ESA Document - Emits - ESA

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HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 184 of 422
As regards power, the OEM mode does not need closer study. Indeed, the link with a platform
providing the request power is assumed. This platform has not been designed in this study.
During all the propulsion modes (TMIM, MOAM and TEIM), the mechanical load of the solar
panels is too high. Therefore, the solar panels will be folded during these manoeuvres. For
covering all these modes and also for safety purposes, the power system shall be able to supply
the nominal required power for a duration of 6 hours without relying on the solar panels.
3.3.4.2.2 Power requirements
In this study, the power requirements have been computed module per module, unit per unit and
mode per mode.
Each unit power profile is defined by 3 values:
• a peak power
• a standby power
• a duty cycle value (duration of the peak power compared to the total duration)
For every mode, the peak and standby values have been added to obtain values at system level.
An equivalent duty cycle is also computed to keep the same level of energy (See Table 3-29).
Table 3-29 also shows the power consumption requested for the MEV and the ERC modules.
Table 3-29: Computation of power inputs
The equivalent power profiles obtained are not realistic for all points of view. The system peak
power (which consists of the sum of the individual unit peak power) is a worst case never
reached. It corresponds to the case in which all the equipment is simultaneously: that is
dishwasher, laundry, communications, thermal, heaters…
Better insight in the power profiles cannot be obtained at this stage of the study.