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The Euclid spacecraft will have a launch mass of around 2100 kg. It will be about 4.5 metres tall and 3.1 metres in 'diameter' (with appendages stowed). The nominal mission lifetime is six years.

Artist's impression of Euclid. Credit: ESA/ATG medialab

The Euclid spacecraft will be made up of two major assemblies:

  • payload module – houses the telescope, the focal plane components of the instruments and some of the data processing electronics;
  • service module – contains the satellite systems: power distribution, attitude control, propulsion, telecommand, telemetry and data handling.

Payload Module

Image credit: Airbus Defence & Space

The Euclid payload consists of a 1.2-m-aperture telescope with two instruments: the visual imager (VIS) and the near-infrared spectrometer and photometer (NISP).

Both instruments share a large common field of view. VIS provides high quality images to carry out the weak lensing galaxy shear measurements. NISP performs imaging photometry to provide near-infrared photometric measurements for photometric redshifts, and also carries out slitless spectroscopy to obtain spectroscopic redshifts.

The telescope and instrument designs are challenging, but proven heritage from, for example, Gaia and JWST ensures high confidence to deliver the performance required.


Instrument characteristics
Visual imager (VIS)
Field-of-view 0.787 deg × 0.709 deg
Capability Visual imaging
Wavelength range 550 - 900 nm
Sensitivity 2.5 mag
10σ extended source
Detector Technology 36 arrays
4k × 4k CCD
Pixel Size
Spectral resolution
0.1 arcsec


Instrument characteristics
Near-infrared spectrometer and photometer (NISP)
Field-of-view 0.763 deg × 0.722 deg
Capability Near-infrared imaging photometry Near-infrared spectroscopy
Wavelength range Y (920 - 1146 nm) J (1146 - 1372 nm) H (1372 - 2000 nm) 1100 - 2000 nm
Sensitivity 24 mag
5σ  point source
24 mag
5σ  point source
24 mag
5σ  point source
3 × 10-16 erg cm-2 s-1
3.5σ  unresolved line flux
Detector Technology 16 arrays
2k × 2k near-infrared sensitive HgCdTe detectors
Pixel Size
Spectral resolution
0.3 arcsec 0.3 arcsec



Image credit: Airbus Defence & Space

The design of the Euclid telescope is mainly driven by the requirements to provide both excellent visible channel imaging quality and a simultaneous field for near-infrared spectroscopy and photometry.

The Euclid telescope is a three mirror Korsch configuration with a 0.45 deg off-axis field and an aperture stop at the primary mirror. The entrance pupil diameter is 1.2 metres, the optically corrected and unvigneted field of view is 0.79 × 1.16 deg², and the focal length is 24.5 m.

In order to meet the scientific performance requirements, such as having internal background well below the zodiacal sky background, the telescope must operate at a reduced temperature - a maximum operating temperature of about 240 K can be tolerated for the telescope.


Service Module

The service module hosts most of the spacecraft subsystems that are needed to operate the payload, including telemetry, power, thermal control, and attitude and orbit control (AOCS). For Euclid, the service module provides X and K band communications, with a K band science data rate of ~55 Mbit/s during the daily telecommanding and communications period of 4 hours. To store the large data volume that will be accumulated during observations, Euclid will have a mass memory of at least 2.6 Tbit. To meet the high precision imaging requirements, the Euclid AOCS provides an extremely stable pointing with a dispersion of less than 35 milli-arcseconds per visual exposure. At those accuracies, a high thermal stability is also required to protect the telescope assembly from optical misalignments.

Last Update: 23 September 2019
24-Sep-2019 09:14 UT

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