The average temperature of a high-altitude balloon gondola in the upper atmosphere is modeled as: Cr(t)=(T(t)-Tam-T(1)*+Q(t) + Qu where: R T(t)-Output average temperature (K) C-Thermal capacitance (J/K) R.Thermal resistance due to convection and conduction (K/W) R-Radiative thermal resistance(K/W) Q(t)= Input heat from on board heater (W) Qun Constant solar heat input (W) Tam Atmospheric Temperature (K) Find a linear time-invariant approximation of this system around the operating temperature, T=244 (K) and provide an expression for the nonlinear system's actual input, assuming that you have designed a controller based upon the approximated system.