JPL's measured gravity and radius put a surface-grazing Deimos orbit near 14.2 km/h and local escape near 20.1 km/h, although Mars and the moon's irregular shape complicate real flight.
On Earth, orbit belongs to the realm of rockets. The International Space Station travels at roughly 28,000 kilometres per hour, and a projectile would need about 40,000 kilometres per hour near Earth… [+9503 chars]