The European Space Agency's (ESA) Euclid telescope, launched in July 2023 to study the dark universe, has encountered a significant challenge. Gradually losing its vision due to layers of frozen water molecules on its mirrors, the telescope's mission to observe the dark universe using super-sensitive cameras is at risk. However, the team behind Euclid has devised a plan to combat the freezing temperatures of space and keep the telescope operational.

During the calibration process of Euclid's instruments, the mission's science team noticed a decline in the amount of light measured from stars observed with the visible light camera (VIS). Mischa Schirmer, calibration scientist for Euclid, stated that the faint and gradual decline in incoming photons could not be attributed to the stars themselves, but rather to the telescope's optical instruments.

After extensive investigation, the team concluded that thin layers of water molecules had frozen onto Euclid's mirrors. These water molecules are believed to have been absorbed from the air during the telescope's assembly on Earth and are now being released in the harsh temperatures of space, adhering to any surface they encounter.

Located approximately one million miles away from Earth, where temperatures can reach as low as -455 degrees Fahrenheit, the freezing of water molecules is a common issue for spacecraft at this distance. However, for Euclid, it is crucial to keep its optical system free from ice in order to successfully observe the dark universe.

To address this problem, the team has devised a decontamination procedure to heat the spacecraft. However, concerns about the potential impact on the telescope's mechanical structure have arisen. The activation of onboard heaters could cause expansion that might prevent the spacecraft from returning to its original size.

Instead, mission control plans to send commands to heat specific low-risk optical parts of Euclid, starting with two independent mirrors. If successful, this approach will be extended to heating other groups of mirrors on the telescope. Reiko Nakajima, VIS instrument scientist, emphasized the experimental nature of the de-icing procedure but expressed confidence that it would restore and preserve Euclid's ability to collect light from ancient galaxies.

This experimental intervention is seen as crucial, as the frozen water ice has the potential to compromise Euclid's ability to survey one-third of the sky with unprecedented sensitivity, enabling the detection of even the smallest galaxies.

It is worth noting that Euclid has overcome challenges before. Shortly after its launch, the telescope's fine guidance sensors occasionally lost track of guide stars, making precise pointing difficult. However, the team successfully designed a software patch to address the issue and ensure a full recovery.

As mission control prepares to heat Euclid's mirrors in an attempt to restore its vision, the outcome remains uncertain. Nevertheless, the mitigation plan showcases the team's determination to overcome obstacles and ensure the telescope's mission to explore the mysteries of the dark universe continues.