Preflight
Interview: Franklin Chang-Díaz
The
STS-111 Crew Interview with Franklin
Chang-Díaz, mission
specialist.
Sean O'Keefe recently unveiled NASA's vision for the future,
which is to improve life here, to extend life to there, to find
life beyond. Does the International Space Station play a role in
this vision?
Yes. I think
it does. The most important thing on the space station is that it
is a permanent steppingstone to all of these other ventures that
you just mentioned. The station will give us the staying power in
the environment that we are trying to conquer, trying to explore.
The station is a, it's a beautiful test bed to develop the fundamental
technologies that we need to have at our disposal to enable all
of these trips that we want to take out into the outer reaches of
the solar system. Sometimes people focus on Mars. But we really
don't need to focus on any specific planet. We need to develop the
fundamental infrastructure that will allow us to go fast and very
far.
I know you've worked on getting there faster...
Yes.
...with your research. Actually now, this time you're going to
the space station. How did it feel to get that phone call that told
you, you were slated to visit the International Space Station?
Oh, it was
a tremendous excitement. For me, it was a bit of a surprise. I wasn't
expecting to fly quite so soon. Although it has been a few years
since my last mission. But nevertheless, I was a lucky person to
receive that call. And I jumped at the opportunity. For me going
into space is really the pinnacle of my spirit, my wish as an astronaut
is to, of course, to be there. And, to visit the space station,
a new spacecraft that I've never been to. And, on top of that, to
be able to actually walk outside, you know, walk in space, which
is something I've never done, that was a tremendous thrill for me
to hear that news.
With this mission, you join Jerry Ross as the only humans to
launch from Earth as many as seven times. How does it feel to go
down in the record books in this way?
It doesn't
really, to me, it doesn't do much to me in terms of keeping records.
That is, I'm hoping that these kinds of records will be easily broken
and many times over. And, I'm hoping that there will be many, many
other people who will fly not seven or eight but you know, 10, 15
times as part of their careers. Because space travel and certainly
to visit an environment like low Earth orbit and space station,
should be a fairly commonplace thing in the years to come, which
will enable pretty much every interested researcher from Earth to
have an opportunity to actually do research in outer space in his
or her flesh and bones.
You mentioned the spacewalks. Is that what you think will be
your favorite part of this mission?
Yes. I think
so. In all honesty I have done quite a number of things in space
in my flights before. But, I have never had the opportunity to walk
outside. So, I am extremely excited about this opportunity! We've
been training very hard for [these] spacewalks. They are, they are
not super complicated. So but they're not that, quite that simple
either. They're sort of middle of the road spacewalks, which will
be just right for Pepe and I to execute. Now recently they [gave]
us another one which is a bit more responsibility, which we take
on with great interest. And, of course, we're very serious about
what we're doing. The third spacewalk will involve the repair of
something that has failed. And, that is really what humans are all
about in space, is to keep things going. And we'll have many other
failures along the way that will require intervention by humans
to keep things moving along the way we want them.
The launch date for this mission has been pushed back to make
way for additional training for this task. Is it hard to see that
happen?
No, not for
me. I feel that that was exactly the right decision. And it gives
us enough time to do a very thorough preparation for this new task,
which we certainly don't take lightly. It requires of course, also
some ground support work which will be ongoing to prepare the spare
parts that will be needed to do the repair. So, those two activities
will work in parallel so that we're ready. And, the equipment will
be ready for the flight. And, it's only a month. So, it's really
not a tremendous hit to the schedule.
So, what is STS-111 all about?
Well, STS-111
is one more step in, towards the completion of that major enterprise,
which is the assembly of this international laboratory. It is one
of the most remarkable engineering feats that you know, humanity
has endeavored to do. And I think that all in all, all things considered,
that we will see, back in time on the day when we opened up the
first real research laboratory where we conducted continuous research
in multi-disciplines in a round-the-clock operation, I think it
will eventually begin to pay off, all these difficult trying times
that we have gone through to get it done. And, it has been a tremendous
success, technically speaking.
Let's talk about the spacewalks a little bit more. Your first
space walk is to begin installing a device called the mobile base
system. What is the Mobile Base System? And what capabilities does
it add to the station?
Well, the mobile
base system is an interface. It's essentially a structure which
mates to the little cart that goes up and down the truss that was
installed on STS-110. And that allows the station robotic arm to
mate to it. And, therefore, the robotic arm can then now travel
from one point to the other on the station, enabling a tremendous
amount of reach and enabling, of course, the transport of payloads
and other structures from one place to another. So, it gives us
a lot more mobility. And, a lot more capability which will be required
for the assembly process later on.
Take us with you during your spacewalk, starting with putting
your suit on.
Well, there
will be a fairly long process inside the spacecraft, inside the
station. This time, we're going to be walking out of the station
airlock. And there will be a fairly lengthy process which mainly
involves getting the nitrogen out of our blood. Because, of course,
our space suit operates at a lower pressure. And so, because of
this, that, it has to operate in pure oxygen. And we don't want
any nitrogen in our blood because if it were there, then bubbles
will begin to come out. And, those bubbles are not good for human
beings. And, they will make you, give you the bends and a few other
bad things. So, we want to get rid of all that nitrogen. And, that
requires a process which has been certified by our medical team
where we gradually undergo a purification of, depuration of the
nitrogen from our blood by proper breathing of oxygen. Then when
we're ready and we are now in our suits, our intravehicular team
member, which is Paco, he will take us and put us into the what
we call the crew lock, which is a skinny part of the airlock, and
he will close the door. At that point Pepe and I are basically by
ourselves, and, we'll be talking to Paco on the radio, and getting
commands from him. and he will be helping us step through all the
process. I will be opening the door at the right moment. I will
actually depress, depressurize the crew lock; and then, when we
are at vacuum, I will open the door, and we'll be walking outside.
I will be first daisy-chained with tethers to Pepe; and Pepe, of
course, will be connected to the internal structure of the airlock.
So, we, I'm not going to be flying away. But as soon as I walk out,
the very first thing I do is I go to connect a safety tether to
the station arm, which is waiting for me right outside. And, as
soon as I get there I will be installing a little platform, what
we call a foot restraint; and I will jump on the arm. And, from
that point on, the arm will be taking me from one point to another
to accomplish the variety of tasks I have to do. The arm will be
operated by Valery Korzun, and he will be inside the station doing
all of the controls on the arm. So, it should be a very interesting
ride on the arm.
This spacewalk takes you several different places around the
station. What's your first stop?
The first stop
actually will be the cargo bay of the shuttle. In fact, Pepe will
also be going a few places as well. But, he will be a hand-over-hand,
you know, translating throughout the structure. But the first stop
will be the cargo bay of the shuttle. There, there is a device,
which we call a PDGF (it's called a…power and data grapple
fixture), it's really nothing but a round interface which allows
the arm to grab a hold too. And, I will be taking that out of the
cargo bay and installing it in a specified point on the P6 truss.
That will be the first task. Then after that I will go back to the
cargo bay, this time to the opposite side of the cargo bay, where
there will be a package of debris shields, which are packaged pretty
much the way you package a bunch of folding chairs. They'll be wrapped
with some girders and straps. And I will be taking that whole package
out, and transporting it to another location on the station. And,
so...
You'll stow these for later use.
That will be
stowed for later use. That's right. Presumably the Expedition Five
crew will get a chance to then go out and take this package of shields
and install them in the final location. And then there'll be a few
other activities that we'll have to do. We'll have to remove some
blankets. We'll have to get the MBS ready for installation, which
actually happens at the end of our EVA. When we go back inside,
then the operators of the remote manipulator, Peggy Whitson specifically,
will be actually grappling the MBS and finally putting it on to
the station.
So, that brings us to your next spacewalk.
That's right.
The next spacewalk will take place right after that MBS is now essentially
mated on top of the little cart. And, our job in that EVA is mainly
to do a lot of connections. We'll be connecting a number of umbilicals,
electrical, data, video cables which we'll be, have to be very careful,
make sure that we connect everything in the right place and make
sure that there're no debris or bent pins or any damage to the hardware.
And so this is a very methodical process that it is mainly orchestrated
by our IV crewmember, Paul Lockhart, who is inside with his checklist,
making sure that we get all the connections done properly.
So, let's talk about the third spacewalk. The third spacewalk
was added a little bit late in your mission planning. Evidently,
your crew is the best qualified to do that at this point. So, it's
an honor to be chosen to do that.
Well, I would
say a lot of people would be qualified to do this job. We happen
to be at the right place at the right time. And, in fact, it is
just the right choice at the moment for executing this task. As
you know the arm has suffered…what appears to be a short in
the roll joint of its wrist. And, that is a cluster of motors that
actually has some redundancy involved in the system, which still
allows it to operate. But, we are in a situation where if we have
another failure in that joint, why we would lose the function altogether.
So, our job is to replace that failed joint because it is a critical
piece for using the arm for subsequent assembly operations. We shall
be very heavily loaded later in the assembly process. So, it is
very important to get this fixed quickly. So they added this EVA
for us to actually do it. And, we are right now in the midst of
a lot of training to orchestrate the replacement of this joint.
It involves, actually, it's interesting that the failure occurred
in the best possible place for us. It, that is, it is the easiest
one to replace. If it were to have failed on another joint, that
would be a lot more difficult. And the reason is that we have to
take the arm apart. In the case, we basically have to remove the
hand so that we can replace the wrist. And what we call "the
hand," it really is called the LEE, or the end effector, of
the arm. This is a cylindrical piece. It weighs about 500 pounds.
And, it has to be moved with care. It is attached to the wrist by
some very special kinds of bolts, which we call them EDFs. They're
very similar to those bolts that you put in your, in the wall that
are blind and that when you turn them, the bolt expands and mates
as a pressure mate to the surrounding structure. So this is the
way these bolts work. Our job will be to unscrew these bolts. And,
when we all unscrew them, then their circumference gets smaller
and the bolt will easily be extracted. There will be six bolts on
this on each one of the interfaces. And, we'll have to remove one
set, take the LEE off, then remove another set, and take the joint
off. Take that joint and stow it, which we, the stowage place is
in the cargo bay. And then, pick up the new one, which also comes
in that same stowage area, bring it up to where we do the work,
replace it, put the bolts back in, and then bring the LEE back and
put it on the joint. That is in a, kind of in a big picture, the
task.
How long will this take?
Well, it will
probably take on the order of 4½ to maybe 5 hours. We are
scheduling a full EVA for this. So, it will be a very methodical
process, a very slow…we'll make sure that these bolts are properly
inserted and tightened. We wouldn't want any of these bolts to fail
or to come off. And, there is a great deal of orchestration and
cleanup activities after the EVA. So, it is a full EVA, and we are
training very hard for it right now.
In your opinion, what needs to happen for you to consider STS-111
a success?
Really I would
be very happy if we get the MBS fully installed and connected and
working properly. And, of course that we will be able to repair
this damaged wrist joint. I think those are the, right now, in terms
of the overall mission, at least in the EVA part, those are the
salient points. We have, of course, to…transport a new crew.
And we will also have to transport and bring back a whole bunch
of payloads and cargo and supplies, and those are also important
elements of the mission that I think will be necessary to consider
it a success. I would say the most important thing for us overall
in the mission is to make sure that we bring back the crew from
the station back home. Because their families are probably very
eager to see them, and we will be happy to have them home again.
|
