NASA has dispatched a trio of experimental satellites into orbit. Each of the fun-sized microsatellites carries miniaturised kit for investigating Earth's magnetic field.

A Pegasus rocket blasted off from a carrier plane over Vandenberg Air Force Base, California, yesterday. The launch was delayed from 11 March by technical gremlins.

Each microsatellite weighs about 25kg when fully juiced and is about the size of a 13-inch TV. The microsats were released in a 'string of pearls' formation a few metres apart. Over the next few weeks they'll spread out up to 200km apart, enabling them to make coordinated measurements of the magnetosphere over the next 90 days.

The magnetosphere acts as a bubble, shielding Earth from potentially harmful solar radiation, sometimes known as 'space weather'.

The drive behind the pilot mission is to demonstrate the power and cost savings of a distributed approach for future, more in-depth missions.®

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