Hayabusa spacecraft

The only in situ chemical data for asteroids are from the NEAR Shoemaker spacecraft, which orbited 433 Eros in 2000-1, and from the Japanese Hayabusa spacecraft, which visited 25143 Itokawa in 2003. NEAR obtained numerous measurements of the surface composition using X-ray fluorescence and gamma-ray spectrometers, and Hayabusa carried an XRF. The magnesium/silicon and aluminum/siUcon ratios for both asteroids are consistent with the compositions of chondrites. However, sulfur is depleted in Eros relative to chondritic compositions, possibly due to devolatilization by impacts or small degrees of melting. 

Image of asteroid Itokawa, taken by the Hayabusa spacecraft. The dumbbell shape and abundant boulders suggest this asteroid is a rubble pile, an idea supported by the asteroid s bulk density of -1.95 g cm 3. Image courtesy of JAXA. 

X-ray spectrum of (a) asteroid Itokawa, and (b) a standard, measured by the Hayabusa spacecraft. Locations of the Ka lines for magnesium, aluminum, and silicon are also shown. Modified from Okada et al. (2006). 

Japan s Hayabusa. The Boeing Satellite Development Genter bills itself as the world s leading manufacturer of commercial communications satellites, a major supplier of spacecraft and equipment, and as the supplier for weather satellites for the United States and Japan. 

Sone Y et al (2007) Charge and discharge performance of over-discharged lithium-ion secondary battery - Lessons learned from the operation of the interplanetary spacecraft HAYABUSA. Electrochemistry 75 950-957... 

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