A sympathetic ear came with Griffin's appointment as NASA chief in 2005.
"Griffin came in with a commitment to and understanding that he had been assigned to repair Hubble if he could do it," said Wheeler, who is also an astronomy professor at the University of Texas in Austin.
Safety protocols implemented by NASA after the Columbia tragedy maintain that shuttle astronauts should be able to inspect and repair a shuttle in flight. The protocols also say that there should be a plan for rescuing shuttle astronauts if necessary.
The International Space Station, the destination for all shuttle flights except the Hubble mission, is considered a safe harbor for inspection, repair, and rescue.
But the space station is not an option for a shuttle that heads for Hubble.
Hubble and the space station have very different orbits, so the shuttle would not have enough fuel to change orbit and reach the station in an emergency.
Griffin and his colleagues were therefore forced to determine whether the shuttle could be safely inspected and repaired while in orbit near Hubble.
They also assessed the feasibility of keeping a backup shuttle ready for launch, should it be required for a rescue.
After an exhaustive analysis, NASA concluded that the answer is yes, Griffin announced.
Tests on recent shuttle flights proved the entire spaceship could be properly inspected—and most repairs could be made—in orbit. NASA will also keep a rescue shuttle on the launch pad during the Hubble mission.
"The safety of our crew conducting this mission will be as much as we can possibly do," Griffin said.
"All of you know beyond question, [and] we all as a nation now know, that flying the shuttle carries with it the risk of [loss of] life."
The Hubble repair mission announced today will be the fifth and likely last time a space shuttle will fly to the telescope.
Among the tasks to be performed will be the replacement of batteries, gyroscopes, and guidance sensors.
Also, two new instruments will be added to Hubble, greatly increasing its ability to peer deep into space and study the structure of the universe.
Hubble has already provided scientists with unprecedented information about black holes, fixed the age of the universe at 13.7 billion years, and helped popularize astronomy with stunning images.
Senator Barbara Mikulski, a Democrat from Maryland, joined Griffin for today's announcement.
She applauded the agency for reconsidering a service mission to Hubble.
"It's a great day for science, it's a great day for discovery, it's a great day for inspiration," she said. "Because that's one of the things that Hubble has meant to so many people."
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