The International Space Station’s robotic powerhouse, Canadarm2, took centre stage this morning as it captured and installed Northrop Grumman’s Cygnus XL cargo ship, delivering over 11,000 pounds of critical science and supplies.
At 7.24 am EDT, on September 18, astronaut Jonny Kim (with Zena Cardman as backup) used Canadarm2 to grapple the Cygnus XL, then manoeuvred it into position for installation at the ISS’s Unity module.
The supply ship launched from Cape Canaveral on September 14, aboard a SpaceX Falcon 9. It will stay docked until March 2026, when it will depart carrying waste to burn up during re-entry.
The Canadarm2: robotics details and capabilities
The robotic operations were handled by Canadarm2 (officially the Space Station Remote Manipulator System, SSRMS), a key part of the ISS’s Mobile Servicing System.
Built by MacDonald, Dettwiler and Associates (now known as MDA Space) in Brampton, Ontario, it has been in service since 2001.
Here are its salient specifications and features:
- Length and mass: Approximately 17 meters long (57.7 feet) and weighing around 1,500-1,800 kg depending on configuration.
- Degrees of freedom: Seven jointed sections: three shoulder joints, one elbow joint, three wrist joints – gives the arm human-arm-like flexibility.
- End effectors: Identical “hands” at each end called Latching End Effectors (LEEs). They function both to grip payloads and to anchor the arm itself to designated fixtures (Power Data Grapple Fixtures, or PDGFs) on the station.
- Payload capability: Up to ~116,000 kg (around 256,000 lb) under certain conditions, depending on the gripping points and load geometry.
- Mobility / repositioning: Canadarm2 is “self‐relocatable” – it can move end‐over‐end, gripping at one end while freeing the other, walking along the exterior of the ISS via PDGFs. It also relies on the Mobile Base System (MBS) which rides along rails on the station’s truss structure. This gives it wide reach and flexibility.
- Modularity and maintenance: Designed to be serviced in orbit: joints and LEEs can be replaced via spacewalks or other robotic means; the arm has had end effectors swapped out in past maintenance missions.
Onboard investigations aboard Cygnus XL
While Canadarm2 made the dramatic capture and installation, Cygnus XL carries a suite of scientific experiments:
- Semiconductor crystal growth in microgravity, aimed at producing more reliable, high-performance electronics.
- Ultraviolet light experiments to disrupt microbial biofilms that can form in water systems, which have implications for both space habitats and Earth environments.
- Pharmaceutical crystallization work to explore how drug molecules crystallize in space, potentially leading to better medicines.
- Cryogenic fuel tank pressure management research, important for long-duration missions like Artemis, to minimise boil-off and improve fuel efficiency.
Why it matters for robotics and automation
Canadarm2 exemplifies robotics in extreme environments: high precision, modular design, remote operation, and longevity.
Its ability to handle large and delicate payloads (Cygnus XL in this case), to reposition itself flexibly, and to be serviced in orbit make it a model for future robotic systems – whether in orbit, on other planetary surfaces, or under harsh environmental conditions.
