The missions described above use satellites that are large in size, heavy and therefore expensive. A rocket is typically required to launch each of these satellites. By way of improving this, Planet Labs is spearheading the use of a constellation of small satellites (mini/micro) to image the whole earth on a daily basis.
Each small satellite has a dimension of 10 x 10 x 30 cm and weighs 4 kg, which is a 1000th of the weight of commercial imaging satellites. These small satellites orbit the earth at an altitude of about 400 km and deliver imagery with a spatial resolution of 3–5 m. Planet Labs currently operates the largest constellation of satellites, and plans to add more satellites to the current constellation.
The daily provision of images of the globe will permit a real-time monitoring of urban and environmental changes that are rapidly occurring on earth. For example, urban growth in cities, extent of water bodies, deforestation, floods, crop growth and fire can be monitored on a daily basis to improve decision making and resource management. More details about Planet Labs, their constellation of satellites and future plans can be found here.