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Since 1991, along track scanning radiometers (A)ATSR have been flown on a series of satellite platforms. These
instruments use an along-track scanning design that provides two views of the same earth target through different
atmospheric paths. Dual-view multispectral measurements can be used to derive an accurate atmospheric correction
when retrieving geophysical parameters such as Sea Surface Temperature (SST). In addition, the (A)ATSR family of
instruments use actively cooled detector systems and two precision calibration blackbody targets to maintain and manage
on-board calibration. Visible channel calibration is implemented using a solar diffuser viewed once per orbit. As a
consequence of these design features, resulting data derived from (A)ATSR instruments is both accurate and well
characterized. After 10 years of Service the ENVISAT platform was lost in early 2012 asnd AATSR operations stopped.
The Global Monitoring for Environment and Security (GMES) Sentinel-3 “Sea Land Surface Temperature Radiometer“
(SLSTR) instrument is the successor to the AATSR family of instruments and is expected to launch in April 2014. The
challenge for SLSTR is to develop and deliver a new instrument with identical or improved performance to that of the
(A)ATSR family.
The SLSTR design builds on the heritage features of the (A)ATSR with important extensions to address GMES
requirements. SLSTR maintains the main instrument principles (along-track scanning, a two point infrared on-board
radiometric calibration, actively cooled detectors, solar diffuser). The design also includes more spectral channels
including additional bands at 1.3 and 2.2 μm providing enhanced cloud detection, dedicated fire channels, an increase of
dual view swath from 500 to 740 km, an increase in the nadir swath of 1400 km. The increase in swath has led to, a new
optical front-end design incorporating two rotating scan mirrors (with encoders to provide pointing knowledge) and an
innovative flip mechanism to select a specific optical chain. Unavoidably, these improvements introduce complexity,
risk, increased mass and power. Bearing these aspects in mind, this paper reviews the design and performance of the
Sentinel-3 SLSTR.
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