Canada’s “Mr. Dextre” Intended To Reduce Need for Spacewalks Outside ISS

CAPE CANAVERAL, — Mr. Dextre stands taller than a house, has two seven-jointed arms and can fly around the Earth in about 90 minutes. But he is not a superhero, nor is “he” a person.

“Mr. Dextre,” as the crew of NASA’s space shuttle Endeavour coined it, is actually a Canadian robot that was launched to the international space station (ISS) March 11 along with
Japan
‘s first module for the orbiting laboratory. Led by commander Dominic Gorie, the seven-astronaut STS-123 crew began assembly of Dextre in space during a late night spacewalk March 14.

“Dextre is probably the most sophisticated robot to go on orbit,” said Pierre Jean, acting program manager for the Canadian space station program, during a press conference here at
Kennedy
Space
Center
.

Soon after the shuttle Endeavour arrived at the space station March 12, NASA’s mission management team discovered a strange power glitch with the platform containing Dextre.

LeRoy
Cain, chair of NASA’s mission management team, said the first attempts to power up the platform and robot pieces ̵> a step taken to keep the electronics warm and protected from the harshness of space ̵> were not successful. Cain said, however, that the issue was likely to be worked around and should not cause problems for the initial assembly of Dextre.

“This is a problem we don’t need a solution for right this hour or this day,” Cain said, noting that Dextre’s heaters can remain un-powered for several days without consequence. “There’s not a great sense of urgency.”

Space station flight director Ginger Kerrick said March 13 that the glitch could be the result of a software hiccup, and Canadian engineers were drawing up a patch for the bug if that theory pans out. Other troubleshooting efforts could prompt spacewalkers to inspect cable connections or grapple the Dextre robot with the station’s robotic arm, which also can feed power to the massive, two-armed automaton.

“There’s a lot more specialists that need to be called in,” Kerrick said.

The special purpose dexterous manipulator, as Dextre is formally known, is a 1,560- kilogram maintenance tool designed to cut back on the number of dangerous trips astronauts make outside of the space station.

Dextre
can gently replace failed space station devices from as small as a phonebook to phone booth-sized objects weighing more than 450 kilograms. Jean said changing batteries, for example, is a routine yet delicate task the robot can do with a person at its controls, either inside the ISS or on the ground.

“It’s a dumb operation. You [remove] the battery, you put a new one in,” Jean said. “When you have to do these operations over and over, every time you have to use a [space station] crew person.”

And using crewmembers means conducting risky spacewalks that expose astronauts to dangerous micrometeoroids, severe temperature swings and strong radiation.

“In some ways a human may do the task quicker. Dextre, on the other hand, may take longer than a human to do certain servicing tasks,” Jean said. He noted, however, that the device gives space station managers valuable options when it comes to performing orbital busy work, including the ability to fetch items for astronauts when they do have to work outside the ISS.

“You give the ability to not tax the crew by forcing them to conduct an [extravehicular activity],” he said of utilizing Dextre’s five cameras, two gripper “hands” and a belt full of tools.

One might think an astronaut would feel threatened by such technological prowess. Wrong, says Canadian Space Agency astronaut Julie Payette, a veteran spaceflyer slated to journey to the ISS later this year.

“The robot, I think, is never going to replace humans in space,” Payette told Space News. “Humans will always need to be around to perform tasks robots may never be able to achieve.”

Payette said Dextre will be extremely useful when assembled on orbit, but will never match the mobility, dexterity or independent thinking abilities of people in almost any situation. She also thinks the design, construction and future operation of Dextre ̵> the final piece of
Canada
‘s ISS mobile servicing system ̵> will inform the creation of even better on-orbit robots.

That is a prospect, she said, that is not the least bit threatening to astronauts, but rather is exciting.

“It’s an absolutely essential, necessary step for what we want to do in the future,” Payette said. “Just imagine being on the Moon and being able to send a robot outside to do some dangerous work. I think that’s where this is headed.”