Development Status of JERS-1 Mission Equipment. Initial Checkout of OPS, MDT and MDR

Abstract

Mission Data Transmitter (MDT) Fl system functions were checked out on March 3 and F2 system functions were checked out in the Optical Sensors (OPS) checkout. On March 18 images were transmitted in the two-wave transmission mode and operations were confirmed to be normal. In off-line evaluations, the effective isotropic radiated power (EFRP) was checked over the entire area visible in Japan and the values found to exceed the standards.
Mission Data Recorder (MDR) functions were checked out on March 2 and the recording and play back time satisfied the standards off-line evaluations were used to check the bit error rate and the values were comfortably below the standard error rate 10^-6.
For OPS, first the operating restrictions were checked. The cooler's cooldown time was 15 min-utes (within 20 minutes as the spec.) and the restart interval was 73 minutes (within 90 minutes as the spec.). The shortened prep time for Short Wave Infrared Rediometer (SWIR) photography will greatly increase the operational effectiveness. In optical calibration tests, the lamp optics were radiated at all bands and all pixels, and the sensitivity was checked.
Data collected in orbit and thermal vacuum test data were compared and matched well, indicating that system changes caused by the launch are minor enough to ignore. Quantitatively evaluated pixels in particular, matched to within 1 LSB. When it is considered that images were recorded/replayed with the MDR and sent to the earth by the MDT, both OPS sensitivity and transmission system performance were within normal prameters.
In electrical calibration tests for each item, results were analogous to those described above. In image tests, the following categories were evaluated for the images captured:
[1] existence of noise and blooming.
[2] differentiation of sea, land and clouds/appropriateness of output levels, and
[3] sensitivity evaluations.
Data was evaluated qualitatively and quantitatively for those items. Results showed that output for all bands and each type of subject was optained and output levels (sensitivity) were normal. Overall, the above results indicated that the OPS easily satisfied the development specifications and that characteristics and performance base-line data for input at ordinary operation stage were obtainable.