Astronomy Picture of the Day Search Results for "Itokawa OR Hayabusa"

APOD: 2014 February 9 - The Missing Craters of Asteroid Itokawa
Explanation: Where are the craters on asteroid Itokawa? Missing -- unexpectedly. The Japanese robot probe Hayabusa approached the Earth-crossing asteroid in 2005 and returned pictures showing a surface unlike any other Solar System body yet photographed -- a surface possibly devoid of craters. The leading hypothesis for the lack of common circular indentations is that asteroid Itokawa is a rubble pile -- a bunch of rocks and ice chunks only loosely held together by a small amount of gravity. If so, craters might not form so easily -- or be filled in whenever the asteroid gets jiggled by a passing planet or struck by a massive meteor. Recent Earth-based observations of asteroid Itokawa have shown that one part of the interior even has a higher average interior density than the other part, another unexpected discovery. The Hayabusa mission returned soil samples from Itokawa which are also giving clues the ancient history of the unusual asteroid and our entire Solar System.

APOD: 2012 November 6 - Methone: Smooth Egg Moon of Saturn
Explanation: Why is this moon shaped like a smooth egg? The robotic Cassini spacecraft completed the first flyby ever of Saturn's small moon Methone in May and discovered that the moon has no obvious craters. Craters, usually caused by impacts, have been seen on every moon, asteroid, and comet nucleus ever imaged in detail -- until now. Even the Earth and Titan have craters. The smoothness and egg-like shape of the 3-kilometer diameter moon might be caused by Methone's surface being able to shift -- something that might occur were the moon coated by a deep pile of sub-visual rubble. If so, the most similar objects in our Solar System would include Saturn's moons Telesto, Pandora, Calypso, as well as asteroid Itokawa, all of which show sections that are unusually smooth. Methone is not entirely featureless, though, as some surface sections appear darker than others. Although flybys of Methone are difficult, interest in the nature and history of this unusual moon is sure to continue.

APOD: 2010 June 19 - Stereo Itokawa
Explanation: Get out your red/blue glasses and float next to asteroid Itokawa, a diminutive world of the solar system only half a kilometer across. Boulders strewn across its rough surface and the lack of craters indicate that this asteroid is a rubble pile, formed as smaller pieces collected and were kept together by gravity. The stereo view was constructed from images made by the Hayabusa spacecraft when it encountered the asteroid in 2005. After a long journey, the spacecraft re-entered the atmosphere on June 13 over Australia, successfully parachuting a capsule to Earth. Hayabusa's capsule could contain a small sample of material from rubble pile asteroid Itokawa.

APOD: 2007 April 22 - Smooth Sections on Asteroid Itokawa
Explanation: Why are parts of this asteroid's surface so smooth? No one is yet sure, but it may have to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock. The unusual asteroid has been visited recently by the Japanese spacecraft Hayabusa that has been documenting its unusual structure and mysterious lack of craters. Recent analyses of the border regions between smooth and rugged sections of Itokawa indicate that jostling of the asteroid might be creating segregation between large and small rocks near the surface, like the Brazil nut effect. In late 2005, Hayabusa actually touched down on one of the smooth patches, dubbed the MUSES Sea, and collected soil samples that are to be returned to Earth for analysis. Hayabusa will start its three-year long return trip to Earth this month. Computer simulations show that 500-meter asteroid Itokawa may impact the Earth within the next few million years.

APOD: 2005 December 28- Smooth Sections on Asteroid Itokawa
Explanation: Why are parts of this asteroid's surface so smooth? No one is yet sure, but it may have to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock. The unusual asteroid is currently being visited by the Japanese spacecraft Hayabusa that is documenting its unusual structure and mysterious lack of craters. Last month, Hayabusa actually touched down on one of the smooth patches, dubbed the MUSES Sea, and collected soil samples that will eventually be returned to Earth for analysis. Unfortunately, the robot Hayabusa craft has been experiencing communications problems and so its departure for Earth has been delayed until 2007. Computer simulations show that 500-meter asteroid Itokawa may impact the Earth within the next few million years.

APOD: 2005 November 21 - The Missing Craters of Asteroid Itokawa
Explanation: Where are the craters on asteroid Itokawa? No one knows. The Japanese robot probe Hayabusa recently approached the Earth-crossing asteroid and is returning pictures showing a surface unlike any other Solar System body yet photographed -- a surface possibly devoid of craters. One possibility for the lack of common circular indentations is that asteroid Itokawa is a rubble pile -- a bunch of rocks and ice chunks only loosely held together by a small amount of gravity. If so, craters might be filled in whenever the asteroid gets jiggled by a passing planet -- Earth in this case. Alternatively, surface particles may become electrically charged by the Sun, levitate in the microgravity field, and move to fill in craters. Over the weekend, Hayabusa lowered itself to the surface of the strange asteroid in an effort to study the unusual body and collect surface samples that could be returned to Earth in 2007.

APOD: 2005 November 16 - A Robots Shadow on Asteroid Itokawa
Explanation: What's that unusual looking spot on asteroid Itokawa? It's the shadow of the robot spacecraft Hayabusa that took the image. Japan's Hayabusa mission arrived at the asteroid in early September and has been imaging and maneuvering around the floating space mountain ever since. The above picture was taken earlier this month. Asteroid Itokawa spans about 300 meters. One scientific goal of the Hayabusa mission is to determine out how much ice, rock and trace elements reside on the asteroid's surface, which should give indications about how asteroids and planets formed in the early Solar System. A can-sized robot MINERVA that was scheduled to hop around the asteroid's surface has not, so far, functioned as hoped. Later this month, Hayabusa is scheduled to descend to asteroid Itokawa and collect surface samples in a return capsule. In December, Hayabusa will fire its rockets toward Earth and drop the return capsule down to Earth's Australian outback in 2007 June.

APOD: 2005 September 19 - Approaching Asteroid Itokawa
Explanation: What are asteroids made of? To help find out, Japan's JAXA space agency launched the Hayabusa mission to rendezvous with asteroid Itokawa. Last week, the small robotic Hayabusa spacecraft arrived at asteroid Itokawa and stationed itself only 20 kilometers away. Although a long term goal is to find out how much ice, rock and trace elements reside on the asteroid's surface, a shorter term goal is to determine the mass of the asteroid by measuring the attraction of the drifting Hayabusa spacecraft. During the next few months, Hayabusa will also image and map asteroid Itokawa as it orbits the Sun. The above time-lapse image sequence was taken by Hayabusa upon final approach, showing the general oblong shape of the asteroid. In November, a small coffee-can sized robot dubbed MINERVA is scheduled for release and is expected to hop around the asteroid taking pictures. Also in November, Hayabusa will fire pellets into asteroid Itokawa and collect some of the debris in a return capsule. In December, Hayabusa will fire its rockets toward Earth and drop the return capsule to Earth in 2007 June.