At around 6.17pm on Wednesday 21 February, the ERS-2 satellite completed its atmospheric reentry over the North Pacific Ocean, between Alaska and Hawaii, in uninhabited areas, the European Space Agency (ESA) announced on Wednesday evening.
This satellite, launched on 21 April 1995 and weighing just over 2 tonnes, ceased operations in 2011. ESA has decided to deorbit the satellite, which has collected a wealth of data on land surfaces, oceans and polar ice caps, and has been used to monitor natural disasters and mitigate the proliferation of space debris. There are currently 35,000 pieces of debris larger than 10cm orbiting the Earth.
ERS-2 underwent a series of 66 deorbit manoeuvres in July and August 2011, which depleted its remaining fuel. Its altitude was lowered from 785 km to around 573 km in order to considerably reduce the risk of collision with other satellites or space debris, and to ensure that the satellite’s orbit would disintegrate quickly enough for it to reenter the atmosphere within 15 years.
Since then, the satellite’s altitude has steadily decreased and on 21 February, ERS-2 reached the critical altitude of around 80 km at which the atmospheric drag is so strong that the satellite began to break up. No material damage was reported following this reintegration.
Green light for two new small satellites
On Tuesday 20 February, ESA’s Earth Observation Programme Council gave the go-ahead for the development of two new small Scout satellites: NanoMagSat and Tango. NanoMagSat will measure the Earth’s magnetic field to help assess space weather risks, and will continue ESA’s existing Swarm mission. Tango will measure greenhouse gas emissions caused by human activity, and complements the forthcoming Copernicus mission to monitor carbon dioxide and the Sentinel-5 mission.
Scouts are small satellites that add scientific value either by miniaturising existing space technologies or by demonstrating new observation techniques.
A Scout mission should cost less than €35 million and be developed within three years, from kick-off to launch. (Original version in French by Camille-Cerise Gessant)