Canadarm2 was not designed to catch spacecraft at the ISS. Now it's about to grab its 50th

A Canadian robot arm on the International Space Station is days from a big milestone.

MDA Space's Canadarm2 will celebrate its 50th cosmic catch no earlier than Aug. 5, when a Northrop Grumman Cygnus cargo ship berths with the International Space Station (ISS) with thousands of pounds of experiments, supplies and food for the Expedition 71 astronauts, the Canadian Space Agency (CSA) announced today (Aug. 2).

Cygnus will launch to the ISS no earlier than 11:29 a.m. EDT (0329 GMT) on Aug. 3, and you can watch the mission here at Space.com, courtesy of NASA+, formerly NASA Television. If Cygnus launches on time, will be captured by Canadarm2 and will dock with the ISS on Aug. 5 at approximately 3:55 a.m. EDT (0755 GMT). Coverage will start at 2:30 a.m. EDT (0630 GMT) on NASA+.

Canadarm2, managed by MDA Space under CSA funding, was first launched to space April 19, 2001 on space shuttle mission STS-100. Mission astronaut Chris Hadfield performed the first-ever CSA spacewalks to install the arm, a milestone celebrated by playing the Canadian national anthem in space and jokingly referring to fellow spacewalker Scott Parazynski (of NASA) as "an honorary Canadian."

The arm's first spacecraft catch was on Sept. 17, 2009 when it captured Japan's HTV-1 ("HTV", a now-retired cargo spacecraft series, stood for H-II Transfer Vehicle). In the 15 years since, spacecraft berthing with Canadarm2 ranged from SpaceX's Cargo Dragon to Northrop Grumman's Cygnus.

Canadarm2 forms part of a series of Canadian robotic arms based on generations of telescoping tube technology seen in space examples ranging from extendable antennas to the Apollo program's lunar legs, according to "Canadarm and Collaboration" (Elizabeth Howell, ECW Press, 2020.) 

Canadarm was first flown in space Nov. 12, 1981 during shuttle mission STS-2 with Spar Aerospace and Canada's National Research Council (the government council that managed astronauts before the CSA was formed in 1989). Canadarm was used for spacewalking, several Hubble Space Telescope missions and some impromptu maneuvers such as knocking an ice plug off a frozen shuttle drain line, according to NASA.

Canadarm's success in space allowed the NRC, and then CSA, to pay for astronaut seats on the shuttle as the robot arm provided a net benefit to NASA activities in orbit. (The first Canadian astronaut, then with NRC, was Marc Garneau aboard STS-41G in October 1983.) That astronaut arrangement has continued to the present day, and will continue with the future Artemis program missions to the moon.

Related: Artemis 2's Canadian astronaut got their moon mission seat with 'potato salad'

MDA Space (then MDA) brought the space robotics division of Spar Aerospace in 1999, according to the National Post. MDA Space's Canadarm2 has been operational since 2001, starring in a tricky and near-emergency spacewalk by Parazynski in 2007 that saw him mend a torn solar panel with adapted tools. 

Canadarm2 more generally helped build the ISS alongside Canadarm, and continues to feature in ISS maintenance spacewalks. A CSA-funded robotic helper by MDA Space, Dextre, launched in 2008 for more delicate ISS maintenance tasks.

In recent years, the Canadarm2 team has gained so much trust with NASA that many tasks are now authorized to be carried out in ground control facilities at CSA headquarters near Montreal, Quebec. And CSA was invited to join Artemis in 2019 by supplying a new robotic arm, Canadarm3. MDA Space received a series of Canadarm3 contracts and is finalizing its design for an expected 2029 launch to support NASA's Gateway space station at the moon.

NASA was stalwart in saying the CSA was known for its reliable side dish of robotics, Podwalski told Space.com in 2023. Robotics is a strategic spend on the part of a space agency that has a tiny, $300 million ($413 million CAD) annual budget relative to NASA's $25.4 billion in 2025. Aside from space, robotics can also be repurposed for medical and mining needs in remote areas of Canada, making it another reason to invest in the technology.

Canadarm3 funded CSA astronaut Jeremy Hansen's round-the-moon seat aboard the Artemis 2 mission, making him the first Canadian to leave low Earth orbit. His 2025 mission with three NASA astronauts will be the first of an anticipated series of CSA Artemis missions to Gateway and perhaps to the moon's surface itself.

Ken Podwalski, CSA executive director of the Gateway program, has been commanding Canadian space robotics for most of his career. He was involved in the negotiations for Hansen's seat, which took four years to obtain as both NASA and CSA policy priorities had to align on the matter, and funding to be obtained.

In an interview, Podwalski likened the CSA robotics to incredible "potato salad" created to complement other main dishes in a feast.

"Everybody expects Canada to bring the potato salad," Podwalksi told Space.com 2023, shortly before Hansen's seat was announced that April 3. And he said it was possible to build up other moon programs from that: "The potato salad gets you in the door, no problem [...] and it doesn't stop you from bringing anything else. You're now a part of the party. Now's a good time to bring up other things."

To be sure, CSA has other means of funding beyond its annual budget: it partners with other Canadian government agencies and with industry to stretch its dollars further, for example. It has also received repeated billion-dollar-scale infusions of one-time government funding for Artemis in recent years.

CSA's other moon contracts include funding a mini-rover for science and utility rover for Artemis astronaut cargo, as well as a series of moon-related technologies particularly focused on moon science, astronaut health and appropriate deep-space food.