September 10, 2008
Fixing "Mr. Hubble"
“It’s almost impossible not to feel like Hubble is almost a living being,” STS-125 astronaut John Grunsfeld said at a press conference September 9. “I feel like Hubble is kind of a friend I haven’t seen for a long time.”
The October shuttle flight to repair the Hubble Space Telescope will be Grunsfeld’s fifth trip into space and third visit to the orbiting facility he affectionately calls “Mr. Hubble.” He did 16 hours of spacewalks on STS-103 in December 1999, and 21 hours more on STS-109 in March 2002 to repair and upgrade the famous telescope. The astrophysicist turned telescope mechanic will participate in three of the five spacewalks planned for the STS-125 mission.
This shuttle mission is considered the most dangerous to date. The chance of impact from orbital debris is estimated at 1 in 185 for the 350-mile altitude orbit, versus a 1 in 300 risk for the 200-mile-high space station orbit. But the primary danger is of damage to the shuttle tiles during launch. Damage to the wings from foam falling off the external fuel tank caused the breakup and destruction of the Space Shuttle Columbia in 2003. Though processes have been changed to limit the amount of foam that comes off during launch, the risk remains at about 1 in 80. Shuttle Program Manager John Shannon told reporters that historically, the risk of a catastrophic failure is closer to 1 in 60.
If an orbital inspection reveals damage to critical areas on Atlantis such as what caused the destruction of Columbia, the space station is not available as a safe haven. The crew will power down the vehicle and wait for the Space Shuttle Endeavour (STS-400), to launch and provide a ride home for the seven crewmembers.
STS-125 Commander Scott Altman said that if necessary, they are prepared to abandon Atlantis in space and spacewalk over to Endeavour. “It is a viable rescue option,” he said. Noting that having four well-trained spacewalkers to escort the other three crewmembers across the void, “We’re very well prepared for that.”
When asked if they considered the repair of Hubble to be worth the risk, the crew were unanimous in their agreement. “Hubble has a huge science payoff,” one of the rookie spacewalkers, Mike Good (“Bueno”) said. “It’s well worth the cost.”
Commander Altman summed up the crew’s opinion: “This is a mission that can and should be flown.”
Grunsfeld said that he was “thrilled to be able to go back to Hubble,” and that what the telescope will do with its five to ten years of new capability will “knock your socks off.” He added that “There is a story to Hubble that has been unfolding over the last 20 years like a great novel. There are surprises, and we don’t know how it will end.
The next chapter is currently scheduled to launch Friday, October 10, 2008.
To the stars,
Former NASA flight controller;
Posted by m_dyson at 01:00 PM