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Pioneer 4 Marked NASA’s First Exploration Mission Beyond Earth

NASA’s commitment to exploration beyond low-Earth orbit is continuing with plans to launch the Orion spacecraft on Exploration Flight Test (EFT-1) in September 2014. Since its formation in 1958, one of the agency’s core missions has been to discover what lies beyond. The fledgling space agency’s first successful mission past Earth orbit was Pioneer 4, 55 years ago.

Dr. Wernher von Braun, John Casani, and Dr. James Van Allen inspect components of the Pioneer IV spacecraft on March 1, 1959.
Dr. Wernher von Braun, then director of the U.S. Army Ballistic Missile Agency’s Development Operations Division at Redstone Arsenal in Huntsville, Ala., left, John Casani of the Jet Propulsion Laboratory, center, and Dr. James Van Allen, professor of Physics and Astronomy at the University of Iowa, inspect components of the Pioneer IV spacecraft on March 1, 1959. The probe contained a radio transmitter, cosmic radiation counter and other instruments.

Just two months after its inception, NASA planned two attempts to fly by the moon and return data about cosmic radiation in the Earth and lunar environments. Developed at the Jet Propulsion Laboratory in Pasadena, Calif., the conical-shaped Pioneer 3 and 4 spacecraft were small by today’s standards, weighing just 13.2 pounds, and measuring 1.67 feet in length and 9 inches in diameter at the base.

Pioneer 3 lifted off on Dec. 6, 1958, atop an Army Ballistic Missile Agency Juno II rocket from Cape Canaveral Air Force Station’s Launch Complex 5. However, depletion of propellant caused the first stage engine to shut down 3.7 seconds prematurely, preventing the spacecraft from reaching the speed necessary to break free of the Earth’s gravity.

Pioneer 4 launch.
The Juno II rocket lifts off on March 3, 1959 successfully boosting the Pioneer 4 spacecraft. It was America’s first probe to escape Earth’s gravity, passing within 37,000 miles of the lunar surface.

Although Pioneer 3 did not achieve escape velocity, it reached an altitude of 63 miles and discovered a second radiation belt around Earth. America’s first satellite, Explorer 1, was launched Jan. 31, 1958, and made the initial discovery of what became known as the Van Allen Radiation Belts. University of Iowa Physics and Astronomy professor Dr. James Van Allen, for whom the energetic charged particle layers are named, developed the instruments for the satellite.

On the second attempt, on March 3, 1959, Pioneer 4 successfully lifted off from Launch Complex 5 and became the first American spacecraft to escape Earth’s gravity.

The Soviet Union’s Luna 1 was the first probe to do so on Jan. 2, 1959. It was designed to impact the moon, but due to an incorrectly timed upper-stage burn during launch, Luna 1 missed the moon but became the first spacecraft to enter orbit around the sun.

Technicians help secure the Orion crew module onto a work stand.
Inside the Operations and Checkout Building high bay at NASA’s Kennedy Space Center on June 7, 2013, technicians help secure the Orion crew module onto a work stand after it was lifted out of a special test fixture. Lockheed Martin Space Systems and NASA engineers performed a series of static load tests on Orion that simulated the massive loads the spacecraft will experience during its Exploration Flight Test-1 mission.
NASA/Daniel Casper

Pioneer 4 made its closest approach to the moon on the second day of the mission, passing within 37,000 miles of the lunar surface. The payload included two Geiger counters, similar to those developed by Van Allen for Explorer 1, and a camera trigger mechanism as a test for future photographic missions. While the spacecraft did fly past the moon, the camera sensor failed to trigger because its fly-by was at a greater distance than originally planned due to a trajectory error.

Pioneer 4 did provide extensive and valuable data on radiation and the tracking of space objects. Contact was lost from Pioneer 4’s tiny radio on March 6, 1959, after 82 hours of transmissions and 655,000 miles of travel. It was the farthest tracking distance for a human-made object at the time.

Learning more about travel beyond Earth is also the objective of the upcoming first flight of Orion as NASA continues plans to explore.

A technician on a scissor lift works on the service module for the Orion spacecraft.
A technician on a scissor lift works on the service module for the Orion spacecraft inside Kennedy’s Operations and Checkout Building high bay on Dec. 2, 2013. To the right and left are two of the three fairings that will be installed around the service module. The Orion spacecraft is being prepared for its first unpiloted flight test, Exploration Flight Test-1, scheduled for launch atop a Delta IV rocket in September 2014.
NASA/Daniel Casper

The spacecraft is designed to take astronauts beyond low-Earth orbit to deep space. When boosted by NASA’s Space Launch System (SLS), an advanced heavy-lift launch vehicle under development, Orion will provide the capability to transport astronauts to destinations such as an asteroid and Mars.

For EFT-1, plans call for the Lockheed Martin-built Orion to launch atop a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex 37-B at Cape Canaveral for the test flight. The planned two orbit mission will send Orion farther into space than any human spaceflight vehicle since the Apollo 17 mission in December 1972.

The test will feature a 3,671-mile high apogee on the second orbit and a high-energy re-entry at 20,000 mph. This will simulate the conditions that are expected as Orion returns from deep space destinations.

After splashdown in the Pacific Ocean, U.S. Navy crews will recover the Orion spacecraft. Data gathered from EFT 1 will be analyzed in the agency’s Critical Design Review in April 2015.

Orion will launch atop a Delta IV Heavy rocket for the test flight, as shown in this configuration. The planned two orbit flight will send Orion farther into space than any human spaceflight vehicle since the Apollo 17 mission in 1972.