Robots

One page per robotic system: manipulators, rovers, landers with deployable sampling hardware, free-flyers, and rotorcraft. Each page records what the machine masses, how it moves, what powers it, how it is commanded, and what it achieved or failed to achieve in operation, with the measurement conditions attached to every number. Flown hardware, canceled flight builds and development prototypes are all covered, and each page states which of those the machine is.

The grouping is by operating environment rather than by mechanism or by agency, because the environment fixes the constraints the design answers to: gravity, thermal range, communication delay, surface mechanics and radiation. Destination values are settled once on the environments pages and cited from here. Where a system’s control approach or avionics is the subject rather than the vehicle, it is on the software and avionics pages.

The six groups

• Microgravity and orbital. The base a manipulator works from is not fixed: the ETS-VII arm masses about 140 kg on a 2550 kg spacecraft, so arm motion moves the base and the attitude controller’s response feeds back into the arm [1]. The second constraint is delay, 6 to 7 s round trip through the relay satellite on that mission [2]. The group covers manipulators on stations and on free-flying spacecraft, satellite servicers, debris removal demonstrators and intravehicular free-flyers: the Shuttle and station arm line from Canadarm through Canadarm2, Dextre, JEMRMS, the European Robotic Arm and CSSRMS; the servicing demonstrations ETS-VII, Orbital Express, RRM, OSAM-1 and the MEV vehicles; the capture demonstrators ELSA-d, ADRAS-J and ClearSpace-1; the humanoids Rollin’ Justin, FEDOR and Robonaut 2; and the free-flyers SPHERES, Astrobee, Int-Ball and CIMON.
• Lunar surface. The largest group, spanning the Soviet and Apollo record (the Lunokhod 1 and Lunokhod 2 rovers, the Luna sample return drills, the Surveyor scoop and the Apollo LRV), the Chinese and Indian surface missions (Yutu, Yutu-2, the Chang’e-5 and Chang’e-6 samplers, Pragyan), the current commercial-lander microrovers (MAPP, Iris, CubeRover, YAOKI, SORA-Q, LEV-1, Rashid, TENACIOUS, AstroAnt, Colmena, Micro-Nova, FLIP and FLEX), and the excavation, drilling and mobility development line (RASSOR, Scarab, ATHLETE, MoonRanger, CADRE, Asagumo, TRIDENT, LISTER, PlanetVac, SAMPLR, the Infrastructure Pilot Excavator, the Canadian Lunar Rover, the Lunar Vertex rover and VIPER). Survival across the lunar night, rather than driving, is what has historically bounded a mission: Lunokhod 1 was designed for three lunar days and operated eleven [3].
• Martian surface. Sojourner masses 10.6 kg, was planned for seven sols and returned data for 83 [4]. Ingenuity was designed for five test flights and completed 72 [5], spread from April 2021 to January 2024 [6]. The group holds the rover line Sojourner, Spirit, Opportunity, Curiosity, Perseverance, Zhurong and Rosalind Franklin; the lander arms and subsurface hardware of Viking, the Beagle 2 PAW, Phoenix and InSight, including the HP3 mole; and the rotorcraft Ingenuity with the canceled Sample Fetch Rover and recovery helicopters.
• Small bodies. Landers, hoppers and sampling mechanisms: Philae, MINERVA, the Hayabusa2 landers, the MMX rover IDEFIX and the touch-and-go sampler TAGSAM. Holding the lander down at contact is the recurring problem. Philae’s anchoring harpoons did not fire and its hold-down thruster gas tank did not open, so the lander bounced away from Agilkia on an almost two-hour hopping tour, and at the resting site the solar cells could not generate enough power to continue once the batteries were exhausted [7].
• Outer planets. Three entries: the Galileo Probe, Huygens, which reached the surface of Titan and was still moving in the seconds after first contact [8], and Dragonfly, a rotorcraft for the same body.
• Extreme environments. The Venera and VeGa landers are the only machines that have worked on the surface of Venus. Nine of the fourteen Soviet landers reached the surface and survived between 23 and 127 minutes before their electronics failed [9], which is the whole flight record of Venus surface operation.