In a spotless cleanroom, engineers at Redwire’s facilities in Belgium, have completed the assembly of a key part ESA’s ALTIUS ozone mission – the all-important satellite platform is now fully formed ready to receive its measuring instrument.

ALTIUS – short for Atmospheric Limb Tracker for Investigation of the Upcoming Stratosphere – is an Earth observation satellite designed to track ozone and other atmospheric trace gases.

The importance of tracking atmospheric ozone goes back to the 1970s when scientists discovered that the ozone layer was being depleted, particularly above the South Pole resulting in what is known as the ozone hole.

Atmospheric ozone acts as Earth’s sunscreen, absorbing ultraviolet radiation from the Sun, particularly harmful UV-B rays. Exposure to UV-B radiation can lead to an increased risk of skin cancer and cataracts, as well as damage to plants and other wildlife.

Thanks to the Montreal Protocol, over the last three decades much progress has been made in stopping damage to the ozone layer through restrictions on the use of certain chemicals in appliances such as refrigerators. However, while this atmospheric shield in the stratosphere, 15–30 km above Earth’s surface, is on the road to recovery, monitoring and understanding the processes involved are of the upmost importance.

Ozone also influences the temperature of the stratosphere and it plays a role in heat absorption affecting global circulation patterns, therefore its monitoring improves climate prediction models.

Unlike other satellite missions that measure ozone, ALTIUS is designed to perform ‘limb sounding’ – a technique where its 2D spectral imager scans Earth’s atmosphere along the horizon, instead of looking straight down.

This technique allows ozone to be viewed at different altitudes, thereby providing vertical profiles of different ozone concentrations. The instrument uses three independent spectral imagers that operate in the ultraviolet, visible and near-infrared, and the mission will achieve global coverage in a three-day revisit cycle.

The satellite platform, the technical backbone of the satellite, is responsible for the power supply and management, thermal regulation, navigation, attitude pointing and orbit control, communications, and the overall system and data management that will allow the ALTIUS instrument to do its vital work once in orbit.

The completion of the platform’s assembly signals the mission’s transition into the verification and integration phase – where engineers will begin connecting and testing all onboard systems as one cohesive unit.

Michael Francois, ESA’s ALTIUS Project Manager, said, “The completion of ALTIUS’ satellite platform is an important milestone for the mission. We thank the Redwire team for their focused effort and technical expertise. While ALTIUS is a relatively small satellite, measuring 1.3 m in height and 4.5 m across its solar panel, and weighing less than 300 kg, its development requires precision, collaboration, and a high level of engineering skill.”

Meanwhile, at OIP Sensor Systems, also in Belgium, work is underway on assembling the heart of the mission: the versatile spectral imager. The first pieces to take shape are the optical benches – high-precision components critical for capturing atmospheric data in the ultraviolet, visible, and near-infrared bands.

With the platform now fully assembled and testing set to begin, the ALTIUS team is on track for launch foreseen at the end of 2027. If all goes as planned, this new satellite mission will soon be orbiting Earth, eyes fixed on the fragile veil of gases that protects all life below.

Developed within ESA’s Earth Observation Earth Watch programme, ALTIUS is primarily funded by Belgium, with support from Canada, Luxembourg, and Romania – an international collaboration reflecting the global importance of its mission.

Source: ESA