A space station orbits 350 km above the ground.

Near a planet, $g = \dfrac{GM}{R^2}$; at a distance $r$ from its centre, $g$ falls as $\dfrac{1}{r^2}$. On the Earth's surface $g = 9.8\ \text{m/s}^2$; at $n$ Earth radii above the ground it is $\dfrac{9.8}{(1 + n)^2}\ \text{m/s}^2$.

The law of gravitation: $F = \dfrac{Gm_1m_2}{r^2}$, with $G = 6.67 \times 10^{-11}\ \text{N m}^2/\text{kg}^2$ and $r$ the distance between the centres. The Earth: $M = 6.0 \times 10^{24}\ \text{kg}$, $R = 6.4 \times 10^{6}\ \text{m}$.