SPOT 1, 2, and 3 Since 1986 the SPOT family of satellites has been orbiting the Earth and has already taken more than 10 million high quality images. SPOT 1 was launched with the last
Ariane 1 rocket on February 22, 1986. Two days later, the SPOT 1 transmitted its first image with a spatial resolution of . SPOT 2 joined SPOT 1 in orbit on January 22, 1990, on the
Ariane 4 maiden flight, and SPOT 3 followed on September 26, 1993, also on an Ariane 4. The satellite loads were identical, each including two identical HRV (High Resolution Visible) imaging instruments that were able to operate in two modes, either simultaneously or individually. The two spectral modes are panchromatic and multispectral. The panchromatic band has a resolution of , and the three multispectral bands (G, R, NIR) have resolutions of s. They have a scene size of and a revisit interval of one to four days, depending on the latitude. Because the orbit of SPOT 1 was lowered in 2003, it will gradually lose altitude and break up naturally in the atmosphere. Deorbiting of SPOT 2, in accordance with
Inter-Agency Space Debris Coordination Committee (IADC), commenced in mid-July 2009 for a period of two weeks, with a final burn on 29 July 2009. SPOT 3 is no longer functioning, due to problems with its stabilization system.
SPOT 4 SPOT 4 launched March 24, 1998 and stopped functioning July, 2013. In 2013, CNES lowered the altitude of SPOT 4 by to put it on a phased orbit with a five-day repeat cycle. On this orbit, SPOT4 was programmed to acquire a time-lapse series of images over 42 sites with a five days revisit period from February to end of May 2013. The data set it produced is aimed at helping future users of the
Sentinel-2 mission to learn working with time-lapse series. The time-lapse series provided by SPOT4 (Take5) have the same repetitiveness as those that will be delivered by the Sentinel-2 satellites, starting in 2015 and 2016.
SPOT 5 SPOT 5 was launched on May 4, 2002, and has the goal to ensure continuity of services for customers and to improve the quality of data and images by anticipating changes in market requirements. SPOT 5 has two high resolution geometrical (HRG) instruments that were deduced from the HRVIR of SPOT 4. They offer a higher resolution of 2.5 to 5 meters in panchromatic mode and 10 meters in multispectral mode (20 metre on short wave infrared 1.58 – 1.75 μm). SPOT 5 also features an HRS imaging instrument operating in panchromatic mode. HRS points forward and backward of the satellite. Thus, it is able to take stereopair images almost simultaneously to map relief.
SPOT 6 and SPOT 7 SPOT 6 was launched by India's
Polar Satellite Launch Vehicle on flight C21 • The architecture is similar to that of the
Pleiades satellites, with a centrally mounted optical instrument, a three-axis
star tracker, a fiber-optic gyro (FOG) and four control moment gyros (CMGs). • SPOT 6 and SPOT 7 are phased in the same orbit as Pléiades 1A and Pléiades 1B at an altitude of , forming a constellation of 2-by-2 satellites - 90° apart from one another. • Image product resolution: • Panchromatic: 1.5 m • Colour merge: 1.5 m • Multi-spectral: 6 m • Spectral bands, with simultaneous panchromatic and multi-spectral acquisitions: •
Panchromatic (450 – 745 nm) • Blue (450 – 525 nm) • Green (530 – 590 nm) • Red (625 – 695 nm) •
Near-infrared (760 – 890 nm) • Footprint: 60 km × 60 km • Responsive satellite tasking, with six tasking plans per day, per satellite • Capacity to acquire up to 3 million km2 daily == References ==