After years of debate, NASA Administrator Mike Griffin gave the go-ahead on Tuesday for what could be one of the space shuttle program's most dramatic missions: a final repair visit to the Hubble Space Telescope.
"We are going to add a shuttle servicing mission to the Hubble Space Telescope to the shuttle's manifest, to be flown before it retires," Griffin told agency employees here at NASA's Goddard Space Flight Center. The news was greeted with a standing ovation.
The service call is tentatively scheduled for launch no earlier than October 2008, with Atlantis as the designated shuttle. The aim is to keep the orbiting observatory, which has provided thousands of dazzling pictures of the cosmos during its 16 years in orbit, in operation for at least seven years more.
During the 11-day flight, astronauts would install fresh batteries and fix the gyroscopes and guidance system on the $1.5 billion, 12-ton telescope. Those are Hubble's most vulnerable components, and without their replacement, Hubble is thought to have only two or three years left before it quits working.
The repair crew will be headed by shuttle commander Scott Altman, with rookie astronaut Gregory Johnson serving as pilot. Other crew members include veteran spacewalkers John Grunsfeld and Michael Massimino as well as first-time space fliers Andrew Feustel, Michael Good and Megan McArthur.
Spacewalkers would install the Wide Field Camera 3 and the Cosmic Origin Spectrograph, which would improve Hubble's observing capabilities by at least a factor of 10. They also would try to repair the Space Telescope Imaging Spectrograph, which stopped working two years ago.
After the morning announcement, Griffin told reporters that the "cradle to grave" cost of the servicing mission was estimated at $900 million: half a billion dollars to keep the Hubble team in operation, $200 million for new instruments, $100 million for components such as an extra shuttle fuel tank and solid-rocket boosters, and another $100 million for shuttle processing.
Hubble mission's ups and downs
Originally, this fifth Hubble servicing mission had been planned for 2004 — but that plan had to be changed in 2003, when the shuttle Columbia and its crew were lost due to damage done by flying foam insulation shortly after launch.
In the tragedy's aftermath, then-administrator Sean O'Keefe decided against sending a shuttle to the space telescope because of safety concerns — and particularly because crew members could not seek refuge in the international space station if Columbia-style damage ruled out the shuttle's return to Earth.
Mission planners looked into sending an autonomous space robot to do the repairs, but that idea was nixed last year after the National Academy of Sciences said sending a shuttle was the better option.
When Griffin took NASA's top post last year, he signaled that a shuttle mission might be considered for Hubble's repairs — but only if the shuttle fleet was proven safe, and only if there was a way to rescue the crew in the event of another Columbia scenario.
He met with other NASA managers on Friday for a final debate on the Hubble servicing mission's pros and cons. Griffin was swayed by the fact that the past two shuttle missions were trouble-free, and also took account of the progress being made on methods for inspecting the shuttle for damage and possibly repairing damage while in orbit. For instance, a procedure to put spacewalkers on the end of a shuttle inspection boom was successfully tested during Discovery's flight in July.
"We had [the capability for] inspection, we had repair, we had the ability to get the astronaut to the repair site … so we felt that we were in pretty good shape," Griffin explained.
The mission plan also calls for another shuttle to be placed on standby for launch, to rescue the Hubble crew members in the event that their shuttle couldn't return to Earth. To provide safe-haven capability, the shuttle would be loaded up with enough supplies to stay in orbit for 25 days, Altman said.
Griffin told MSNBC.com that many of the details of the rescue mission still had to be worked out, but the leading scenario calls for astronauts to make their way from the stricken shuttle to the rescue craft during a series of spacewalks.
Griffin said the requirement for a potential rescue mission might delay some of the early launch-pad tests for the shuttle's successor, an effort known as Project Constellation. But he added that "we're certainly not in danger of slipping any major Constellation milestones."
Another dramatic chapter
Even if the shuttle makes it safely to orbit, the mission's five spacewalks will hold drama enough: In addition to the installation of all the scientific instruments and replacement parts, astronauts will attempt an unprecedented in-orbit repair of the Space Telescope Imaging Spectrometer, or STIS.
Preston Burch, Hubble's program manager, said new tools had to be developed for the operation — including a perforated plastic plate that would capture the 111 screws on the instrument's cover as they're unscrewed. The screw-laden cover would be replaced with an "astronaut-friendly" cover equipped with easy-fasten latches.
"One of the early worries was, how long would this take, and would they get fatigued?" senior project scientist David Leckrone said. "Now we envision a NASCAR wheel-changing operation."
During a news briefing at Johnson Space Center in Houston, some of the mission's seven astronauts said they learned only days before that they would be on the Hubble repair team. "I didn't fully believe it until I heard the words come out of the administrator's mouth," Altman said.
Altman, Grunsfeld and Massimino all took part in the most recent Hubble servicing mission in 2002, during which the Advanced Camera for Surveys was installed. "We were the last people to touch Hubble," Grunsfeld observed.
Altman and Grunsfeld both said they felt the servicing mission would be safer in 2008 than in 2002, but they agreed that there would always have to be some risk. "I feel like a mission to Hubble is worth risking my life for."
Setbacks and triumphs
Tuesday's round of announcements served as the start of a new chapter in the tale of Hubble's setbacks and triumphs. "It's been a roller-coaster ride," said Ed Weiler, director of Goddard Space Flight Center and a former chief scientist for the Hubble project.
Shortly after Hubble was deployed in 1990, scientists were horrified to find that the telescope produced out-of-focus pictures, due to an incorrectly shaped mirror. It wasn't until after corrective optics were installed during the first shuttle servicing mission in 1993 that Hubble reached its full glory.
Hubble's past results have helped astronomers figure out the age of the universe and identify dusty disks surrounding other stars — places where scientists believe alien worlds might lurk. Adam Riess, an astrophysicist at the Space Telescope Science Institute who uses Hubble data to probe the mysteries of dark energy, said the Wide Field Camera 3 would be particularly useful for his research.
"Right now, measuring dark energy is one of main things that Hubble does, but we need many more observations," Riess told MSNBC.com.
Leckrone, NASA's top Hubble scientist, said the nature of dark energy was one of the most important scientific puzzles that the telescope's new instruments could help answer, but there are many others:
- The Wide Field Camera 3 should be able to extend the limits of Hubble's vision by hundreds of millions of light-years, back to a time when the first galaxies were making the transition "from toddler galaxies to little-children galaxies," Leckrone said.
- The Cosmic Origins Spectrograph could provide a "core sample" of the visible universe, shedding new light on its large-scale structure. Scientists say that structure takes the form of a cosmic web, dominated by invisible dark matter.
- Just before it failed, STIS conducted the first-ever chemical analysis of the atmosphere surrounding a planet beyond the solar system. Leckrone said he expected a refurbished STIS to check the atmospheres of another 10 to 12 extrasolar planets, perhaps even looking for the signature of organic activity.
If the servicing mission is successful, NASA could keep Hubble going until the 2013 time frame, when its scientific heir, the James Webb Space Telescope, is scheduled for launch. Grunsfeld even held out the hope that Hubble could last significantly longer, providing some overlap with the Webb telescope.
During the mission, spacewalkers will attach a docking device that will make it easier for future spacecraft to link up with Hubble — either for further servicing in the post-shuttle era, or for pushing Hubble out of orbit safely.
Celebrating ‘fantastic news’
Tuesday's announcement was hailed as "fantastic news" by the Baltimore-based Space Telescope Science Institute, which manages Hubble's scientific program. "We've been waiting for this for four years," said Matt Mountain, the institute's director.
He acknowledged that a renewed Hubble would increase the workload on the institute's scientists, but told MSNBC.com that "it's the kind of problem you like to have."
Senators as well as schoolchildren have joined the push to keep Hubble going. One of the telescope's biggest congressional champions, Sen. Barbara Mikulski, D-Md., joined Griffin for Tuesday's announcement. She praised Griffin and O'Keefe for seeking a second opinion "from the engineers, not the accountants."
"It's a great day for science, it's a great day for discovery, it's a great day for inspiration, because that's one of the things that Hubble has meant to so many people," she said.
Max Mutchler, a science instrument analyst at the Space Telescope Science Institute, told MSNBC.com that he was gratified to see how the public has embraced the space telescope as something eminently worth saving.
"It's nice when other people compliment your 'kids,'" Mutchler said.
Goddard's Weiler said he was pleased with the decision to save Hubble, but there was a note of restraint to his rejoicing — perhaps because he was familiar with the telescope's previous ups and downs.
"Never celebrate until you succeed," he counseled. "The champagne doesn't get opened until the servicing mission is over and the light comes through."
Leckrone, however, apparently didn't get the message. He told reporters that he was planning to open a bottle of champagne to mark Tuesday's decision.
"Listen," he said, "I celebrate easy."
The director of the Space Telescope Science Institute was misidentified in a previous version of this report. Also, this report has been updated since initial publication to reflect the revised schedule for the Hubble servicing mission. Initially, the flight was planned for no earlier than May 2008, with Discovery as the dedicated shuttle.