Obtaining ASTER Data

(WIST) or from the Japanese ASTER is an on-demand instrument. This means that data is only acquired over a location if a request has been submitted to observe that area. Any data that ASTER has already acquired are available by searching and ordering those data from the Warehouse Inventory Search Tool system. Processing of Level 1A data to Level 1B is provided on demand through the LPDAAC WIST, and the Japanese ASTER Ground Data System. Higher level data products are also produced on demand; instructions for requesting these products can be found by following the links at the left. To request that ASTER acquire new data see instructions found at the link "New Acquisition". If you have scheduled an acquisition coincident with a field campaign, you can see if your acquisition has been scheduled by going to the "Acquisition Calendar".

ASTER Data

his section provides descriptions of the ASTER data products, information on how to obtain existing data, and guidance on how to request acquisitions of new data. Other links point you to additional tools for data browse, ordering and processing, developed outside of the EOSDIS framework. Here you will also find a link to the ASTER spectral library.

ASTER Level 1 data are archived and can be searched and ordered. Higher level, calibrated and derived products, are created on-demand for each user. Information is provided under "Obtaining Data" to help with the process.

ASTER Mission

ASTER is a cooperative effort between NASA and Japan's Ministry of Economy Trade and Industry (METI), with the collaboration of scientific and industry organizations in both countries. The ASTER instrument provides the next generation in remote sensing imaging capabilities compared with the older Landsat Thematic Mapper, and Japan's JERS-1 OPS scanner. ASTER captures high spatial resolution data in 14 bands, from the visible to the thermal infrared wavelengths; and provides stereo viewing capability for digital elevation model creation. As the "zoom lens" for Terra, ASTER data are used by other Terra and space-borne instruments for validation and calibration.

Above is an illustration of the Terra spacecraft with the ASTER instrument highlighted. The links to the left under "Mission" will tell you about EOS, science applications, the instrument, and the ASTER airborne simulator.

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

About ASTER

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.