The European Space Agency announced on Tuesday that layers of water ice are beginning to affect the vision of its Euclid spacecraft. Collaborating with other entities, the space agency is currently testing a newly devised procedure to remove the ice from the spacecraft.
Euclid, dubbed ESA’s “dark universe detective,” is specifically engineered to explore the origins of the universe by delving into the mysteries of dark matter and dark energy. These enigmatic forces, constituting approximately 95% of the known universe, remain largely elusive to our understanding.
The thin layers of ice encasing Euclid’s optics are as narrow as a strand of DNA, yet they are already causing disruptions to the spacecraft’s vision. This poses a significant concern for the mission’s precision-dependent objective of unraveling the mysteries of the dark universe. A successful outcome from the “deicing” test would provide the Euclid team with a novel strategy to maintain the spacecraft’s optical systems free from ice accumulation throughout its operational lifespan.
Euclid’s issue is a common challenge encountered by spacecraft once they enter space. Water absorbed from Earth’s atmosphere during assembly is gradually released by certain spacecraft components due to the vacuum of space. Coupled with the frigid temperatures of the spacecraft’s environment, these water molecules adhere to the first surface they encounter. Unfortunately, in Euclid’s case, this means they land on its highly sensitive optics, exacerbating the problem.
“We conducted a comparison between the starlight entering through the VIS instrument and the previously recorded brightness of the same stars observed by both Euclid and ESA’s Gaia mission,” explained Mischa Schirmer, the calibration scientist for the Euclid consortium and a key contributor to the development of the new de-icing strategy, in a press release. “While some stars exhibit variations in luminosity, the majority remain stable for millions of years. Thus, when our instruments detected a faint, gradual decrease in incoming photons, we concluded it wasn’t due to the stars themselves but rather to our own spacecraft.”
For many spacecraft, employing built-in heaters to elevate the overall temperature of the craft would typically suffice to cleanse the optics. However, due to the expansion of materials when heated, which may not consistently revert to their original state upon cooling, this approach poses challenges for a mission requiring high sensitivity.
To mitigate the risk of thermal fluctuations compromising sensitivity, the Euclid team will cautiously heat specific, low-risk components of the spacecraft individually until the desired outcome is achieved.
