Just as doctors keep a patient under observation, satellite technology allows us to watch over our planet in order to monitor its health, or understand it better.
The early years of the space race produced iconic photographs of the Earth that helped nurture greater environmental awareness. Today, satellite technology allows us to track changes and patterns in weather, agriculture, urban development and other land use. And, thanks to Google Earth, observing landscapes from the point of view of an orbiting satellite has become an everyday experience.
Earth observation (EO) satellites were first launched for military and security applications during the Cold War. Since the 1990s, their images have become more widely available for a number of civilian and commercial uses. The latest generation of EO satellites offer quick access to very-high-resolution pictures - of objects of less than 0.5 m across.
According to the OECD, there are currently more than 100 EO programmes run by civilian space agencies. Satellite numbers continue to increase as different countries and regions compete in this strategically important sector, in which the United States, Europe, China and India are the biggest players. Many of the national players are also collaborating on the Global Earth Observation System of Systems (GEOSS) - an international infrastructure for sharing and disseminating EO data.
The OECD estimated the total EO market for commercial satellite operators at around €750-800 million in 2009. And Euroconsult, a space and ICT consultancy, calculated that the 128 EO satellites launched between 2000 and 2010 resulted in manufacturing revenues of €15.4 billion for the space industry.
Earth observation technology can aid archaeology, detect forest fires, measure ocean wave heights and assess the levels of gas emissions such as carbon dioxide and methane, as well as analyse patterns of agriculture and soil moisture. Multispectral images show heat patterns in cities, helping planners to predict urban weather and design cityscapes. EO images can help civil engineers track the progress of large construction projects, such as stadiums or highways, and by examining the colour of the ocean, satellites can even check on the health of fisheries and other biological resources.
In April 2014, the European Space Agency (ESA) launched Sentinel-1, the first satellite in the EU's new EO programme, Copernicus. Designed to improve maritime security, climate-change monitoring and support for emergency and crisis situations (such as earthquakes and floods), Sentinel-1 produces radar-based images that show the surface of Earth through cloudy weather conditions, day or night.
ESA makes its EO data freely available on the internet and supports development of new applications and services. For example, Germany's Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research has used measurements from ESA's CryoSat mission to map the thickness of the ice sheets covering Greenland and Antarctica, showing how they are rapidly losing ice.
The greater availability of satellite images and EO data, combined with ever-cheaper processing costs – thanks to advances in computing – means that the door is open for innovation to find new applications. The EPO’s free, online patent database, Espacenet, shows that there are hundreds of patent applications for technologies useful in mapping a variety of surface features from orbit, be it height, density, moisture, reflectance or absorption.
For instance, Mario Costantini and Massimo Zavagli of the Italian aerospace company Telespazio applied for a European patent for a method for automatically detecting fires on Earth's surface using satellite images. Teams from the French aerospace company Astrium have also applied to the EPO for patents on relaying signals from low-Earth orbit observation satellites and on detecting lightning.
The EO market is now evolving towards enriched data visualisation, aided by computer models, according to Dr Thomas Heege, CEO of EOMAP. Dr Heege has applied for patents for technology that can map the water depth and chlorophyll content of lakes in satellite photographs, providing quality control for environmental projects that clean algae from lakes. Such software processing is challenging to describe in patents, but the company made the investment to protect their innovations from competitors.
The sector continues to grow. In 2010, Euroconsult estimated that an additional 260 EO and meteorology satellites would be manufactured and launched by 2020, generating €20.7 billion for the space industry. Of these, 12 or more are expected to be radar satellites, with their ability to drive new applications monitoring volcanic activity, dark polar regions and cloud-covered rainforests.
The EU expects that the economic benefits from Copernicus, and innovative uses of its data, could generate some €30 billion and around 50 000 jobs in Europe by 2030. Satellite images will become increasingly valuable in analysing climate change, and computer processing will reveal ever-more complex data.
We have come a long way from those first moving portraits of the Earth from the Apollo missions but, thanks to satellite-based Earth observation, we are getting to know our world better and better.
Dr Thomas Heege, CEO of aquatic remote-sensing company EOMAP, explains that, by using computer models to take account of satellite orbital trajectory or atmospheric light conditions, their technology can calculate the water depth and chlorophyll content of lakes in satellite photographs, producing maps for clients and providing quality control for environmental projects.