Preliminary design review document application of multi-foil insulation to the Brayton Isotope Power System and conceptual design of multi-foil insulation for the flight system (phase I)

The status of the effort to apply MULTI-FOIL thermal insulation in an effective manner to the Ground Development System (GDS) is reviewed. Heat loss measurements made on cylindrical and elbow heat sources using ''Tape'' and ''Conventional'' MULTI-FOIL indicate that the thermal losses are comparable on a per layer basis. However, use of the tape incurs a weight penalty, per layer, of about 20 percent. The effective thermal emissivity of the nickel layer/zirconia powder MULTI-FOIL is approximately 0.32. Parametric studies of GDS insulation losses (using a computer program developed for this purpose) indicate: (1) that the Heat Source Assembly (HSA) heat losses are a major fraction of the total and (2) that a significant reduction in heat loss is possible by optimizing the distribution of foil layers. A meltdown test of a miniature HSA configuration suggests that additional MULTI-FOIL layers can be safety added to the HSA insulation. Test data indicate that ''Electroformed'' MULTI-FOIL insulation assemblies (as a consequence of decreased edge loss and lower foil emissivity) are approximately four times as effective as either ''Conventional'' or ''Tape'' MULTI-FOIL packages on a weight basis. Preliminary GDS insulation design and planning have been completed