History of Asteroid in Timeline
Asteroids are rocky, metallic, or icy bodies that orbit the inner Solar System. Unlike planets, they lack an atmosphere and are smaller, with sizes ranging from less than a kilometer to almost 1000 km in diameter (Ceres). Classified as C-type, M-type, or S-type based on their composition, they differ from comets by the absence of a visible coma (tail) when heated by the Sun, although recent findings suggest a blurred line between these classifications.
1914: Asteroid Designation Variations
In 1914, a system using the year and a Greek letter to designate asteroids was tried but ultimately replaced.
1918: Kiyotsugu Hirayama Identifies Asteroid Families
Main belt families of asteroids were first recognized in 1918 by Kiyotsugu Hirayama and are often called Hirayama families in his honor.
1925: Chronological Numbering System for Asteroids
By 1925, a simple chronological numbering system was established for asteroids replacing previous systems.
1937: Near-Earth Asteroid Discoveries
The discovery of several near-Earth asteroids in the 1930s, including 69230 Hermes's close approach in 1937, raised concerns about potential Earth impacts.
1967: Project Icarus
Project Icarus, conceived in 1967, proposed a contingency plan involving nuclear warheads to deflect or destroy asteroid 1566 Icarus if it posed a threat to Earth.
1975: Asteroid Taxonomy System Developed
An asteroid taxonomic system based on color, albedo, and spectral shape was developed in 1975 by Chapman, Morrison, and Zellner. These properties are thought to correspond to the composition of the asteroid's surface material.
1977: Discovery of 2060 Chiron
In 1977, astronomers discovered 2060 Chiron, marking the first observation of a small body permanently residing beyond Jupiter. These objects are now categorized as centaurs.
1979: Discovery of Asteroid 7968 Elst–Pizarro
The asteroid 7968 Elst–Pizarro was discovered in 1979.
1984: Tholen Asteroid Classification Proposed
The Tholen classification, an asteroid taxonomy, was proposed in 1984 by David J. Tholen.
1990: Acfer 049 Meteorite Discovered
The Acfer 049 meteorite was discovered in Algeria in 1990.
1991: First Close-up Photograph of an Asteroid
In 1991, the asteroid 951 Gaspra was the first asteroid to be photographed in close-up, followed in 1993 by 243 Ida and its moon Dactyl, all of which were imaged by the Galileo probe en route to Jupiter.
1992: Discovery of 15760 Albion
The first object, 15760 Albion, to be discovered beyond Neptune's orbit (excluding Pluto), was observed in 1992. Following this discovery, many similar objects were observed and categorized as trans-Neptunian objects.
1993: 243 Ida and its moon Dactyl Imaged
The Galileo probe imaged 243 Ida and its moon Dactyl in 1993.
1994: Shoemaker-Levy 9 Impact
The observation of Comet Shoemaker-Levy 9 colliding with Jupiter in 1994 heightened concerns about the potential threat of asteroid impacts.
1996: 7968 Elst–Pizarro Found to Have a Tail
7968 Elst–Pizarro was found to have a tail in 1996 by Eric Elst and Guido Pizarro and given the cometary designation 133P/Elst-Pizarro.
1997: NEAR Shoemaker Photographs 253 Mathilde
NASA's NEAR Shoemaker spacecraft photographed the asteroid 253 Mathilde in 1997.
1998: Provisional Asteroid Designation Example
Provisional designations are given to asteroids upon their discovery to track their apparitions. An example of this is 1998 FJ74. Once the asteroid's orbit is confirmed, it receives a permanent catalogue number.
1999: Deep Space 1 Images 9969 Braille
The Deep Space 1 spacecraft imaged the asteroid 9969 Braille in 1999.
2001: NEAR Shoemaker Lands on 433 Eros
In 2001, NEAR Shoemaker landed on the asteroid 433 Eros, becoming the first spacecraft to successfully orbit and land on an asteroid.
2002: Provisional Asteroid Designation Example
Newly discovered asteroids receive a provisional designation, such as 2002 AT4. This system uses the year of discovery and an alphanumeric code to indicate the month and sequence of discovery.
2002: Stardust Images 5535 Annefrank
The Stardust spacecraft imaged the asteroid 5535 Annefrank in 2002.
2002: Discovery of Asteroid 2002 AA29 with Horseshoe Orbit
The asteroid 2002 AA29 was discovered in 2002 and is an example of an asteroid with a horseshoe orbit that is co-orbital with Earth.
2002: Small Main-Belt Asteroid Spectroscopic Survey Modifies Tholen Taxonomy
In 2002, the Small Main-Belt Asteroid Spectroscopic Survey resulted in a modified version of the Tholen taxonomy of asteroid classification.
November 2005: Hayabusa Studies 25143 Itokawa
From September to November 2005, the Japanese Hayabusa probe studied 25143 Itokawa in detail.
2006: Active Asteroids Classified
In 2006, astronomers David Jewitt and Henry Hsieh designated objects that have asteroid-like orbits but show comet-like visual characteristics as main-belt comets (MBCs).
2006: Introduction of "Small Solar System Body"
In 2006, the International Astronomical Union (IAU) introduced the term "Small Solar System Body" to encompass objects that are neither planets, dwarf planets, nor moons. This term includes asteroids, comets and other recently discovered celestial objects.
2006: Dwarf Planet Classification
In 2006, the International Astronomical Union (IAU) established the classification of "dwarf planet" for the largest minor planets, those massive enough to achieve hydrostatic equilibrium (become ellipsoidal under their own gravity). The largest object in the asteroid belt, Ceres, at approximately 975 km in diameter, was classified as a dwarf planet.
2007: Dawn Spacecraft Launched
In 2007, NASA launched the Dawn spacecraft, which orbited 4 Vesta for a year, and observed the dwarf planet Ceres for three years.
2008: Rosetta Images 2867 Šteins and 21 Lutetia
The Rosetta probe imaged asteroids 2867 Šteins and 21 Lutetia in 2008.
2009: Water Ice Confirmed on 24 Themis
In 2009, using NASA's Infrared Telescope Facility, scientists confirmed the presence of water ice on the surface of the asteroid 24 Themis. The surface appeared to be completely covered in ice. It may be that as the surface ice layer sublimates, it is replenished by a reservoir of ice under the surface. Organic compounds were also found on the surface.
June 2010: Hayabusa Returns Samples of 25143 Itokawa to Earth
On June 13, 2010, the Japanese spacecraft Hayabusa returned samples of the surface of asteroid 25143 Itokawa to Earth, the first asteroid sample-return mission.
August 2011: Study Suggests DNA and RNA Components May Have Formed in Space
In August 2011, a report based on NASA studies with meteorites suggested that DNA and RNA components (adenine, guanine and related organic molecules) may have been formed on asteroids and comets in outer space.
2011: Near-Earth Asteroid Discoveries
By 2011, a significant percentage of near-Earth asteroids larger than one kilometer had been discovered, indicating progress in identifying potential threats.
2012: Chang'e 2 Flies Within 3.2 km of 4179 Toutatis
China's lunar orbiter Chang'e 2 flew within 3.2 km of the asteroid 4179 Toutatis in 2012.
October 2013: Water Detected on an Extrasolar Asteroid
October 2013 marked the first time water was detected on an extrasolar body, specifically an asteroid orbiting the white dwarf GD 61.
2013: Congressional Testimony on Asteroid Threat
Expert testimony in the United States Congress in 2013 revealed that NASA would require a minimum of five years to prepare for an asteroid interception mission, emphasizing the need for proactive measures.
January 2014: Water Vapor Detected on Ceres
On January 2014, European Space Agency (ESA) scientists announced the detection of water vapor on Ceres, the largest object in the asteroid belt. The detection was made using the far-infrared abilities of the Herschel Space Observatory. The finding was unexpected as comets, not asteroids, are typically considered to "sprout jets and plumes".
2014: Hayabusa2 Launched
Hayabusa2, a probe launched by JAXA in 2014, orbited its target asteroid 162173 Ryugu for more than a year and took samples that were delivered to Earth in 2020. The spacecraft is now on an extended mission and expected to arrive at a new target in 2031.
2016: OSIRIS-REx Launched
NASA launched the OSIRIS-REx in 2016, a sample return mission to asteroid 101955 Bennu.
2017: Moons of Asteroid 3122 Florence
In 2017, radar imaging of asteroid 3122 Florence during its approach to Earth revealed that it has two moons measuring between 100-300 meters across.
2017: Observations of Hygiea's Shape
Observations conducted in 2017 and 2018 using the Very Large Telescope's SPHERE imager revealed that Hygiea, the largest carbonaceous asteroid, has a nearly spherical shape.
June 2018: U.S. Asteroid Preparedness Warning
In June 2018, the National Science and Technology Council issued a warning about the United States' lack of preparedness for asteroid impacts, prompting the development of a national preparedness plan.
October 2018: LINEAR Discoveries
By October 2018, the LINEAR system had significantly contributed to the discovery of numerous asteroids, highlighting the advancements in asteroid detection.
2018: Observations of Hygiea's Shape
Observations conducted in 2017 and 2018 using the Very Large Telescope's SPHERE imager revealed that Hygiea, the largest carbonaceous asteroid, has a nearly spherical shape.
November 2019: Sugar Molecules Detected in Meteorites
In November 2019, scientists announced the detection of sugar molecules, including ribose, in meteorites. This suggests that chemical processes on asteroids can produce some fundamentally essential bio-ingredients important to life, and supports the notion of an RNA world prior to a DNA-based origin of life on Earth, and possibly, as well, the notion of panspermia.
2019: Ultraporous Lithology in Acfer 049 Suggesting Primordial Ice
In 2019, Acfer 049 was shown to have an ultraporous lithology (UPL): porous texture that could be formed by removal of ice that filled these pores, this suggests that UPL "represent fossils of primordial ice".
2020: OSIRIS-REx Sample Collection
In 2020, NASA's OSIRIS-REx spacecraft successfully collected a sample from the asteroid Bennu.
2020: Hayabusa2 Delivers Samples of Ryugu to Earth
In 2020 Hayabusa2 delivered samples from the asteroid Ryugu to Earth.
October 2021: Asteroids with Moons
As of October 2021, there were 85 near-Earth asteroids with at least one moon, and three were observed to have two moons.
2021: Lucy Mission Launch
In 2021, NASA launched the Lucy spacecraft, tasked with studying a total of ten different asteroids. This mission included the study of both asteroid types: two from the main belt and eight Jupiter trojans.
2021: OSIRIS-REx Departs Bennu
In 2021, the probe departed the asteroid Bennu with a sample from its surface.
2021: DART Launch
In 2021, NASA launched the Double Asteroid Redirection Test (DART) mission to assess the feasibility of deflecting an asteroid on a collision course with Earth.
April 2022: Near-Earth Asteroids Data
As of April 2022, 28,772 near-Earth asteroids had been identified, with 878 being at least one kilometer in diameter.
April 2022: Minor Planet Center Data
By April 2022, the Minor Planet Center had data on over 1 million minor planets in both the inner and outer solar systems, with over half having enough data to be numbered and designated.
September 2022: DART Impact
In September 2022, NASA's DART spacecraft successfully crashed into Dimorphos, the moonlet of asteroid Didymos, to test asteroid deflection technology.
September 2022: Double Asteroid Redirection Test (DART)
In September 2022, as an experiment in planetary defense against near-Earth asteroids, the DART spacecraft successfully altered the trajectory of the asteroid Dimorphos by impacting it.
September 2023: OSIRIS-REx Delivers Samples from Bennu
In September 2023, OSIRIS-REx delivered samples of asteroid Bennu to Earth. The spacecraft continues its extended mission, designated OSIRIS-APEX, to explore near-Earth asteroid Apophis in 2029.
October 2023: Psyche Mission Launch
In October 2023, NASA launched the Psyche spacecraft with the mission objective of studying the metallic asteroid Psyche.
2029: OSIRIS-APEX to Explore Apophis
The spacecraft OSIRIS-APEX will explore the near-Earth asteroid Apophis in 2029.
2031: Hayabusa2 Expected to Arrive at New Target
Hayabusa2 is expected to arrive at a new target asteroid in 2031.