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DEXTRE

Hubble's in Trouble. Who You Gonna Call?

Tuesday, November 16, 2004; Page C13

For a while, it looked like the Hubble Space Telescope -- responsible for some of the most amazing pictures ever taken of the stars and heavens -- would die slowly as its batteries lost power, sending Hubble falling back to Earth. But when the American people heard that Hubble was in jeopardy because the national space agency -- NASA -- didn't think it was safe to send astronauts to change the telescope's batteries and do other repair work, they started thinking. Schoolkids and scientists, moms and mathematicians started coming up with ideas and sending them to NASA. The message was simple: We must save Hubble.

Now, a huge robot handyman named Dextre may be coming to the telescope's rescue. Guy Gugliotta explains what Dextre is and how it may save Hubble.

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What is Dextre?

Dextre is 2,200-pound robot made of titanium, a silvery metal used in the making of airplanes and satellites. Dextre looks a lot like a stick figure with a thin body and two 10-foot-long arms. The arms can turn, reach and grab in seven different ways. Those arms can unscrew bolts (and keep them from drifting away in space), open hatches and hook up jumper cables. The robot can do some work alone because of sensors in its arms, but most of the work would be directed by people on the ground twisting and turning the robot using controllers, much like the ones you use to play video games.

Dextre is actually a nickname that's short for Special Purpose Dextrous Manipulator. We like Dextre a lot better!

What does Dextre need to do?

Let's just say he has more repair work to do than your dad does on a typical weekend. The most important job is giving Hubble new batteries (1). (Without new batteries the telescope would stop operating sometime between 2007 and 2009.) Hubble, like all the coolest toys, takes a lot of big batteries. Hubble will need six new batteries, which will be kept in a special compartment that will hook up to the belly of the telescope. But for the power to flow from the batteries to Hubble, Dextre will need to connect intergalactic jumper cables (2) from the batteries to solar panels (3) on Hubble.

Next Dextre will give Hubble a new camera (4). After all, it's the camera that takes those cool pictures. To make the switch, Dextre needs to unfasten a latch and take the old camera out, which is like pulling open a drawer, then put the new camera in.

Dextre also will try to mount six new gyroscopes -- devices which help keep the telescope level -- onto the camera's sides.

How long will this take?

NASA scientists think Dextre can do the job in about a month. Robots, after all, can work around the clock, without needing to stop to sleep, eat or go to the bathroom.

How will Dextre get up to Hubble?

NASA needs to build a Hubble Robotic Vehicle (5), which will be able to dock with Hubble 360 miles above Earth. This vehicle will hook up to Hubble. The de-orbit module (6) will stay, and when the time comes for Hubble's mission to end, it will steer the telescope into the ocean.

If this works, Hubble will be able to "live" until about 2014. Scientists don't want Dextre to upset Hubble's balance, so once the repairs are finished, the robot, its grappling arm (7) and the ejection module (8) will fall into Earth's atmosphere and burn up.


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