Sentinel-4 Launches Successfully: CfAI’s OGSE Plays Key Role

Sentinel-4, a key Earth observation mission calibrated with CfAI’s Optical Ground Support Equipment (OGSE), is now in orbit.

On 1^st July 2025, Sentinel-4 was launched into geostationary transfer orbit by a Space X Falcon 9 from Kennedy Space Centre. The first instrument for the Copernicus Sentinel-4 mission, developed by Airbus under ESA contract, is a UV-VIS-NIR spectrometer hosted on the MTG-S1 satellite. Operated by EUMETSAT, it will become the first instrument to monitor air quality over Europe and northern Africa from geostationary orbit. It will provide hourly sampling of key atmospheric trace gases and pollutants, including nitrogen dioxide, ozone, sulphur dioxide and formaldehyde.

Sentinel-4 was calibrated and characterised at RAL Space, using Optical Ground Support Equipment developed by CfAI at NETPark. The OGSE system deliverables included:

Light Source Module: Provided multiple light sources covering 305nm-775nm to the Collimator and Polariser Modules, via optical fibre bundles.
Collimator Module: Projected collimated light through the target mask into Sentinel-4, to help characterise optical performance.
Polariser Module: Delivered a source of linearly polarised light, to characterise polarisation sensitivity of Sentinel-4.

More information about Sentinel-4: https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-4

“Sentinel-4 on MTG-S1 in the cleanroom at Astrotech”,