A satellite released a small cloud of barium into space Saturday, creating a greenish-blue cloud visible across North America in the first of several skyshows designed to learn more about Earth's magnetic field and its spectacular auroras.

As the $250 million Combined Release and Radiation Effects Satellite - CRRES - passed over the coast of Mexico, a small canister was ejected and detonated at 9:17 p.m. EST, releasing barium vapor into space at an altitude of about 3,824 miles."It's huge!" said former astronaut Michael McCulley, at a Cocoa Beach, Fla., beach party for the crew of the shuttle flight.

"It looks like the moon's made out of green cheese," said shuttle launch commentator Lisa Malone as the greenish-blue cloud appeared overhead.

The cloud grew from a starlike point into a softly glowing sphere about one-third the size of the full moon. The cloud was clearly visible in the dark sky, looking like a greenish-blue moon against the deep black of space.

The release, the first in a series scheduled through Jan. 25, was postponed from Thursday to Saturday because of cloudy weather.

The goal of the experiment is to learn more about Earth's magnetic field and the forces that power the planet's spectacular auroras. In the process, scientists hope to learn how to predict the magnetic storms and disturbances that frequently disrupt radio communications.

The clouds are created by releasing canisters of barium or lithium from the CRRES satellite and then blowing them up after the containers are a safe distance away. The explosions vaporize the chemicals, causing the vapor to glow and creating a celestial showexpected to be visible across the United States, when weather permits. weather permitting.