Consortium delivers VIS camera to ESA Euclid mission

ESA’s Euclid mission is closer to launch following the delivery of VIS, a massive optical digital camera from an international consortium led by the UCL Mullard Space Science Laboratory.

The VIS Focal Plane. The 36 dark blue CCDs are held in the grey Silicon Carbide structure seen here under a protective cover (to be removed before launch) at the top of the unit, while the electronics to measure and digitise the images are in the gold structure below with their power supplies on the outside. The silver sections are the thermal shrouds which isolate the cold CCDs from the warm electronics. Image credit: CEA

Once Euclid is launched from French Guiana in 2022, the visible imager (VIS) instrument will capture light from distant galaxies, providing a more detailed look at the visible universe over a larger part of the sky than previously possible.

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According to UCL, Euclid has a 1.2m mirror telescope designed to work at visible and near-infrared wavelengths. It will collect light from distant cosmic objects and feed it into VIS and another instrument, the Near Infrared Spectrometer and Photometer (NISP).

Now that the instruments have been delivered to Airbus, they will be integrated with the telescope and the rest of the payload module over the course of several months.

Euclid will survey the shapes of galaxies and map the geometry of the Universe with the aim of making accurate measurements of mysterious Dark Matter and Dark Energy, which make up most of the cosmos. No-one yet knows what Dark Energy is, but Euclid will be a powerful tool for astronomers looking to find out.

Dr Yannick Mellier, head of the Euclid Consortium said: “Euclid will revolutionise our knowledge of the Universe by making the most accurate measurements of Dark Matter and Dark Energy, testing whether Einstein’s theory of General Relativity requires modification, weighing neutrinos and exploring the details of how galaxies evolve.”

The VIS shutter with the shutter door on the right, which opens and closes at the start and end of exposures. This mechanism is finely balanced and momentum-compensated to minimize any disturbance to the stability of the satellite. Image credit: ESA

VIS and the Euclid telescope are built to be incredibly stable and to take very sharp high-resolution images. To do this the instrument has a mosaic of 36 CCDs, to give a total of just over 600 megapixels.

Professor Mark Cropper, UCL Mullard Space Science Laboratory and leader of the VIS instrument team, said: “The VIS camera will take pictures of entire sky that is accessible for large scale cosmology and reach out to the most distant parts of the universe over the course of six years. Each of these images will be more than 70 times larger than those captured using the Hubble Space Telescope and will contain information useful for all fields of astronomical research. They will be available for astronomers and the public alike, allowing everyone to enjoy the beauty of the Cosmos.”

The UCL team provided the system-level role, and produced, tested and calibrated the electronics for the detector array to ensure they survive the cold environment of space.

The NISP instrument, which is being built by a consortium of nationally funded institutes led by the Laboratoire d’astrophysique de Marseille in France, is dedicated to making distance measurements of galaxies. With VIS, it will allow Euclid’s data to be turned into the largest, most accurate 3D survey of the Universe ever conducted.