Euclid’s Vision Embarks on De-icing Operations

Euclid, the spacecraft tasked with investigating the nature of the dark Universe, is facing a common issue that spacecraft encounter in the freezing cold of space – the formation of ice on its optics. However, the Euclid team has devised a new de-icing approach that shows promising results.

After months of research and testing, the team has developed a procedure to de-ice Euclid’s optics. The initial analysis of the data confirms the success of this approach, validating the team’s plan to keep the spacecraft’s optical system as ice-free as possible throughout its life in orbit.

The issue arises from water absorbed from the air during the spacecraft’s assembly on Earth, which is gradually being released in the vacuum of space. In Euclid’s new environment, this released water tends to stick to the spacecraft’s optics, causing a decrease in the amount of light measured from observed stars.

To address this, the team embarked on an “outgassing campaign” shortly after launch, which involved warming up the telescope with onboard heaters and partially exposing it to the Sun. While this sublimated most of the water molecules present at launch, a significant fraction still remains in the multi-layer insulation. Months of research and calibrations have revealed that several layers of water molecules are likely frozen onto mirrors in Euclid’s optics.

The team has developed a brand-new plan to decontaminate Euclid from a distance of 1.5 million km. The easiest option would be to heat the entire spacecraft using onboard heaters for several days. However, this approach could affect the mechanical structure and optical alignment of the spacecraft, potentially compromising its sensitivity and calibration.

To mitigate these risks, the team will begin by individually heating low-risk optical parts of the spacecraft. They will start with two mirrors that can be warmed up independently and monitor the impact on light loss. If necessary, they will continue to warm up other groups of mirrors, checking each time the percentage of photons received.

The goal is to isolate the affected areas and develop a long-term solution that can regularly de-ice Euclid’s optics without consuming too much mission time. This especially important as Euclid has six years to complete its survey, which involves measuring weak gravitational lensing and observing billions of galaxies to understand how matter has congregated under the influence of gravity.

While this issue is common for spacecraft operating in cold conditions, there is surprisingly little published research on the formation of ice on optical mirrors and its impact on observations. Euclid’s investigation into the nature of dark matter may also shed light on this longstanding problem faced by space missions observing Earth and the Universe.

The team awaits further analysis of the results and plans to provide updates in the coming days. Excitement grows as they hope to pinpoint the areas where the ice is accumulating and evaluate the effectiveness of their de-icing plan. Euclid’s successful restoration of its sharp vision will not only enable it to carry out its scientific mission but also contribute to our understanding of space exploration challenges.