MDS-1

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{{Use dmy dates|date=November 2020}}

Mission Demonstration Satellite 1 (MDS-1) or Tsubasa (COSPAR 2002-003A, SATCAT 27367) was a Japanese technology test mission. It was launched by the second H-2A on February 4, 2002 from the Tanegashima Space Center. After the launch, MDS-1 was renamed Tsubasa, meaning wings in Japanese. Tsubasa was placed in a geostationary transfer orbit (GTO). It ended its operational phase on 26 February 2003. A similar mission, MDS-2, was cancelled.{{cite web|title=MDS 2|url=https://space.skyrocket.de/doc_sdat/mds-2.htm|website=space.skyrocket.de|publisher=Gunter's Space Page|access-date=7 January 2019}}

The purpose of the mission was to test the performance of commercial off-the-shelf components, including solar batteries, semiconductors and computers.{{cite web|title=MDS-1 – NSSDC Master Catalog|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2002-003A|website=nssdc.gsfc.nasa.gov|publisher=NSSDC|access-date=7 January 2019}} {{PD-notice}}{{cite web|title=JAXA {{!}} Mission Demonstration test Satellite-1 "TSUBASA" (MDS-1)|url=http://www.jaxa.jp/projects/sat/mds1/index_e.html|website=jaxa.jp|publisher=JAXA|access-date=7 January 2019|archive-date=29 May 2013|archive-url=https://web.archive.org/web/20130529000947/http://www.jaxa.jp/projects/sat/mds1/index_e.html|url-status=dead}} MDS-1 also carried instrumentation to observe how changes in the environment as the satellite passed through the Van Allen radiation belts affected the performance of each component. Among these instruments were a dosimeter using radiation-sensitive field effect transistors,{{cite journal|last1=Kimoto|first1=Y. |last2=Koshiishi|first2=H.|last3=Matsumoto|first3=H.|last4=Goka|first4=T.|title=Total dose orbital data by dosimeter onboard tsubasa (mds-1) satellite|journal=IEEE Transactions on Nuclear Science|date=December 2003|volume=50|issue=6|pages=2301–2306|doi=10.1109/TNS.2003.821399|bibcode=2003ITNS...50.2301K }} a magnetometer, and a device for tracking heavy ions.{{cite journal |last1=Koshiishi|first1=H.|last2=Matsumoto|first2=H.|last3=Kimoto|first3=Y.|last4=Liu|first4=H.|last5=Goka|first5=T.|title=Space Environment Data Acquisition Equipment Board Mission Demonstration Test Satellite-1|journal=COSPAR Colloqui Series|series=COSPAR Colloquia Series |date=2002|volume=14|pages=369–371|doi=10.1016/S0964-2749(02)80184-6|isbn=9780080441108 }} During the mission, MDS-1 tracked the occurrence of single event upsets (SEU), finding the majority occurred while passing the inner belt during solar maximum and were likely caused by high energy protons.{{cite journal|last1=Koshiishi|first1=H.|last2=Matsumoto |first2=H.|last3=Goka|first3=T.|title=Single-event upset in geostationary transfer orbit during solar-activity maximum period measured by the Tsubasa satellite|journal=Advances in Space Research|date=November 2008|volume=42|issue=9|pages=1500–1503|doi=10.1016/j.asr.2007.11.026|bibcode=2008AdSpR..42.1500K }} The whole weight of the satellite was 480 kg.