Orbital velocity: v_o = sqrt(GM/r) = sqrt(gR^2/r) where r = R + h

For near-surface orbit: v_o = sqrt(gR) = 7.9 km/s Time period: T = 2pir/v_o = 2pisqrt(r^3/(GM))

Near-surface: T = 2pisqrt(R/g) = 2pisqrt(6.4x10^6/9.8) = 5075 s ≈ 84.6 min

Important relations:

• v_o decreases as orbital radius increases (outer orbits are slower)
• T increases as orbital radius increases (outer orbits take longer)
• v_e = sqrt(2) * v_o (at the same radius)