Unmanned spacecraft are
spacecraft without
people ("man") on board, used for
unmanned spaceflight. Unmanned spacecraft may have varying levels of autonomy from human input, they may be remote controlled, remote guided or even autonomous ("robotic"). Many habitable spacecraft also have varying levels of robotic features. For example, the space stations
Salyut 7 and
Mir, and the
ISS module
Zarya were capable of unmanned remote guided station-keeping, and docking maneuvers with both resupply craft and new modules. The most common unmanned spacecraft categories are
robotic spacecraft,
unmanned resupply spacecraft,
space probes and
space observatories. Not every unmanned spacecraft is a robotic spacecraft, for example a reflector ball is a non-robotic unmanned spacecraft.