Thursday, April 10, 2008

ASTER Satellite System: Sensor Characteristics

Launch Date 18 December 1999 at Vandenberg Air Force Base, California, USA
Equator Crossing 10:30 AM (north to south)
Orbit 705 km altitude, sun synchronous
Orbit Inclination 98.3 degrees from the equator
Orbit Period 98.88 minutes
Grounding Track Repeat Cycle 16 days
Resolution 15 to 90 meters

The ASTER instrument consists of three separate instrument subsystems:

VNIR (Visible Near Infrared), a backward looking telescope which is only used to acquire a stereo pair image

SWIR (ShortWave Infrared), a single fixed aspheric refracting telescope

TIR (Thermal Infrared)

ASTER high-resolution sensor is capable of producing stereoscopic (three-dimensional) images and detailed terrain height models. Other key features of ASTER are:

  • Multispectral thermal infrared data of high spatial resolution
  • Highest spatial resolution surface spectral reflectance, temperature, and emissivity data within the Terra instrument suite
  • Capability to schedule on-demand data acquisition requests

ASTER has 14 bands of information. For more information, please see the following table:

Instrument VNIR SWIR TIR
Bands 1-3 4-9 10-14
Spatial Resolution 15m 30m 90m
Swath Width 60km 60km 60km
Cross Track Pointing ± 318km (± 24 deg) ± 116km (± 8.55 deg) ± 116km (± 8.55 deg)
Quantisation (bits) 8 8 12


ASTER is one of the five state-of-the-art instrument sensor systems on-board Terra a satellite launched in December 1999. It was built by a consortium of Japanese government, industry, and research groups. ASTER monitors cloud cover, glaciers, land temperature, land use, natural disasters, sea ice, snow cover and vegetation patterns at a spatial resolution of 90 to 15 meters. The multispectral images obtained from this sensor have 14 different colors, which allow scientists to interpret wavelengths that cannot be seen by the human eye, such as near infrared, short wave infrared and thermal infrared.

ASTER is the only high spatial resolution instrument on Terra that is important for change detection, calibration and/or validation, and land surface studies. ASTER data is expected to contribute to a wide array of global change-related application areas, including vegetation and ecosystem dynamics, hazard monitoring, geology and soils, land surface climatology, hydrology, land cover change, and the generation of digital elevation models (DEMs). Satellite Imaging Corporation (SIC) is an official distributor for ASTER Imagery through USGS.