A satellite is in elliptical orbit with a period of $8.00 \times 10^{4} \mathrm{~s}$ about a planet of mass $7.00 \times 10^{24} \mathrm{~kg} .$ At aphelion, at radius $4.5 \times 10^{7} \mathrm{~m},$ the satellite's angular speed is $7.158 \times 10^{-5} \mathrm{rad} / \mathrm{s} .$ What is its angular speed at perihelion?