WorldView-1 - 50cm resolution panchromatic satellite imagery

QuickBird - 60cm resolution commercial remote sensing satellite

SPOT - comes in a full range of resolutions from 20 m down to 2.5 m

Landsat - the longest running commercial mission provides decades of data at medium resolution

Envisat - continuity with ERS, with new, advanced sensors for environmental monitoring

ERS -1 & 2 - all -weather synthetic aperture radar and other advanced sensors from these European Space Agency missions

IRS - flexibility in medium-resolution optical data