Scientists to judge ESA Earth Explorer missions
Scientists from across Europe will gather in Granada, Spain, on 30 October to judge which Earth Explorer earth observation missions will be taken to the next assessment stage by the European space agency (ESA). The two-day peer review is taking place under the umbrella of the ESA's Living Planet programme, which aims to use data collected from Earth Explorer satellites to examine interactions between the earth's atmosphere, the oceans and the land to enable the planet to be understood as a complete system. The ultimate aim of the project is to use the data collected from space to fine-tune planetary models of the Earth and accurately forecast the consequences of climate change. The head of the ESA's earth sciences division, Einar-Arne Herland, explained: 'The idea behind ESA's Living Planet is to model the Earth as an integrated system.' There are two types of Earth Explorer satellite: 'core explorers,' which are ESA-led missions dedicated to long-term research objectives, and 'opportunity explorers,' smaller-scale projects not necessarily led by the ESA. Both types of satellite will build on ESA's experience in constructing earth observation spacecraft like ERS-1 and Envisat, but they will be more cost effective and smaller than previous missions, each one weighing less than two tonnes. At the Granada meeting, experts will choose three out of five Earth Explorer missions currently under consideration. Their recommendations will then be passed to the ESA's Earth science advisory committee and Earth observation programme board. This will be followed by a full feasibility study, as a result of which two of the remaining three satellite missions will be chosen for construction. There are five core missions under evaluation: - ACECHEM (atmospheric composition explorer for chemistry and climate interaction): Spectrometers will investigate how human-induced chemical alterations to the troposphere and stratosphere may cause climate change. - WALES (water vapour and lidar experiment in space): A laser-based device that works on the same principle as radar, a lidar, will map atmospheric water vapour concentrations. - EarthCARE (Earth clouds, aerosol and radiation explorer): Instruments including radars, lidars, imagers, radiometers and spectrometers will look at the interaction between clouds, aerosols and radiation to gain a better understanding of their impact on the earth's climate. - SPECTRA (surface processes and ecosystem changes through response analysis): A high-performance imaging spectrometer and a thermal imager will study the relationship between vegetation and climate change across the world's ecosystems. - WATS (water vapour and temperature in the troposphere and stratosphere): A flotilla of small satellites will measure tropospheric and stratospheric humidity and temperature by checking how GPS radio signals bend when passing through them.