The Aeolus wind satellite from the European Space Agency (ESA) is returning to Earth after spending longer in orbit than anticipated. The spacecraft, which has been in orbit around our planet for close to five years, is now plummeting at a rate of around one kilometre per day, and it is quickening its descent.
Aeolus was initially intended to be a research mission that would showcase cutting-edge technologies. However, it was so effective that for the most of its orbital life, it delivered data to Europe’s top meteorological institutions, greatly enhancing worldwide weather forecasts. Seven billion UV light pulses were sent down by its amazing Aladin sensor to study the Earth’s wind.
The mission is now complete because Aeolus’ fuel is practically gone. Aladin, the ground-breaking wind-mapping laser, was operated as long as it was possible by engineers before reentry procedures started. Aeolus is now being lowered from its operating height of 320 km by gravity, the atmosphere of Earth, and solar activity.
ESA’s spacecraft operators will shortly intervene and attempt an aided reentry in a first-of-its-kind operation. This action exceeds the mission’s safety requirements, which were planned and developed in the late 1990s. The goal is to further lower the existing low danger to infrastructure or human life.
The remaining fuel will be used by mission control at the ESA’s Space Operations Centre in Germany to guide Aeolus throughout its journey back to Earth. When the satellite reaches an altitude of around 80 km, the majority of it will start to burn up. Models suggest that numerous debris fragments could yet make it to the Earth’s surface.
The normal reentry of Aeolus will proceed even if this reentry effort must be stopped. To help Aeolus and make its return even safer than it was intended to be, a number of movements and operations have been developed.
As time passes, predictions get more precise, but it is still unclear exactly when Aeolus will reenter the atmosphere of Earth. The sun’s activity affects a number of things. Solar flares and coronal mass ejections may hasten the process, but a period of low solar activity may result in a little delay in Aeolus’ descent.
The already extremely remote prospect that falling debris might pose a harm to life or infrastructure is being minimised by the flight control team, which is aiming at a section of ocean underneath the satellite’s route for reentry. Aeolus will be guided towards the ideal place for reentry by a sequence of orders that are issued over the course of six days after it reaches an altitude of 280 km.
At 150 km, Aeolus will make one more, crucial manoeuvre that will guide him home. In a few hours, the satellite will come back, with the majority of it exploding in Earth’s atmosphere.
This initial effort at an aided reentry establishes a new standard for missions that could be adjusted to retrospectively follow rules even though they didn’t at the time of their inception.