A Final Trip to Hubble
NASA launches a risky mission to repair the Hubble Space Telescope one last time
High above the Earth, seven astronauts are racing after the Hubble Space Telescope.
They blasted off into outer space on Monday aboard the space shuttle Atlantis. Their 11-day mission is to grab Hubble and make some much-needed repairs to the telescope.
This is the final scheduled repair mission to Hubble before the space shuttle fleet is retired in 2010.
Atlantis is scheduled to reach Hubble on Wednesday. Once it does, astronauts will pull the telescope out of orbit using a robotic arm and bring it into the shuttle's repair dock. Once they have Hubble, astronauts will spend five days making spacewalks to install new cameras, repair broken equipment, and make other repairs.
This will be a dangerous and challenging mission for the Atlantis astronauts.
The biggest threat they face is space junk. Hubble is located 350 miles above the Earth, where a lot of debris circles the planet at high rates of speed.
If the shuttle is hit with this fast-moving garbage, it could be so badly damaged that it couldn't make the return flight to Earth. And since it's in such a high orbit, it will be too far from the International Space Station for astronauts to seek shelter there.
Scientists and engineers at NASA have prepared for this possibility.
When Atlantis lifted off Monday from Kennedy Space Center in Cape Canaveral, Florida, a second shuttle, the Endeavor, was sitting on a nearby launchpad. Endeavor and its four-person crew are on standby in case it needs to be used for a rescue mission.
If Atlantis is damaged, NASA will send Endeavor into space to bring the Atlantis astronauts home. Once the Endeavor crew rescues the Atlantis astronauts, they would start a self-destruct sequence for Atlantis to make sure it doesn't crash in some populated area on Earth.
This is the first time that a second shuttle has been placed on standby to serve as a rescue vessel. Knowing that Endeavor is ready to come to the rescue is reassuring to Atlantis commander Scott Altman.
"Even in the worst-possible imaginable case, we can stay up there and last until somebody comes up and gets us," Altman said. "So it feels like we have all our bases covered."
The repairs to Hubble themselves are also risky.
There have been four repair missions to the telescope since it was launched in 1990. The last repairs were made in March 2002. Those repair missions had astronauts replacing things like batteries and gyroscopes.
This time, astronauts have more complicated tasks. Delicate equipment like circuit boards that control electronics and cameras will be repaired in space, which has never been done before.
"It's actually going into the very guts of instruments that have suffered failures that were never meant to be touched [while in] orbit," Michael Weiss, a Hubble technical manager, told National Public Radio.
Astronauts will replace six gyroscopes, six batteries, and a failed data processing computer on Hubble. They will install the Cosmic Origins Spectrograph, a tool that will allow Hubble to look 13.2 billion light-years into space. And astronauts will try to fix a broken camera and science instrument.
These repairs should allow Hubble to operate until at least 2014. By then, NASA hopes the James Webb Space Telescope will be ready to replace Hubble.
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|The Atlantis astronauts heading to the Hubble Space Telescope will be making the final repairs to the 19-year-old telescope. NASA says another telescope will be ready to replace Hubble when it finally fails. Do you think NASA should let Hubble fail? Should Hubble and its replacement coexist? Why or why not?|
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