Table 1. ShadowCam system performance, with requirement where applicable

Parameter Performance: requirement
FOV 2.86
IFOV (nadir) 17.16 µrad: ≤ 20 µrad
Image scale at 100 km altitude 1.7 meter/pixel: ≤ 2 meter/pixel
Max. swath at 100 km altitude 5.2 × 144 km: ≥ 5 × 136 km
f/# 3.6
Focal length 699.275 ± 0.01 mm
Optical center location Sample 1558 (1545, 1572 95% bounds)
Primary mirror diameter 195 mm
Aperture 194.4 mm
MTF (Nyquist) 0.21: ≥ 0.2
Effective number of stages of TDI 32
Inverse gain Shallow 23 e/DN, deep 30 e/DN
Detector noise Shallow 62 e, deep 58 e
Maximum signal at flight gains Shallow 94,000 e, deep 123,000 e
SNR performance > 100 for radiance > 0.12 W/m2/sr/µm :
SNR requirement > 100 for optimal secondary lighting
Radiometric calibration coefficient Shallow 6,740, deep 4,940 (DN/ms)/ (W/m2/sr/µm)
Spatial response uniformity 1% : < 2%
Absolute radiometric uncertainty 6%
Active pixels 3,072
Maximum lines 84,992
Detector digitization 12 bit, encoded to 8 bit
Data link 30 Mbps
Voltage 28 ± 7 V DC
Peak power 9.3 W
Standby power 4.5 W
Mass 8.75 kg
Volume (length × diameter) 118 cm × 27 cm (including radiator)
FOV, field of view; IFOV, instantaneous field of view; MTF, modulation transfer function; TDI, time delay integration; SNR, signal to noise ratio.