Concept, Deep Space Atomic Clock in Earth Orbit

The planned Deep Space Atomic Clock mission will demonstrate the clock's operability and performance while flown in Earth orbit as a hosted payload. A Global Positioning System receiver and antenna will be connected with the clock in an integrated payload. The clock will have, on average, a view of four satellites and will measure signals transmitted by each. Together, with data from a global network of dozens of ground GPS receivers, signals can simultaneously estimate the accuracy of the Deep Space Atomic Clock.

Image credit: NASA/JPL