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As the successor of OPS/JERS-1, ASTER was designed and developped in compliance with the essential performance requirements set forth by ASTER Science Team. Its features are described as follows;
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high spatial and radiometric resolution, |
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broad spectral coverage (visible- through thermal-infrared), and |
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stereo capability for the same path. |
To allow such broad coverage as from visible through thermal infrared regions of spectrum, ASTER consists of three separate subsystems: VNIR, SWIR and TIR
The VNIR subsystem has a spatial resolution of 15m. Consisting of two telescopes - one that looks backward and the other looks nadir, it enables to produce pairs of stereo images with a base-to-height ratio of 0.6.
The SWIR subsystem has a spatial resolution of 30m and operates in six bands in the shortwave infrared (SWIR) portions of spectrum, while its forerunner, JERS-1/OPS, operated in four. Given this ability, it is expected to obtain finer data for rocks, minerals, plants, etc.
The TIR subsystem has a spatial resolution of 90m and five bands in the thermal infrared (TIR) spectral range; multiband operation from space is unprecedented. It is expected to derive land surface temperature and land surface emissivity with a precision that no previous scanners have reached.
ASTER has a viewing swath width of 60km, while an adjacent orbiting span /an orbital returning span of TERRA, the platform, is much wider: 172km. To bridge the gap and scan the whole earth' surface, tiltable telescopes are employed for ASTER - the pointing function. Espetially, the VNIR subsystem was designed to be pointable up to 24 degrees so that anywhere on the earth , in case of emergency, can be observed within 5 days.
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Table@ASTER System Design
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Spectral coverage |
0.53`11.65mm |
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Spatial resolution |
15m(Bands 1`3) 0.52 - 0.86mm
30m(Bands 4`9) 1.60 - 2.43mm
90m(Bands 10`14) 8.125 - 11.65mm |
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Radiometric resolution |
0.5% NEDr(Bands 1`3)
0.5`1.3% NEDr(Bands 4`9)
0.3K NEDT(Bands 10`14) |
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Absolute radiometric accuracy |
±4% |
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Absolute temperature accuracy |
3k(200`240 K)
2k(240`270 K)
1k(270`340 K)
2k(340`370 K) |
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Signal quantization levels |
8 bits(Bands 1`9)
12 bits(Bands 10`14) |
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Base-to-height ratio of stereo capability |
0.6(along-track) |
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Swath width |
60km |
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Total coverage in cross-track direction by pointing function |
232km |
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Mission life |
5 years |
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MTF at Nyquist frequency |
0.25(cross-track)
0.20(along-track) |
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Peak data rate |
89.2Mbps |
| Weight |
406kg |
| Peak power |
726W |
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