International Space Station Benefits for Humanity

Using the Space Station to Support Studies Relevant to Understanding Climate Change

For many astronauts the most memorable experience during their space flight is seeing the fragile blue globe of Earth beneath the space station. With the changing illumination conditions and passing seasons, one never tires of the dynamic view. Dust storms sweeping in the U.S. South-west, low pressure areas bringing rain to northern Europe, a typhoon hitting Japan and noctilucent clouds at high latitudes – all these can be easily seen from the orbital outpost. Scientific instruments onboard an international fleet of satellites are routinely sounding, measuring and analysing the Earth's environment, providing key data for understanding long-term changes in the Earth's climate. To supplement the work of the dedicated Earth Observation satellites. The European Space Agency or ESA has launched an announcement of opportunity or AO for new station experiments for climate change relevant studies.

Various natural physical processes modify the atmosphere, oceans and land surfaces on short and long-term scales. In the past 150 years human activities have resulted in significant changes in many aspects of Earth's environment, including increasing greenhouse gas concentrations, modification of the nitrogen and phosphorous cycle and major alterations of land use (e.g. deforestation). It is crucial that we understand the interaction of human-caused alterations with natural changes to predict future changes in the Earth's environment. In turn this information will assist sustainable development in relation to human activities, while minimizing degradation of the environment and limiting the vulnerability of society to climate change.

ESA, along with other international agencies, is currently operating a number of Earth observation satellites carrying dedicated instruments to address specific mission objectives. These are supported mainly by ESA's Living Planet Program and the Global Monitoring for Environment and Security (GMES) Program (jointly carried out with the European Union) and ESA's Climate Change Initiative.

Space station assembly is now complete, with a large variety of international research activities being routinely performed onboard by a crew of six astronauts. Historically, the main focus of European research has been in the area of life and physical sciences, taking advantage of the microgravity and exposure to the space environment provided by the station. However, the station has a clear potential to be used as a multiuser platform for studies in astrophysics, solar science, fundamental physics, Earth science and climate change relevant studies.

Internationnal Space Station

The station flies in the same stable attitude relative to the Earth's surface (approximately local vertical, local horizontal) as it orbits above. Multiple locations onboard the station can be used to mount instruments for Earth observation, including external locations as internal locations viewing through various windows (Image: NASA)

To assess the level of interest in the European and international research community in deploying remote-sensing instruments on the space station for global change studies a Call for Ideas was issued by ESA's Directorate of Human Spaceflight,(now Directorate of Human Spaceflight and Operations) supported by the Directorate of Earth Observation Programs, in October 2009. A total of 45 proposed ideas was received, with many promising concepts proposed. This confirmed a high level of interest in the use of ISS for climate change studies and several interesting thematic areas were identified. The recent announcement of opportunity proposals will be peer reviewed, and several candidate experiments will be selected for further detailed study and developed for flight on the space station. Further details are available at :

http://www.esa.int/SPECIALS/HSF_Research/SEMPM17TLPG_0.html

The space station offers the possibilities to fly instruments and experiments without the development of a dedicated satellite platform. The orbit inclination of 51.6° and altitude of 220-250 miles (350–400 kilometers) is different from those of most Earth observation satellites. Instruments can be mounted on a variety of external locations, including the truss structure and dedicated platforms on the European Columbus, Japanese Kibo and Russian segment modules. The European Columbus module External Payloads Facility or CEPF has four payload attachment sites on the end of the module, permitting nadir, zenith and side (limb) viewing. Several instruments relevant to Earth science and climate change are either in development or already deployed on the station. The zenith port of the CEPF is currently occupied by the ESA Sun Monitoring on the External Payload Facility of Columbus or SOLAR instrument, which measures the Suns energy irradiance – an important parameter for climate studies. The ESA Atmosphsere Space Interactions Monitor or ASIM, which will study high energy optical and gamma ray events associated with thunderstorms will be deployed on Columbus in 2015. On the external platform of the Japanese Kibo module the JAXA Superconducting Submillimeter-Wave Limb Sounder or SMILES instrument measured trace gases in the stratosphere {insert link to SMILES article}, including chemicals that interact with the Earth's ozone layer. Also mounted on the outside of the Kibo, the NASA Hyperspectral Imager for Coastal Ocean (HICO) is an imaging spectrometer for studying coastal waters {See HICO article}.

 Noctilucent clouds

Above: Noctilucent clouds observed from the space station, back illuminated by sunlight following sunset. Unlike normal weather clouds found in the lower atmosphere (troposphere) to a maximum altitude of 631 miles (1,015 kilometers), noctilucent clouds consist of ice particles and occur at around 50 miles (80 km) altitude in a region of the atmosphere called the mesosphere. These clouds generally only occur during the summer months at high latitudes. The mesosphere is very dry and noctilucent ice clouds need very specific conditions for formation, which are not well understood. Therefore, observation of noctilucent clouds may provide clues to the processes occurring in the mesosphere.

An additional location for instruments is inside the station, taking advantage high quality viewing ports and windows. The NASA Destiny Laboratory has the Window Observational Research Facility or WORF (http://www.nasa.gov/mission_pages/station/research/experiments/WORF.html) viewing through a dedicated nadir-viewing window , while the Cupola module has seven windows providing panoramic nadir and limb views of the Earth. Earth observation imaging using handheld digital cameras is currently performed by the crew members through the station windows as part of the Crew Earth Observations or CEO experiment (http://www.nasa.gov/mission_pages/station/research/experiments/CEO.html ). Potentially, laboratory or airborne instruments could be developed and flown within relatively short lead times. Operating instruments inside the station provides a normal “shirt sleeve” environment, as well as the possibility for the crew to directly interact with the experiment (e.g. to change configuration or filters).

The Cupola on the ISS

The Cupola on the ISS provides a panoramic view of the Earth for observations (image: NASA)

Above: A nighttime image of the Nile Delta region and Eastern Mediterranean taken by an astronaut onboard the space station through the Cupola windows using a handheld digital still camera. This simple image provides a lot of interesting information on land use – artificial lights show both the distribution and density of human habitation in this arid region. Towns and villages are closely associated with close availability of fresh water, necessary for agriculture and drinking water along the River Nile and Nile Delta (central part of the image). The city of Cairo appears as a particularly bright spot at the beginning of the Nile delta in the centre of the image, while the port of Alexandria is apparent on the Mediterranean coast on the western edge of the delta. Just south of Cairo, a small cluster of towns and villages is visible on the western side of the Nile. This is the Faiyum Oasis, which is a basin with fields watered from a channel running from the Nile. Elsewhere in the region, towns are clustered around the coast with only a few settlements visible in the desert that are often associated with oasis. Natural phenomena also are apparent in the image. Moonlight illuminates the scene, showing the clouds and land surface. There is little cloud cover over the dry desert, but much more over the Mediterranean sea and the northern Mediterranean coastline. Along the limb of the Earth, a faint green line is visible. This is airglow, a natural fluorescence of air molecules at approximately 53 miles (85 km). This is close to the officially recognized 62 miles (100 km) altitude when space begins, hence the airglow layer graphically shows the sensible upper limits of the Earth's atmosphere (Image: NASA)

Jason Hatton
Science and Applications Division (HSO-AS) Astronauts and ISS Utilization Department Directorate of Human Spaceflight and Operations European Space Agency – ESTEC Noordwijk, Netherlands