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 orbi ...

on February 4, 2002 from the

Tanegashima Space Center The (TNSC) is Japan's primary spaceport, covering approximately about . It is located on the southeastern tip of Tanegashima, the easternmost of the Ōsumi Islands, approximately south of the major island of Kyushu. The site was selected on ...

. 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 In space mission design, a geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a highly elliptical type of geocentric orbit, usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit ...

(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 with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping levels ...

and

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

. MDS-1 also carried instrumentation to observe how changes in the environment as the satellite passed through the

Van Allen radiation belts The Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetosphere. Earth has two such belts, and sometimes others ma ...

affected the performance of each component. Among these instruments were a

dosimeter A radiation dosimeter is a device that measures the equivalent dose, 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 el ...

using radiation-sensitive

field effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the current through a semiconductor. It comes in two types: junction FET (JFET) and metal-oxide-semiconductor FET (MOSFET). FETs have three termi ...

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, ...

, and a device for tracking heavy ions. 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 (e.g. ions, electrons, photons) striking a sensitive node in a live micro-electronic device, such as in a microproce ...

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 take ...

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