ESA Document - Emits - ESA

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HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 188 of 422
• One solar wing
• A Shunt Regulator Module
• Battery Charger and Discharger Regulators and the corresponding power control module
• A battery module
• A power distribution unit for delivering the regulated voltage bus to all the equipments
The solar wing is mounted with a solar-array driving mechanisms module.
The power system is designed to be able to be fully operational in case of failure of one of the
four power modules.
With advanced multi-junction cells, the solar panels need to be 5.07 m long. The mass of one
wing is estimated without margin to 205.4 kg (and without all mechanical parts that are counted
in the mechanisms subsystem). A battery module is estimated to 552 kg without margin. It
corresponds to the main part of the mass of the power subsystem. Such a PCDU module has a
mass of about 151.8 kg.
20% of margin is taken up by all the equipments since technical improvements are taken into
account for every module.
3.3.4.5 Options
Figure 3-45: Mass budget
As a backup option, the solar arrays have been also computed with the present multi-junction
(triple cells characteristics and also with the CIS thin film-cells.
Table 3-31 shows:
• The total area of four panels (baseline) and three panels (single case failure) of the arrays
• The mass of the solar arrays
• The length required for each panel
Area (m 2 )
4 panels 3 panels Mass (kg) Delta P (Wh) Nb wings Large (m)
Current AsGa TJ cells 444 333 958 0 3 7.40
Future AsGa TJ cells 304 228 610 0 3 5.07
Thin film CIS 608 456 273 0 3 10.13
Table 3-31: Solar arrays options budget