Petite Payloads

The first satellites were tiny, antenna-studded devices that often weighed little more than the men and women who built them. But big was better as the space age progressed. The largest satellites today tip the scales at 15 tons, cost hundreds of millions of dollars and are roughly the size of Mack trucks. They must be put into orbit by giant rockets or space shuttles.

But in the skies over California last week, a launch took place that broke all the rules. A diminutive rocket named Pegasus, built by a Virginia-based entrepreneurial firm called Orbital Sciences, dropped from under the wing of a B-52 and carried into orbit a small 200-kg (450-lb.) satellite, one of a new type of craft that promises to bring space history full circle. Called lightsats, the new payloads pack as much function into a few hundred kilograms as satellites many times their size. At $8 million a launch, they could open space to new military and industrial uses.

The shrinkage has only begun. In July a second Pegasus is scheduled to launch seven 22.5-kg (50-lb.) communications satellites the size of car tires. And scientists are already dreaming about peppering space with swarms of "microspacecraft," each no bigger than a coffee can.