Orbiter in the context of Trace Gas Orbiter

Huygens (/ˈhɔɪɡənz/ HOY-gənz) was an atmospheric entry robotic space probe that landed successfully on Saturn's moon Titan in 2005. Built and operated by the European Space Agency (ESA), and launched by NASA, it was part of the Cassini–Huygens mission and became the first spacecraft to land on Titan and the farthest landing from Earth a spacecraft has ever made. The probe was named after the 17th-century Dutch astronomer Christiaan Huygens, who discovered Titan in 1655.

The combined Cassini–Huygens spacecraft was launched from Earth on 15 October 1997. Huygens separated from the Cassini orbiter on 25 December 2004, and landed on Titan on 14 January 2005 near the Adiri region. Huygens's landing is so far the only one accomplished in the outer Solar System and on a moon other than Earth's.

In spaceflight an orbit insertion is an orbital maneuver which adjusts a spacecraft’s trajectory, allowing entry into an orbit around a planet, moon, or other celestial body, becoming an artificial satellite. An orbiter is a spacecraft designed for orbital insertion. An orbit insertion maneuver involves either deceleration from a speed in excess of the respective body's escape velocity, or acceleration to it from a lower speed.

When the result is a transfer orbit, e.g. a descent orbit insertion, the maneuver is an orbit injection.

The Luna programme (from the Russian word Луна "Luna" meaning "Moon"), sometimes called Lunik by western media, was a series of robotic spacecraft missions sent to the Moon by the Soviet Union between 1959 and 1976. The programme accomplished many firsts in space exploration, including first flyby of the Moon, first impact of the Moon and first photos of the far side of the Moon. Each mission was designed as either an orbiter or lander. They also performed many experiments, studying the Moon's chemical composition, gravity, temperature, and radiation.

Twenty-four spacecraft were formally given the Luna designation, although more were launched. Those that failed to reach orbit were not publicly acknowledged at the time, and not assigned a Luna number. Those that failed in low Earth orbit were usually given Cosmos designations. The estimated cost of the Luna programme in 1964 was US$6–10 billion (equivalent to US$46–77 billion in 2024). The Luna 25 mission also continues the Luna designation, although it is considered to be a part of the Luna-Glob exploration programme. The same applies to other planned missions such as Luna 26, Luna 27 and Luna 28.

Lunokhod (Russian: Луноход, IPA: [lʊnɐˈxot], "Moonwalker") was a series of Soviet robotic lunar rovers designed to land on the Moon between 1969 and 1977. Lunokhod 1 was the first roving remote-controlled robot to land on an extraterrestrial body.

The 1969 Lunokhod 1A (Lunokhod 0, Lunokhod No. 201) was destroyed during launch, the 1970 Lunokhod 1 and the 1973 Lunokhod 2 landed on the Moon, and Lunokhod 3 (Lunokhod No. 205, planned for 1977) was never launched. The successful missions were in operation concurrently with the Zond and Luna series of Moon flyby, orbiter and landing missions.

Mars Global Surveyor (MGS) was an American robotic space probe developed by NASA's Jet Propulsion Laboratory. It was launched on November 7, 1996, and collected data in orbit around Mars from 1997 to 2006. MGS was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed atmospheric monitoring for sister orbiters during aerobraking, and helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.

The spacecraft completed its primary mission in January 2001 and was in its third extended mission phase when, on 2 November 2006, it failed to respond to messages and commands. A faint signal was detected three days later which indicated that it had gone into safe mode. Attempts to recontact the spacecraft and resolve the problem failed, and NASA officially ended the mission in January 2007. An investigation attributed the loss of the spacecraft to a flaw in an update to its system software. MGS remains in a stable near-polar circular orbit at about 450 km altitude and as of 1996, was expected to crash onto the surface of the planet in 2050.

The Viking program consisted of a pair of identical American space probes, Viking 1 and Viking 2 both launched in 1975, and landed on Mars in 1976. The mission effort began in 1968 and was managed by the NASA Langley Research Center. Each spacecraft was composed of two main parts: an orbiter spacecraft which photographed the surface of Mars from orbit, and a lander which studied the planet from the surface. The orbiters also served as communication relays for the landers once they touched down.

The Viking program grew from NASA's earlier, even more ambitious, Voyager Mars program, which was not related to the successful Voyager deep space probes of the late 1970s. Viking 1 was launched on August 20, 1975, and the second craft, Viking 2, was launched on September 9, 1975, both riding atop Titan IIIE rockets with Centaur upper stages. Viking 1 entered Mars orbit on June 19, 1976, with Viking 2 following on August 7.

Chang'e 3 ( /tʃæŋˈʌ/; Chinese: 嫦娥三号; pinyin: Cháng'é Sānhào; lit. 'Chang'e No. 3') is a robotic lunar exploration mission operated by the China National Space Administration (CNSA), incorporating a robotic lander and China's first lunar rover. It was launched in December 2013 as part of the second phase of the Chinese Lunar Exploration Program. The mission's chief commander was Ma Xingrui.

The spacecraft was named after Chang'e, the goddess of the Moon in Chinese mythology, and is a follow-up to the Chang'e 1 and Chang'e 2 lunar orbiters. The rover was named Yutu (Chinese: 玉兔; lit. 'Jade Rabbit') following an online poll, after the mythological rabbit that lives on the Moon as a pet of the Moon goddess.

The following table is a list of Mars orbiters, consisting of space probes which were launched from Earth and are currently orbiting Mars. As of August 2023, there have been 18 spacecraft missions operating in Mars' orbit, 7 of which are currently active.

The Mariner program was conducted by the American space agency NASA to explore other planets. Between 1962 and late 1973, NASA's Jet Propulsion Laboratory (JPL) designed and built 10 robotic interplanetary probes named Mariner to explore the inner Solar System – visiting the planets Venus, Mars and Mercury for the first time, and returning to Venus and Mars for additional close observations.

The program included a number of interplanetary firsts, including the first successful planetary flyby, the planetary orbiter, and the first gravity assist maneuver. Of the 10 vehicles in the Mariner series, seven were successful, forming the starting point for many subsequent NASA/JPL space probe programs. The planned Mariner Jupiter-Saturn vehicles were adapted into the Voyager program, while the Viking program orbiters were enlarged versions of the Mariner 9 spacecraft. Later Mariner-based spacecraft include Galileo and Magellan, while the second-generation Mariner Mark II series evolved into the Cassini–Huygens probe.