De-icing of Euclid’s Optics Has Gone Better Than Expected! [UPDATED]

ESA’s Euclid mission is now facing a distinctive hurdle in mapping the dark universe. However, thin layers of water ice on spacecraft mirrors are beginning to impede the Euclid space telescope’s vision.

The ice buildup on spacecraft mirrors is a serious issue for scientists. Although this phenomenon is a common problem for missions venturing into the icy vastness of the universe, surprisingly, little research has been done to address it.

Hence, the researchers are now working on a strategy to comprehend the distribution of ice within the optical system. If they manage to do this, Euclid’s mission could provide valuable insights for future missions of this type.

De-icing of Euclid’s Optics Performed Way Better Than Hoped

Updated on 4 April

The Euclid Space Telescope just got a major sight-saving makeover! In an update from ESA on March 26th, scientists announced a game-changing solution to combat freezing issues that were clouding Euclid’s vision. By warming just the first two mirrors by a mere 34 degrees, Euclid’s optics received a stunning 15% boost in sensitivity! The entire process took just a few minutes: from a chilly -147 to a toasty -113 degrees, the telescope’s clarity was restored, shining brighter than ever before.

But the best part? This procedure is so successful that scientists are confident in repeating it every few months, ensuring Euclid’s vision stays crystal clear throughout its six-year survey mission.

Reiko Nakajima, Euclid’s VIS instrument scientist, explains: “We expect ice to cloud the VIS instrument’s vision again in the future, but it will be simple to repeat this selective decontamination procedure every six to twelve months and with very little cost to science observations or the rest of the mission.”

Euclid’s Sight Restored

Updated on 20 March

ESA has just confirmed that Euclid’s vision is crystal clear once again! Initial findings from the mission’s data confirm the success of the de-icing strategy implemented by the team. Stay tuned for further analysis and insights coming in the next few days!

What Is The Source Of The Problem with Euclid Space Telescope?

After the Euclid space telescope launched, scientists noted a decrease in the detectable light from the observed stars within the visible spectrum. Subsequently, they revealed that the problem was caused by minute quantities of water absorbed from the atmosphere during the telescope’s assembly on Earth.

The water absorbed by the spacecraft gradually escapes into the vacuum of space. In Euclid’s extremely cold surroundings, when this water is released, it tends to freeze on the delicate optical components.

“Some stars in the Universe vary in their luminosity, but the majority are stable for millions of years. So, when our instruments detected a faint, gradual decline in photons coming in, we knew it wasn’t them – it was us,” – Mischa Schirmer, calibration scientist for the Euclid consortium and one of the main designers of the new de-icing plan explained.

Efforts To Minimize Ice Effect On Sensitive Euclid’s Instruments

Engineers had predicted this problem and carried out an “outgassing campaign” post-launch to minimize water contamination. However, some water molecules that had been absorbed remained within the spacecraft’s multi-layer insulation. After months, several layers of ice had accumulated on the telescope’s mirrors. 

The instruments of the Euclid space telescope are remarkably sensitive, and they can detect the presence of ice layers as thin as a few nanometers.

What Are The Solutions To Fight This Obstacle?

Euclid teams across the continent are currently facing the challenge. The most suitable solution, normally, is to heat the spacecraft to several degrees Celsius. All the heaters should be turned on for a few days, warming the spacecraft from about -140°C to a bit warmer, around -3°C in some parts. The mission control teams would be in charge of sending the commands to start this cleaning process.

Why Doesn’t This Decision Fit the Euclid Space Telescope?

Heating the spacecraft to clean its optics sounds logical, but it would affect the quality of its images. When spacecraft materials are heated, they expand, and there is a risk they won’t return to their original shape when they cool down. This would jeopardize the mission’s main objective – 3D mapping of the Universe.

“Most space missions don’t need the same level of temperature stability as Euclid. To map billions of galaxies across the Universe, Euclid must remain incredibly stable, including its temperature. We have to be extremely cautious about turning on the heaters,” – explained Andreas Rudolph, Euclid Flight Director.

A New Approach To Clean The Euclid Space Telescope’s Mirrors

A new method for removing ice aims to identify the areas most affected by ice and come up with a heating plan to de-ice them regularly.

Instead of heating the entire optics system, the team will focus on warming up parts that are less likely to be damaged. They’ll start by heating two mirrors separately to see how this affects the Euclid space telescope’s ability to gather light. If light interference is still a problem, they’ll gradually heat up more groups of mirrors.

“We hope to isolate the affected area on the spacecraft and warm it up to manage the ice contamination. This is a complex process, but it will save us time and resources. I’m excited to see how our plan works,” Mischa summarized.