List of minor planets and comets visited by spacecraft

The following tables list all minor planets and comets that have been visited by spacecraft.

List of minor planets visited by spacecraft

Since the 1990s, a total of 13 minor planets – currently all of them are asteroids and dwarf planets – have been visited by space probes. Note that moons (not directly orbiting the Sun), comets and planets are not minor planets and thus are not included in the table below.

In addition to the listed objects, three asteroids have been imaged by spacecraft at distances too large to resolve features (over 100,000 km), and are hence not considered as "visited". Asteroid 132524 APL was imaged by New Horizons in 2006 at a distance of 101,867 km, 2685 Masursky by Cassini in 2000 at a distance of 1,600,000 km, and 307 Nike by Pioneer 10 in 1972 at a distance of 8,800,000 km. The Hubble Space Telescope, a spacecraft in Earth orbit, has imaged several large asteroids, including 2 Pallas and 3 Juno.

Minor planet				Space probe
Name	Image	Dimensions (km) ^(a)	Discovery year	Name	Closest approach			Remarks
					year	in km	in radii ^(b)
1 Ceres		952	1801	Dawn	2015–present	200 approx. (planned)	0.42	first "close up" picture of Ceres taken in December 2014; probe entered orbit in March 2015; first dwarf planet visited by a spacecraft, largest asteroid visited by a spacecraft
4 Vesta		529	1807	Dawn	2011–2012	200 approx.	0.76	space probe broke orbit on 5 September 2012 and headed to Ceres; first "big four" asteroid visited by a spacecraft, largest asteroid visited by a spacecraft at the time
21 Lutetia		120×100×80	1852	Rosetta	2010	3,162	64.9	flyby on 10 July 2010; largest asteroid visited by a spacecraft at the time
243 Ida		56×24×21	1884	Galileo	1993	2,390	152	flyby; discovered Dactyl; first asteroid with a moon visited by a spacecraft, largest asteroid visited by spacecraft at the time
253 Mathilde		66×48×46	1885	NEAR Shoemaker	1997	1,212	49.5	flyby; largest asteroid visited by a spacecraft at the time
433 Eros		34×11×11	1898	NEAR Shoemaker	1998–2001	0	0	1998 flyby; 2000 orbited (first asteroid studied from orbit); 2001 landing; first asteroid landing, first asteroid orbited by a spacecraft, first near-Earth asteroid (NEA) visited by a spacecraft
951 Gaspra		18.2×10.5×8.9	1916	Galileo	1991	1,600	262	flyby; first asteroid visited by a spacecraft
2867 Šteins		4.6	1969	Rosetta	2008	800	302	flyby; first asteroid visited by the ESA
4179 Toutatis		4.5×~2	1934	Chang'e 2	2012	3.2	0.70	flyby;[1] closest asteroid flyby, first asteroid visited by a Chinese probe
5535 Annefrank		4.0	1942	Stardust	2002	3,079	1230	flyby
9969 Braille		2.2×0.6	1992	Deep Space 1	1999	26	12.7	flyby; followed by flyby of Comet Borrelly; failure, missed it during flyby
25143 Itokawa		0.5×0.3×0.2	1998	Hayabusa	2005	0	0	landed; returned dust samples to Earth in 2010 - first sample return mission from asteroid; smallest asteroid visited by a spacecraft, first asteroid visited by a non-NASA spacecraft
134340 Pluto		2,370	1930	New Horizons	2015	12,500	10.5	flyby; first trans-Neptunian object visited, most distant object visited by a spacecraft
Notes: ^a A minor planet's dimensions may be described by x, y, and z axes instead of an (average) diameter due to its non-spherical, irregular shape. ^b Closest approach given in multiples of the minor planet's mean radius  ·  Default order of list: by the minor planet's designation, ascending.

List of comets visited by spacecraft

Comet				Space probe
Name	Image	Dimensions (km) ^(a)	Discovery year	Name	Closest approach			Remarks
					year	in km	in radii ^(b)
Giacobini–Zinner		2	1900	ICE	1985	7,800	7,800	first flyby of comet
Halley		15×9	Known since antiquity	Vega 1	1986	8,889	1,620	flyby
				Vega 2	1986	8,030	1,460	flyby
				Suisei	1986	151,000	27,450	distant flyby
				Sakigake	1986	6,990,000	1,270,747	distant flyby
				Giotto	1986	596	108	flyby; first direct images of a comet nucleus
Grigg–Skjellerup		2.6	1902	Giotto	1992	200	154	flyby
Borrelly		8×4×4	1904	Deep Space 1	2001	2,171	814	flyby; closest approach in September 2001 when probe entered the comet's coma[2]
Wild 2		5.5×4.0×3.3	1978	Stardust	2004	240	113	flyby; first sample return mission from comet to Earth (2006)
Tempel 1		7.6×4.9	1867	Deep Impact	2005	500	80	flyby; delivered an impactor
				Deep Impact's impactor vehicle	2005	0	0	first landing on a comet (blasted a crater)
				Stardust	2011	181	57.9	flyby; imaged the crater created by Deep Impact
C/2006 P1		?	2006	Ulysses	2007	260 million	?	unexpected ride through the comet's tail; detected complex chemistry; solar wind speed was halved
Hartley 2		1.4	1986	EPOXI (was Deep Impact)	2010	700	1,000	flyby; smallest comet visited
Churyumov–Gerasimenko		4.1×3.3×1.8	1969	Rosetta	2014	6	3.91 5.37	first orbiter of comet (November 2014); in orbit as of 2015; OSIRIS captured image with 11 cm/px-resolution in Spring 2015[3]
				Philae (Rosetta's lander)	2014	0	0	first soft landing on a comet (November 2014)
Notes: ^(a) Due to a non-spherical, irregular shape, a comet's x, y, and z axes instead of an (average) diameter are often used to describe its dimensions. ^(b) Closest approach given in multiples of the comet's (average mean) radius  ·  List ordered in descending order by a comet's first visit

Spacecraft visited by comets

Comet C/2013 A1 passed close by Mars in October 2014, closer than the Moon is to Earth.^[4] As of early 2014 it was calculated to pass as close as 0.00087 AU (130,000 km; 81,000 mi).^[4] This was so close that the event was deemed dangerous to spacecraft in orbit around Mars.^[5] Spacecraft that were active at that time included 2001 Mars Odyssey, Mars Express, MAVEN, Mars Orbiter Mission, and Mars Reconnaissance Orbiter in Mars orbit – and two on the surface – Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity.

Planned visits

List of minor planets targeted for spacecraft visitation

The following table lists minor planets that are planned to be visited by spacecraft (given diameters are estimates). Asteroids that come to close enough to Earth can sometimes be observed, such as 4769 Castalia. See List of asteroid close approaches to Earth.

Name	Diameter (km)	Year of discovery	Spacecraft	Agency	Year of visit	Notes
2014 MU69	35	2014	New Horizons	NASA	2019	Flyby – 1 January 2019[6]
65803 Didymos	1	1996	AIDA	ESA	2022	Proposal[7][8]
101955 Bennu	0.5	1999	OSIRIS-REx	NASA	2020	Future planned landing
162173 Ryugu	1	1999	Hayabusa 2	JAXA	2018	Orbit expected June 2018 – December 2019. Several landers and sample collecting touchdowns planned.

List of minor planets formerly targeted for spacecraft visitation

Former targets (were at one time proposed as a target).

Name	Diameter (km)	Discovered	Spacecraft	Year	Notes
Siwa, 140140 Siwa	103	October 13, 1874	Rosetta	2007	target changed due to launch postponement[9]
Adeona, 145145 Adeona	151	June 3, 1875	Dawn	2016	abandoned target
Hamburga, 449449 Hamburga	86	October 31, 1899	CRAF	1998	mission cancelled
Geographos, 16201620 Geographos	5.1×1.8	September 14, 1951	Clementine	1995	mission failed before retargeting
van Albada, 20192019 van Albada	n.a.	September 28, 1935	NEAR	1998	abandoned target
Shipka, 25302530 Shipka	n.a.	July 9, 1978	Rosetta	2007	secondary target changed for better trajectory[9]
Rodari, 27032703 Rodari	n.a.	March 29, 1979	Rosetta	2007	target in early mission planning but not chosen[9]
McAuliffe, 33523352 McAuliffe	2–5	February 6, 1981	Deep Space 1	1998	abandoned target
Mimistrobell, 38403840 Mimistrobell	n.a.	October 9, 1980	Rosetta	2007	target changed[9]
Wilson–Harrington, 40154015 Wilson–Harrington	4	November 19, 1949	Deep Space 1 Hayabusa Mk2	1999 2022	abandoned target, also a comet mission cancelled
Nereus, 46604660 Nereus	~1	February 28, 1982	NEAR NEAP Hayabusa	1997	abandoned target mission cancelled abandoned target
Otawara, 49794979 Otawara	5.5	August 2, 1949	Rosetta	2007	target changed due to launch postponement[9]
(10302) 1989 ML	n.a.	June 29, 1989	Hayabusa	2002	abandoned target
(163249) 2002 GT	n.a.	April 3, 2002	Deep Impact	2020	communications with spacecraft lost
(185851) 2000 DP107	~0.8	February 29, 2000	PROCYON	2016	ion engine failure in heliocentric orbit [10]

References

1. Chang'E 2 images of Toutatis – December 13, 2012 – The Planetary Society
2. "Deep Space 1 – NSSDC/COSPAR ID: 1998-061A". NASA. 26 August 2014. Retrieved 1 July 2015.
3. "Rosetta Spacecraft Sees Its Shadow on a Comet (Photo)". Space.com. 5 March 2015. Rosetta flew just 3.7 miles (6 kilometers) from Comet 67P's surface, resulting in a resolution of 4.3 inches (11 centimeters) per pixel [for OSIRIS].
4. "JPL Close-Approach Data: C/2013 A1 (Siding Spring)". 2014-02-09. Retrieved 2013-02-19. last obs (arc=493 days w/619 obs)
5. Grossman, Lisa (6 December 2013). "Fiercest meteor shower on record to hit Mars via comet". New Scientist. Archived from the original on 2013-12-12.
6. Talbert, Tricia. "NASA's New Horizons Team Selects Potential Kuiper Belt Flyby Target". www.nasa.gov. Retrieved 29 August 2015.
7. Asteroid Impact & Deflection Assessment (AIDA) study.
8. Miriam Kramer (26 March 2013). "Asteroid Deflection Mission AIDA Set To Crash Two Spacecraft Into Space Rock In 2022". Huffington Post. Retrieved 19 September 2014.
9. Luigi Colangeli, Elena Mazzotta Epifani, Pasquale Palumbo, The New Rosetta Targets: Observations, Simulations and Instrument Performances, pp. 71-72, Springer Verlag, 2013.
10. http://www.planetary.org/blogs/emily-lakdawalla/2015/05081421-procyon-failure.html