Astronauts narrowly avoided disaster Thursday during their first spacewalk to upgrade the Hubble Space Telescope, but the more treacherous tasks still await them.
Astronaut Andrew Feustel on Thursday successfully wrenched out a stubborn bolt that, if it had broken off, could have blocked installation of a $132 million camera on Hubble. The camera is one of astronomers’ highest priorities for this mission, the fifth and final visit to fix and modernize the Hubble.
There will be no weekend off for Feustel and the other six crewmembers of space shuttle Atlantis, which pulled up to the Hubble on Wednesday. In the next few days, they’ll undertake work so difficult that NASA is downplaying their chance of success.
“Today was a speed bump,” Hubble senior scientist David Leckrone said. “Two days from now is going to be the hold-your-breath day.”
• On Saturday, Feustel and astronaut John Grunsfeld will attempt the first repair on a Hubble scientific instrument while in orbit. Fixing the Advanced Camera for Surveys requires them to remove tiny screws that they won’t be able to see – while wearing bulky space gloves.
“This will be a nail-biter all the way,” Grunsfeld said before Atlantis’ May 11 launch.
• On Sunday, astronauts Michael Massimino and Michael Good will try to mend another broken scientific instrument. To bring the Space Telescope Imaging Spectrograph back to life, they’ll have to undo more than 110 screws not much bigger than watch screws.
The telescope could be crippled if a single stray screw floats into it.
“I don’t know exactly how it’s going to turn out,” Massimino said before launch. “A lot of miracles have to occur.”
The scientific instruments on Hubble – unlike its standard components, such as the observatory’s batteries – were not designed to be fixed in orbit. So it’s extraordinarily difficult to access them. Hubble’s managers decided the two instruments are so scientifically valuable that it’s worth the risk to try to repair them.
If the astronauts pull off the repairs, Hubble will have five functional scientific instruments for the first time since 1993, but Hubble’s overseers are trying to tamp down expectations.
“On this mission, the final mission, we’re going for broke,” Leckrone said.
Thursday’s spacewalk was not expected to be challenging, but the astronauts encountered an unexpected obstacle as they tried to remove a scientific instrument known as Wide Field Planetary Camera 2.
The camera has been a scientific workhorse, but it’s 15 years old, and its replacement will be 15 to 35 times more powerful. Astronomers are eager to start using the new camera.