A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surf ...

; approach the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...

; travel through interplanetary space; flyby,

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such a ...

, or land or fly on other planetary

bodies Bodies may refer to: * The plural of body * ''Bodies'' (2004 TV series), BBC television programme * Bodies (upcoming TV series), an upcoming British crime thriller limited series * "Bodies" (''Law & Order''), 2003 episode of ''Law & Order'' * ...

; or enter interstellar space. Many countries and private companies have launched probes to planets, asteroids, moons around the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

, including the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

, the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

, and many more.

History

On 4 October 1957, the first artificial satellite to orbit Earth was Sputnik 1, launched by the USSR. Four months later, on 1 February 1958,

Explorer 1 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 the previous year; the Soviet Union's ...

was launched by the United States, being the first space probe. Explorer 1, collecting data on temperature, cosmic rays, and micrometeorite impacts. The first attempted lunar probe was the

Luna E-1 No.1 Luna E-1 No.1, sometimes identified by NASA as Luna 1958A, was a Soviet Luna E-1 spacecraft which was intended to impact the Moon. It did not accomplish this objective as it was lost in a launch failure. It was the first of four E-1 missions to b ...

, launched on 23 September 1958. The goal of a lunar probe repeatedly failed until 4 January 1959 when Luna 1 orbited around the moon and then the sun. The success of these early missions began a race between the US and the USSR to outdo each other with increasingly ambitious probes. Each new satellite cast a shadow on the one that came before. '' Mariner 2'' was the first probe to study another planet, revealing Venus' extremely hot temperature to scientists in 1962, while the Soviet '' Venera 4'' was the first atmospheric probe to study Venus. '' Mariner 4'' 's 1965 Mars flyby snapped the first images of its cratered surface, which the Soviets responded to a few months later with images from on its surface from '' Luna 9''. In 1967, America's ''

Surveyor 3 Surveyor 3 was the third lander of the American uncrewed Surveyor program sent to explore the surface of the Moon in 1967. It was the first mission to carry a surface-soil sampling-scoop. Surveyor 3 was visited by Apollo 12 astronauts Pete Con ...

'' gathered information about the Moon's surface that would prove crucial to the ''

Apollo 11 Apollo 11 (July 16–24, 1969) was the American spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin landed the Apollo Lunar Module ''Eagle'' on July 20, 1969, at 20:17 UTC, a ...

'' mission that landed humans on the moon two years later. The first interstellar probe was

Voyager 1 ''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin '' Voyager 2'', ''Voy ...

, launched 5 September 1977. It entered interstellar space on 25 August 2012, followed by its twin

Voyager 2 ''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, ''Voyager 1'', on ...

on 5 November 2018. Both have collected science outside the heliosphere.

Characteristics

A space probe generally need an antenna to communicate back with Earth. Probes do not have astronauts. Probes send data back to Earth for scientists to study.

Trajectories

Once a probe has left the vicinity of Earth, its trajectory will likely take it along an orbit around the Sun similar to the Earth's orbit. To reach another planet, the simplest practical method is a

Hohmann transfer orbit In astronautics, the Hohmann transfer orbit () is an orbital maneuver used to transfer a spacecraft between two orbits of different altitudes around a central body. Examples would be used for travel between low Earth orbit and the Moon, or ...

. More complex techniques, such as gravitational slingshots, can be more fuel-efficient, though they may require the probe to spend more time in transit. Some high Delta-V missions (such as those with high inclination changes) can only be performed, within the limits of modern propulsion, using gravitational slingshots. A technique using very little propulsion, but requiring a considerable amount of time, is to follow a trajectory on the Interplanetary Transport Network.

References

{{DEFAULTSORT:Space Probe Uncrewed spacecraft

History

Characteristics

Trajectories

See also

References