Preflight
Interview: Ellen Ochoa
The
STS-110 Crew Interviews with Ellen Ochoa, mission specialist.
Ellen,
tell us about the mission in a nutshell: what are the main goals
of STS-110?
Well, looking
at where we are with the space station right now-we've assembled
a working space station, and it has one major laboratory, provided
by the United States-and now we're trying to look to the next level,
where we're going to build up the Laboratory space and allow a wider
variety of experiments to be conducted. And in order to do that
we're going to need to provide more power. And so, what we're doing
is bringing up the first piece of the truss, which will eventually
be three hundred feet long and have an acre of solar arrays hung
off the end to provide that power.
This
is your fourth shuttle mission; how's it stack up against what you've
done before?
Well, my last
mission, my third mission, was actually the first mission to dock
with the International Space Station, and at that time it only had
two modules and no crew on board. So it's really exciting to be
able to come back now and visit it when it has so many more modules-
I think the inhabitable volume now is about that of a three-bedroom
house-and there's a crew living on board who will greet us once
we get there, and then to be able to grow the station and add a
piece that it really needs in order to make it a more useful laboratory.
Having
been to this station before, albeit a remarkably smaller version
of the station, is that experience advantageous to you and your
crewmates as you get ready to fly this mission?
It's helpful
for our crew to have had some of the members having been to station
before; it makes you a little bit more familiar with the rendezvous
and docking, with the ingress into station and the egress. But in
fact, the module that I'm going to be spending the most time in
has been added since I was last there, and that's the U.S. Lab,
Destiny, where the robotic workstation is. So that'll be a new experience
for me, to see that module and to be able to actually operate from
it.
Your,
as you've said, your fourth shuttle mission…tell me how you
got to be an astronaut, anyway…I mean, the course of your education
or your career that got you qualified for a job like this.
I became interested
in science and engineering when I was in college, and ended up majoring
in physics, and then I went on to graduate school because I wanted
to do research in engineering. And, it was when I was at graduate
school that some friends of mine were applying to NASA, and that
was really the first time I heard about what the process is like
and what type of people NASA looks for. And after I contacted NASA
myself and realized that I would be eligible to apply once I finished
up my Ph.D., well, that's when I became really excited about trying
to pursue this as a career and combine my interests in research
and space exploration.
Do
you know where the interest in science and research in itself came
from?
Well, I think
my interest in math is probably what led me into science and engineering.
I always liked math in school, and took calculus in high school,
and finished it up in college even though I wasn't, at that time,
studying in math and science. And that's kind of what led me to
look at the fields of study that used math and used calculus and
differential equations and that's what got me interested in physics.
Leading,
as you just said, on to college and an interest in, awakening an
interest in becoming an astronaut. You look back now at those various
steps along the way, do you see that there were special people,
or individuals, or more than one, that were pretty influential in
you making the progression that you did?
I had a number
of teachers that certainly encouraged me in specific areas, or just
overall were important influences, but I think the number one influence
would be my mother partly just because of the way she raised me
and my four siblings, and partly because of her love of learning.
She went to college part-time for twenty years, and finally graduated
a couple of years after I did. And it was just because she was interesting
in all the courses that the school had to offer and wanted to learn
more.
Let's
talk about the mission. You mentioned the primary payload on this
mission, which is a truss segment known by the designation S0. Introduce
me to it: tell me about how big it is, and where it goes, and what
it does.
Well, S0 is
about forty-three feet long, and it's the first segment, it's the
middle segment, actually, of a long truss structure which will eventually
be three hundred feet long. It's hexagonal in cross section, and
the width and the height are about fourteen feet each. And we call
it a structural attach point, or a structural segment, but it's
really quite a bit more than that: if you get close to S0 you realize
that it's covered with equipment. It has computers, it has fluid
lines, miles of cable, almost a thousand electrical connections-so
it's really quite a bit more than what we normally refer to it as.
So,
not just a structural member but a place where systems reside, including
something that's launching on it, the Mobile Transporter. Tell us
how that adds to the station, too.
Well, the
Mobile Transporter is one piece of a larger system which will allow
the station's robot arm to move all up and down the length of the
truss segment. The flight that goes to station after ours will bring
up another piece, which will allow the robot arm to attach to the
Mobile Transporter. And on our flight the Mobile Transporter-it's
already attached to S0 when we bring it up-during the spacewalks
we'll be unreeling and installing the power and data cables to the
Mobile Transporter, and then through ground commanding we'll actually
see it move for the first time.
I
understand it's going to really zip along.
Well, it doesn't
move very fast, but it doesn't need to. Its primary goal, of course,
is to allow the robot arm to get to all different servicing sites
along the truss, and that's generally something that you would plan
for in advance and have plenty of time to move to that site whenever
you would need to.
Before
we talk about the details of the spacewalks, as you referred to,
set the stage by telling us about what your top jobs are going to
be during the ten, twelve days of this mission.
Well, I've
been fortunate enough to fly the shuttle robot arm on my three previous
flights, and on this flight I'm moving on to the new station robot
arm. And we're using that arm in two main ways: and the first is
to actually reach into the shuttle payload bay to unberth the S0
truss and move it around and install it onto the space station,
on top of the Lab; and then, we use it during all four of the spacewalks
with a crewmember attached to it to move that crewmember around
to all the various different worksites that he'll need to get to
during the spacewalks.
What's
the reasoning behind the assignment of a shuttle crewmember to be
an operator of the space station robot arm, or am I thinking in
too strict a proprietary way about that?
Well, we actually
have three people that are trained on the station robot arm, and
two of them are already on station right now -- Dan Bursch and Carl
Walz -- and I'm the third person. And the reason we've trained people
on both the shuttle and the station crew is so that, a lot of the
training for this mission, both for the S0 install and for the spacewalks,
occurred after Dan and Carl launched into orbit. And while they
can do some types of training on orbit, it really helps to be down
here on the ground working directly, day-to-day, with the spacewalkers,
or with any last minute changes to the install. So I'll have sort
of the up-to-date information about all the tasks, whereas Dan and
Carl will bring to the table the actual flight experience of using
the arm.
You
mentioned that you have had a lot of experience in running the space
shuttle robot arm on your previous missions; from your training
on the Big Arm and I'm sure talking with folks who've run it before,
what do you think are going to be the important differences in terms
of operating one robot versus the other?
Well, when
you first look at the station arm, I think the main difference that
you see from that and the shuttle arm is that both ends are identical,
so either end can operate as the shoulder joint, which is the joint
that attaches to the station and either end can operate as the wrist
joint, which is the joint that you think of that's free flying and
the one that you move around. And that means each end has the same
three joints that allow pitch, yaw, and roll motions, and then there's
a joint in the middle, so that's a total of seven joints versus
six on the shuttle arm. And that means that the arm can choose a
variety of ways to move to a designated point in space, and one
of the differences, then, is choosing how it's going to move, which
control algorithm to use. We often choose to hold or lock one of
the joints, and kind of turn it from a seven-joint into a six-joint
arm just to make the trajectory known and something that you can
practice to that's repeatable. Another difference is that all the
joints have a range of motion of 440 degrees, which is different
again than the shuttle arm, and it's quite a bit wider range of
motion. So, these things add up to a lot more flexibility in the
station arm and also more capability-it can actually move around
a mass the size of the space shuttle itself. But it also adds complexity,
both to the planning task and to the flying task. And so when you
have tasks with the station arm that you want to complete in a fairly
short amount of time, such as when you're supporting a spacewalk,
then you really need to carefully choreograph those tasks so that
you make sure you don't get into a situation where it would take
a real long time to have to reconfigure all the joints to get from
one position to another.
Let's
talk about the events of the mission, carried through from start
to finish. After launch the first really critical thing is to dock
the two spaceships together. Tell me what you're going to do on
docking day, and describe how that activity's completed.
My primary
job during the rendezvous is to operate a laptop computer that runs
a trajectory program. And you get information from various sensors
as the inputs to this program-from the shuttle rendezvous radar,
from a laser ranging device that we have in the payload bay, and
from a handheld device that Rex is actually shooting out the window
at the station-and we plot that all on a screen and that gives a
lot of good information on the range and the range rate and trajectory
predictions to the Commander, who's flying the rendezvous. During
the actual, once we've actually docked and we're starting the hard
mate with the two mating surfaces, then I work with Jerry to complete
that whole hard-mating process, which usually takes several minutes
after the initial contact.
The
rendezvous protocol on this mission is the reverse of what it was
on your last trip to the station, isn't it?
In terms of
the trajectory, where…
…where
you're coming from.
That's right.
On the last time, we had the Earth below us and we were coming down
essentially from above the Earth with the station in between. And
now, we're along what we call the V-bar, which is a trajectory out
in front of the station and the Earth is below both us and the station,
and we're moving sort of backwards toward the station.
After
Mike Bloomfield brings these two ships together during the rest
of that day, the third day of your flight, most of the time is taken
up with the scheduled S0 dry run installation…thank you. Tell
me what you're going to be doing, what, and why, you're going to
walk through that procedure on that day.
Well, actually
after we dock, probably one of the main things that we do is Steve
Frick and I do a, set up a checkout of the video system because
all of the robotic tasks really depend on us being able to route
shuttle camera scenes over to the robotic workstation on the International
Space Station, and there's a couple of specific cameras that aren't
normally set up that we have to set up for our use, and we're going
to check out all that system. And then I'm going to get a chance
to actually operate the station robotic arm for the first time,
and it's really a chance for me to get on the controls, see what
they actually feel like, see how the arm flies for myself, before
the next morning when I actually unberth the S0 truss segment out
of the payload bay.
A
chance to actually do the work a bit before you have this piece
of hardware exposed?
Right.
The
installation of the S0 truss, as you said, comes up the next day,
and it starts with robot arm operations hours before your crewmates
walk, go out of the Airlock. Tell me about that day. Tell us what's
going to happen.
The plan is
to have the S0 truss segment mechanically attached to the U.S. Lab
before the spacewalk ever starts, so that you make the maximum amount
of use of the spacewalking time. So, it will start with me on the
station arm, and I will go ahead and grapple it in the shuttle payload
bay, then unberth it out of the bay. And then at other points in
this procedure both Carl and Dan will be operating the station arm,
and we'll move it around into position where we're getting ready
to actually install it on the Lab, and Dan will be doing the final
install where he actually makes the first connection onto the Lab.
And then Lee, on the shuttle crew, and Carl Walz, on the station
crew, will send the commands which actually close the capture latches
and provide that mechanical attachment. Once that's complete, then
the spacewalking crewmembers, who have spent the morning getting
ready for their spacewalk, will come out of the Airlock and start
their tasks.
Given
the way the shuttle is docked to the station and where the payload
bay is pointed, then you're really reaching under the Lab with the
arm to grab something and then put it on top of your head?
Yes. In fact
the arm itself is attached under the Lab. So, it then reaches further
back into the payload bay, but then it does come around onto the
zenith side of the Laboratory to do the actual installation.
Once
it's latched into place, as you described, Steve and Rex go out
the Airlock but the arms are still involved. Tell us about what's
going to happen during the hours that they're outside.
While Steve
and Rex are just starting the EVA, coming out of the Airlock, we're
ungrappling the arm from S0, now that it has that mechanical attachment,
and moving around in place so that Steve's going to come over and
attach a footplate to the arm, and then Rex is going to get on the
arm and he's going to stay on, attached to the arm, during the entire
spacewalk. The first couple of things that we're going to do are
to make the hard structural attachment of two struts on the forward
side of S0, so we swing them out from S0 and then they attach to
the Lab, and there's a number of bolts that have to be driven and
Rex is actually driving those bolts. So he'll be on the arm on both
of those struts, doing those. Then, the second major task is to
go up to the zenith side of S0, and there's two very long avionics
trays, and we're going to unbolt those from S0, and then Rex is
going to install one on the starboard side of the Lab and one on
the port side of the Lab, and in each case he makes a number of
connections, which are going to provide power and data to S0 itself.
Once that's complete, then we do a task where we unreel and install
one of the two cables that attaches to the Mobile Transporter, and
that will allow the ground to send up some preliminary commands
to turn the heaters on the Mobile Transporter.
And
all along this time you-all of you, the group of you-are working
against something of a deadline in getting these connections made,
right?
Well, that's
right. Once we unberth S0 from the payload bay, it's now in a very
different thermal environment than when it was in the payload bay.
And, what we're concerned about is temperatures dropping and some
of the boxes, some of the computers, and electrical distribution
boxes attached to S0, getting too cold. So we do need to make these
connections pretty quickly on the first EVA so that we can actually
power up some heaters and keep these boxes warm enough.
There's
a second spacewalk scheduled for day after that…skip a day,
and the day after that… once again you're going to be at the
arm controls; tell us about what the arm is going to do and what
the tasks are in the second spacewalk of the mission.
On the second
spacewalk, Lee is going to be the person riding on the arm the whole
time. And on the first spacewalk we completed the attachment of
the two forward struts, and our first task on the second EVA is
to do the attachment of the two aft struts. So, I'll be taking Lee
first to one position, and then moving sort of all the way under
the Lab with the arm and back up the other side, to do the other
aft strut. And once that's complete, that's a real milestone for
our crew because that means the entire structural attachment of
S0 to the station is complete. And then, our next task is to remove
some pieces of equipment from S0 that were only needed to attach
it to the shuttle payload bay for the trip into orbit, so we're
going to be taking those off and stowing them out of the way. And
then, finally, we're going to be unreeling and installing the second
of the two cables for the Mobile Transporter, so that will actually
have all of its cables hooked up after that.
And
so, I think then that you've got another spacewalk where you're
maneuvering one of your crewmates around throughout the whole operation.
The third spacewalk is scheduled for the day after that, and the
work, as far as the arm's concerned, a little different this time.
On the third
spacewalk the shuttle and the station arm kind of switch roles.
In the first two we were using the station arm to move a crewmember
around, and we were using the shuttle arm only to provide camera
views to the station arm operator; on the third EVA it's the exact
opposite-the shuttle arm is moving a spacewalking crewmember around,
and we're using the station arm to provide some views. And the major
goal of the third spacewalk is to do a complete power and data cable
reconfiguration so that once it's done, the station robot arm is
actually powered through S0, and then the power flows out to the
arm through the S0. So, at the end of the EVA, we will power up
the station arm, and one of the last tasks, we will have Steve attached
to the arm to deploy the Airlock Spur, which is essentially a translation
aid that allows spacewalkers to get easily from the Airlock to S0
and then onto the Lab.
A
little walkway from the airlock...
Right…
…out
to…
…a handhold.
…that
area. And so during the third spacewalk, since the plug's being
pulled on Canadarm2, so to speak, it's not going to be in use.
Not until
near the end, after it's powered back up and we go on to the Airlock
Spur task. The rest of the time we won't be using the arm other
than the cameras, but we do have some reconfiguration inside the
space station, some cable reconfiguration, that has to occur in
conjunction with the cable reconfiguration that they're doing outside.
The
following day the major activity that's planned is a checkout of
the Mobile Transporter; we haven't forgotten that he's out there.
What is it that you all, you crewmembers, have to do or are planning
to do, during that day?
Really, the
on board task is just to provide some camera views to the ground
so that as they send their commands, they have a good visual feedback
on whether or not the Mobile Transporter is moving and whether it
seems to be moving normally. But in fact, all the commanding is
planned to be done by the ground team at Mission Control.
But
this is the point at which we, if it goes right, we will see this
begin to slide up and down on the truss?
Yes, this
would be the day that we would, for the first time, see the Mobile
Transporter actually move.
I
think you mentioned earlier that there's still an additional component
of this whole system still to come before the arm would start to
ride this, right?
That's right.
It's called the Mobile Base System, and it's really the "adapter
plate" between the Mobile Transporter and the station robot
arm. It actually has four different grapple fixtures that the arm
can attach to giving it again a wider range of motion as it moves
up and down along the truss to reach various worksites.
The
day after the Mobile Transporter checkout is the fourth spacewalk
of your mission; you're going to [go] back to work in the Destiny
Laboratory, right?
Yes, I'll
be back at the robotics workstation, and on the fourth EVA Jerry
will be riding an arm, so that means everybody's gotten a chance
to be on the arm. And we're doing a variety of different tasks on
this spacewalk: we'll be installing lights on the Node and the Lab,
we'll be installing energy absorbers on the Mobile Transporter,
and also be installing some handrails on S0 itself.
As
I think your crewmates have described that those are sort of catch-up
tasks or small tasks, none of which are critical. There's always
a possibility that some of what you want to do to install the S0
or the MT won't go exactly the way you've been training for it,
although I know you've been training to respond to things that don't
go right-what are some of the important failure scenarios that you
would look for, and how do you intend to respond to them if they
crop up?
Well, we have
backup methods of providing power to S0 if our primary method of
installing the avionics trays and making all the connections either
gets behind the timeline or there's some problem with that, 'cause
we do want to make sure and get power to S0, somehow, during the
first EVA. And then, the spacewalking community has come up with
a variety of backup plans if various tasks don't go quite as planned.
And because we have four spacewalks planned, we always have the
opportunity on the fourth spacewalk to finish up higher-priority
tasks from the first three, if they weren't accomplished on those.
While
the bulk of the activity, obviously, is taken up with spacewalking,
there's other work going on during the time that Atlantis is docked
to the station: transfers of supplies and equipment and whatnot.
Tell me about some of the other items that you and your crewmates
are bringing up for Yury, Carl and Dan.
The items
that we're transferring probably fall into two categories, and one
is the science experiments-so we are changing out a few of the experiments,
bringing up some new ones for them to operate, and taking home some
of the ones that they've actually been working on for quite a while.
And then the other category would be just operational or personal
items like laptop computers, transferring water, things like that,
extra spacewalking equipment… things that they need to live
and work every day on board the space station.
It's
a lot of work that's scheduled for your trip; are you guys going
to have, be able to find any time to have any fun?
Well, we do
have a very busy timeline, but we are planning, of course, some
time together with both crews, we have a couple of special meals
planned where we've brought some special food and music, and I think
we're all really looking forward to sitting down together and swapping
stories.
We
are bringing instruments?
Well of course,
you probably know Carl is a singer and has a keyboard on board already,
so that's probably what we'll hear the most of. And then we just
have some tapes and other things like that.
The
International Space Station is a, going to be a much bigger science
laboratory than it already is; it's the main mission of it. It's
also a place that's being designed to develop technology and encourage
research and development, and it's a place where people can learn
how to work together, people from different countries. You've been
there once, you've been an astronaut for a number of years and been
around while we've worked with various countries, so I'd like to
get your perspective: do you think, what is it that you think is
the most valuable aspect of the International Space Station?
Well, I don't
know that I can really choose one. I really see the benefits as
being threefold. And one of them is that the research we're conducting
on board is of benefit to the Earth. We're looking at medical advances,
at new materials development, at environmental sensing, all things
that are important to people here on Earth. And secondly, is the
technology aspects, especially of developing ways for advanced human
space exploration. If we do want to mount a mission to the moon
or to Mars, there's still a lot that we have to learn, and really,
we think of the space station as our test bed for checking out those
technologies and also learning more about the medical aspects for
humans. And then, third, it's just an incredible international venture
where you have people from all over the world getting together assembling
an incredibly complex vehicle, and working together for items that
really benefit people around the world.
All
of that in mind, how do you feel about the idea that you get to
play such an important and visible part in it?
I feel very
fortunate to play what is really essentially a small role in the
overall assembly and operation of the International Space Station.
And I know when I was there before what I really thought about were
all the people-not just at NASA, but around the country and around
the world, whose hard work and dedication had made it a reality.
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