An uncrewed spacecraft. Although landers and rovers are most often identified with robots, all uncrewed spacecraft receiving commands from on-board computers and ground stations are robotic. Such vehicles are more suited than astronauts for lengthy travel to other planets and for repetitive measurements. Human beings can best handle tasks involving analytical decisions and quick adjustments, such as retrieving or repairing satellites.

Since the Challenger space shuttle disaster in 1986, NASA has launched as many robotic spacecraft as possible on expendable rockets rather than from space shuttles.

https://www-robotics.jpl.nasa.gov Presentation of the activities of the JPL robotics group. The site has information about missions and the ongoing development of robotic craft, as well as photographs and information about the ‘Mars Yard’—a simulated Mars surface designed to test rovers such as Sojourner.