Unmanned spacecraft may have varying levels of autonomy from human input , they may be remote controlled , remote guided or even autonomous , meaning they have a pre-programmed list of operations , which they will execute , .
Otherwise instructed by the Earth .
Unmanned spacecraft may have varying levels of autonomy from human input , they may be remote controlled , remote guided or even autonomous , meaning they have a pre-programmed list of operations , which they will execute , unless otherwise instructed by the Earth .