25143 Itokawa
Encyclopedia
25143 Itokawa is an Apollo
and Mars-crosser asteroid
. It was the first asteroid to be the target of a sample return mission
, the Japanese space probe
Hayabusa
.
project and was given the provisional designation
. In August 2003, it was officially named after Hideo Itokawa
, a Japan
ese rocket scientist.
Itokawa is an S-type asteroid
. Radar
imaging by Goldstone in 2001 observed an ellipsoid 630 ± 60 m long and 250 ± 30 m wide.
The Hayabusa mission confirmed these findings and also suggested that Itokawa may be a contact binary
formed by two or more smaller asteroids that have gravitated toward each other and stuck together. The Hayabusa images show a surprising lack of impact crater
s and a very rough surface studded with boulders, described by the mission team as a 'rubble pile'. Furthermore, the density of the asteroid is too low for it to be made from solid rock.
This would mean that Itokawa is not a monolith
but rather a ‘rubble pile
’ formed from fragments that have cohered over time.
Shape from Goldstone
and Arecibo Radars
(Itokawa).
's Hayabusa
mission. The probe arrived in the vicinity of Itokawa on September 12, 2005 and initially "parked" in an asteroid–sun line at 20 km (12.4 mi), and later 7 km (4.3 mi), from the asteroid (Itokawa's gravity was too weak to provide an orbit, so the spacecraft adjusted its orbit around the sun until it matched the asteroid). Hayabusa landed on November 20 for thirty minutes, but failed to operate a device designed to collect soil samples. On November 25, a second landing and sampling sequence was attempted. The sample capsule was returned to Earth and landed at Woomera, South Australia
on June 13, 2010, around 13:51 UTC. On November 16, 2010, the Japan Aerospace Exploration Agency
reported that dust collected during Hayabusa's voyage was indeed from the asteroid.
were proposed by Hayabusa scientists and accepted by the Working Group for Planetary System Nomenclature of the International Astronomical Union
. Also, the Hayabusa science team is using working names for smaller surface features. The following tables list the names of geological features on the asteroid. No naming conventions have been disclosed for surface features on Itokawa.
Scientists used varied techniques of chemistry
and mineralogy
to analyze the dust from Itokawa. Itokawa's composition was found to match the common type of meteorites known as " low-total-iron, low metal ordinary chondrite
s". Another team of scientists determined that the dark iron color on the surface of Itokawa was the result of abrasion by micrometeoroid
s and high-speed particles from the sun which had converted the normally whitish iron oxide coloring.
Apollo asteroid
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, the first asteroid of this group to be discovered by Karl Wilhelm Reinmuth...
and Mars-crosser asteroid
Mars-crosser asteroid
A Mars-crosser is an asteroid whose orbit crosses that of Mars. The known numbered Mars-crossers are listed here. They include the two numbered Mars trojans 5261 Eureka and ....
. It was the first asteroid to be the target of a sample return mission
Sample return mission
A sample return mission is a spacecraft mission with the goal of returning tangible 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 dirt and rocks...
, the Japanese space probe
Space probe
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
Hayabusa
Hayabusa
was an unmanned spacecraft developed by the Japan Aerospace Exploration Agency to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis....
.
Discovery and naming
The asteroid was discovered in 1998 by the LINEARLinear
In mathematics, a linear map or function f is a function which satisfies the following two properties:* Additivity : f = f + f...
project and was given the provisional designation
Provisional designation in astronomy
Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calculated...
. In August 2003, it was officially named after Hideo Itokawa
Hideo Itokawa
was a pioneer of Japanese rocketry and of the Japanese space program. In Japan, he was popularly known as Dr. Rocket, and he has been described in the media as the father of Japanese space development....
, a Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese rocket scientist.
Description
S-type asteroid
S-type asteroids are of a stony composition, hence the name. Approximately 17% of asteroids are of this type, making it the second most common after the C-type.-Characteristics:...
. Radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
imaging by Goldstone in 2001 observed an ellipsoid 630 ± 60 m long and 250 ± 30 m wide.
The Hayabusa mission confirmed these findings and also suggested that Itokawa may be a contact binary
Contact binary (asteroid)
In the study of asteroids, a contact binary is caused when two asteroids gravitate toward each other until they touch, forming an oddly-shaped single body. Asteroids suspected of being contact binaries include the unusually elongated 624 Hektor and the bilobated 216 Kleopatra and 4769 Castalia...
formed by two or more smaller asteroids that have gravitated toward each other and stuck together. The Hayabusa images show a surprising lack of impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
s and a very rough surface studded with boulders, described by the mission team as a 'rubble pile'. Furthermore, the density of the asteroid is too low for it to be made from solid rock.
This would mean that Itokawa is not a monolith
Monolith
A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument...
but rather a ‘rubble pile
Rubble pile
In astronomy, rubble pile is the informal name for an object that is not a monolith, consisting instead of numerous pieces of rock that have coalesced under the influence of gravity...
’ formed from fragments that have cohered over time.
Shape from Goldstone
Goldstone Deep Space Communications Complex
The Goldstone Deep Space Communications Complex — commonly called the Goldstone Observatory — is located in California's Mojave Desert. Operated by ITT Corporation for the Jet Propulsion Laboratory, its main purpose is to track and communicate with space missions. It includes the Pioneer...
and Arecibo Radars
Arecibo Observatory
The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...
(Itokawa).
Exploration
In 2000, it was selected as the target of JapanJapan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
's Hayabusa
Hayabusa
was an unmanned spacecraft developed by the Japan Aerospace Exploration Agency to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis....
mission. The probe arrived in the vicinity of Itokawa on September 12, 2005 and initially "parked" in an asteroid–sun line at 20 km (12.4 mi), and later 7 km (4.3 mi), from the asteroid (Itokawa's gravity was too weak to provide an orbit, so the spacecraft adjusted its orbit around the sun until it matched the asteroid). Hayabusa landed on November 20 for thirty minutes, but failed to operate a device designed to collect soil samples. On November 25, a second landing and sampling sequence was attempted. The sample capsule was returned to Earth and landed at Woomera, South Australia
Woomera, South Australia
The town, or village, of Woomera is located in the south east corner of the Woomera Prohibited Area ; colloquially known as the Woomera Rocket Range...
on June 13, 2010, around 13:51 UTC. On November 16, 2010, the Japan Aerospace Exploration Agency
Japan Aerospace Exploration Agency
The , or JAXA, is Japan's national aerospace agency. Through the merger of three previously independent organizations, JAXA was formed on October 1, 2003, as an Independent Administrative Institution administered by the Ministry of Education, Culture, Sports, Science and Technology and the...
reported that dust collected during Hayabusa's voyage was indeed from the asteroid.
Surface features
Names of major surface featuresPlanetary nomenclature
Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. The task of assigning official names to features is taken up by the International...
were proposed by Hayabusa scientists and accepted by the Working Group for Planetary System Nomenclature of the International Astronomical Union
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
. Also, the Hayabusa science team is using working names for smaller surface features. The following tables list the names of geological features on the asteroid. No naming conventions have been disclosed for surface features on Itokawa.
Craters
| Crater | Named after |
|---|---|
| Catalina | Catalina Observatory which performs Catalina Sky Survey Catalina Sky Survey Catalina Sky Survey is a project to discover comets and asteroids, and to search for Near-Earth objects. More specifically, to search for potentially hazardous asteroids , that may pose a threat of impact.-Mission:... |
| Fuchinobe | Fuchinobe in Sagamihara Sagamihara, Kanagawa is a city located in north central Kanagawa Prefecture, bordering Tokyo, Japan. It is the third most populous city in the prefecture, after Yokohama and Kawasaki, and the fifth most populous suburb of Greater Tokyo. Its northern neighbor is Machida, with which a cross-prefectural merger has been... , Japan |
| Gando | Gando, Canary Islands Canary Islands The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union... |
| Hammaguira | Hammaguira French Special Weapons Test Centre, Hammaguir Hammaguir Hammaguir is a town in Algeria, south-west of Béchar. Between 1947 and 1967 there was a rocket launch site near Hammaguir, used by France for launching sounding rockets and the satellite carrier "Diamant" between 1965 and 1967.... |
| Kamisunagawa | Kamisunagawa, Hokkaidō Kamisunagawa, Hokkaido is a town located in Sorachi District, Sorachi Subprefecture, Hokkaidō, Japan.As of 2008, the town has an estimated population of 4,282 and a density of 117.49 persons per km². The total area is 39.91 km².- History :... |
| Kamoi | Kamoi, Yokohama Yokohama is the capital city of Kanagawa Prefecture and the second largest city in Japan by population after Tokyo and most populous municipality of Japan. It lies on Tokyo Bay, south of Tokyo, in the Kantō region of the main island of Honshu... |
| Komaba | Komaba in Meguro, Tokyo Meguro, Tokyo is one of the 23 special wards of Tokyo, Japan. It calls itself Meguro City in English.Meguro hosts fifteen foreign embassies and consulates. One of Tokyo's most exclusive residential neighborhoods is located in Meguro.... |
| Laurel | Laurel, Maryland Laurel, Maryland Laurel is a city in northern Prince George's County, Anne Arundel County, and Howard County, Maryland, United States, located midway between Washington, D.C. and Baltimore. Incorporated in 1870, the city maintains a historic district including its Main Street... |
| Miyabaru | Radar site of the Uchinoura Space Center Uchinoura Space Center The is a space launch facility close to the Japanese town of Kimotsuki, in Kagoshima Prefecture. Before the establishment of the JAXA space agency in 2003, it was simply called the . All Japan's scientific satellites were launched from Uchinoura prior to the M-V launch vehicles being decommissioned... in Japan. |
| San Marco | San Marco platform San Marco platform The Luigi Broglio Space Centre is an Italian-owned spaceport near Malindi, Kenya, named after its founder and Italian space pioneer Luigi Broglio. Developed in the 1960s through a partnership between the University of Rome La Sapienza's Aerospace Research Centre and NASA, the BSC served as a... , an old oil platform near Kenya that served as a launch pad for Italian spacecraft. |
Regiones
Regiones (geologically distinct areas) on Itokawa.| Regio | Named after |
|---|---|
| Arcoona Regio | Arcoona, Australia |
| LINEAR Regio | Lincoln Near-Earth Asteroid Research Lincoln Near-Earth Asteroid Research The Lincoln Near-Earth Asteroid Research project is a cooperative project between the United States Air Force, NASA, and MIT's Lincoln Laboratory for the systematic discovery and tracking of near-Earth asteroids. LINEAR was responsible for the majority of asteroid detections since 1998 until... |
| MUSES-C Regio | MUSES-C Hayabusa was an unmanned spacecraft developed by the Japan Aerospace Exploration Agency to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis.... , name of the Hayabusa Hayabusa was an unmanned spacecraft developed by the Japan Aerospace Exploration Agency to return a sample of material from a small near-Earth asteroid named 25143 Itokawa to Earth for further analysis.... probe prior to launch. |
| Ohsumi Regio | Ōsumi Peninsula Osumi Peninsula thumb|right|240px|Satellite image of Osumi PeninsulaThe projects south from the Japanese island of Kyūshū and includes the southernmost point on the island, Cape Sata. Its east coast lies on the Pacific Ocean, while to the west it faces the Satsuma Peninsula across Kagoshima Bay... |
| Sagamihara Regio | Sagamihara, a town in Japan Japan Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south... where Institute of Space and Astronautical Science Institute of Space and Astronautical Science is a Japanese national research organization of astrophysics using rockets, astronomical satellites and interplanetary probes. It is a division of Japan Aerospace Exploration Agency .- History :... is located. |
| Uchinoura Regio | Uchinoura Uchinoura, Kagoshima was a town located in Kimotsuki District, Kagoshima, Japan.On July 1, 2005 Uchinoura was merged with the town of Kōyama, also from Kimotsuki District, to form the new town of Kimotsuki.... , a town in Japan (now part of Kimotsuki Kimotsuki, Kagoshima is a town located in Kimotsuki District, Kagoshima, Japan.The town was formed on July 1, 2005 from the merger of the towns of Kōyama and Uchinoura, both from Kimotsuki District.... ), the location of Uchinoura Space Center Uchinoura Space Center The is a space launch facility close to the Japanese town of Kimotsuki, in Kagoshima Prefecture. Before the establishment of the JAXA space agency in 2003, it was simply called the . All Japan's scientific satellites were launched from Uchinoura prior to the M-V launch vehicles being decommissioned... , Hayabusa launch site. |
| Yoshinobu Regio | Launch site in the Tanegashima Space Center, Japan. |
Analysis of particles reported in August 2011
The August 26, 2011, issue of Science devoted six articles to findings based on dust that Hayabusa had collected from Itokawa. Scientists' analysis suggested that Itokawa was probably made up from interior fragments of a larger asteroid that broke apart. Dust collected from the asteroid surface was believed to have been exposed there for about eight million years.Scientists used varied techniques of chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
and mineralogy
Mineralogy
Mineralogy is the study of chemistry, crystal structure, and physical properties of minerals. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.-History:Early writing...
to analyze the dust from Itokawa. Itokawa's composition was found to match the common type of meteorites known as " low-total-iron, low metal ordinary chondrite
Chondrite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids...
s". Another team of scientists determined that the dark iron color on the surface of Itokawa was the result of abrasion by micrometeoroid
Micrometeoroid
A micrometeoroid is a tiny meteoroid; a small particle of rock in space, usually weighing less than a gram. A micrometeor or micrometeorite is such a particle that enters the Earth's atmosphere or falls to Earth.-Scientific interest:...
s and high-speed particles from the sun which had converted the normally whitish iron oxide coloring.
External links
- Close-up images of Itokawa, a rubble pile asteroid
- Hayabusa mission Video March 2007
- Gazetteer of Planetary Nomenclature
- MIT's LINEAR asteroid named for Japan's 'Dr. Rocket' (MIT press release)
- Latest news and images from Hayabusa (JAXA Hayabusa official page)
- Hayabusa's Scientific and Engineering Achievements during Proximity Operations around Itokawa (JAXA press release)
- Earth impact probability of the Asteroid (25143) Itokawa to be sampled by the spacecraft Hayabusa (paper abstract)
- Astronomy Picture Of The Day: Approaching Asteroid Itokawa, A Robot's Shadow on Asteroid Itokawa, The Missing Craters of Asteroid Itokawa, Smooth Sections on Asteroid Itokawa
- Special issue: Hayabusa at Itokawa, Science, Vol. 312, no. 5778, June 2, 2006
- Initial Scientific Results of Hayabusa’s Investigation on Itokawa ~Summary of the Special Issue of “Science”Magazine~ (ISAS/JAXA press release)
- Animated model of Itokawa rotating (in anaglyph form for use with red-blue glasses)
- Itokawa in enhanced color (From this presentation)
