The following tables list all minor planets and comets that have been visited by robotic spacecraft.
A total of 18 minor planets (asteroids, dwarf planets, and Kuiper belt objects) have been visited by space probes. Moons (not directly orbiting the Sun) and planets are not minor planets and thus are not included in the table below.
Minor planet | Space probe | |||||||
---|---|---|---|---|---|---|---|---|
Name | Image | Dimensions (km)(a) | Discovery year | Name | Closest approach | Remarks | ||
year | in km | in radii(b) | ||||||
951 Gaspra | 18.2 × 10.5 × 8.9 (12.2 km) | 1916 | Galileo | 1991 | 1,600 | 262 | Flyby; first asteroid visited by a spacecraft. | |
243 Ida | 56 × 24 × 21 (28 km) | 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 (58 km) | 1885 | NEAR Shoemaker | 1997 | 1,212 | 49.5 | Flyby; largest asteroid visited by a spacecraft at the time. | |
433 Eros | 34 × 11 × 11 (17 km) | 1898 | NEAR Shoemaker | 1998–2001 | landed | landed | 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. | |
9969 Braille | 2.2 × 0.6 (1.6 km) | 1992 | Deep Space 1 | 1999 | 26 | 12.7 | Flyby; followed by flyby of Comet Borrelly; failed to image it during closest approach, only taking images 14,000 km from the asteroid. | |
5535 Annefrank | 4.0 | 1942 | Stardust | 2002 | 3,079 | 1,230 | Flyby | |
25143 Itokawa | 0.5 × 0.3 × 0.2 (350 meters) | 1998 | Hayabusa | 2005 | landed | landed | 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. | |
2867 Šteins | 4.6 | 1969 | Rosetta | 2008 | 800 | 302 | Flyby; first asteroid visited by the ESA. | |
21 Lutetia | 120 × 100 × 75 (100 km) | 1852 | Rosetta | 2010 | 3,162 | 64.9 | Flyby on 10 July 2010; largest asteroid visited by a spacecraft at the time. | |
4 Vesta | 525.4 | 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. | |
4179 Toutatis | 2.45 | 1934 | Chang'e 2 | 2012 | 3.2 | 0.70 | Flyby; [1] closest asteroid flyby, first asteroid visited by a Chinese probe. | |
1 Ceres | 939.4 | 1801 | Dawn | 2015–2018 | 35 | 0.07 | 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. | |
134340 Pluto | 2376.6 | 1930 | New Horizons | 2015 | 12,500 | 10.5 | Flyby; first trans-Neptunian object visited, most distant object visited by a spacecraft (at the time of the visit). | |
162173 Ryugu | 0.896 | 1999 | Hayabusa2 | 2018-2019 | landed | landed | Rendezvoused with asteroid from June 2018 to November 2019. Successful touchdowns to collect a sample in February and July 2019. [2] Three landers and an explosive impactor successfully deployed to the surface. [3] Returned dust samples to Earth in December 2020. [4] | |
101955 Bennu | 0.490 | 1999 | OSIRIS-REx | 2018-2020 | landed | landed | Arrived on 3 December 2018; entered lowest orbit on 12 June 2019; smallest object to be orbited by spacecraft and closest ever orbit; [5] [6] touchdown on 20 October 2020 to collect sample. | |
486958 Arrokoth | 36 × 18 × 10 | 2014 | New Horizons | 2019 | 3,500 | 380 | Flew by Arrokoth (nicknamed Ultima Thule) on 1 January 2019, currently farthest object to be visited by a spacecraft. | |
65803 Didymos | 0.78 | 1996 | DART / LICIACube | 2022 | 1.19 | 3.1 | Asteroid of a near-Earth Apollo group; a flyby target; its moon being the kinetic impact target to test asteroid deflection [7] [8] | |
Dimorphos 65803 Didymos I | 0.16 | 2003 | DART / LICIACube | 2022 | landed | landed | Moon of a near-Earth asteroid of the Apollo group; flyby target of one and kinetic impact target of another spacecraft to test asteroid deflection [7] [8] | |
152830 Dinkinesh | 0.79 | 1999 | Lucy | 2023 | 425 | 1,100 | Flyby; discovered Selam; smallest main-belt asteroid to be visited by a spacecraft [9] [10] | |
Notes:
| ||||||||
In addition to the above listed objects, three asteroids have been imaged by spacecraft at distances too large to resolve features (over 100,000 km).
Minor planet | Space probe | |||||||
---|---|---|---|---|---|---|---|---|
Name | Image | Dimensions (km)(a) | Discovery year | Name | Closest approach | Remarks | ||
year | in km | in radii(b) | ||||||
2685 Masursky | 10.7 | 1981 | Cassini–Huygens | 2000 | 1,600,000 | 297,840 | Distant incidental flyby. | |
132524 APL | 2.5 | 2002 | New Horizons | 2006 | 101,867 | 81,493 | Distant incidental flyby. | |
2012 PM35 | 0.9-2.5 | 2012 | Dawn | 2017 | 200,000 | 130,000 | Distant incidental flyby; approached Ceres to 200,000 km in September 2017 while Dawn was in orbit. [11] |
Comet | Space probe | |||||||
---|---|---|---|---|---|---|---|---|
Name | Image | Dimensions (km)(a) | Discovery year | Name | Closest approach | Remarks | ||
year | in km | in radii(b) | ||||||
21P/Giacobini–Zinner | 2 | 1900 | ICE | 1985 | 7,800 | 7,800 | first flyby of a comet | |
1P/Halley | 15×9 | Known since 1759 (Precovered to 240 BCE) | 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 | ||||
ICE | 1986 | 31,000,000 | 5,647,000 | distant flyby | ||||
26P/Grigg–Skjellerup | 2.6 | 1902 | Giotto | 1992 | 200 | 154 | flyby | |
19P/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 [12] | |
81P/Wild | 5.5×4.0×3.3 | 1978 | Stardust | 2004 | 240 | 113 | flyby; first sample return mission from comet to Earth (2006) | |
9P/Tempel | 7.6×4.9 | 1867 | Deep Impact | 2005 | 500 | 80 | flyby; delivered an impactor | |
Deep Impact's impactor vehicle | 2005 | landed | landed | first landing on a comet (blasted a crater) | ||||
Stardust | 2011 | 181 | 57.9 | flyby; imaged the crater created by Deep Impact | ||||
103P/Hartley | 1.4 | 1986 | EPOXI ( Deep Impact ) | 2010 | 700 | 1,000 | flyby; smallest comet visited | |
67P/Churyumov–Gerasimenko | 4.1×3.3×1.8 | 1969 | Rosetta | 2016 | landed | landed | first orbiter of comet (November 2014); impacted surface as of 2016; OSIRIS captured image with 11 cm/px-resolution in Spring 2015 [13] | |
Philae (Rosetta's lander) | 2014 | landed | landed | first soft landing on a comet (November 2014) | ||||
Notes:
|
Comet C/2013 A1 passed close by planet Mars in October 2014, closer than the Moon is to Earth. [14] As of early 2014 it was calculated to pass as close as 0.00087 AU (130,000 km; 81,000 mi). [14] This was so close that the event was deemed dangerous to spacecraft in orbit around Mars. [15] 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 .
Name | Diameter (a) (km) | Year of discovery | Spacecraft | Year of visit | Notes | |
---|---|---|---|---|---|---|
16 Psyche | 186 | 1852 | Psyche | 2029 | Large metallic main-belt asteroid [16] | |
617 Patroclus-Menoetius | 141 | 1906 | Lucy | 2033 | Binary Jupiter trojan, Trojan camp, 5th-largest Jupiter trojan [17] | |
3200 Phaethon | 5 | 1983 | DESTINY+ | 2028 | Rock comet and parent body of Geminids meteor shower [18] | |
3548 Eurybates | 72 | 1973 | Lucy | 2027 | Jupiter trojan with satellite, Greek camp [17] | |
11351 Leucus | 42 | 1997 | Lucy | 2028 | Jupiter trojan, Greek camp, a slow rotator [17] | |
15094 Polymele | 21 | 1999 | Lucy | 2027 | Jupiter trojan with satellite, Greek camp [17] | |
21900 Orus | 53 | 1999 | Lucy | 2028 | Jupiter trojan, Greek camp [17] | |
52246 Donaldjohanson | 3.9 | 1981 | Lucy | 2025 | Main-belt asteroid and member of the Erigone family [19] | |
65803 Didymos | 0.8 | 1996 | Hera | 2026 | Probe will study the results obtained by the NASA's DART impactor 4 years after its mission. [20] [21] | |
Dimorphos 65803 Didymos I | 0.16 | 2003 | Hera | 2026 | Probe will study the results obtained by the NASA's DART impactor 4 years after its mission. [21] | |
(98943) 2001 CC21 | 0.5 | 2001 | Hayabusa2# | 2026 | Near-Earth asteroid of the Apollo group; extended mission target [22] | |
99942 Apophis | 0.370 | 2004 | OSIRIS-APEX | 2029 | Extended mission after sample delivery [23] | |
469219 Kamoʻoalewa | 0.041 | 2016 | Tianwen-2 | 2025 | Co-orbital near-Earth asteroid; sample return target [24] | |
1998 KY26 | 0.030 | 1998 | Hayabusa2# | 2031 | Near-Earth asteroid of the Apollo group; extended mission target [22] | |
2019 VL5 | 0.03 | 2019 | Unnamed CNSA mission | 2025 | Near-Earth asteroid of the Aten group, will be visited by an orbiter and impactor for an asteroid deflection test. [25] | |
311P/PanSTARRS | 0.48 | 2013 | Tianwen-2 | 2032 | Active asteroid [24] | |
undisclosed | ? | ? | Brokkr-2 | 2024 | M-type near-Earth asteroid [26] [27] [28] [29] | |
|
The following table lists minor planets that are proposed to be visited by spacecraft missions that have not yet been approved.
Name | Diameter (km) | Year of discovery | Spacecraft | Proposed dates | Notes |
---|---|---|---|---|---|
29P/Schwassmann–Wachmann | 65 | 1927 | Centaurus | Launch: 2026 Flyby: 2030s | A flyby proposal. [30] |
50 Virginia | 99.8 | 1857 | MANTIS | Launch: 2020s Flyby: 2020s | A flyby proposal of 14 asteroids, the largest being 50 Virginia. |
2060 Chiron | 271 | 1977 | Centaurus | Launch: 2026 Flyby: 2030s | A flyby proposal. [30] |
10199 Chariklo | 260.35 | 1997 | Camilla | Launch: 2026 Flyby: 2039 | A mission concept for a flyby and impactor. [31] |
50000 Quaoar | 1086 | 2002 | Interstellar Express | Launch: 2024 Flyby: 2030s | A Voyager -like mission proposed to be launched in 2024 by the CNSA. A pair of probes would flyby Neptune, Quaoar, and one other KBO. [32] [33] |
(153591) 2001 SN263 | 2.6 | 2001 | ASTER | Launch: 2025 Flyby: 2027 | Brazilian Space Agency mission to triple near-Earth asteroid system of the Amor group [34] |
Trojan asteroids | 1906 | OKEANOS | Launch: 2026 | Proposed multiple flyby mission to Jupiter's Trojan asteroids using solar sail propulsion. [35] | |
10253 Westerwald | 2.3 | 1973 | MBR Explorer | Launch: 2028 | Flyby [36] |
623 Chimaera | 22 | 1907 | MBR Explorer | Launch: 2028 | Flyby [36] |
13294 Rockox | 5.2 | 1998 | MBR Explorer | Launch: 2028 | Flyby [36] |
(88055) 2000 VA28 | 5.4 | 2000 | MBR Explorer | Launch: 2028 | Flyby [36] |
(23871) 1998 RC76 | 6.7 | 1998 | MBR Explorer | Launch: 2028 | Flyby [36] |
(59980) 1999 SG6 | 8.0 | 1999 | MBR Explorer | Launch: 2028 | Flyby [36] |
269 Justitia | 53.62 | 1887 | MBR Explorer | Launch: 2028 | Landing [36] |
99942 Apophis | 0.370 | 2004 | RAMSES | Launch: 2027 Flyby: 2029 | ESA proposal [37] |
Former targets for launched spacecraft.
spacecraft failure | |
---|---|
mission planning decisions |
Name | Diameter (km) | Date of discovery | Spacecraft | Year | Notes |
---|---|---|---|---|---|
2P/Encke | 4.8 | January 17, 1786 | CONTOUR | 1998 | Spacecraft lost while leaving Earth orbit [38] |
2P/Encke | 4.8 | January 17, 1786 | NEAR | 1998 | Target changed before launch [39] |
4 Vesta | 525 | March 29, 1807 | NEAR | 1998 | Target changed before launch [39] |
6P/d'Arrest | 3.2 | June 28, 1851 | CONTOUR | 2008 | Spacecraft lost while leaving Earth orbit [38] |
21P/Giacobini–Zinner | 2 | December 20, 1900 | Suisei | 1998 | Extended mission, spacecraft ran out of fuel en route. [40] |
46P/Wirtanen | 1.2 | January 17, 1948 | Rosetta | 2011 | Initial target, was changed due to delay. [41] [42] |
73P/Schwassmann–Wachmann | 1.1 (before breakup) | May 2, 1930 | CONTOUR | 2006 | Spacecraft lost while leaving Earth orbit [38] |
76P/West–Kohoutek–Ikemura | 0.66 | January 1975 | Deep Space 1 | 2000 | Target changed due to launch postponement [43] |
85D/Boethin | January 4, 1975 | EPOXI ( Deep Impact ) | 2007 | Astronomers were unable to locate the comet, which is too faint to be observed. [44] | |
140 Siwa | 103 | October 13, 1874 | Rosetta | 2007 | Target changed due to launch postponement [45] |
145 Adeona | 151 | June 3, 1875 | Dawn | 2016 | Abandoned target (not seriously considered) [46] |
223 Rosa | 82.7 | March 9, 1882 | JUICE | 2029 | Secondary target; abandoned to conserve fuel for primary Jupiter orbiter mission. [47] [48] |
1036 Ganymed | 35 | October 23, 1924 | NEAR | 1998 | Target changed before launch [39] |
1620 Geographos | 5.1×1.8 | September 14, 1951 | Clementine | 1995 | Mission failed before retargeting |
2019 van Albada | 7.5-9.4 | September 28, 1935 | NEAR | 1998 | Target changed before launch [39] |
2101 Adonis | 0.6 | February 12, 1936 | Vega 2 | 1987 | Secondary target; insufficient fuel [49] |
2530 Shipka | 12.4 [50] | July 9, 1978 | Rosetta | 2007 | Secondary target; changed for better trajectory [45] |
2703 Rodari | 9 [51] | March 29, 1979 | Rosetta | 2007 | Target in early mission planning,[ when? ] but not chosen [45] |
3352 McAuliffe | 2–5 | February 6, 1981 | Deep Space 1 | 1998 | Target changed due to launch postponement |
3840 Mimistrobell | 5.2 [52] | October 9, 1980 | Rosetta | 2007 | Target changed [45] |
4015 Wilson–Harrington | 4 | November 19, 1949 | NEAR | 1998 | Target changed before launch [39] |
4015 Wilson–Harrington | 4 | November 19, 1949 | Deep Space 1 | 2001 | Secondary target; abandoned due to instrument failure [53] |
4660 Nereus | ~1 | February 28, 1982 | NEAR | 1997 | Target changed before launch [39] |
4660 Nereus | ~1 | February 28, 1982 | Hayabusa | 2002 | Target changed due to launch postponement |
4979 Otawara | 5.5 | August 2, 1949 | Rosetta | 2007 | Target changed due to launch postponement [45] |
(5604) 1992 FE | 0.6 | March 26, 1992 | OSIRIS-REx | 2018 | Secondary target abandoned in 2010 during early mission planning[ citation needed ] |
(10302) 1989 ML | 0.6 | June 29, 1989 | Hayabusa | 2002 | Target changed due to launch postponement |
(163249) 2002 GT | 0.35-0.5 | April 3, 2002 | EPOXI ( Deep Impact ) | 2020 | Communications with spacecraft lost |
(172034) 2001 WR1 | 0.66 | November 17, 2001 | Hayabusa2 | 2023 | Target proposed for extended mission but not selected. [54] |
(185851) 2000 DP107 | ~0.8 | February 29, 2000 | PROCYON | 2016 | Ion engine failure in heliocentric orbit [55] |
1991 VG | 0.005-0.012 | November 6, 1991 | NEA Scout | 2022 | Target changed due to launch postponement [56] |
2001 AV43 | 0.03 | January 5, 2001 | Hayabusa2 | 2029 | Target proposed but not selected [57] |
2020 GE | 0.018 | 2020 | NEA Scout | 2023 | Communications with spacecraft lost |
Name | Diameter (km) | Date of discovery | Spacecraft | Year | Notes |
---|---|---|---|---|---|
1 Ceres | 939 | January 1, 1801 | Ceres Polar Lander | [58] | |
1 Ceres | 939 | January 1, 1801 | Calathus | [59] | |
2 Pallas | 512 | March 28, 1802 | Athena | 2024 | |
4 Vesta | 525 | March 29, 1807 | AGORA | 1990-1994 | |
4 Vesta | 525 | March 29, 1807 | MAOSEP | 1990s | |
4 Vesta | 525 | March 29, 1807 | Vesta | 1994 | |
46P/Wirtanen | 1.2 | January 17, 1948 | Comet Hopper | 2022 | [60] |
67P/Churyumov–Gerasimenko | 4.1×3.3×1.8 | September 20, 1969 | CAESAR | 2024 | [61] |
67P/Churyumov–Gerasimenko | 4.1×3.3×1.8 | September 20, 1969 | CONDOR | 2024 | Proposed comet sample-return mission. [62] |
88P/Howell | 4.4 | 1981 | CORSAIR | 2024 | Proposed comet sample-return mission. [63] |
433 Eros | 34 × 11 × 11 | 1898 | Clementine 2 | 1996 | |
449 Hamburga | 86 | October 31, 1899 | CRAF | 1998 | |
4015 Wilson–Harrington | 4 | November 19, 1949 | Marco Polo / Hayabusa Mk2 | 2022 | |
4179 Toutatis | 2.45 | 1934 | Clementine 2 | 1996 | |
4660 Nereus | ~1 | February 28, 1982 | NEAP | 1997 | |
7968 Elst–Pizarro or 133P/Elst–Pizarro | ~0.6 | July 24, 1979 | Castalia | 2028 | [64] |
25143 Itokawa | 0.5 × 0.3 × 0.2 | 1998 | Asteroid Redirect Mission | 2021 | [65] |
(35107) 1991 VH | 1.04 | November 9, 1991 | Janus | 2026 | Launch delayed, target not available [66] |
47171 Lempo | 0.272 | October 1, 1999 | New Horizons 2 | [67] | |
(55637) 2002 UX25 | ~0.69 | October 30, 2002 | New Horizons 2 | [68] | |
(65679) 1989 UQ | Marco Polo | 2018-2020 | |||
66652 Borasisi | ~0.1 | September 8, 1999 | New Horizons 2 | [69] | |
99942 Apophis | 0.37 | June 19, 2004 | Don Quijote | 2015 | [70] |
101955 Bennu | 0.490 | 1999 | Asteroid Redirect Mission | 2021 | [65] |
101955 Bennu | 0.490 | 1999 | HAMMER | [71] | |
134340 Pluto | 2376 | February 18, 1930 | Pluto Kuiper Express | 2004 | [72] |
162173 Ryugu | 0.9 | May 10, 1999 | Marco Polo | 2018-2020 | |
162173 Ryugu | 0.9 | May 10, 1999 | Asteroid Redirect Mission | 2021 | [73] |
(162998) 2001 SK162 | Marco Polo | 2018-2020 | |||
(175706) 1996 FG3 | 1.69 | March 24, 1996 | Janus | 2026 | Launch delayed, target not available [66] |
(175706) 1996 FG3 | 1.7 | March 24, 1996 | Marco Polo | 2018-2020 | |
(341843) 2008 EV5 | 0.4 | March 4, 2008 | Marco Polo | 2018-2020 | |
(341843) 2008 EV5 | 0.4 | March 4, 2008 | Asteroid Redirect Mission | 2021 | [65] |
(612267) 2001 SG286 | Marco Polo | 2018-2020 | |||
(612600) 2003 SM84 | 0.086-0.16 | September 20, 2003 | Don Quijote | 2015 | [70] |
An asteroid is a minor planet—an object that is neither a true planet nor a comet—that orbits within the inner Solar System. They are rocky, metallic, or icy bodies with no atmosphere. The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres, a dwarf planet almost 1000 km in diameter.
A near-Earth object (NEO) is any small Solar System body with an orbit around the Sun that can bring it near the Earth. By astronomical convention, a small natural Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). This definition applies to the object's orbit, rather than its current position, thus an object is considered a NEO even if it is far from making a close approach of Earth. If a NEO's orbit crosses the Earth's orbit, and the object is larger than 140 meters (460 ft) across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but about 0.35% are comets.
A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby which makes use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense.
Rosetta was a space probe built by the European Space Agency launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a detailed study of comet 67P/Churyumov–Gerasimenko (67P). During its journey to the comet, the spacecraft performed flybys of Earth, Mars, and the asteroids 21 Lutetia and 2867 Šteins. It was launched as the third cornerstone mission of the ESA's Horizon 2000 programme, after SOHO / Cluster and XMM-Newton.
The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level than missions from NASA's New Frontiers or Flagship Programs. As a result, Discovery missions tend to be more focused on a specific scientific goal rather than serving a general purpose.
2867 Šteins is an irregular, diamond-shaped background asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 4 November 1969 by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij on the Crimean peninsula. In September 2008, ESA's spacecraft Rosetta flew by Šteins, making it one of few minor planets ever visited by a spacecraft. The bright E-type asteroid features 23 named craters and has a rotation period of 6.05 hours. It was named for Soviet Latvian astronomer Kārlis Šteins.
A sample-return mission is a spacecraft mission to collect and return samples from an extraterrestrial location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as loose material and rocks. These samples may be obtained in a number of ways, such as soil and rock excavation or a collector array used for capturing particles of solar wind or cometary debris. Nonetheless, concerns have been raised that the return of such samples to planet Earth may endanger Earth itself.
The New Frontiers program is a series of space exploration missions being conducted by NASA with the purpose of furthering the understanding of the Solar System. The program selects medium-class missions which can provide high science returns.
Hayabusa2 is an asteroid sample-return mission operated by the Japanese state space agency JAXA. It is a successor to the Hayabusa mission, which returned asteroid samples for the first time in June 2010. Hayabusa2 was launched on 3 December 2014 and rendezvoused in space with near-Earth asteroid 162173 Ryugu on 27 June 2018. It surveyed the asteroid for a year and a half and took samples. It left the asteroid in November 2019 and returned the samples to Earth on 5 December 2020 UTC. Its mission has now been extended through at least 2031, when it will rendezvous with the small, rapidly-rotating asteroid 1998 KY26.
Extraterrestrial material refers to natural objects now on Earth that originated in outer space. Such materials include cosmic dust and meteorites, as well as samples brought to Earth by sample return missions from the Moon, asteroids and comets, as well as solar wind particles.
65803 Didymos is a sub-kilometer asteroid and binary system that is classified as a potentially hazardous asteroid and near-Earth object of the Apollo group. The asteroid was discovered in 1996 by the Spacewatch survey at Kitt Peak, and its small 160-meter minor-planet moon, named Dimorphos, was discovered in 2003. Due to its binary nature, the asteroid was then named Didymos, the Greek word for 'twin'.
Discovery and exploration of the Solar System is observation, visitation, and increase in knowledge and understanding of Earth's "cosmic neighborhood". This includes the Sun, Earth and the Moon, the major planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, their satellites, as well as smaller bodies including comets, asteroids, and dust.
101955 Bennu (provisional designation 1999 RQ36) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table and has the highest cumulative rating on the Palermo Technical Impact Hazard Scale. It has a cumulative 1-in-1,750 chance of impacting Earth between 2178 and 2290 with the greatest risk being on 24 September 2182. It is named after Bennu, the ancient Egyptian mythological bird associated with the Sun, creation, and rebirth.
A Mars flyby is a movement of spacecraft passing in the vicinity of the planet Mars, but not entering orbit or landing on it. Uncrewed space probes have used this method to collect data on Mars, as opposed to orbiting or landing. A spacecraft designed for a flyby is also known as a "flyby bus" or "flyby spacecraft".
The Asteroid Impact and Deflection Assessment (AIDA) missions are a proposed pair of space probes which will study and demonstrate the kinetic effects of crashing an impactor spacecraft into an asteroid moon. The mission is intended to test and validate impact models of whether a spacecraft could successfully deflect an asteroid on a collision course with Earth.
A flyby is a spaceflight operation in which a spacecraft passes in proximity to another body, usually a target of its space exploration mission and/or a source of a gravity assist to impel it towards another target. Spacecraft which are specifically designed for this purpose are known as flyby spacecraft, although the term has also been used in regard to asteroid flybys of Earth for example. Important parameters are the time and distance of closest approach.
Double Asteroid Redirection Test (DART) was a NASA space mission aimed at testing a method of planetary defense against near-Earth objects (NEOs). It was designed to assess how much a spacecraft impact deflects an asteroid through its transfer of momentum when hitting the asteroid head-on. The selected target asteroid, Dimorphos, is a minor-planet moon of the asteroid Didymos; neither asteroid poses an impact threat to Earth, but their joint characteristics made them an ideal benchmarking target. Launched on 24 November 2021, the DART spacecraft successfully collided with Dimorphos on 26 September 2022 at 23:14 UTC about 11 million kilometers from Earth. The collision shortened Dimorphos' orbit by 32 minutes, greatly in excess of the pre-defined success threshold of 73 seconds. DART's success in deflecting Dimorphos was due to the momentum transfer associated with the recoil of the ejected debris, which was substantially larger than that caused by the impact itself.
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].
last obs (arc=493 days w/619 obs)