Atomic oxygen measured in Earth's atmospheric layers
September 2, 2025
Atomic oxygen measured in Earth's atmospheric layers
The gondola in the stratosphere
Exploring the different layers of Earth's atmosphere is a key element of space research and plays an important role in the development and operation of satellites.
Image: 1/2, Credit:
The Dorothy Project
OSAS-B in the gondola of the stratospheric balloon
The OSAS-B spectrometer from the DLR Institute of Space Research is the only instrument worldwide capable of directly detecting the concentration of atomic oxygen in Earth's mesosphere and thermosphere.
Atomic oxygen has been measured with high precision for the first time using the OSAS-B spectrometer on a stratospheric balloon.
The measurements provide important data for atmospheric and climate research, as well as for forecasting space weather and determining the lifespan of satellites.
Focus: Space research, spectral measurement, Earth’s atmosphere
Using high-altitude balloons in the stratosphere, Earth can be observed from altitudes of up to approximately 40 kilometres, enabling important atmospheric data to be collected. During this year’s Strato-Science 2025 campaign in Timmins, Canada, researchers from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) were able to send OSAS-B (the Oxygen Spectrometer for Atmospheric Science on a Balloon) on a stratospheric flight. The Strato-Science 2025 campaign was organised by the French space agency (Centre National d'Études Spatiales; CNES) and the Canadian Space Agency (CSA).
Earth's atmosphere influences satellite lifespan
Exploring the different layers of Earth's atmosphere is a key aspect of space research and plays a special role in the development and operation of satellites. The influence of UV radiation from the Sun on the atmosphere's individual layers is crucial. In the upper layers – the mesosphere and thermosphere – intense UV radiation creates free oxygen atoms that influence chemical processes as well as the physical properties of the atmosphere. This 'atomic oxygen' is highly corrosive and degrades materials such as aluminium and plastics in satellites, directly impacting their orbital period and lifespan. The chemistry of the upper atmosphere is shaped by atomic oxygen, the concentration of which depends on solar radiation. This data is of particular importance for atmospheric and climate research, and for predicting space weather.
First measurements from a high-altitude balloon
OSAS-B, developed by the DLR Institute of Space Research, is the only instrument in the world that can directly detect the concentration of atomic oxygen in Earth's mesosphere and thermosphere, at altitudes of approximately 80 to several hundred kilometres. It measures the emission of atomic oxygen with high spectral resolution at frequencies of 2.1 terahertz and 4.7 terahertz. Using both frequency channels ensures even more precise measurements.
During the 14-hour flight at an altitude of 31 kilometres, the two emission lines of atomic oxygen were measured for the first time from a stratospheric balloon. "The effort put into developing OSAS-B was well worth it – the instrument worked flawlessly throughout the entire flight and provided us with high-quality spectra of the two terahertz lines," says Martin Wienold, OSAS-B project lead at DLR. "These measurements contribute to a better understanding of the upper atmosphere. They also support the Keystone satellite mission currently being planned by ESA," adds Heinz-Wilhelm Hübers, Director of the DLR Institute of Space Research and scientific lead of OSAS-B. He adds: "The cooperation and support from our colleagues at CNES and CSA was outstanding and essential to the success of this stratospheric flight. We would like to express our sincere thanks to them."
