Sphere, 0.30 m in radius, has a surface emissivity of 0.48 and is at a temperature of 600 K. The sphere is surrounded by a concentric spherical shell, of which the inner surface has a radius of 0.90m and an emissivity of 1.00. The temperature of the shell is 400 K. The net heat current radiated, including direction, in the space between the sphere and the shell, in kW, is closest to what value?