Sputnik 2 in the context of "Dogs in space"

Sputnik (Спутник, Russian for "satellite") is a name for multiple spacecrafts launched under the Soviet space program. "Sputnik 1", "Sputnik 2" and "Sputnik 3" were the official Soviet names of those objects, and the remaining designations in the series ("Sputnik 4" and so on) were not official names but names applied in the West to objects whose original Soviet names may not have been known at the time.

Project Vanguard was a program managed by the United States Navy Naval Research Laboratory (NRL), which intended to launch the first artificial satellite into low Earth orbit using a Vanguard rocket as the launch vehicle from Cape Canaveral Missile Annex, Florida.

In response to the launch of Sputnik 1 on 4 October 1957, the U.S. restarted the Explorer program, which had been proposed earlier by the Army Ballistic Missile Agency (ABMA). Privately, however, the Central Intelligence Agency (CIA) and President Dwight D. Eisenhower were aware of progress being made by the Soviets on Sputnik from secret spy plane imagery. Together with the Jet Propulsion Laboratory (JPL), ABMA built Explorer 1 and launched it on 1 February 1958 (UTC). Before work was completed, however, the Soviet Union launched a second satellite, Sputnik 2, on 3 November 1957. Meanwhile, the spectacular failure of Vanguard TV3 on 6 December 1957, deepened American dismay over the country's position in the Space Race.

Explorer 1 was the first satellite launched by the United States in 1958 and was part of the U.S. participation in the International Geophysical Year (IGY). The mission followed the first two satellites, both launched by the Soviet Union during the previous year, Sputnik 1 and Sputnik 2. This began a Space Race during the Cold War between the two nations.

Explorer 1 was launched on 1 February 1958 at 03:47:56 GMT (or 31 January 1958 at 22:47:56 Eastern Time) atop the first Juno I booster from LC-26A at the Cape Canaveral Missile Test Center of the Atlantic Missile Range (AMR), in Florida. It was the first spacecraft to detect the Van Allen radiation belt, returning data until its batteries were exhausted after nearly four months. It remained in orbit until 1970.

Vanguard TV-3 (also called Vanguard Test Vehicle-Three), was the first attempt of the United States to launch a satellite into orbit around the Earth, after the successful Soviet launches of Sputnik 1 and Sputnik 2. Vanguard TV-3 was a small satellite designed to test the launch capabilities of the three-stage Vanguard and study the effects of the environment on a satellite and its systems in Earth orbit. It was also to be used to obtain geodetic measurements through orbit analysis. Solar cells on Vanguard TV-3 were manufactured by Bell Laboratories.

At its launch attempt on 6 December 1957, at Cape Canaveral Air Force Station, the booster ignited and began to rise, but about two seconds after liftoff, after rising about 1.2 m (four feet), the rocket lost thrust and fell back to the launch pad. As it settled, the fuel tanks ruptured and exploded, destroying the rocket and severely damaging the launch pad. The Vanguard 1A satellite was thrown clear and landed on the ground a short distance away with its transmitters still sending out a beacon signal. The satellite was damaged, however, and could not be reused. It is now on display at the National Air and Space Museum of the Smithsonian Institution.

Vanguard 1 (Harvard designation: 1958-Beta 2, COSPAR ID: 1958-002B) is an American satellite that was the fourth artificial Earth-orbiting satellite to be successfully launched, following Sputnik 1, Sputnik 2, and Explorer 1. It was launched 17 March 1958. Vanguard 1 was the first satellite to have solar electric power. Although communications with the satellite were lost in 1964, it remains the oldest artificial object still in orbit, together with the upper stage of its launch vehicle.

Vanguard 1 was designed to test the launch capabilities of a three-stage launch vehicle as a part of Project Vanguard, and the effects of the space environment on a satellite and its systems in Earth orbit. It also was used to obtain geodetic measurements through orbit analysis. Vanguard 1, being small and light enough to carry with one hand, was described by the Soviet Premier, Nikita Khrushchev, as "the grapefruit satellite".