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Robot Helps NASA Refocus on Hubble

Written-Off Mission to Extend Telescope's Life Is Revived Because of 'Dextre'

By Guy Gugliotta
Washington Post Staff Writer
Friday, November 12, 2004; Page A03

The promotional video shows a multi-jointed titanium handyman untwisting knobs and disconnecting an electrical cable with slow-motion aplomb, displaying fine motor skills that the voice-over assures will enable it to install "new batteries, gyroscopes and scientific instruments" aboard the aging Hubble Space Telescope.

But the video is only a teaser. In April, when NASA's Goddard Space Flight Center in Greenbelt showed the whole sequence to headquarters VIPs, what had first seemed an elusive dream -- a robotic mission to service Hubble and extend its life by five years or more -- suddenly became real.


Goddard Director Edward Weiler, reflected in a copy of the Hubble's photo of Eagle Nebula, calls the mission almost as difficult as landing on Mars twice. (Preston Keres -- The Washington Post)

__ Mars Exploration __
__ Photo Galleries __
Spirit Rover Eyes Mars
Opportunity Rover Sends Images

__ Panoramas __
3-D Color Mars Image
3-D View of Mars Surface

__ Graphics __
A detailed look at the Mars Exploration Rovers
A survey of U.S. and European Mars explorers.
A depiction of robotic repair to the Hubble.

__ From the Post __


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"I remember coming to look at this stuff and asking, 'Is that an [animation]?' And somebody said, 'No, it's really happening,' " recalled Edward J. Weiler, who was NASA's associate administrator for space science at the time and is now Goddard's director. "I didn't think robots could do this kind of stuff."

It is by no means a sure thing. Yet largely because of the Canadian robot named "Dextre," NASA has gone in less than a year from virtually writing off the Hubble to embracing a mission that will cost between $1 billion and $1.6 billion and approach in complexity the hardest jobs the agency has ever undertaken.

"Almost as difficult as landing on Mars successfully twice," Weiler called it. Servicing the Hubble, like the nine-month tour de force that has kept two rovers tooling around the Martian countryside, will demand a host of technical tasks and tricks that have never been tried.

To do it, the United States must develop its first-ever robotic docking vehicle, fill a bag with tools that, in many cases, have not been invented, and use the robot repairman to unscrew j-hooks, open and shut doors and "drawers," disconnect and attach electric connectors, and rig jumper cables.

By the end of 2007, NASA hopes to put into orbit its Hubble Robotic Vehicle of four components: a de-orbit module designed to dock with Hubble; a grappling arm to seize the telescope during docking and serve as a repair platform; an ejection module to carry spare parts and tools; and Dextre.

The jobs, in descending order of importance, are to change Hubble's batteries; install new gyroscopes; swap an old camera for a new, more sophisticated one; install a new spectrograph; and, if possible, replace a telescope pointing device and repair another spectrograph.

"There's nothing easy about it. It's all firsts," said Goddard's Preston M. Burch, Hubble's program manager. "And some of the things we're thinking about make people nervous." The fundamental tenet for a servicing mission, he noted, is the same one that doctors espouse: "Above all, do no harm."

In the past, shuttle astronauts had the job of servicing Hubble, missions that required a few days of spacewalks lasting six hours each. Dextre "can work 24-7," Weiler said -- a fortunate feature, because robots are not as supple as humans. "Watching it is like watching grass grow," Weiler said.

Burch hopes to complete the mission in a month. Some of it will be done by the robot working on its own, but most will be handled by ground controllers manipulating the robot's two arms -- like playing a video game.

"Astronauts are keen to do this," Burch said, and they will probably get the call because of their experience and knowledge of the perils inherent in handling large objects in space -- where something pushed or pulled does not slow down until it is checked.

"Hey, if they ask me, I would be very happy to do this," said Michael Massimino, an astronaut who serviced the Hubble in 2002 and has joysticked Dextre in the lab. "It's an interesting and challenging project -- it's cool, really cool."

Dextre, so nicknamed by the Canadian Space Agency, was developed by MD Robotics, of Brampton, Ontario, as the Special Purpose Dextrous Manipulator, a robotic repairman destined for eventual duty on the international space station.


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