Fundamental Technologies Galileo Spacecraft Pages

Mechanical System Overview (continued)

With the exception of the LM124, the EPD Radiation Analysis in Table 2 has been submitted to JPL. JPL will run a computer simulation to determine what the estimated radiation dose will be for the parts and points of interest (POIs) shown in Table 2.

TABLE 2. EPD RADIATION ANALYSIS

The preliminary radiation analysis for the experiment is shown in Table 3. This analysis was completed ten months ago. The dosages shown were calculated by a computer simulation. Some of the device locations have since changed.

TABLE 3. PRELIMINARY RADIATION ANALYSIS

Table 4 shows a summary of the radiation dosages that some of the parts in the instrument are capable of withstanding. If the dosage levels for the parts are exceeded in the JPL simulation, spot shielding will be installed.

TABLE 4. PARTS CAPABILITY SUMMARY

Dr. Studemann commented that the hybrids and the transistors in the voltage switching portion of the electronics are being tested. At least five of each type of part are being tested. Ted Mueller commented that only the discriminators for the LEMMS electronics have been investigated by JPL.

Our estimate of the EPD masses is shown in Table 5. The estimate shows the change in mass between the present estimate and the previous estimate. This is a summary of previously published numbers, rather than a comprehensive review of the instrument itself. The latest estimate shows an increase of 94 grams. The latest calculations for the protective cover show that it is heavier than expected, and the pottings and coatings increased in weight because of a different coating technique.

TABLE 5. EPD MASS ESTIMATE

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Updated 2/23/04, T. Hunt-Ward
tizby@ftecs.com