Space Topics: Kaguya (SELENE)
The Year in Pictures: 2007
Kaguya: Earth Sets Below the South Pole
Credit: JAXA / NHK / animation by Emily Lakdawalla |
Japan's Kaguya spacecraft has inaugurated
a return to the Moon and the start of the International
Lunar Decade. In addition to its many science instruments, Kaguya carries
a high-definition television camera provided to the mission by the Japan Broadcasting
Corporation strictly for public communication purposes. This five-image Earthset
sequence is cropped from some of the first
HD movies returned from the
Moon.
Earthrises and Earthsets happen frequently for Kaguya because it is on
a polar orbit. The orientation of this orbit is such that it alternately passes
behind and in front of the Moon as seen from Earth, going from north to south
when it passes in front of the Moon, and rising from south to north on the
farside. To capture
this movie, the spacecraft was oriented so that the telephoto HD camera pointed
backward along the orbit, watching Earth appear to set below the lunar south
pole as the spacecraft traveled behind the Moon as seen from Earth. Because
the Moon is locked in synchronous rotation with Earth, such Earthsets and Earthrises
are not visible over most of the Moon; instead, as the Moon travels around
Earth in its monthlong elliptical orbit, Earth appears to oscillate around
a small area of the sky.
Kaguya is designed to perform
a detailed study of the lunar gravity field and is also returning the first
high-definition format movies from beyond Earth orbit. Kaguya's
launch in September
was closely followed by that of China's Chang’e-1 in
October. Next year, India plans to join other nations with Chandrayaan
1, and
the United States plans to launch the Lunar
Reconnaissance Orbiter.
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