Aeolus’ fiery demise to set the standard for safe re-entry

After exceeding its planned lifetime in orbit, the 1360 kg satellite is running out of fuel. To ensure enough fuel remains for a few final maneuvers, ESA spacecraft operators will bring Aeolus back toward our planet’s atmosphere for its inevitable demise.

They will direct the mission towards the ocean, further reducing the very small chance that fragments could cause damage should any reach the Earth’s surface.

This is the first assisted reentry of its kind and sets a precedent for a responsible approach to reducing the ever-increasing problem of space debris and uncontrolled re-entry.

Why is Aeolus coming home?

Launched in 2018, Aeolus has outlived its planned three-year life in space by more than 18 months. During its mission, its ground-breaking wind-mapping laser, once considered an almost impossible feat of engineering, has greatly improved weather forecasting worldwide.

Aeolus has been hailed as one of the most successful missions ever built and flown by ESA. As a research mission for Earth Explorer, it was designed to demonstrate new space technology, but it became one of the weather satellites with the highest output per observation, and its laser is still working as well as ever.

But Aeolus’ fuel is now almost depleted and orbiting low, at an altitude of just 320 km, means it is already being trapped by Earth’s harsh atmosphere.

The sun hastens the return of Aeolus.

Solar flares and coronal mass ejections release matter and radiation, and as this washes past Earth, it increases the density of Earth’s atmosphere. Intense solar activity in recent months means the satellite has used even more fuel to stay in orbit. For Aeolus, it has been like running against the wind.

That’s why, after five years of spectacular science, ESA’s wind mission ended its operations on April 30, 2023.

By taking advantage of this phase, scientists have put the instrument in a special mode to perform end-of-life activities that will help prepare the Aeolus-2 follow-up mission, which, like a phoenix, will rise from the ashes of its predecessor to Find the way. .

Aeolus’ last breath

Over the next few months, Aeolus will naturally descend from its current height of 320 km to 280 km. At this point, spacecraft operators at ESA’s Mission Control Center, ESOC, in Darmstadt, Germany, will gradually lower it to 150 km above Earth’s surface. The satellite will burn up when it descends to about 80 km.

Because populated regions make up a relatively small percentage of the Earth’s surface, the chance of a re-entry causing damage is exceptionally low.

The final date depends on how solar activity speeds up the process, but Aeolus is expected to be gone before the end of August.

Aeolus engineers and industry partners have carefully worked out how to best position Aeolus in Earth’s atmosphere to target open ocean water on re-entry, greatly reducing the amount of land over which pieces of debris can fall.

ESA’s Aeolus mission manager, Tommaso Parrinello, said: “The exact details of the re-entry approach and the series of maneuvers and operations, as well as a more detailed timeline, will be made public in mid-June.

“At the moment, we can anticipate that we are targeting the best ocean corridor to re-enter.”

With Aeolus’ re-entry, ESA is paving the way for future missions to continue taking the pulse of our planet. They can only do this if Earth’s orbits are not littered with hazardous space debris, and safety is paramount when it comes to end-of-life activities.