THEOS (satellite)

{{Short description|Thai satellite}}

{{Use American English|date=April 2021}}

{{Use dmy dates|date=April 2021}}

{{Infobox spaceflight

| name = THEOS

| names_list = Thaichote

| image =

| image_caption =

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| mission_type = Earth Observation

| operator = GISTDA

| Harvard_designation =

| COSPAR_ID = 2008-049A

| SATCAT = 33396

| website =

| mission_duration =

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| spacecraft =

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| spacecraft_bus =

| manufacturer = Astrium SAS

| launch_mass = {{convert|715|kg|abbr=on}}

| BOL_mass =

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| dimensions = 2.1x2.1x2.4 m (6.89x6.89x7.87 ft)

| power = 840 W

| launch_date = {{start date|2008|10|01|06|37|00|7=Z|df=yes}}

| launch_rocket = Dnepr

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| orbit_reference = Geocentric

| orbit_regime = Sun-synchronous, LEO

| orbit_longitude =

| orbit_slot =

| orbit_semimajor =

| orbit_eccentricity = ≈0

| orbit_periapsis = {{convert|825|km|mi|abbr=on|0}}

| orbit_apoapsis = {{convert|826|km|mi|abbr=on|0}}

| orbit_inclination = 98.78°

| orbit_period = 101.4 minutes

| orbit_RAAN =

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| orbit_mean_anomaly =

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| apsis = gee

| trans_band =

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| insignia =

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}}

THEOS, also known as Thaichote,{{cite web |url=http://www.gistda.or.th/gistda_n/en/index.php?option=com_content&view=article&catid=3:newsflash&id=240:thaichote |title=Thaichote, the first Thai earth observation satellite |author=GISTDA |publisher=GISTDA.or.th |access-date=2012-09-06}}{{cite web |url=http://nstda.or.th/news/8014-thaichote |script-title=th:"ดาวเทียมไทยโชต": นามพระราชทาน |author=NSTDA |publisher=NSTDA.or.th |date=2012-03-08 |access-date=2012-09-06 |language=th |archive-date=6 May 2012 |archive-url=https://web.archive.org/web/20120506072357/http://www.nstda.or.th/news/8014-thaichote |url-status=dead }} is an Earth observation mission of Thailand, developed at EADS Astrium SAS, Toulouse, France. In July 2004, EADS Astrium SAS signed a contract for delivery of THEOS with GISTDA (Geo-Informatics and Space Technology Development Agency) of Bangkok, Thailand. GISTDA is Thailand's leading national organization (i.e., space agency) in the field of space activities and applications. The Thai Ministry of Science and Technology funds the program.

THEOS was launched from Dombarovskiy at 06:37 UTC on 1 October 2008, by a Dnepr rocket.{{cite web|title=THEOS (Thailand Earth Observation System)|date=June 14, 2012|url=https://isstracker.pl/en/satelity/33396

|website=isstracker.pl|access-date=April 26, 2023}} The satellite was initially planned for a 2007 launch using the space vehicle Rokot of Eurockot Launch Services . The contract was however canceled when Eurockot faced a parts shortage.{{Cite news|url=https://www.space.com/5923-dnepr-rocket-launches-earth-watching-satellite-thailand.html|title=Dnepr Rocket Launches Earth-Watching Satellite for Thailand|work=Space.com|access-date=2018-02-02}}

On 24 March 2014, THEOS captured images showing some 300 objects in close proximity to the suspected crash site of Malaysia Airlines Flight MH370, in the Indian Ocean. The discovery was reported by GISTDA on 27 March 2014.{{cite web |url=https://www.nationthailand.com/detail/national/30230225 |title=Thaichote satellite detects debris |work=The Nation |date=2014-03-27}} The objects have not yet been identified as debris.