Field experiments – or campaigns – are an integral part of ESA's continuing effort to develop new and better instruments for observing Earth from space.
Earth observation satellite missions carry novel technology and use new measuring techniques to yield the data needed to shed new light on how our plant works and for data that is used for everyday applications to improve our daily lives.
Before embarking on building a new Earth observation satellite, it is important to make sure the instrument and measuring technique under consideration are not only capable of providing information from space, but also that they will achieve the accuracy required.
This cannot always be done by scientific studies and laboratory experiments alone, but often requires dedicated measurements using aircraft or towers as a proxy for the satellite.
In partnership with universities, science institutes and other space agencies, these campaigns are carried out all over the world, from the icy reaches of the Arctic and Antarctica to tropical rainforests.
As part of these large international efforts, scientists venture out to some of the most inhospitable places on the planet to take measurements from aircraft, from towers, from ships and down on the ground.
These measurements are taken with a wide range of instruments such as radar altimeters, lidars, polarimetric synthetic aperture radars and imaging spectrometers that have often been developed for the sole purpose of testing a mission concept, mimicking what may eventually fly in space.
The measurements are essential for proving concepts, for understanding the information that new measurements could provide, for developing methods to extract this information from satellite data, and, lastly, to determine and increase the accuracy of the final information product. This is complex and takes time. It involves a learning process both inside ESA and within the potential user community. Its importance however, cannot be overestimated.
For some satellite missions, campaigns continue during the mission’s life in orbit.
Measurements gathered from the air and on the ground, often at the same time as the satellite passes overhead, are used for comparison. This is essential to ensure that the satellite is still delivering accurate information.