On command from the control center the on Earth they change their speed and thus their orbit. They automatically swivel their solar panels toward the Sun and keep the antenna systems directed towards the Earth. They follow the selected space objects by their telescopes and other instruments. But typically, only different types of landers carrying out surface exploration of other planets and their moons, comets and asteroids are considered robots. Depending on whether the examined body has an atmosphere, liquid seas, strong or weak gravity, different types of landing maneuvers and motions on the body surface are used.
Historically, first robot to survey the lunar surface was the Soviet Lunokhod 1, launched in 1970 as part of the mission Luna 17. Teleoperation on the Moon’s surface is relatively easy with respect to the acceptable time delay of the control signal of approximately 2.5 seconds on its way there and back.
The first successful exploration of Mars surface was accomplished within the U.S. mission Sojourner in 1997. Well-known American Mars rovers Spirit, Opportunity (2004) and later Curiosity (2012) followed. To manage them one needs to address the long delay of the transmitted signal (6-45 minutes), loss of connection due to the rotation of Mars, changing of the seasons on Mars, possible sand storms etc. These complications accelerated technological advancements which enable the Mars rover to manage itself partially autonomously: the Earth control center sends only strategic instructions and the robot executes operational management commands by itself.
There were also robotic landings on Venus (Soviet expeditions Venera), Saturn’s moon Titan (Huygens lander launched within the Cassini mission) as well as some asteroids and comets (Philae released from the probe Rosetta). Various exotic missions are planned for the future – airships for Venus and Titan exploration, aerial reconnaissance of Mars, exploration of the water ocean concealed under an ice layer on Jupiter’s moon Europa and others. The robots can be also used for mineral extraction on asteroids or within missions aimed at preventing collisions of asteroids with the Earth.
Rover Curiosity on Mars (NASA)
