The astronaut chosen to make emergency repairs yesterday on the space station's ripped solar wing -- a dangerous and unprecedented electrical job -- is actually an emergency medical doctor and mountaineer whose specialty at NASA just happens to be spacewalks.
What is more, Scott Parazynski is 1.87m and has long arms, a lucky stroke since he will be working alongside a damaged electrical generator with hot wires possibly exposed.
"We have a bunch of challenges ... but the beauty of having Scott available to us is that it's one piece that you don't worry about," flight director Derek Hassmann said on Friday.
To save the solar wing, Parazynski needs to clear whatever snagged the panels and caused the wing to tear while it was being unfurled on Tuesday. He will not know what he is up against until he sees the damage up close.
As it is now, the wing poses a structural hazard for the international space station. The damage could worsen and the wing could become unstable, quite possibly forcing NASA to cut it loose and lose a vital power source for future laboratories.
That is why NASA is willing to undertake this riskier and trickier than usual spacewalk before shuttle Discovery undocks from the space station in just another few days.
Complicating matters for NASA is a malfunctioning solar rotary joint on the opposite side of the space station. It's needed to turn another set of solar wings toward the sun, but is gummed up with steel shavings and, for the most part, unusable.
It will be Parazynski's fourth spacewalk this mission and the seventh of his 15-year astronaut career.
Parazynski, 46, who is married with a 10-year-old son and eight-year-old daughter, became an astronaut three years after graduating from Stanford Medical School.
Parazynski and his spacewalking partner, Army Colonel Douglas Wheelock, will wear partial mittens over their gloves for extra protection. Wheelock pierced the outer layer of a glove near the end of Tuesday's spacewalk.
The solar panel will be teeming with electricity.
"It's not the kind of thing that would burn you, but we could get conduction through the heart, let's say, or mild shocks," said David Wolf, the spacewalk branch chief for the astronaut office.
The astronauts got an early start yesterday, receiving a wakeup call from Mission Control. The song, dedicated to Parazynski, was the theme to Star Wars. Parazynski has a son named Luke, who shares a first name with Luke Skywalker, the main character from the Star Wars movies.