Astronomer-astronaut John Grunsfeld, veteran of eight Hubble Space Telescope spacewalks and a self-described "Hubble hugger," inadvertently bumped into one of the observatory's two low-gain antennas toward the end of an otherwise smooth spacewalk Monday, knocking off a small end piece. Groaning with disbelief, Grunsfeld said, "Oh, I feel terrible."
But engineers at the Goddard Space Flight Center quickly reported the antenna was still working normally. Grunsfeld and fellow spacewalker Andrew Feustel were asked to put a protective cover over the cone-shaped device for added insulation before ending the Atlantis crew's fifth and final spacewalk.
"Sorry, Mr. Hubble," Grunsfeld said as he headed back to Atlantis' airlock. "Have a good voyage."
"Consider it a goodbye kiss, John," someone said.
Dan Burbank in mission control tried to reassure Grunsfeld that he hadn't harmed the telescope.
"Just to let you know, we're feeling real good about this," Burbank said. "We think that antenna's going to be just fine. Again, in receive mode it works just fine, expectation is it'll work great in transmit mode, too. There are a lot of happy folks down here on the ground...and all around the world. We just look back and kind of marvel at the last five days and all the amazing work--electronic brain surgery and I don't know how else you could put it--that you guys accomplished on that telescope. Hubble's never had it better, it's never been more capable and it's just been a marvel to watch you guys do this."
"Thanks so much, Dan, I couldn't agree more," commander Scott "Scooter" Altman radioed from the shuttle's flight deck. "John, remember, take a moment here. This is it. The last spacewalk on Hubble and maybe our last visit to space. So enjoy this. You earned it."
"Thanks, I appreciate that. And Dan, thanks for those kind words. I hope we don't lose too many db (decibels). We really have achieved a lot out here. Thanks a lot, Scooter."
Grunsfeld and Feustel began repressurizing the shuttle Atlantis' airlock at 2:22 p.m. to close out a seven-hour two-minute spacewalk, the crew's fifth and final EVA (extravehicular activity) to service and upgrade the Hubble Space Telescope and the twenty-third in the 19 years since the observatory's launch.
With today's installation of a second battery pack, a refurbished fine guidance sensor, and three insulation panels--one more than originally planned--the astronauts completed the last remaining objectives of NASA's final Hubble service call.
Before repressurizing the airlock, Grunsfeld, one of the space telescope's most ardent (and eloquent) supporters, took a moment to mark a "tour de force of tools and human ingenuity" and to thank the men and women who made Atlantis' mission possible.
"As Arthur C. Clarke says, the only way of finding the limits on the possible is by going beyond them into the impossible," he said. "And on this mission, we tried some things that many people said were impossible--fixing STIS, repairing ACS, achieving all the content that we have in this mission. But we've achieved that and we wish Hubble the very best.
"It's really a sign of the great country that we live in that we're able to do things like this on a marvelous spaceship like the space shuttle Atlantis. And I'm convinced that if we can solve problems like repairing Hubble, getting to space, doing the servicing we do traveling 17,500 miles an hour around the Earth, that we can achieve other great things, like solving our energy problems and our climate problems, all things that are in the middle of NASA's prime and core values.
"As Drew and I go into the airlock, I want to wish Hubble its own set of adventures, and with the new set of instruments we've installed, that it may unlock further mysteries of the universe."
Jon Morse, director of astrophysics at NASA headquarters, said with the completion of Monday's spacewalk, "Hubble is returned to flagship status and it now has a full arsenal of instruments and tools for astronomers to use to make the new discoveries in the next several years."
The antenna incident occurred near the end of the excursion as Grunsfeld was rigging Hubble's support platform for the telescope's deployment Tuesday.
"Oh no, I hope the antenna's OK," Grunsfeld said. "Oh, I feel terrible."
"You hit the low-gain?" asked crewmate Michael Massimino.
"I tapped the low-gain antenna with my foot," Grunsfeld said. "Ahh...."
"There are two of them," Massimino said in an effort to cheer up his crewmate.
"No, Houston, do you have a picture of this?" Grunsfeld asked.
"Atlantis, Houston, we can't see you right now," Dan Burbank called from mission control.
"OK. I'm sick," Grunsfeld said. "It kind of knocked off the end cap."
Hubble Program Manager Preston Burch said Hubble's two low-gain antennas are primarily used to beam down engineering data when a malfunction or software glitch triggers a "safe mode" response. He said both antennas were designed to operate normally even if the protective covers are in place and that no problems are anticipated.
The Atlantis astronauts plan to release the space telescope Tuesday. The shuttle is scheduled to land Friday at the Kennedy Space Center.