View source for Advanced Land Observing Satellite

{{Short description|Japanese Earth observation satellite launched in 2006}}
{{Redirect|ALOS||Alos (disambiguation)}}
{{Use American English|date=May 2021}}
{{Use dmy dates|date=January 2021}}
{{Infobox spaceflight
| name               = Advanced Land Observing Satellite
| names_list         = Daichi<br/>ALOS
| image              = JAXA_advanced_land_observing_satelite.jpg
| image_caption      = ALOS model
| image_alt          = ALOS spacecraft model
| image_size         = 300px
| mission_type       = [[Earth observation satellite|Earth observation]]
| operator           = [[Japan Aerospace Exploration Agency]] ([[JAXA]])
| COSPAR_ID          = 2006-002A
| SATCAT             = 28931
| website            = https://global.jaxa.jp/projects/sat/alos/index.html
| mission_duration   = 5 years (planned);<br/>5 years, 3 months, 18 days (achieved)
| spacecraft         = ALOS
| spacecraft_type    = 
| spacecraft_bus     = 
| manufacturer       = [[NEC]]<br/>[[Toshiba]]<br/>[[Mitsubishi Electric]]
| launch_mass        = {{cvt|3810|kg}} <ref name="eoPortal">{{cite web|url=https://directory.eoportal.org/web/eoportal/satellite-missions/a/alos|title=ALOS (Advanced Land Observing Satellite) / Daichi |publisher=eoPortal.org|access-date=2 February 2015}}</ref>
| dry_mass           = 
| dimensions         = {{cvt|8.9|x|27.4|x|6.2|m}}
| power              = 7 [[Watt|kW]]
| launch_date        = 24 January 2006, 01:33 [[Coordinated Universal Time|UTC]]<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2006-002A|title=Display: ALOS 2006-002A |publisher=NASA|date=27 April 2021|access-date=9 May 2021}} {{PD-notice}}</ref>
| launch_rocket      = [[H-IIA]]-2022 (No. 8)
| launch_site        = [[Tanegashima Space Center]]
| launch_contractor  = [[Mitsubishi]]
| entered_service    = 
| disposal_type      = Decommissioned
| deactivated        = 12 May 2011, 10:50 UTC
| decay_date         = 
| orbit_reference    = [[Geocentric orbit]]<ref name="n2yo">{{cite web|url=http://www.n2yo.com/satellite/?s=28931|title=ALOS|publisher=N2YO|access-date=9 May 2021}}</ref>
| orbit_regime       = [[Sun-synchronous orbit]]
| orbit_periapsis    = {{cvt|694|km}}
| orbit_apoapsis     = {{cvt|696|km}}
| orbit_inclination  = 98.0°
| orbit_period       = 98.5 minutes
| apsis              = gee
| instruments        = '''PRISM''': Panchromatic Remote-sensing Instruments for Stereo Mapping, to measure precise land elevation<br/>'''AVNIR-2''': Advanced Visible and Near Infrared Radiometer type 2, which observes what covers land surfaces. 10-meter resolution at nadir<br/>'''[[PALSAR]]''': Phased Array type L-band Synthetic Aperture Radar, which enables day-and-night and all-weather land observation
| programme          = [[ALOS Series]]
| previous_mission   = 
| next_mission       = [[ALOS-2]]
}}

'''Advanced Land Observing Satellite''' ('''ALOS'''), also called '''Daichi''' (a Japanese word meaning "land"), was a 3810&nbsp;kg Japanese [[satellite]] launched in 2006. After five years of service, the satellite lost power and ceased communication with Earth, but remains in orbit.

== Launch ==
ALOS was launched from [[Tanegashima]], Japan, on 24 January 2006 by [[H-IIA]] No. 8. The launch had been delayed three times by weather and sensor problems.

== Mission ==
The satellite contained three sensors that were used for cartography and disaster monitoring of [[Asia]] and the [[Pacific Ocean]]. The Japan Aerospace Exploration Agency ([[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.<ref>{{cite web |title=Japanese satellite flops at map-making: official|url=http://afp.google.com/article/ALeqM5g5iq_BbE3WwyCvOmxfWDvfSJzXlg|date=8 January 2008|url-status=dead|archive-url=https://web.archive.org/web/20110520115235/http://afp.google.com/article/ALeqM5g5iq_BbE3WwyCvOmxfWDvfSJzXlg|archive-date=20 May 2011}}</ref><ref>{{cite web|title=Utilization of Data Acquired by "DAICHI" |url=http://www.jaxa.jp/press/2008/01/20080116_sac_daichi_e.pdf|date=16 January 2008}}</ref> Then, JAXA announced the problem was solved.<ref>{{cite web|title=陸域観測技術衛星「だいち」データの地図への利用に関する改善状況について|url=http://www.jaxa.jp/press/2008/04/20080409_sac_daichi_j.html|date=9 April 2008}}</ref>

ALOS was used to analyze several disaster sites.<ref>{{cite web|title=ALOS (Daichi) observes Landslide in Leyte Island, Philippines|url=http://www.eorc.jaxa.jp/en/earthview/2006/tp060302.html|date=2 March 2006 |publisher=Japan Aerospace Exploration Agency}}</ref><ref>{{cite web|title=Continuous monitoring of landslides area caused by Iwate–Miyagi Nairiku earthquake in 2008 using ALOS images |url=http://www.isprs.org/proceedings/xxxviii/part8/pdf/JTS32_20100307155923.pdf}}</ref><ref>{{cite web|title=Latin America Volcano Monitoring With ALOS|url=http://www.asf.alaska.edu/news_notes/6-1/latin-america-volcano-monitoring-alos|url-status=dead|archive-url=https://web.archive.org/web/20130728155910/http://www.asf.alaska.edu/news_notes/6-1/latin-america-volcano-monitoring-alos|archive-date=28 July 2013}}</ref> Images of the devastated Japanese coast following the [[2011 Tōhoku earthquake and tsunami]] were among the last major contributions from ALOS.<ref name=51211-jsddo/><ref name=coastguard>{{cite web|url=https://global.jaxa.jp/projects/sat/alos/topics.html |title=Advanced Land Observing Satellite "DAICHI" (ALOS) Topics:Last thank-you message to DAICHI from Japan Coast Guard|date=October 20, 2011|publisher=JAXA|access-date=January 31, 2023}}</ref>

== Decommissioning ==
[[File:ALOS Daichi orbits.png|thumb|upright=1.0|left|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.<ref name=51211-jsddo/> Technicians could no longer confirm that any power was being generated. It was suggested that [[meteoroid]]s may have struck ALOS, creating the anomaly which eventually led to its shutdown.<ref>Satellite Imaging Corporation, [http://www.satimagingcorp.com/satellite-sensors/other-satellite-sensors/alos/ ALOS Satellite Sensor (2.5m)] Accessed 15 September 2015</ref>

On 12 May 2011, JAXA sent a command to the satellite to power down its batteries and declared it dead in orbit.<ref name=51211-jsddo>{{cite web|title=Japanese Satellite Declared Dead in Orbit |date=12 May 2011|url=http://www.space.com/11653-japanese-satellite-declared-dead-daichi.html|publisher=SPACE.com|access-date=25 October 2013}}</ref><ref>{{cite web|title=DAICHI (ALOS) Operation Completion |url=http://www.jaxa.jp/press/2011/05/20110512_daichi_e.html|publisher=JAXA|access-date=25 October 2013|date=12 May 2011|archive-date=18 October 2012|archive-url=https://web.archive.org/web/20121018125703/http://www.jaxa.jp/press/2011/05/20110512_daichi_e.html|url-status=dead}}</ref>

== See also ==
{{Portal|Spaceflight}}

* [[2006 in spaceflight]]
* [[ADEOS I]], [[JERS-1]] (predecessor spacecraft)
* [[ALOS-2]]
* [[Japan Coast Guard]]<ref name=coastguard/>

== References ==
{{Reflist}}

== External links ==
* [https://www.isprs.org/proceedings/XXXV/congress/comm1/papers/57.pdf Paper on ALOS]

{{Japanese space program}}
{{Orbital launches in 2006}}

[[Category:Earth observation satellites of Japan]]
[[Category:JAXA]]
[[Category:Synthetic aperture radar satellites]]
[[Category:Japan Coast Guard]]
[[Category:2011 Tōhoku earthquake and tsunami]]
[[Category:Derelict satellites orbiting Earth]]
[[Category:Spacecraft launched by H-II rockets]]
[[Category:Spacecraft launched in 2006]]