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The mission

The Atmospheric Limb Tracker for Investigation of the Upcoming Stratosphere (Altius) mission carries a high-resolution spectral imager and uses a limb-sounding technique to deliver profiles of ozone and other trace gases in the upper atmosphere to support services such as weather forecasting, and to monitor long-term trends. Altius is developed within ESA’s Earth Watch programme and financed mainly by Belgium with contributions from Canada, Luxembourg and Romania.


The launch

Date: 2028
Site: Kourou, French Guiana
Rocket: Vega-C

Altius.jpg
2D spectral limb sounder
3 days global coverage
266 kg satellite mass
668 km orbital altitude

Latest news

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[ Altius ]
Altius to track ozone
03 MAR. 2026

Testing ozone-monitoring satellite’s solar wings

Over the past year, satellite engineers at Redwire Space in Belgium have been hard at work assembling European Space Agency’s ozone-monitoring satellite, ALTIUS. The team has now passed a major milestone: testing the deployment of the satellite’s two solar panels, a critical step in preparing it for life in orbit.
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[ Altius ]
ALTIUS satellite platform in the cleanroom
ARCHIVE CONTENT: 17 JUL. 2025

ALTIUS ozone mission’s satellite platform assembled

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.
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[ FLEX ]
FLEX
ARCHIVE CONTENT: 11 JAN. 2022

Ride into space on Vega-C secured for FLEX and Altius

A contract signed with Arianespace secures the joint launch for two satellites that will further knowledge of our home planet. Scheduled to lift off on a new class of rocket, ESA’s Vega-C, from Europe’s Spaceport in mid-2025, FLEX will yield new information about the health of the world’s plants and Altius will deliver profiles of ozone and other trace gases in the upper atmosphere to support services such as weather forecasting.
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[ Altius ]
Altius
ARCHIVE CONTENT: 24 JAN. 2020

Contract secures build of ozone-monitoring Altius satellite

ESA has awarded a contract to QinetiQ to build Altius. This new mission will deliver profiles of concentrations of stratospheric ozone with high vertical resolution, as well as profiles of other atmospheric trace gases.
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Latest images

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Discover Altius

[ Altius ]
Ozone hole 2020
06 JUL. 2021

Introducing Altius

The ozone layer is a natural layer of gas in the upper atmosphere. Stratospheric ozone acts as sunscreen, absorbing much of the ultraviolet radiation in sunlight before it reaches Earth’s surface – hence playing a vital role in protecting life on our planet.
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[ Altius ]
Altius satellite platform and solar array structural and thermal model
06 JUL. 2021

Facts and figures

Launch2028LauncherVega-C from Europe’s Spaceport in French GuianaSatellite and instrument sizeThree-axis stabilised Proba-NEXT satellite platformMass266 kg (including 12 kg fuel)InstrumentHigh-resolution 2D spectral limb-sounding imager using three channels: ultraviolet (250–355 nm), visible ...
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[ Altius ]
Measuring ozone
06 JUL. 2021

Ozone

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.
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[ Altius ]
Altius to track ozone
07 JUL. 2021

Measuring ozone

The Dobson spectrophotometer and light detection and ranging are commonly used to measure overhead ozone from the ground. Developed in 1924, the Dobson spectrophotometer is the earliest instrument used to measure ozone, and modern versions continue to provide data. However, instruments carried by satellites provide consistent global measurements over decades.
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