The historic reentry of Aeolus is anticipated to take place on Friday, July
28, over a section of the Atlantic Ocean.
This week marks a historic return to Earth for a European spacecraft.
The Aeolus wind-studying satellite is now being guided by the European
Space Agency (ESA) into a controlled explosion in Earth's atmosphere. This
plan is a significant change for Aeolus, whose first death wish planned for
an unassisted fall.
Additionally, the deorbiting of a satellite has never been "assisted" in
this way before, according to ESA, making it a historic occasion in space
travel. (Such actions are frequently taken by rocket stages, which
frequently direct themselves to secure reentries over open water.)
What you need to know about Aeolus and its reentry campaign is provided
here. It is anticipated that the spacecraft will burn up on Friday, July
28.
In August 2018, the 1,360-kilogram (3,000-pound) Aeolus launched on a
ground-breaking mission to research Earth's winds, which had never been
closely observed from orbit.
Doppler wind lidar, also known as a "light detection and ranging" sensor,
is the only scientific tool the spacecraft is equipped with, and according
to ESA, its findings have helped scientists improve their climate models and
weather forecasts.
From a sun-synchronous orbit 200 miles (320 kilometers) above Earth, Aeolus
recorded winds. Compared to the International Space Station, which orbits
our globe at an average height of around 250 miles (400 km), that is a
comparatively low altitude.
The three-year mission of the spacecraft was originally planned. Although
Aeolus significantly outlived its warranty, its time is already almost up.
ESA is currently bringing down the spacecraft since it is running low on
fuel.
When a satellite's job is complete, it usually falls back to Earth
uncontrollably, being drawn lower and lower by the atmosphere of our planet,
which gets denser the higher it rises.
That was also the initial idea for Aeolus's destruction. However, the
mission crew opted to choose a different path since it appeared more
responsible and they had the potential to do so (they had saved enough fuel
for the necessary maneuvers).
Typically, 20% or less of a spacecraft's mass makes it through the violent
passage through Earth's atmosphere. Therefore, there is always a chance of
injury and possible harm to the ground's infrastructure with every
uncontrolled fall.
In addition to lowering that risk, ESA and the Aeolus team wished to serve
as a role model for other satellite operators.
"Aeolus' reentry, and ESA's desire to reduce the risk in accordance with
current guidelines, sets a new precedent for safe spacecraft operations and
sustainable spaceflight, for both future missions and those already in
orbit,"
said Rosa Jesse of the ESA
in a
blog post
last month.
Since June 19, Aeolus has begun descending from its operating altitude.
According to ESA's Rosa, the satellite carried out its first significant
reentry maneuver on Monday, July 24, firing its thrusters twice for a total
of 37.5 minutes in burns that decreased its altitude by around 19 miles (30
km), to 155 miles (250 km).
On Thursday, July 27, four additional burns are planned to decrease the
orbit even further. "A final order will guide Aeolus home from an altitude
of 150 km to just 120 km [93 to 75 miles] on Friday (July 28)." The
satellite will thereafter reenter, Rosa noted in the statement on
Monday.
About five hours after the last maneuver, reentry is anticipated to take
place over the Atlantic Ocean, according to mission crew members.
It's too early to determine the exact position of the reentry; specific
projections won't probably be produced until after the last maneuver on
Friday. The cities and towns that will be near enough to the reentry route
to maybe catch a glimpse of the satellite's flaming death plummet are thus
unknown to us. But keep checking back; we'll provide you those updates as
soon as ESA and the Aeolus team send them.
