This invention relates to heat resistant sheathed insulated electrical conductors, and more particularly to a flexible heat resistant cable.
Satellites in space may include thrusters of various types. One type of monopropellant thruster is an electrothermal hydrazine engine. A basic requirement is to provide a high efficiency, long life monopropellant thruster. A decomposition chamber heater is required to maintain the temperature above 900.degree. F. If the temperature falls below 800.degree. F., the hydrazine would not decompose and the liquid would pass through the thruster undecomposed (i.e., chamber has flooded out). The heater itself is required to have a peak temperature of 2000.degree. F. The electrical leads adjacent to the heater comprise conductors, insulation, and a metal sheath which are heat resistant. A typical construction for the leads has been tungsten or platinum conductors, magnesia (MgO) insulation, and a sheath of columbiam or platinum. Among the problems experienced by electrothermal heaters was shorting of the heater because of damaged heater leads.