"In terms of propulsion energy requirements, a mission to a near-Earth asteroid compares favorably to alternative mining missions. An example of a potential target for an early asteroid mining expedition is 4660 Nereus, expected to be mainly enstatite. This body has a very low Δv compared to lifting materials from the surface of the Moon. However it would require a much longer round-trip to return the material. Multiple types of asteroids have been identified but the three main types would include the C-type, S-type, and M-type asteroids: A class of ""easily recoverable objects"" (EROs) was identified by a group of"
"its mission, Rosetta was crashed into the comet′s surface in 2016. Near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 19,000 known near-Earth asteroids (NEAs), over a"
"is still the fourth largest asteroid detected coming closer to the Earth than the Moon. Had this object hit Earth, it would probably have detonated high in the atmosphere. It might have produced a blast measured in hundreds of kilotons of TNT, but may not have produced any effect on the ground. It could also have been an Earth-grazing fireball if it had been much closer but not close enough to impact. On 17 March 2044 the asteroid will pass no closer than from the Earth. also has the distinction of having the lowest inclination of any known near-Earth asteroids."
"with an orbit similar to , for comparison, has an absolute magnitude of 16.28 and is notably larger. As a near-Earth object, often comes within ] of Earth. On 29 April 2014, it traveled to 0.0843 AU from Earth, about 33 times further than the Moon. Below is a list of close approaches until 2100 where travels closer than 0.1 AU to Earth. 2013 JX28 Despite being officially classified as a near-Earth object, has a MOID (minimum orbit intersection distance) with Earth of ~0.067 AU, making it highly unlikely to ever hit Earth. For comparison, the Moon orbits Earth at"
"from the Sun than Earth does at its closest, but due to the eccentricity of Earth's orbit, still remain entirely within it. The known pseudo-Atira asteroids are listed below: Atira asteroid Atira asteroids or Apohele asteroids, also known as Interior-Earth Objects (IEOs), are asteroids, whose orbits are entirely confined within Earth's orbit, that is, their orbit has an aphelion (farthest point from the Sun) smaller than Earth's perihelion (nearest point to the Sun), which is 0.983 astronomical units (AU). Atira asteroids are by far the smallest group of near-Earth objects, compared to the Aten, Apollo and Amor asteroids. The first"
"asteroid, which require an absolute magnitude of 22.0 or less. 2014 EC 2014 EC is a 10-meter sized, eccentric asteroid, classified as near-Earth object of the Apollo group that passed within of Earth in early March 2014. This was six times closer to the Earth than the Moon. It was first observed on 5 March 2014, by the Catalina Sky Survey at Mount Lemmon Observatory in Arizona, United States. As of 2017, it has not since been observed. has only been observed on two nights for a period of less than 48 hours, with a remaining orbital uncertainty of 4"
"other small objects have been found on an orbital path associated with Earth. Although these objects are in 1:1 orbital resonance, they are not Earth trojans, because they do not librate around a definite Sun–Earth Lagrangian point, either or . Earth has another noted companion, asteroid 3753 Cruithne. About 5 km across, it has a peculiar type of orbital resonance called an overlapping horseshoe, and is probably only a temporary liaison. , an asteroid discovered on 27 April 2016, is possibly the most stable quasi-satellite of Earth. Earth trojan An Earth trojan is an asteroid that orbits the Sun in"
"that it formed from the collision of a Mars-size protoplanet called Theia with the early Earth. This hypothesis explains (among other things) the Moon's relative lack of iron and volatile elements and the fact that its composition is nearly identical to that of Earth's crust. Earth has at least five co-orbital asteroids, including 3753 Cruithne and . A trojan asteroid companion, , is librating around the leading Lagrange triangular point, L4, in the Earth's orbit around the Sun. The tiny near-Earth asteroid makes close approaches to the Earth–Moon system roughly every twenty years. During these approaches, it can orbit Earth"
"Charlie Brown"", ""Spooky"", the ""Halloween Asteroid"", and the ""Skull Asteroid"" due to its human skull-like appearance following radio frequency images taken at Arecibo Observatory and closest approach coincidentally occurring on Halloween day. On 31 October 2015 the asteroid passed from the Moon and then passed from Earth. The last approach this close by an object with absolute magnitude brighter than 20 was on 3 July 2006 at 1.1 lunar distances. The next object this large known to pass this close to Earth is that will pass about 1 lunar distance from Earth on 7 August 2027. It is estimated that"
"These have been called, inaccurately but provocatively, ""second"", ""third"" or ""other"" moons of Earth. , an asteroid discovered on 27 April 2016, is possibly the most stable quasi-satellite of Earth. As it orbits the Sun, appears to circle around Earth as well. It is too distant to be a true satellite of Earth, but is the best and most stable example of a quasi-satellite, a type of near-Earth object. They appear to orbit a point other than Earth itself, such as the orbital path of the NEO asteroid 3753 Cruithne. Earth trojans, such as , are NEOs that orbit the"
"Near-Earth object A near-Earth object (NEO) is any small Solar System body whose orbit brings it to proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 19,000 known near-Earth asteroids (NEAs), over a hundred short-period near-Earth comets (NECs), and a number of solar-orbiting spacecraft"
"an Earth-crosser asteroid. Because of its relatively low inclination (7.34°), it is able to come close to each of these planets. Its orbit takes it within 0.021 AU of Mercury's orbit, 0.0368 AU of Venus's orbit, and 0.00989 AU of Earth's orbit. It makes frequent encounters with these inner planets. The last time it came close to Mercury, Venus and Earth was 2010, 1977, and November 12, 2004 respectively. The most recent close approach to Earth was on 11 December 2015 at about 4.2 million kilometers (2.6 million miles, 11 lunar distances). The next visit of the asteroid to Earth's"
"not make an Earth approach closer than the 2017 passage until December 14, 2093, when it will pass from Earth. 3200 Phaethon 3200 Phaethon ( , sometimes incorrectly spelled Phaeton), provisional designation , is an Apollo asteroid with an orbit that brings it closer to the Sun than any other named asteroid (though there are numerous unnamed asteroids with smaller perihelia, such as ). For this reason, it was named after the Greek myth of Phaëthon, son of the sun god Helios. It is in diameter and is the parent body of the Geminids meteor shower of mid-December. With an"
"On 2 March 2018, at 05:54 UT, this object passed Earth at a nominal distance of which corresponds to a distance of . The object also approached the Moon at a similar distance of the day before. It was the 18th known asteroid to flyby Earth within 1 lunar distance (LD) since the start of 2018 and 6th closest. Five days earlier, a similar object, , came within 175,000 miles (284,000 km). However, the two encounters were unrelated and neither of them represent any hazard to the Earth ""(also see )"". has a notably low minimum orbital intersection distance with"
"3200 Phaethon 3200 Phaethon ( , sometimes incorrectly spelled Phaeton), provisional designation , is an Apollo asteroid with an orbit that brings it closer to the Sun than any other named asteroid (though there are numerous unnamed asteroids with smaller perihelia, such as ). For this reason, it was named after the Greek myth of Phaëthon, son of the sun god Helios. It is in diameter and is the parent body of the Geminids meteor shower of mid-December. With an observation arc of 30+ years, it has a very well determined orbit. The 2017 Earth approach distance of about 10"
"of the Moon, but would not strike Earth. The object passed so close to Earth that its orbit was modified by Earth's gravity. 2009 VA 2009 VA is an asteroid that came within of Earth on November 6, 2009 making it the 3rd closest non-impacting approach of a cataloged asteroid. With a diameter of only , scientists think that even if it had been on a direct collision course with Earth, it would have likely burned up in the atmosphere. The space rock made its pass by Earth just fifteen hours after its discovery. The asteroid was first discovered by"
"orbit more than a century in advance, though there is no known impact risk within that timeframe. The asteroid has an ""Earth minimum orbital intersection distance"" of which translates into 1.6 LD. On 30 October 1937, ""Hermes"" passed from the Earth and on 26 April 1942, it passed from Earth. In retrospect it turned out that Hermes came even closer to the Earth in 1942 than in 1937, within 1.7 lunar distances, unobserved at the height of WWII. For decades, ""Hermes"" was known to have made the closest known approach of an asteroid to the Earth. Not until 1989 was"
"to the Earth was above the surface. It was captured by two all-sky cameras of the European Fireball Network, which for the first time enabled geometric calculations of the orbit of such a body. On March 18, 2004, LINEAR announced that a asteroid, 2004 FH, would pass the Earth that day at only , about one-tenth the distance to the Moon, and the closest miss ever noticed until then. They estimated that similar-sized asteroids come as close about every two years. On March 31, 2004, two weeks after 2004 FH, set a new record for closest recorded approach above the"
"period in orbit and at the surface. Asteroid belt The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid"
"the naked eye. On some rare occasions, a near-Earth asteroid may briefly become visible without technical aid; see 99942 Apophis. The mass of all the objects of the asteroid belt, lying between the orbits of Mars and Jupiter, is estimated to be about 2.8–, or about 4% of the mass of the Moon. Of this, Ceres comprises , a third of the total. Adding in the next three most massive objects, Vesta (9%), Pallas (7%), and Hygiea (3%), brings this figure up to 51%; whereas the three after that, 511 Davida (1.2%), 704 Interamnia (1.0%), and 52 Europa (0.9%), only"
"discovery observation at Johannesburg in 1950. ""Betulia"" is a near-Earth asteroid with an ""Earth minimum orbital intersection distance"" of , which corresponds to 53.2 lunar distances. As an Amor asteroid, and contrary to the Apollo and Aten asteroids, it approaches Earth's orbit from beyond but does not cross it. ""Betulia"" is also a Mars-crosser due to its eccentric orbit. In the Tholen classification, ""Betulia"" is an unusual C-type asteroid, as near-Earth objects are typically of stony rather than carbonaceous composition. Based on images taken by the Sloan Digital Sky Survey, the asteroid has also been characterized as a carbonaceous but"
"Asteroid 1566 Icarus, best known for its close approach to Earth and the Sun, has been the subject of multiple fictional works, such as: Asteroid 3 Juno is one of the largest belt asteroids, the second-most-massive stony S-type. Asteroid 2 Pallas is the third-largest belt asteroid. Asteroid 4 Vesta is the second largest of the asteroids. A common depiction of asteroids (and less often, of comets) in fiction is as a threat, whose impact on Earth could result with incalculable damage and loss of life. This scenario is based on such past events as the impact event responsible for the"
"close as of the Earth (on 19 February 1993) and as close as of Venus (on 15 October 1933, and 30 September 2077). For comparison, the distance to the Moon is about 0.0026 AU (384,400 km). Because the orbit was determined with only 5 days worth of observations, the orbit of has an uncertainty of 6 on a scale of 0 to 9, with 0 being the most certain, and 9 being the most uncertain. This uncertainty is common for small asteroids that are difficult to observe. 1993 DA was first observed on 17 February 1993, by the Spacewatch survey"
"2018 AH 2018 AH is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group, approximately in diameter. It was first observed on 4 January 2018, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on Mauna Loa and quickly followed-up by many other surveys, with precovery observations found from Pan-STARRS and PTF from the day previous. It is the largest known asteroid to pass so close to Earth () since in 1971, and until in 2028, although it was only discovered two days after its closest approach on 2 January 2018, at 04:25 UTC. The Tunguska asteroid was likely"
"atmosphere, passing Earth's surface only away (about one Earth radius or one-sixtieth of the distance to the Moon). Because it was very small (6 meters/20 feet), FU was detected only hours before its closest approach. If it had collided with Earth, it probably would have disintegrated harmlessly in the atmosphere. On February 4, 2011, an asteroid designated , estimated at in diameter, passed within of the Earth, setting a new record for closest approach without impact, which still stands . On November 8, 2011, asteroid , relatively large at about in diameter, passed within (0.85 lunar distances) of Earth. On"
"Asteroid belt The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets. The asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids: Ceres, Vesta, Pallas, and Hygiea. The total mass of the asteroid belt is approximately 4% that of the"
"Atira asteroid Atira asteroids or Apohele asteroids, also known as Interior-Earth Objects (IEOs), are asteroids, whose orbits are entirely confined within Earth's orbit, that is, their orbit has an aphelion (farthest point from the Sun) smaller than Earth's perihelion (nearest point to the Sun), which is 0.983 astronomical units (AU). Atira asteroids are by far the smallest group of near-Earth objects, compared to the Aten, Apollo and Amor asteroids. The first suspected Apohele was , and the first confirmed was 163693 Atira in 2003. There are 18 suspected Apoheles, of which 15 have well-known orbits, of which six have been"
"groups of near-Earth objects (NEOs) are the Apollo and Amor asteroids, which are both significantly larger than the Atens, while the Atira asteroids form the smallest NEO-group by far. The asteroid has an Earth minimum orbit intersection distance of which corresponds to 44.1 lunar distances. In the Tholen classification, ""Aten"" is a common S-type asteroid. In the SMASS taxonomy it is classified as an Sr-type, a subtype which transitions to the R-type asteroids. In the 1990s, Italian astronomer Stefano Mottola obtained a rotational lightcurve of ""Aten"" during the EUNEASO survey at La Silla, which was a European near-Earth object search"
"had their size directly measured. 2018 AH 2018 AH is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group, approximately in diameter. It was first observed on 4 January 2018, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on Mauna Loa and quickly followed-up by many other surveys, with precovery observations found from Pan-STARRS and PTF from the day previous. It is the largest known asteroid to pass so close to Earth () since in 1971, and until in 2028, although it was only discovered two days after its closest approach on 2 January 2018, at 04:25 UTC."
"at a distance of or 5.3 LD from Earth. 2017 TD6 On 19 October 2017, the asteroid transited Earth at a nominal distance of , which corresponds to 0.5 lunar distances (LD). On the following day it also passed near the Moon at . Peaking near a magnitude of 18, the object was too faint to be seen—except for the largest telescopes. As of 2018, has a poorly determined orbit with an uncertainty of 6 and a short observation arc of 8 days only. Due to its small size, the asteroid is likely to remain unobserved until its next, still"
"53 days with an uncertainty parameter of 6. There is a cumulative 1 in 360,000 chance that the asteroid could impact Earth sometime after 2070. 2002 MN 2002 MN is the provisional name given to a 73-meter Apollo near-Earth asteroid that on June 14, 2002 missed the Earth by only , about one third the distance to the Moon (0.3 LD). The close approach was second only to the Earth approach by the 10-meter asteroid 1994 XM1. 2002 MN was discovered on June 17, 2002 three days after closest approach. Its mass and relative velocity were in the same general"
"unnamed. 2017 VL2 is a Apollo asteroid, the largest subgroup of near-Earth objects. It orbits the Sun at a distance of 0.9–1.5 AU once every 16 months (498 days; semi-major axis of 1.23 AU). Its orbit has an eccentricity of 0.23 and an inclination of 12° with respect to the ecliptic. It is, however, not a Mars-crossing asteroid, as its aphelion of 1.51 AU is less than the orbit of the Red Planet at 1.666 AU. The object has a minimum orbital intersection distance with Earth of , which corresponds to 0.5 lunar distances. On 9 November 2017, it came"
"the cryogen ran out. There are therefore currently no active or planned thermal infrared sky surveys which are focused on discovering near-Earth objects. The minimum orbit intersection distance (MOID) between an asteroid and the Earth is the distance between the closest points of their orbits. This first check is a coarse measure that does not allow an impact prediction to be made, but is based solely on the orbit parameters and gives an initial measure of how close to Earth the asteroid could come. If the MOID is large then the two objects never come near each other. In this"