The craft are further grouped by mission status – "en route", "mission in progress" or "mission complete" – based on their primary mission. For example, though Voyager 1 is still contactable en route to the heliopause, it is listed as "mission complete" because its primary task of studying Jupiter and Saturn has been accomplished. Once a probe has reached its first primary target, it is no longer listed as "en route" whether or not further travel is involved.
Mission: Lander engaging in low-frequency radio spectrometry experiment, neutron and dosimetry experiment, and biological experiment. Rover seeking to characterize lunar far-side environment (including possible lunar mantel material) using visible/near-infrared spectrometer, ground penetrating radar, cameras, and neutral particle analyzer.
Mission: Spacecraft consists of the Mercury Transfer Module (MTM), Mercury Planetary Orbiter (MPO), and the Mercury Magnetospheric Orbiter (MMO or Mio). MTM and MPO are built by ESA while the MMO is mostly built by JAXA. Once the MTM delivers the MPO and MMO to Mercury orbit, the two orbiters will have the following objectives: to study Mercury's form, interior structure, geology, composition, and craters; to study the origin, structure, and dynamics of its magnetic field; to characterize the composition and dynamics of Mercury's vestigial atmosphere; to test Einstein's theory of general relativity; to search for asteroids sunward of Earth; and to generally study the origin and evolution of a planet close to a parent star.
Mission: The first JapaneseVenusian probe. Also known as Planet-C and Venus Climate Orbiter, Akatsuki failed to enter Venusian orbit in December 2010. It continued to function and entered Venus orbit in 2015.
Mission: one of six currently active human-made Mars satellites. It is continuing its extended mission to map the surface of Mars and also acts as a relay for the Curiosity rover. Its name is a tribute to the novel and film 2001: A Space Odyssey.
Mission: Mars orbiter designed to study the planet's atmosphere and geology, search for sub-surface water, and deploy the Beagle 2 lander. In 2017 the mission was extended until at least the end of 2020.
Montage of planets and some moons that the two Voyager spacecraft have visited and studied, still active in the 2010s they are heading out into interstellar space returning data from newly explored distances
Mission: investigating Jupiter and Saturn, and the moons of these planets. Its continuing data feed offered the first direct measurements of the heliosheath and the heliopause. It is currently the farthest man-made object from Earth, as well as the first object to leave the heliosphere and cross into interstellar space. As of November 2017 it has a distance from the Sun of about 140 astronomical units (AU) (21 billion kilometers, or 0.002 light years), and it will not be overtaken by any other current craft. In August 2012, Voyager 1 became the first human-built spacecraft to enter interstellar space. Though declining, the onboard power source should keep some of the probe's instruments running until 2025.
Mission: studying all four gas giants. This mission was one of NASA's most successful, yielding a wealth of new information. As of November 2017 it is some 116 AU from the Sun (17.34 billion kilometers), and it is hoped the probe will continue to operate until at least 2020. It has left the heliosphere and crossed into interstellar space in December 2018. As with Voyager 1, scientists are now using Voyager 2 to learn what the Solar System is like beyond the heliosphere.
Mission: measurements of the solar wind, solar magnetic field and cosmic rays. Oldest functioning probe (if still operating). Contact was last attempted 8 December 2000 to celebrate its 35th anniversary, and the attempt was successful.
Mission: studying the interaction between the solar wind and (1) the Earth's magnetosphere, (2) the tail of comet Giacobini-Zinner, (3) the tail of Halley's Comet. Contact with the probe was lost on 16 September 2014. It is unknown whether contact can be reestablished because the probe's exact orbit is uncertain.
Mission: flyby and observation of Halley's Comet and Comet Grigg-Skjellerup to capture scientific data and images of the nucleus. The multicolor camera was destroyed in the encounter with Halley, but the probe remained otherwise functional for the second encounter.
Mission: Cassini orbiter studying Saturn and its moons after passing Venus and Jupiter; Huygens landing probe investigating Titan. Cassini primarily investigated Saturn's rings, its magnetosphere, and the geologic composition of its satellites.