The Japan Aerospace Exploration Agency (JAXA) has a rather interesting robot currently floating around the ISS. The JEM Internal Ball Camera, dubbed "Int-Ball," is a tiny, floating sphere which records footage of the activity aboard the ISS and sends it back to ground crews.
Roughly the size of a basketball, the 3D-printed Crew Interactive MObile CompanioN (CIMON), developed in partnership between Airbus and IBM, is another visitor aboard the ISS.
Rather than focusing on recording, however, CIMON is an assistant. The robot responds to vocal commands and is being tested for use by astronauts for displaying procedures and suggesting ways to proceed through tasks.
The University of Edinburgh's Valkyrie robot, constructed by NASA, is a research project worthy of note.
While not in space itself, the robot -- coming in at 125 kg and standing 1.8m tall -- is the focus of research in improving humanoid-style robotics for space exploration.
The Robonaut 2 is a dexterous humanoid robot built and designed at the NASA Johnson Space Center in Houston, Texas.
The robot includes a variety of vision systems, climbing systems, image recognition systems, sensor integrations, tendon hands, and control algorithms both new and old, and has taken root on board the ISS since 2012. Astronauts can use the robot for repetitive and dangerous tasks, such as changing air filters.
NASA's Robotic External Leak Locator (RELL) is a robot which "sniffs" out leaks in space equipment.
RELL is used by astronauts to detect potentially hazardous issues such as ammonia coolant loop leaks, and the robot can undertake spacewalks whenever required to perform similar checks in space.
Another highly useful robot for space installations is NASA's Robotic Refueling Mission (RRM) payload, which has paved the way for advances in satellite servicing.
Astronauts tasked with spacewalks understand the dangers, but there are simply some jobs which are better suited to robotics. RRM has tested tools, technologies, and techniques needed to robotically refuel and repair satellites in space that were not originally designed to be serviced.
Astrobee is a compact cube specifically designed for the ISS.
As astronauts are limited in how long they can spend in space and so time is at a premium, the cube can operate automatically or directly by Houston for routine chores, housekeeping, and monitoring duties.
No list would be complete without mentioning the Mars Rover. NASA's Rovers are currently exploring an area we are yet to reach ourselves -- the surface of Mars -- and are constantly providing footage which is proving invaluable to ground teams.
An honorable mention is Kirobo, designed by robotic engineer Tomotaka Takahashi. The robot was Japan's first robot entry upon the ISS.
The small, talkative robot provided entertainment for astronauts onboard the ISS and ended up returning to our planet following over a year in space.
RoboSimian, the ape-like robot developed at NASA's Jet Propulsion Laboratory, competed in a DARPA challenge in 2015.
While not specifically designed for space, RoboSimian has the potential to take on remote tasks in both exploration and disaster scenarios.