Advanced Land Observation Satellite

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Advanced Land Observing Satellite (ALOS)
General information
Organization JAXA's Earth Observation Research and Application Center
Launch date 24 January 2006; 9 years ago (2006-01-24)
Launch site Tanegashima Space Center
Launch vehicle H-IIA rocket
Mission length 3–5 years
Mass 4000 kg
Type of orbit Low Earth orbit (inclination: 98.2 degrees)
Orbit height 697 km
Orbit period 98.74 minutes
Telescope style Earth observation satellite
PRISM Panchromatic Remote-sensing Instruments for Stereo Mapping, to measure precise land elevation
AVNIR-2 Advanced Visible and Near Infrared Radiometer type 2, which observes what covers land surfaces. 10-meter resolution at nadir
PALSAR Phased Array type L-band Synthetic Aperture Radar, which enables day-and-night and all-weather land observation

Advanced Land Observing Satellite (ALOS), also called Daichi, is a 4-ton Japanese satellite launched in 2006. After five years of service, the satellite lost power and ceased communication with Earth, but remains in orbit.


ALOS was launched from Tanegashima, Japan, on 24 January 2006 by a H-IIA rocket. The launch had been delayed three times by weather and sensor problems.


The satellite contained three sensors that were used for cartography and disaster monitoring of Asia and the Pacific. JAXA initially hoped to be able to launch the successor to ALOS during 2011, but this plan did not materialize.

In 2008, it was announced that the images generated by ALOS were too blurry to be of any use for map making. Only 52 of 4,300 images of Japan could be updated based on data from ALOS.[1][2] Nevertheless, ALOS was used to analyze several disaster sites.[3][4][5] Images of the devastated Japanese coast following the 2011 Tōhoku earthquake and tsunami were among the last major contributions from ALOS.[6][7]


Satellite orbital paths, as of October 2013.

In April 2011, the satellite was found to have switched itself into power-saving mode due to deterioration of its solar arrays.[6] Technicians could no longer confirm that any power was being generated. It was suggested that meteoroids may have struck ALOS, creating the anomaly which eventually led to its shutdown.[8]

On 12 May 2011, JAXA sent a command to the satellite to power down its batteries and declared it dead in orbit.[6][9]

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