A satellite of mass m is put into a circular orbit at a height h from the surface of earth (mass $M_e$ and radius R_e). The velocity of satellite is

See fig.
 

The centripetal force on the satellite is given by
${\mathrm{F}}_{\mathrm{C}}=\frac{{\mathrm{mv}}_0^2}{\mathrm{r}}$
The gravitational force exerted by the earth on satellite is given by
$\begin{array}{l}{\mathrm{F}}_{\mathrm{G}}=\frac{{\mathrm{GM}}_{\mathrm{e}}\mathrm{m}}{{\mathrm{r}}^2}\\ \therefore \frac{{\mathrm{mv}}_0^2}{\mathrm{r}}=\frac{{\mathrm{GM}}_{\mathrm{e}}\mathrm{m}}{{\mathrm{r}}^2}\text{ or }{\mathrm{v}}_0^2=\frac{{\mathrm{GM}}_{\mathrm{e}}}{\mathrm{r}}\end{array}$
or ${\mathrm{v}}_0^2=\frac{{\mathrm{GM}}_{\mathrm{e}}}{{\mathrm{R}}_{\mathrm{e}}+\mathrm{h}}\text{ or }{\mathrm{v}}_0=\sqrt{\left(\frac{{\mathrm{GM}}_{\mathrm{e}}}{{\mathrm{R}}_{\mathrm{e}}+\mathrm{h}}\right)}$