In July 1955, the United States announced its program to launch what was planned to be the world's first artificial satellite, as part of the US participation in the International Geophysical Year (July 1957 - December 1958), an 18-month year.

A committee appointed by the US Department of Defense selected a plan offered by the US Naval Research Laboratory.  NRL had been engaged in upper atmosphere research for a number of years, using captured German V-2's, balloons, and the Aerobee and Viking research rockets.  The NRL proposal called for using a modified Viking, with a new second stage based on the Aerobee, and a brand new third stage solid propellant.

The decision to award the project to NRL was highly controversial.  The Redstone Arsenal (later named the Army Ballistic Missile Agency - ABMA),  with Dr. Wernher Von Braun guiding development and testing of its Intermediate Range Ballistic Missile, had demonstrated that a modified version of the Redstone had capability to launch a satellite into Earth orbit.

Reasons for awarding the project to NRL, rather than to the Army, some official and some speculative, included:  the value of keeping an international research project free of any military taint; the undesirability of having a US effort owed to a group of expatriates of a former enemy government; the prevention of interfering with development of the IRBM; the unspoken desire of the Eisenhower administration to have a non-military research program form the basis for implementing its "open skies" proposals; the Navy's brilliant developments in instrumentation; Vanguard's lower costs, higher growth potential, longer duration of orbiting, and potential for more scientific information.

Project Vanguard's mission was defined as placing a satellite into orbit during the IGY; track it and prove it is in orbit; and accomplish a  scientific experiment in orbit. Vanguard not only succeeded in performing its mission, it exceeded its requirements in several regards. It orbited three satellites, all of which are still in orbit, the oldest objects in space from Earth.

As stated in the introductory paragraph, Vanguard was planned to be the world's first artificial satellite. Events overtook the plans. The Soviet Union, which had indeed announced its intentions to launch artificial satellites as part of its IGY participation, nevertheless surprised the world with its launches of Sputniks in October and November of 1957.

Then, the very first attempt to test the first complete assembly of the Vanguard launch vehicle, designated TV-3 (for Test Vehicle number 3), in December of 1957 suddenly became the center of worldwide attention. The Air Force, for the first time, permitted live television to be broadcast from its Cape Canaveral, FL, launch site. The assembly included a test satellite, which would have reached orbit and emitted a signal, provided only that the test launch vehicle performed flawlessly. Lost in the avalanche of media attention and misinformed public reaction to the Soviet successes was the fact that Vanguard was still in its developmental phase; that TV-3 was one of a number of TEST vehicles,; that this was the very first attempt to test the complete assembly, and so on.

On live television, in view of the world, TV-3 rose a few feet above its launch stand, the first-stage engine lost power, and the vehicle collapsed in spectacular flames, its test satellite landing on the concrete launch pad, broken and blackened, and emitting its beep-beep-beep.

On March 17, 1958, after one more unsuccessful attempt, Vanguard I was launched into a highly stable orbit, today the oldest object in orbit from Earth, and destined to remain so for centuries.

Vanguard I was the first satellite to use solar cells for power. It performed a variety of experiments, including measuring the geodesy of Earth (discovering it is pear-shaped); measuring atmospheric density, temperature, and solar pressure. The fact that it is still being tracked has provided and updated some of this same information for a period of 50 years, as of the 50th anniversary date. The van Allen radiation belts discovered by Explorer I used the instrumentation designed, developed, and sponsored by Vanguard.

Development of Vanguard launch vehicles, guidance, and tracking systems spawned several generations of descendants that have achieved countless space "firsts"; and remain in service to this day. The Vanguard Minitrack passive tracking system locates a satellite in three dimensions and provides three vectors of velocity to describe its motion. Minitrack is origin of the Naval Space Surveillance System. Minitrack tracked the Sputniks and later furnished proof that the US Explorer I was in orbit. A direct descendant of Minitrack is today's Global Positioning System (GPS). Establishing the orbital parameters of Vanguard I, using one of the new IBM computers, added immeasurably to the knowledge of orbital mechanics and related computer technology. Vanguard I has a predicted lifetime of 400 to 1200 years.

In just over two years' time, Project Vanguard successfully developed and tested a three-stage launch vehicle, a new first-stage gimbaled engine, a new solid propellant third stage, instrumented and launched satellites and conducted experiments, developed a passive, precise tracking system, constructed, tested, and networked 14 tracking stations in the Americas and in Africa, and launched three satellites into Earth orbit. All of this, at a cost totaling less than $120,000,000.