Belgian Institute for Space Aeronomy (BIRA-IASB) BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Belgian Institute for Space Aeronomy (BIRA-IASB) Institut d’Aéronomie Spatiale de Belgique (IASB) Belgisch Instituut voor Ruimte-Aeronomie (BIRA) BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT-

Belgian Scientific Involvement in STS-45/ATLAS-1 March 23 - 31, 1992

Atmospheric Laboratory for Applications and Science (ATLAS) Key goal: A series of nine NASA Space Shuttle-Spacelab missions to investigate how Earth's atmosphere and climate are affected by the Sun and by anthropogenic activities: to unravel the complicated web of man's impact on the environment. by making simultaneous solar and atmospheric measurements on a global scale. Specific objectives of the ATLAS series: To study the Earth's atmosphere and the Sun's influence upon it over an entire 11-year solar cycle. To provide calibration for NASA's Upper Atmosphere Research Satellite (UARS) launched from the Space Shuttle in September 1991.

ATLAS-1 The first ATLAS mission, used two Spacelab pallets and an igloo, a Shuttle-based research laboratory. ATLAS-1 flew aboard Space Shuttle Atlantis on mission STS-45 in spring 1992. ATLAS-1 carried 13 instruments designed to conduct 14 investigations with scientists from Belgium, France, Germany, Japan, Switzerland, the Netherlands and the United States. Scientific experiments were focused on: atmospheric science, solar science, space plasma physics and astronomy. Many of those experiments were also scheduled for later ATLAS missions so that the data gathered during ATLAS-1 will be among the first collected in a series of long-range studies that measure changes in the atmosphere and the Sun.

ATLAS used Spacelab, a Shuttle-based research laboratory. SPACELAB "made in Europe" ATLAS used Spacelab, a Shuttle-based research laboratory. Why Spacelab? Spacelab flights allow astronauts to perform experiments in microgravity environment, repair satellite experiments in orbit, … Instruments can be carried into space, returned to the ground, refined and re-flown to optimise their scientific return. The Shuttle provides vehicle attitude control and manoeuvring capability, and utilities services. The Shuttle-Spacelab combination serves, as a short-duration space station for scientific research.

SPACELAB "made in Europe" What is Spacelab? Spacelab is a reusable research laboratory carried in the payload bay of the Space Shuttle Orbiter and exposed to Space when the cargo bay doors are opened. The laboratory is modular in design and therefore construction - so can be flown in a number of configurations depending on the scientific scope of the mission. Spacelab consists of two main elements, the 'Module' and the 'Pallets': The Module is a pressurised laboratory in which scientists can work in a shirt-sleeve environment. Pallets are unpressurised platforms. They are directly exposed to space. When pallets are used without a laboratory module, the subsystems necessary for t operation are contained in a pressurized cylinder or "Igloo" mounted on the first pallet.

ATLAS-1 PAYLOAD Solar Physics Experiments: Solar Constant Radiometer (SOLCON) B Solar Spectrum Irradiance Monitor (SOLSPEC) F/B/D Solar UV Spectral irradiance Monitor (SUSIM) USA Active Cavity Radiometer (ACR) USA Atmospheric Physics Experiments: Grille Spectrometer (GRILLE) B/F Atmospheric H and D through Measurement of Lyman-Alpha (ALAE) F/B Atmospheric Trace Molecule Spectroscopy (ATMOS) USA Imaging Spectrometric Observatory (ISO) USA Shuttle Solar Backscatter Ultraviolet Experiment (SSBUV) USA Space Experiments with Particle Accelerators (SEPAQ) USA Atmospheric Emission Photometric Imaging (AEPL) USA Microwave Atmospheric Sounder (MAS) D

ATLAS-1 PAYLOAD

ATLAS-1

ATLAS-1 PAYLOAD: Belgian Scientific Involvements Grille Spectrometer (GRILLE) Dr M. Ackerman, D C. Lippens, Dr J. Vercheval, Dr C. Muller, Dr M. De Mazière … Institut d'Aéronomie Spatiale de Belgique, Belgium Dr A. Girard, Dr. M.-P. Lemaitre, Dr. J. Laurent, Dr J. Besson, … Office National d'Etudes et de Recherches Aérospatiales (ONERA), France Atmospheric H and D through Measurement of Lyman-Alpha (ALAE) Dr J.-L. Bertaux, Dr F. Goutail Service d'Aéronomie du Centre National de la Recherche Scientifique (CNRS), France Dr G. Kockarts Atmospheric Trace Molecule Spectroscopy (ATMOS) data analysis contribution by Dr R. Zander et al. Université de Liège, Belgium

ATLAS-1 PAYLOAD: Belgian Scientific Involvements Solar Spectrum Irradiance Monitor (SOLSPEC) Dr G. Thuiller, Dr M. Hersé, T. Foujols, … Service d'Aeronomie du Centre National de la Recherche Scientifique (CNRS), France. Prof. P. C. Simon, Dr. Gilllotay, … Institut d'Aéronomie Spatiale de Belgique, Belgium Prof. D. Labs Landessternwarte Königstuhl, Heidelberg, Germany Solar Constant Radiometer (SOLCON) Dr D. Crommelynck Institut Royal Météorologique de Belgique (IRM), Belgium Other belgian contribution: «the Belgian suit» Prof. M. Paiva, Université Libre de Bruxelles, Belgium

Understand the Influence of the Sun on the Earth In ATLAS-1, two European experiments have determined exactly the amount of solar energy received at the top of the Earth’s atmosphere: SOLCON, the "Solar Constant Radiometer” experiment, was designed to measure the absolute value of the Solar Constant to an accuracy of 0.1% with a sensitivity better than 0.05%. The Solar Constant is the Sun's total irradiance, the total amount of solar radiation received at 1 AU, at the top of he Earth's atmosphere. SOLCON will also measure the amount of solar energy or irradiance, in two wavelength bands. SOLSPEC, the "Solar Spectrum Irradiance Monitor" experiment, was measuring the solar spectral irradiance, between 170 nm and 3200 nm with an accuracy of 1,5 % in the ultraviolet and 1% in the visible and infrared, in order to determine the absolute value of the solar spectral irradiance at the top of the Earth's atmosphere. On-board calibration system provided the highest accuracy achieved so far in this domain. Both experiments have re-flown on ATLAS 2 and 3, in 1993 and 1994. They are part of the SOLAR Package on board the ISS since 2008

Monitor atmospheric changes and predict consequences GRILLE, the "Grille Spectrometer" is an infrared absorption instrument which works during solar occultations (sunrise, sunset) and measures a wide variety of trace constituents mainly the middle atmosphere, including ozone. It has 'map' their distribution from low to high altitude, and analyse the chemical, transport and thermodynamic processes which control the properties of the Earth's atmosphere. ALAE, the "Atmospheric H and D through measurement of Lyman-Alpha" experiment, will measure the distribution of atomic deuterium (heavy hydrogen) in the upper atmosphere in order to provide a better understanding of planetary atmospheres. When water from Earth evaporates into the atmosphere, sunlight breaks down the water vapour. The hydrogen and deuterium separate and diffuse through the thermosphere. The hydrogen atoms rise higher than the heavier deuterium. Both finally can escape from the terrestrial atmosphere. The objective of ATMOS is to make global measurements of the composition of the stratosphere and mesosphere. The spectrometer simultaneously measures the concentrations of trace gases that are involved in the complex chemical and radiative interactions occurring at altitudes between 10-100 km. Its data are used to test theoretical models that describe the physics and chemistry of the middle atmosphere.

ATLAS-1 Thank you to all the crew and especially to Dirk Frimout. ATLAS-1

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