28 Dove Cubesat satellites each weighing about 5 kilograms of Planet Labs' Flock 1 constellation began deploying in early February of this year from the ISS. Planet Labs, San Francisco, California provides medium-resolution (3- to 5-meter) “whole Earth” imaging with high frequency revisits. The constellation is designed to provide low spatial resolution and high temporal resolution. According to Planet Labs the total constellation will be comprised of 100 Cubesat satellites. Up to 10 % of the satellites can fail without affecting the capability of the whole constellation. To date Planet Labs has launched 71 Doves in 18 months on 6 launch vehicles.
Last week the Antares rocket on a mission to the ISS failed. The rocket was carrying 26 Flock 1d satellites. Because the individual Cubesat satellites are very inexpensive compared to a Worldview-3, for example, a launch failure is not catastrophic. Planet Labs' approach to further mitigate the risk of this type of failure is to deploy their fleets of satellites on multiple launch vehicles, from multiple vendors. Planet Labs also place more satellites in orbit than are required so that if satellites fail in orbit they can ensure constellation continuity.
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