, so it cannot be used to extend the mission duration, which makes it more expensive."

The new methodology is claimed to reduce the amount of propellant needed, as well as the associated costs.

The technology has been tested on the European Space Agency’s (ESA) Integral satellite mission that was launched in 2002 to study energetic radiation coming from space.

Simulation results suggested designing manoeuvres for Integral to re-enter into earth’s atmosphere and disintegrate between September 2028 and July 2029, Armellin said.

Integral has fired its engines four times this year with possible re-entry in February 2029.

Image: An artistic impression of the Integral gamma-ray space observatory. Photo: courtesy of ESA / Medialab.