Homer Joe Stewart remembers sitting around one night in 1950 when a rocket scientist whose name he doesn't remember said the Army could modify the Corporal missile and put an empty beer can on top and fly it all the way to moon. Homer Joe remembers that everybody laughed, knowing that empty beer cans wouldn't get much White House and congressional support.

Seven years later, the Soviet Union put up a Sputnik that wasn't much more than an empty beer can but it had a radio transmitter inside that beep-beeped a message to the world. The White House told the Navy to speed up its Vanguard program and match the Sputnik. The Vanguard blew up on the launch pad and a second Sputnik with a dog named Laika flew into robit. Suddenly, Homer Joe Stewart had his friends in the U.S. Army's rocket program were back in the beer can business.

"There were perpetual squabbles with the Navy and one time we even got orders to destory all our equipment," recalls Stewart, who 20 years ago was the Army's chief scientist at Pasadena's Jet Propulsion Laboratory. "We solved that by assigning our equipment to a terminal test named Aging."

Twenty years ago, nothing came easy. The Navy still had the go-ahead for Vanguard and the Army had a semi-go-ahead for something the JPL scientists called Project Deal. It wasn't until it was launched and safely in ourbit 20 years ago today that the name Explorer was given America's first satellite. Until launch, Explorer's name was Deal.

"We called it Deal as a joke," remembers Dr. Albert Hibbs, then a project scientist at JPL. "We played cards a lot in those days and the joke was 'Winners laugh and losers say deal."

While the Navy smirked from the sidelines, the Air Force (which ran the Eastern Test Range at Cape Canvaeral and still does), gave the Army four days in January of 1958 to launch Explorer. If the Army used the four days without launching, it would have to wait at least two more months to try agains while the Air Force ran "urgent" rocket tests.

The Army lost the first two days when the jet stream unexpectedly moved south, raising winds 40,000 feet over Cape Canaveral to unsafe limits.On the third day, the winds died and the Army fired away. The cards from Project Deal were on the table.

The Navy had promised the Army it would switch its tracking station Antigua over to the Army's frequency when Explorer flew overhead. But the Navy wouldn't let the Army check out its radios on Antigua. The salty Caribbean air had so corroded the Army's radios that signal that Explorer was in flight never made it back to Canaveral. Al Hibbs remembers that Army Gen. Bruce Medaris was drumming his fingers on the desk next to his in a blockhouse at Canaveral about the time the Antigua signal didn't show up.

Hibbs recalled: "I said to Medaris there is a 90 per cent probability that the prestiges (low point in the orbit) is higher than 200 miles and Medaris said, 'Hibbs, is it up or not?' I said, 'Yessir, it's up and it's going to stay up for 10 years.' It was a wild-guess at the time and it turned out to be right."

There was a payoff to Explorer that few people remember. The two tiny Geiger counters it carried for Dr. James van Allen discovered the huge belts of trapped radiation around the Earth that now bear his name. An enduring irony of that discovery is that Sputnik 1 carried Geiger counters too, but the Russians had no radios in the right parts of the Earth to receive Sputnik's signal that it had flown through radiation belts. The U.S. offered to record Spunik's signals if the Russians would tell us how to decode the signals but the Soviets refused. That's why the radiation belts are called the Van Allen Belts.

The National Air and Space Museum marks the anniversary today of Explorer I with a public lecture (at 8 p.m.) and a new exhibit about the satellite.

And some of the scientists involved in Explorer will get together today and tonight to commemorate the historic flight of 20 years ago but it won't be a completely happy occasion. Wernher von Braun, who built the Jupiter rocket that put Explorer into orbit, is dead of cancer. Explorer Project Manager Jack Froelich was killed three years ago in a hunting accident. Project Director William Pickering is in a California hospital recovering from open-heart surgery. Twenty years is a long time.