The launch of

the United States’

first satellite

50 years ago

has come to symbolize

the beginning of the U.S. space program. The successful loft into orbit of Explorer 1

effectively exorcised the nationally televised nightmare

of the Vanguard rocket’s failure that had occurred just a month before. It also

one-upped the Soviet Union’s two previous

Sputnik satellite launches by collecting scientifically important data about the area surrounding Earth.

On Jan. 31, 1958, Explorer 1 launched successfully from Cape Canaveral, Fla., on a

four-stage Jupiter C rocket.

Four years earlier,

Wernher von Braun and his Huntsville, Ala.-based Army

team began designing an orbital launch capability based on their Redstone rocket called Project Orbiter, a Jet Propulsion Laboratory (JPL) media kit said.

However, t

hen-U.S. President Dwight Eisenhower

wanted the military minimally involved with the first U.S. satellite launch. In August 1955 the Vanguard, designed to launch science payloads, was chosen over the Redstone, a military missile, to launch the first U.S. satellite, a JPL media kit said. Vanguard was fundamentally a civilian project supported by the Naval Research Laboratory, said Carl Raggio, who


at JPL as an engineer in 1951 and outfitted

Van Allen’s experiment for

the Explorer 1 satellite.

Soon after

Project Orbiter’s demise

, which occurred with the approval of Vanguard, the Redstone group was reassigned to the Army Ballistic Missile Agency under the command of Maj.


John Medaris, the JPL media kit said. He, along with JPL manager

William Pickering submitted several proposals for Redstone-JPL launches, and

Medaris even readied a few Jupiter C rockets in case Vanguard failed.

The launch scheduled for Dec. 6, 1957, originally was intended as

a test of

the Vanguard rocket.


ut facing public and political pressure, Vanguard’s program director John Hagen



the official first launch date instead, the JPL media kit and the NASA History Web site said. Equipped with a spherical satellite designed to map hydrogen distribution in space, the 22-meter-long rocket lifted off for

2 seconds

, only to crash back

onto the launch platform, destroying the rocket.

Even before Vanguard’s failure, t

he Redstone-JPL team’s opportunity

had arrived

. In early November 1957,

the Redstone-JPL team had been

told to prepare to launch.

Unlike the Vanguard team, the core component of von Braun’s team had been together since before World War II

, said Klaus Dannenberg, a communications officer for the American Institute for Aeronautics and Astronautics whose

father, Konrad Dannenberg, was a propulsion engineer for von Braun’s Redstone team. “They knew what they could do,” the younger Dannenberg said in a Jan. 18 phone interview.

James Van Allen, a University of Iowa professor, had designed Explorer 1’s

primary experiment

to detect cosmic radiation


The satellite was designed without any recording device. Instead, d

ata was collected when the satellite was in range of tracking stations, NASA’s History Web site said.

“At that time it was fairly tense,” Raggio said in a Jan. 19 phone interview, alluding to the pressure of getting a U.S. satellite into orbit in the wake of two Sputnik launches and during a time when the United States and the Soviet Union were locked in the Cold War. “Long hours, long weeks,” he said.

“I saw [that time period] from the perspective of not seeing my dad much,” Dannenberg said


The time spent away from home paid off when Explorer 1 launched successfully

on a

four-stage Jupiter C rocket. The Jupiter C was compo

sed of a Redstone launch vehicle first stage, and two stages of clustered Baby Sergeant rockets, built by Pasadena, Calif.-based JPL. The fourth stage – the satellite itself – was

a modified Baby Sergeant rocket with the instrumentation in the fore.

Dannenberg said he remembers that after word of the success spread

there were parties in downtown Huntsville and “horns honking.”

As for why Explorer succeeded while Vanguard failed, Raggio said it came down to experience


Explorer 1’s rocket “was fundamental and very basic,” compared to Vanguard, which

was a “more sophisticated rocket that needed more time for development,”



By the time it lofted Explorer 1, Jupiter C already had launched successfully three times, he said.

In the end,

Explorer 1 provided more than just a boost for national confidence. The satellite discovered belts of radioactive particles surrounding Earth, dubbed the Van Allen Belts after the experiment’s principal investigator.

It also marked an early stage in electronic miniaturization.

The Soviet Union’s powerful rockets, which allowed for greater mass

, enabled the first two Sputniks to use

the larger vacuum tube-based electronics, Raggio said. But to accommodate

the less-powerful U.S. rockets, the satellites needed to be

small and their instrument packages

even smaller

, so transistors were used, Raggio said.

Since that first satellite the United States has landed astronauts on the Moon six times and maintained a decade-long persistent presence around

Mars, said JPL Director Charles Elachi, who began working at the lab

as a graduate student in 1970. “I find that mind boggling and exciting in a sense,” he said in a Jan. 17 phone interview.