Space


STSAT (Science and Technology Satellite)

The Korea Advanced Institute of Science and Technology Satellite Technology Research Center [SaTReC] was founded in 1989 as Korea's first research organization dedicated to education and research in satellite engineering, space science and remote sensing. It was selected in 1990 as an Engineering Research Center by the Korea Science and Engineering Foundation, which marked the beginning of space activities in Korea. SaTReC developed: Korea's first two satellites: KITSAT-1, KITSAT-2; Korea's first earth observation satellite: KITSAT-3 (13.5m Multi-spectral GSD); and Korea's first space science satellite: STSAT-1 (Other names: KITSAT-4 or KAISTSAT-4).

Science and Technology Satellite STSAT-1 was launched by Cosmos 3M on Sept. 27, 2003 with the main payload of Far Ultra-violet Imaging Spectrograph (FIMS). STSAT-1, the fourth satellite developed by Korea Advanced Institute of Science and Technology and the first under the Korean national scientific satellite program, was launched into a sun-synchronous orbit at 685 km altitude on September 27, 2003.

The mission of FIMS is to observe universe and aurora. A simple and reliable strategy was adopted in STSAT-1 to synchronize time between On-board Computer(OBC) and FIMS. For the characteristics of STSAT-1, this strategy is devised to maintain reliability of satellite system and to reduce implementation cost by using minimized electronic circuits. Far-ultraviolet IMaging Spectrograph would determine which of the highly contentious global models best describes the behavior of the hot, highly ionized interstellar medium in the Milky Way be creating the first-ever maps of the far-UV sky, including CIV and OVI emission. FIMS would therefore determine the impact of high-mass stars on the surrounding, star-forming ISM, known as "feedback". FIMS would also map superbubble emission, constraining hot gas breakout models, which also determine feedback effects.

While the primary objective of the STSAT-1 mission is to perform spectral sky survey of hot Galactic plasmas with Far Ultra-violet Imaging Spectrograph (FIMS, also known as SPEAR), a set of plasma instruments (Space Physics Package) on board the same spacecraft measures electrons of energies from below 1 eV to about 400 keV over the polar region to study the interaction of precipitating electrons with ambient plasmas. These instruments often operate simultaneously with FIMS which observes nightside auroras with the bandwidth 900 - 1175 A and 1335 - 1750 A, including important atomic oxygen lines and Lyman-Birge-Hopfield (LBH) emissions. The data of simultaneous observation of FIMS with SPP provide useful information on the precipitated electron energy associated with auroras.

FUV emission profiles of airglow and aurora were observed by Far-Ultraviolet Imaging Spectrograph (FIMS) on the Science and Technology SATellite-1 (STSAT-1). The observations which almost were performed in 2004 include the prominent atomic oxygen lines, atomic nitrogen lines and the N2 Lyman-Birge-Hopfield bands. The limb profile in dayside airglow compared with simulation results from Atmospheric Ultraviolet Radiance Integrated Code (AURIC). The spectrum of tropical nightglow was executed for examination about the effects of the energetic neutral particles.

Science Technology Satellite-2 (STSAT-2) has been developed since October 2002 as a sequel mission to KAISTSAT-4 (STSAT-1). STSAT-2 was scheduled to be launched into an ellipsoidal orbit of 300km x 1500 km in December 2005 by the first Korea Satellite Launch Vehicle KSLV-1 from the domestic space center (NARO Space Center).

The objectives of STSAT-2 consist of three missions, which are the domestic development of a low earth orbit 100kg satellite which will be launched by KSLV-1 (Korea Space Launch Vehicle-1), the development of advanced technology for small spacecraft, and the development and operation of world-class space science payloads. STSAT-2 have two payloads: the main payload, DREAM (Dual-channel Radiometer for Earth and Atmosphere Monitoring) and the secondary payload, LRA (Laser Retroreflector Array). The DREAM mission objectives are to acquire brightness temperature of the earth at 23.8 GHz and 37 GHz, and to acquire physical parameters such as cold liquid water and water vapor after post-processing. The mission objective of spacecraft techologies is to develop a thermally, mechanically, electrically stable and radial resistant spacecraft system having high-precision attitude determination and control capability in a high eccentric ellipsoidal orbit.

For spacecraft technology experiments, STSAT-2 has the following instrumentations onboard:

  • Pulsed Plasma Thruster (PPT)
  • Dual-Head Star Tracker (DHST)
  • Fine Digital Sun Sensor (FDSS)
  • Compact on-board computer
  • High-speed data transmission (10Mbps)

The Satellite Laser Ranging (SLR) mission objectives are to determine the more precise orbit of STSAT-2 than possible with S-band tracking data alone, to calibrate the main payload (DREAM), and finally to support the science research such as earth science and geodynamics. SLR technology will provide the unique opportunity to investigate the variations of an ellipsoidal orbit. Additionally, the precise orbit determination (POD) of STSAT-2 can be used to evaluate the performance of the first Korean launcher (KSLV-1).

Anticipated Launch Date: Two quarters (between April and June) of 2009 (STSAT-2A), December 2009 (STSAT-2B)

Expected Mission Duration: Two years




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