The UK’s access to important environmental data is set to take a major step forward following launch of EU satellite Sentinel-3A.
The third satellite of Europe’s Copernicus programme – which has a mass of 1150kg and is designed for an operating life of seven years - will focus on Earth’s oceans, measuring the temperature, colour and sea levels.
The first of the two flight models of the Sentinel-3 satellites, Sentinel-3A, was primed by Thales AleniaSpace and launched from the Plesetsk cosmodrome in Russia.
On board Sentinel-3A is an Airbus Defence and Space-built microwave radiometer (MWR) used to remove signal errors caused by water vapour in the atmosphere. This allows accurate tracking over a variety of watery surfaces: open ocean, coastal sea zones, sea ice and inland waters. This 26kg radiometer measures the thermal radiation emitted by Earth, enabling signal delays caused by moisture in the troposphere to be added to the altimeter pulses, to deliver more accurate data.
Airbus Defence and Space was also responsible for the thermal architecture of the service and payload interface module, which will ensure the correct performance under the extreme temperature variations to which the satellite will be subjected once in orbit, and a cryo-cooler system for the Sea and Land Surface Temperature Radiometer (SLSTR) instrument.
Sentinel-3A’s sensors will measure ocean features such as changes in water temperature and surface height – information needed for ocean forecasting and maritime safety.
The sensors will also monitor seawater quality and pollution, and the satellite will also help to map the topography and extent of ice, and to monitor the height of lake and river water. Over land, its uses include detecting fires and mapping.
Sentinel-3A data will also be an important contributor to public services such as the Copernicus Climate Service and Copernicus Marine Service. Additionally, the Met Office plans to use sea surface temperature data from the satellite to initialise their weather forecast models.
SLSTR data will also be carefully combined with data from previous satellite instruments to measure changes across decades. These activities require major computing power, and the UK has created a facility for collecting and processing large volumes of SLSTR and other data, at Harwell. The National Centre for Earth Observation (NCEO) will use SLSTR to provide essential new information on the land, including fires and land surface temperature, and data to map the radiative heat emitted by fires burning worldwide.
UK involvement in Copernicus is through the Department for Environment, Food and Rural Affairs (Defra), whilst the UK Space Agency provides UK investment in the Sentinel satellites.