The battery chosen for the reference concept was proposed by SAFT, and a discussion of the reasons for selecting this battery are presented in the Appendix. The high rate battery selected is one that SAFT is currently qualifying for application on expendable launch vehicles, and it has the following characteristics, • Deliverable energy 8400-10400 Wb • Amperage 250 Ah • Voltage 30 V • Discharge rate 6-10 hours • Peak rate 2 kw (for a few minutes) • Dimensions 333 x 333 x 267 mm • Mass 38 kg SAFT estimates that the cost of one battery would be approximately 120 KAU. The Powersat demonstrator would also provide an opportunity for European space testing of lithium-based batteries which, because of safety concerns, have seen relatively limited use to date. Lithium batteries are baselined as a back-up power source for Hermes, for example. However, with the maiden flight not occurring until early next century, the Powersat could provide a relatively inexpensive opportunity to test these or similar batteries in space many years earlier. The Powersat demonstrator power conditioning subsystem suggested by ETC A is shown in Figure 5.1-14. ETC A has proposed that the technology and topology for this subsystem utilise components being developed within their present ESA Integrated Power System (IPS) contract. (See Appendix) ETCA considers the principal advantages of this approach to be,
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