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.[1] Tsubasa was placed in a geostationary transfer orbit (GTO). It ended its operational phase on 26 February 2003.[2] A similar mission, MDS-2, was cancelled.[3]

The purpose of the mission was to test the performance of commercial off-the-shelf components, including solar batteries, semiconductors and computers.[1][2] 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,[4] a magnetometer, and a device for tracking heavy ions.[5] 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.[6] The whole weight of the satellite was 480 kg.[1]


  1. ^ a b c "MDS-1 – NSSDC Master Catalog". nssdc.gsfc.nasa.gov. NSSDC. Retrieved 7 January 2019. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ^ a b "JAXA | Mission Demonstration test Satellite-1 "TSUBASA" (MDS-1)". jaxa.jp. JAXA. Archived from the original on 29 May 2013. Retrieved 7 January 2019.
  3. ^ "MDS 2". space.skyrocket.de. Gunter's Space Page. Retrieved 7 January 2019.
  4. ^ Kimoto, Y.; Koshiishi, H.; Matsumoto, H.; Goka, T. (December 2003). "Total dose orbital data by dosimeter onboard tsubasa (mds-1) satellite". IEEE Transactions on Nuclear Science. 50 (6): 2301–2306. Bibcode:2003ITNS...50.2301K. doi:10.1109/TNS.2003.821399.
  5. ^ Koshiishi, H.; Matsumoto, H.; Kimoto, Y.; Liu, H.; Goka, T. (2002). "Space Environment Data Acquisition Equipment Board Mission Demonstration Test Satellite-1". COSPAR Colloqui Series. COSPAR Colloquia Series. 14: 369–371. doi:10.1016/S0964-2749(02)80184-6. ISBN 9780080441108.
  6. ^ Koshiishi, H.; Matsumoto, H.; Goka, T. (November 2008). "Single-event upset in geostationary transfer orbit during solar-activity maximum period measured by the Tsubasa satellite". Advances in Space Research. 42 (9): 1500–1503. Bibcode:2008AdSpR..42.1500K. doi:10.1016/j.asr.2007.11.026.