Satellites are unmanned missiles that orbit the planet (or the moon), collecting various kinds of data that are predominantly used for scientific research or technical purposes, such as navigation, telecommunications or television transmission. Some satellites primarily snap pictures of the Earth's surface and are therefore well-suited to illustrating macro changes in weather, climate and landscape. Depending on the application, satellites are situated at different heights in the atmosphere.
In low Earth orbit, meaning a distance between 200 to 2,000 kilometres from the Earth, spy satellites, weather satellites, earth surveying satellites and certain communications can be found. This is followed by the region known as medium Earth orbit, which houses navigation and other communication satellites. The medium Earth orbit area extends to around 36,000 km altitude. Because the orbital period of the satellite here precisely corresponds to the rotational speed of the planet, these satellites hover in a position that is "fixed" to the globe. So you can, for example, align a satellite dish outside your home exactly with a certain satellite location and receive satellite TV programmes.
Based on data from the American organisation Union of Concerned Scientists, more than 1,000 active satellites are currently orbitting the Earth. More than half of these are used for communication such as telecommunications, TV, radio or digital data transmission. Another large portion are used for observation and meteorology. More than 30 satellites are used for GPS navigation while a smaller selection fulfill observation tasks for the military. They all provide us with insightful information about the past, the present and even give us (often very accurate) predictions about future. Whether its via traffic forecasts, weather prognoses or just using the internet in general, we make use of their service every day, whether we are aware of it or not.
The Dawn of Satellite Technology – Telecommunications, Navigation and Planetary Observation
The successful launch of the soviet Sputnik 1 on 4 October 1957, the world's first satellite in orbit, gave way to rapid development in the field of satellite research. This development was a by-product of the Cold War and was spearheaded by two superpowers of the time: the USA and the Soviet Union. As part of this arms race, US researchers later created Transit (1958), the world's first satellite navigation system, which guided missiles on submarines and aircraft carriers for the US Navy. Today, we benefit from Transit's immediate successor system, the "Global Positioning System" or GPS for short.
A short time later, in the 1960s, research satellites for astronomy, weather and cartography were developed. Equipped with radar, infrared or photographic capabilities, Earth observation satellites today provide us with image files and readings of various properties. These satellites work with passive as well as active sensors. While passive methods measure the light or heat energy emitted by the Earth (particularly clouds), active Earth observation is undertaken using radar technology. This transmits exact (to the centimetre, in fact) values about the surface structure of the planet, which are used to measure even the slightest Earth movements and then form the basis of 3D models.
Earth observation satellites are used for Remote Sensing. Even though they have been around for over 50 years, their use in the field of environmental protection is relatively new. These satellites have names like ''Quickbird'', ''Geoeye'' or ''Worldview'' and are fitted out with ultra-modern sensor technology. This feature opens up possibilities to natural and animal rights workers and climate scientists that were considered utopian a few years ago.
Satellites as Climate Protectors
Since the successful launch of the first Earth observation satellite (1959: ''Keyhole'' (spying), 1960: ''TIROS-1'' (weather) and 1972: ''Landsat-1''), the technical capabilities within the Earth observation field have daramtically improved. The Sentinel-2A (launched in 2015) reportedly surveys significant changes in the climate and vegetation to never-before-seen standards. Never before could a satellite capture large areas on Earth so quickly and in such high quality as the first optical imaging satellite of the EU's Copernicus programme. Sentinel-2A races at a speed of seven kilometres per second around the globe, filming the Earth's surface one 290 km-wide strip at a time. The satellite films from a low Earth orbit at an altitude of 786 km and requires about 100 minutes to complete one orbit of the globe, flying over the same place again after ten days.
ESA_events Lift off! Sentinel-2A launched in June 2015
The satellite records Earth in 13 different colour spectrums, including the visible (to the human eye) spectrum and the infrared range allowing the camera to detect elements such as water content or chlorophyll in plant leaves - information that could be important for farmers during irrigation. The photographs and data collected by Sentinel-2A are freely available to researchers, farmers, coast guards or relief workers located in countries belonging to the European Space Agency (ESA).
Satellites – a Revolution for Environmental Protection?
In an article from 2014, Jon Hoekstra, leading scientist at the World Wildlife Fund (WWF), discusses how satellite technology can revolutionise conservation in two key ways: firstly, satellites visualise the current state of the environment in unprecedented detail. Secondly, the data that is collected is being made available to more and more people in numerous locations.
Remote sensing specialists like Aurelie Shapiro from WWF analyse images from observation satellites on a daily basis and scan them for possible changes. For example when too much green in one particular area starts disappearing, this can be an indication that illegal logging or deforestation is taking place. In such cases, they can inform the relevant stakeholders and provide them with the GPS coordinates of the identified location. ''With remote sensing, we see how habitats change as a result of human hands - and how we can take countermeasures. The method provides the field of conservation with many new possibilities to precisely and quickly capture data and therefore to react much faster than before and to implement protective measures,'' Shapiro states. In 2011, Shapiro and her colleagues discovered a logged rectangle of land in a national park in Sri Lanka. An international organisation was attempting to set up a 2000 hectare banana plantation. Using the satellite images, the conservationists were able to take the company to court and have them abandon their project.
Satellite Monitoring for Wildlife Conservation
Satellite technology got its start in the area of wildlife protection via GPS. In the mid-90s, world-renowned penguin expert P. Dee Bersma observed Magellanic Penguins using GPS transmitters. She could prove that animals died en masse after they passed through the polluted waters along the Argentine coast. Contaminated with shipping oil, the dirty water glued together the birds' feathers. The data that was collected finally convinced the relevant authorities: the shipping routes were changed and the pollution reduced. Today, the Magellanic Penguin population is considered stable.
In order to be able to act upon declining species numbers, animal populations need to be monitored and recorded each year. Typically, this involves workers going into a particular region of interest to note any sightings of the desired species. This is often enormously complex and personal costs are high. New techniques for monitoring biodiversity involve the use of multispectral cameras attached to flying objects like drones or aircraft. With an image-capture range of 300 metres, however, the technical limit of these methods is exhausted in a short period of time.
In 2014, biologists from the University of Minnesota undertook a study in which they tested the efficiency of satellite technologies by counting polar bear populations in the Canadian arctic via satellite images and also via aerial shots taken from a plane. Since the respective counts differed only slightly, the researchers are confident in the abilities of satellite technology, stating that "the technology can open vast, remote regions to regular monitoring, facilitating the collection of data across species' ranges and at global scales." However, remote sensing via satellite also has disadvantages: while specific group behaviour of animals could be identified by aerial or ground-based measurements, demographic structures such as family groups or bear cubs on the satellite images were significantly more difficult to recognise.
Satellites as Conservationists
Alongside doing a headcount of animals, satellites can also monitor entire ecosystems in real time such as the tropical rainforests of the Amazon. These forestlands give off oxygen and absorb atmospheric carbon dioxide (CO2). For scientists, it is clear that the protection and conservation of these forests is an immediate and effective strategy to slow down climate change. In Brazil, the Amazon covers more than four million square kilometres, an area almost as big as half of Europe. But clearing is reducing the size of this area substantially. This peaked in 2004 when more than 27,000 square kilometres of rainforest was cleared. However, the country was able to bring this number down to 5,000 square kilometres by 2011. What happened?
Brazilian researchers published a report about this as part of the Climate Policy Initiative in 2013. In this they argued that the huge decline in deforestation in the Brazilian Amazon was due to the state's of implementation DETER (Real Time System for Detection of Deforestation). The satellite-based system processes geospatial data and imagery of the rainforest in a 15-day repeat interval. An automatic alarm system recognises hot-spots in almost real time. Before the introduction of DETER, detecting forest crimes in a timely manner was almost impossible as deforestation in protected areas could only be uncovered based on eyewitness report. Scientists estimate that over 59,500 square km of rainforest between 2007 and 2011 could be saved by the integration of the DETER system into Brazil's policy. This corresponds to a reduction in the rate of deforestation by as much as 59 percent.
Measuring Ocean Acidification from Space
Alongside rainforests, oceans also act as vital biospheres. Here, too, climate change poses a major threat. A considerable portion of the CO2 emitted into the atmosphere is absorbed by the seas. Consequently, the seawater acidifies. The resulting acids attack the calcareous shells of crustaceans such as corals and oysters and destroy underwater biodiversity. To determine the acidity level (pH) of water, scientists previously had to charter research vessels to the areas at risk and take water samples on the spot.
An English research team have now found a way to measure ocean acidification from space. Based upon satellite data such as temperature values and sodium content, ocean maps have been created that display so-called alkalinity or the ability of water to neutralise acids: the higher the alkalinity is, the less acidic the water is. "Satellites are likely to become increasingly important for monitoring ocean acidification, especially in remote waters," Dr Jamie Shutler, a scientist from the University of Exeter who is leading the project, explains. Monitoring from space could be of particular assistance to work conducted in far-lying regions, like the Arctic.
In terms of marine conservation, satellites are also helpful for activists and researchers in other ways. They are able to track dumping of waste and oil on the high seas. In spite of the international MARPOL Convention for the prevention of marine pollution, companies still tip their waste, toxins and oils into the sea. One reason for this: on the sea, these companies are virtually invisible. With the use of satellite images acting as a proxy eye for the government and public, things are about to change.
Satellites in Development Work
In 2014, Ebola, a highly infectious disease that was first recorded in the 1970s in former Central African state Zaire (now known as the Democratic Republic of the Congo), made headlines again across the world. These and other illnesses illustrate the vulnerability of large populations when it comes to infectious diseases. Air travel, population growth, migration patterns, pollution, the destruction of natural ecosystems and international conflicts simplify the transmission of such diseases thus making epidemics and pandemics serious threats to the world's population. How can satellite technology be helpful here?
US and British researchers investigated the relationship between climate change and disease-causing circumstances. Here, satellite images take on a central role: remote sensing images and measurements can be used to create scenarios for future epidemics. The forecasts are based on the satellite-measured status of sea levels, water temperatures and chlorophyll A values, creating a model that would allow authorities to better prepare populations for outbreaks before they occur.
Satellites Track Human Settlement Behaviour
Scientists at Princeton University conducted research on a similar topic. They focused on the statements made by satellite images of the three largest cities in Niger at night (2000-2004). Their thesis was that the migration and settlement behaviour of people relate to epidemics of diseases such as measles and meningitis. Every year, thousands of people die in this area from these diseases. "Temporary and seasonal migrants are very hard to measure," Deborah Balk of New York University said. "The night lights are an important source of data for Africa and Asia, especially, where data is sometimes absent or quite poor."
The researchers discovered that infection rates are supported by growth in populations. With the help of spatial analysis programs such as ArcGIS, they used the satellite imagery to create accurate 3D models on which the respective clusters of lights can be seen. Evaluation of these models provided information about temporary population densities. Tracking such population movements via satellite could, in the future, facilitate major progress in the global disease prevention and health sector.
Satellite Technology – Future Potential?
Jon Hoekstra Chief Researcher from WWF points out that despite the large interest in new technical possibilities, the risks involved must not be forgotten. Like most technologies, satellites can also pose dangers. Although GPS devices support conservationists in the fight against poachers, these location gadgets could prove fatal in the wrong hands. Poachers could hunt endangered species with the help of GPS for a much more targeted form of killing. Ensuring data security is also extremely important. Appropriate measures must therefore be worked out by all parties involved in order to work together for the future. In addition, lack of infrastructure makes it difficult in many areas of the world to implement satellite technology properly. Some natural regions of the world are still inaccessible. The proliferation of affordable satellite connections, mobile towers and solar energy could help to overcome these hurdles.
Satellite technology – when used to help people, animals and the environment – makes sense and particular projects have great potential. Using satellites can save costs in the areas of monitoring, tracking or creating future forecasts. The decreasing cost of the technology coupled with its rapid progress allows for more innovation and further development of possible applications of satellite technology. Technology-based conservation, environmental protection and some development work can be done much more efficiently with this technology.
Author: Simon Dupree / RESET Editorial
In our RESET Special 'Drones and Satellites for Good' we looked at many of the projects using drone and satellite technology in the field of sustainable development. A full list of articles can be found here.