>> JOHN: Yep, when you’re working in a vacuum and you’re
inside a spacesuit with oxygen, you know, you don’t wanna cut
your glove because then the oxygen will leak out and then
you die, so that’s a bad day! >> CHRISTY: It’s suboptimal.
[LAUGHTER]
[UPBEAT MUSIC]
>> JOHN: Hi, I’m John Grunsfeld, NASA astronaut.
>> CHRISTY: Hi, I’m Christy Hansen, NASA
astronaut trainer for spacewalking, and flight
controller. >> ED: I’m Ed Rezac, EVA engineer for the Hubble
Space Telescope Project. >> JOHN: Now EVA is an acronym
that means extravehicular activity, which is just a fancy
way of saying “spacewalk,” and I was lucky enough to do eight
spacewalks on the Hubble Space Telescope, working with Christy
and Ed. The Hubble Space Telescope was designed to be
upgraded and fixed on orbit, occasionally something would
break that wasn’t anticipated, and we had to come up with new
ways of fixing it. And that was the case on this last mission,
the most ambitious of all the Hubble missions, and some of the
most difficult spacewalks ever done. The Space Telescope
Imaging Spectrograph failed, and we had to figure out a way to
fix it on orbit rather than putting in a whole new
scientific instrument, which is what we usually did on Hubble.
Unfortunately, the designers of the Space Telescope Imaging
Spectrograph never imagined that we would have to open it up in
space, and it had hundreds of tiny little screws that we had
to remove to access a circuit board to replace it to bring the
tele- the instrument back to life. So these are some of the
tools that we came up with to be able to do that. >> ED: We tried
to make the tools as astronaut friendly as possible, and one
way we had to do that, or that we chose to do that, was using
colors to color code the different size fasteners and the
fastener bits so the astronauts could easily grab what they need
and proceed with the task. >> CHRISTY: How do we pick up an
interface and not lose something in orbit? Bit caddy! Which one
do you want John? >> JOHN: I’ll take a red bit! [TOOL CLANKS]
>> ED: John’s going for the red bit. The STIS had several
different fastener types that had to be removed which required
different bits. And the fastener capture plate which held all the
fasteners and kept them from drifting into the optics core of
the telescope was also color coded. So John could match the
bit up with the color code on the plate itself. >> JOHN: So we
installed this fastener capture plate on the front of the STIS:
Space Telescope Imaging Spectrograph Instrument, and the
reason why we had to use the fastener capture plate is, as Ed
said, if I were to remove a screw and let go of it and it
floated away it could damage the telescope. So all of the screws
were behind this plate. >> CHRISTY: And you had 111
chances to lose screws. >> JOHN: And you would insert the bit
through a tiny little hole on the fastener capture plate,
engage the head of the screw,
[TOOL WHIRRS] undo it, and then when you take the
bit out the screw would float around inside of this little
cavity, and the screw was big enough that it wouldn’t fit
through the hole. And then repeat 111 times.
>> CHRISTY: And how do we track all that John? >> JOHN: Well,
like any good spacewalk we had a set of procedures that you
helped write. >> CHRISTY: Exactly, so we had a whole
ground team associated with developing the procedures,
capturing all the requirements, and flying an EVA
spacewalking checklist on orbit.
So when John and Mike Massimino, who actually performed this task
on spacewalk number four, removed each one, we had a
requirement that he actually read to the ground, “okay I’m
releasing screw number one,” and we would all be on the ground,
“check, screw number one,” “now screw number two,” 111 times to
make sure that everything was fully released, so that when he
went to remove the interface nothing was stuck, it wasn’t
stuck on the telescope. >> JOHN: Really amazing, all the
complexity to do something as simple as removing hundreds of
tiny screws so that we can get access to the circuit board and
use another tool to pull it out, put a new one in, put a new
cover on with no screws that locked on, >> ED: Right.
>> JOHN: and bring that instrument back to life so that
it could continue looking at black holes and the distant
universe, really pretty amazing, all worked
out great. >> CHRISTY: In addition
to what John said, the astronauts had to be trained on
“stay away from this,” “don’t touch that,” they’re taking
something off and handing it off to another astronaut, they have
to make sure that they don’t cut gloves in the process of doing
those transfers. So all that is designed, and trained, into
their repeated training tasks so they have this muscle memory to
be careful every single time. >> JOHN: Yep, when you’re
working in a vacuum and you're inside a
spacesuit with oxygen, you know,
you don’t wanna cut your glove because then the oxygen will
leak out and then you die, so that’s a bad day!
>> CHRISTY: It’s suboptimal. [LAUGHTER] >> JOHN: Thanks for
joining us on Hubble Tool Time! >> CHRISTY: Thank you!
>> ED: See ya!
[UPBEAT MUSIC]
[SILENCE]
>>CHRISTY: I like all the pretty colors.
[UPBEAT MUSIC]
>>JOHN: That’s pretty stable.
>>MIKE: That’s not bad at all. >>JOHN: Kind of boring.