SPOT 4 - Earth Online

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About SPOT 4

SPOT 4 (Satellite pour l'Observation de la Terre) was a commercial Earth-imaging satellite from CNES (Centre National D’Etudes Spatiales), the French Space Agency. It was launched on 24 March 1998 and ceased operations after a malfunction on 29 June 2013.

*Mission Parameters*
Orbit Height	832 km
Orbit Type	Sun-synchronous circular
Orbit Inclination	98.7°
Orbit Duration	101 mins
Repeat Cycle	26 days

SPOT 4 Objectives

SPOT 4, like all the SPOT missions, was aimed at supplying high-resolution, wide-area optical imagery. This was designed to improve the knowledge and management of Earth's resources, detecting and forecasting phenomena involving climatology and oceanography, and monitoring human activities and natural phenomena.

SPOT 4 Instruments

High-Resolution Visible and InfraRed (HRVIR)

With respect to the HRV instrument on board SPOT 1, 2 and 3 the HRVIR had the same geometric imaging characteristics but improved performance was achieved by adding a new shortwave infrared spectral band (SWIR).

Two identical HRVIR imaging instruments on SPOT 4 were able to operate in two modes either simultaneously or individually.

The HRVIR had an oblique viewing capability of 27° on each side of the local vertical. The swath was 117 km² if both sensors were used simultaneously with a 3 km² overlap.

*HRVIR Instrument Details*
Type	High-resolution optical pushbroom imager
Ground Sample Distance	Panchromatic: 10 m Multispectral: 20 m
Swath Width	60 km
Bands	Monospectral (PAN) Green Red NIR (Near Infrared) SWIR	0.61-0.68 µm 0.50-0.59 µm 0.61-0.68 µm 0.79-0.89 µm 1.53 - 1.75 µm
Instrument Field of View	4.13°
Ground Sampling Interval (Nadir Viewing)	Panchromatic: 10 m x 10 m Multispectral: 20 m x 20 m
Pixel per Line	Panchromatic: 6000 Multispectral: 3000
Swath Width	60 km

Other Instruments

The VEGETATION instrument was carried on SPOT 4 and onward. It acts independently of the HRVIR (Visible & Infrared High-Resolution) sensors. This instrument can cover almost all Earth’s surface in a day because of its swath size of 2250 km. It captures reflected light in four spectral bands (blue, red, near-infrared, and middle-infrared).

SPOT 4 Data

DATA COLLECTIONS

Registered users are allowed access to the SPOT 1 to 5 ESA archive through the online dissemination server. The archive consists mainly of imagery over Europe and Africa that ESA has collected through the years.

SPOT 4 INSTRUMENTS

SPOT 4 DATA