Artist's concept of Cassini 's orbit insertion around Saturn
The approximately twenty space probes operational as of September 2014.
This is a list of active probes which have escaped Earth orbit. It includes lunar probes, but does not include probes orbiting at the Sun-Earth Lagrangian points (for these, see List of objects at Lagrangian points). A craft is deemed "active" if it is still able to transmit usable data to Earth (whether or not it can receive commands).
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.
Launched: 7 April 2001 | Destination: Mars| Arrival: 24 October 2001 | Institution: NASA
Mars Express: Mars orbiter designed to study the planet's atmosphere and geology, search for sub-surface water, and deploy the Beagle lander. Mission extended until at least 31 December 2014.
Launched: 2 June 2003 | Destination: Mars| Arrival: 25 December 2003 | Institution: ESA
Lander: Beagle 2 [mission failed; contact lost at landing];
Lander: Opportunity Rover landed on Meridiani Planum. Expected to last 90 Martian days (sols), it continues to function effectively after 4091 sols. Its twin, Spirit Rover, explored an area on the other side of the planet, but became stuck in soft soil May 1, 2009, and communication was lost March 22, 2010 (sol 2210).
Launched: 10 June 2003 | Destination: Mars| Arrival: 25 January 2004 | Institution: NASA
Launched: 27 September 2007 | Destination: Vesta| Vesta arrival: 16 July 2011 |
Left Vesta: 5 September 2012 | Destination: Ceres| Arrival: 6 March 2015 | Institution: NASA
Lunar Reconnaissance Orbiter is engaged in lunar mapping intended to identify safe landing sites, locate potential resources on the Moon, characterize the radiation environment, and demonstrate new technology.
Launched: 18 June 2009 | Destination: Moon| Arrival: 23 June 2009 | Institution: NASA
Voyager 1 is currently the farthest man-made object from Earth, as well as the first object to leave the Solar System and cross into interstellar space. As of September 2014 it lies about 129 astronomical units (AU) from the sun (19.3 billion kilometers, or 0.002 light years), and it will not be overtaken by any other current craft. It was originally tasked with 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. In August 2012, Voyager 1 became the first human built spacecraft to enter interstellar space. It is hoped that Voyager 1 will continue operating until at least 2020.
Launched: 5 September 1977 | Destination: Jupiter & Saturn| Arrival: January 1979 | Institution: NASA
Primary Mission Completion: November, 1980 | Current Trajectory: entered interstellar space August 2012
Voyager 2 has not yet left the solar system, but will become one of the first five probes to do so eventually. Its mission to study all four gas giants was one of NASA's most successful, yielding a wealth of new information. As of September 2014 it is some 106 AU from the sun (15.85 billion kilometers), and it is hoped that it will continue to operate until at least 2020. As with Voyager 1, scientists are now using Voyager 2 to learn what the solar system is like beyond the heliosphere.
Akatsuki would have been the first JapaneseVenusian probe. Also known as Planet-C and Venus Climate Orbiter, Akatsuki failed to enter Venusian orbit in December 2010. It is still functioning, and has a possible second chance to orbit Venus in 2015.
Pioneer 6, launched in 1965, is the oldest functioning probe (if still operating). Contact was last attempted 8 December 2000 to celebrate its thirty-fifth anniversary, and the attempt was successful. Like the three craft which superseded it, it took measurements of the solar wind, solar magnetic field and cosmic rays.
Giotto approached within 600 kilometers of Halley's Comet on its flyby mission, and survived some particulate impact on the inbound flight to capture scientific data and stunning images of the comet's nucleus. Its multicolor camera was subsequently destroyed, but the probe remained otherwise functional. Its mission completed, deactivation commands were transmitted on 15 March 1986. Awakened four years later on 2 July, it studied the comet Grigg-Skjellerup as it approached within 200 kilometers eight days later, and was again deactivated on the 23rd.
Launched: 2 July 1985 | Destination: Comet Halley| Arrival: 14 March 1986 | Institution: ESA
MESSENGER was studying Mercury. It is only the second probe to do so and is the first to orbit the planet. Technologically, it is far superior to its 1975 predecessor, Mariner 10. Having previously passed Earth once, Venus twice and Mercury three times, it entered orbit in March 2011. Mission ended 30 April 2015, when the probe crashed onto the planet's surface.
Launched: 4 August 2004 | Destination: Mercury| Arrival: 18 March 2011 | Institution: NASA
Venus Express, modeled after the Mars Express, was collecting data on the Venusian atmosphere and cloud conditions. Mission ended 16 December 2014.
Launched: 9 November 2005 | Destination: Venus| Arrival: 11 April 2006 | Institution: ESA