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 H-IIA (H-2A) is an active expendable launch system operated by Mitsubishi Heavy Industries (MHI) for the Japan Aerospace Exploration Agency. These liquid fuel rockets have been used to launch satellites into geostationary orbit; lunar orbit ...

on February 4, 2002 from the

Tanegashima Space Center The (TNSC) is the largest rocket-launch complex in Japan with a total area of about 9.7 square kilometers. It is located on the southeast coast of Tanegashima, an island approximately south of Kyushu. It was established in 1969 when the ...

. After the launch, MDS-1 was renamed Tsubasa, meaning wings in

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

. Tsubasa was placed in a

geostationary transfer orbit A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellite, Satellites that are destined for geosynchronous orbit, geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into ...

(GTO). It ended its operational phase on 26 February 2003. A similar mission, MDS-2, was cancelled. The purpose of the mission was to test the performance of

commercial off-the-shelf Commercial off-the-shelf or commercially available off-the-shelf (COTS) products are packaged or canned (ready-made) hardware or software, which are adapted aftermarket to the needs of the purchasing organization, rather than the commissioning of ...

components, including solar batteries,

semiconductors A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...

and

computers A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs ...

. 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 A radiation dosimeter is a device that measures dose uptake of external ionizing radiation. It is worn by the person being monitored when used as a personal dosimeter, and is a record of the radiation dose received. Modern electronic personal dos ...

using radiation-sensitive

field effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs (JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs control ...

s, a

magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...

, and a device for tracking

heavy ions Heavy may refer to: Measures * Heavy (aeronautics), a term used by pilots and air traffic controllers to refer to aircraft capable of 300,000 lbs or more takeoff weight * Heavy, a characterization of objects with substantial weight * Heavy, ...

. During the mission, MDS-1 tracked the occurrence of

single event upset A single-event upset (SEU), also known as a single-event error (SEE), is a change of state caused by one single ionizing particle (ions, electrons, photons...) striking a sensitive node in a live micro-electronic device, such as in a microprocesso ...

s (SEU), finding the majority occurred while passing the inner belt during

solar maximum Solar maximum is the regular period of greatest solar activity during the Sun's 11-year solar cycle. During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows by about 0.07%. On average, the solar cycle takes ...

and were likely caused by high energy protons. The whole weight of the satellite was 480 kg.

References

Spacecraft launched in 2002 Satellites of Japan Technology demonstration satellites {{Japan-spacecraft-stub