it's been two years since you and your crewmates were assigned to
STS-88 and now you're closing in on the scheduled launch date; what're
your feelings at this point as this flight becomes closer to being
I've been here since 1987; first as a support, flight simulation
engineer on the Shuttle Training Aircraft, and then as an astronaut
since 1990. And I know when I came here in 1987 there were already
people working on the space station program. So to be a part of
the very first flight of the space station program as an astronaut
is really the culmination of all my dreams. And especially in
the last few months, we're just trying as hard as we can to prepare
for the mission. It is extremely complex, extremely demanding,
and so we're just trying to make sure that, because we're entrusted
with the goals and all the hard work of the thousands and thousands
of folks across NASA and the contractor community, that we can
go do this mission right.
The target launch date for your
mission has been postponed twice now because of delays in getting
hardware ready. You look at the delay from your point of view,
you and your crewmates that is, is it simply a source of frustration,
or has it been an opportunity for you to be better prepared?
It has been an opportunity for both the crews to be better prepared
and the hardware and software to be better prepared. We have been
going through integrated testing of the hardware and software
to a much greater detail than was originally planned, so I think,
that the probability of mission success and the probability of
any types of problems that might come up, has changed tremendously
by having that extra year. Essentially, of preparing for the flight,
and we certainly learned a lot, being down at the Cape, being
involved in all the hardware and software testing. So I think
all around, of course, we'd like to fly whenever we can, but we
understand the delays and we've tried to take advantage of those
delays to better prepare for the mission.
Now over the course of the two years
you've been part of a group of five people who've been getting
ready to fly this mission; recently your group has grown with
the addition of Sergei Krikalev to your crew. How will this change,
in crew makeup, relatively late in the game for you folks, effect
how you get ready?
It's gonna help tremendously because, as I said, we have an
extremely complex mission. In our training for the flight we've
added three additional days to the flight because we just have
so many events that occur during the mission. And so to take a
crewmember like Sergei who not only has, literally years of experience
on Mir; is also training to be a long-duration space station crewmember;
he's just going to be a tremendous asset. We can offload some
of our tasks because we were getting to the point where, in an
extremely complex operational environment, the one thing you don't
want to have is a sole person doing a job with nobody looking
over their shoulder. Nobody calling out in kind of a call out
and response to procedures; adding Sergei to the flight will allow
us to do that and, therefore, will give us a greater, success
probability because, possibly reducing human error.
Do you see that it was Krikalev
that was added as opposed to someone else who could've done what
you were describing because of any particular expertise that he
has in the systems of the Russian component, the Zarya control
module, that he's been studying, because of his assignment to
the other crew?
He's, an excellent candidate, he's flown on the shuttle before,
which is a great benefit, and he's been training to be a station
long-duration crewmember so he's familiar with not only the American
segment systems but also certainly the Russian segment systems.
And also the one thing about the systems on Zarya is they're very,
very similar to a lot of the Mir systems, so certainly having
all his years of experience, to carry on and to help us out in
that arena, will be a tremendous asset.
As you get ready to go begin assembly
of the International Space Station, does it also make sense from
a point of view of symbolism to have a multinational crew on board
Certainly. I think everybody's aware that this is a multinational
effort, and as we kick off this program to have a multinational
crew also totally makes sense and serves as a symbol to the multinational
Before we get to detail on what
you're going to do, I want to ask you to look at the International
Space Station from a big picture point of view. To you, what's
the historical significance of your flight, STS-88? Why, should
we be building a space station in Earth orbit in the first place?
Well, you can make the case that we once had a space station,
some time ago, when we had Skylab, but I think it's a natural
progression: we have taken the shuttle and done tremendous things
with shuttle flights, and science on space shuttle flights. However,
I always compare to the public that, if you walk into any laboratory
in this country and tell a scientist, you have two weeks to run
this experiment, get your results, and come up, with a cure for
cancer, or design a new drug, or whatever the results might be-almost
any scientist in the world will tell you it cannot be done. And
those are the kind of limitations that we're faced with - with
the space shuttle. So I think to have long-duration science on
board the International Space Station is extremely important.
The other thing is that as we look beyond space station, and as
we look to a mission to Mars, for example, still to this day the
single limiting factor is human physiology during long-duration
spaceflight. So I think we need to have a greater understanding
of the effects of long-duration spaceflight on the human physiology
and any types of countermeasures that we might be able to impose
on crewmembers that might lessen those effects when they do reach
the surface of Mars.
In the course of a couple of years,
as you've been preparing for this mission, you've had time to
also get familiar with overall plans for the assembly of the entire
space station and not just the couple of pieces that you folks
will be working on, here in a couple of months. For the layman
who might see assembly as simply "fly a space shuttle up, plug
two things together like you would a couple of pieces of LEGOs,
and then, come back down." Talk to us a bit about the complexity
of planning, and then executing, a task of assembling this space
station at that location, 220 miles up.
Typically, when we have a typical space shuttle payload, we
will assemble it at the manufacturer. We will then take it to
Kennedy Space Center and integrate it with the shuttle, completely
test out all the systems, completely ensure that everything is
compatible with one another, whether it is an electrical system
or a mechanical system. For the very first time we are going to
have elements that aren't even being built in the same country,
and being built to such a tolerance that for the first time that
they're mated together is going to be over 200 miles up in orbit.
And so it is a great, a very detailed and complex task in order
to manufacture parts that are to that strict of a tolerance, and
to devise ways to test them on the ground to ensure their compatibility.
So those are some of the sorts of things that we're struggling
with. Also there are very, very few mechanical switches on board
the space station; everything is computer controlled. So even
though a light downstream in a module may still work, if the computer
command to get to that light switch cannot be sent, the light
won't come on. So the integration of computer, software and hardware,
is extremely important in this program, and that also adds to
the complexity of what we're trying to do.
Now you touched on the fact that
there are pieces of this space station that are being built all
over the world, might never see each other, so to speak, until
they do so on orbit. There are plenty of people here on the ground
who've criticized the fact that the United States is working with
Russia and various other countries in doing this, in working together
in order to execute the assembly of the space station. What do
you say to people who would voice that criticism?
Well, there's two things. First of all I think, as we look from
sort of a universal perspective, if we keep in mind Earth orbit
in this universal perspective, then it only makes sense to have
all the countries who are willing to participate in this program
to come together and to build something like the space station.
Where we can all work together in Earth orbit. So it only makes
sense from a political standpoint, and a geopolitical standpoint
that we can all work together orbiting the Earth that we all live
in. The second point is that spaceflight has become so tremendously
expensive that I think, no sole country could afford that great
cost. So I think from a financial perspective also, it makes sense
to bring multinational partners in and everybody brings their
element or their expertise to the table, if you will, to build
this space station.
The United States and Russia, the
two major spacefaring nations of the Earth, have spent most of
the last four years working together to get set for assembly of
this station, the task that you and your crewmates are going to
begin. As you look at the effort of the Shuttle/Mir program, what
do you see as the most valuable lesson that has come out of that
as you get ready to go do your job?
I think probably the most valuable lesson is how we've worked
together in an operational sense; and I'll give you a "for instance."
If anything were to occur, say after we grapple Zarya and their
active control system were not to mode to off, we would have to
rely on the Russian ground station to immediately send a command
to command their control system to off. We feel very confident
that - that will flow very smoothly and very quickly which is
of great importance. I think prior to, Phase 1, maybe we would've
been a little more leery of that, but now we've been working very
closely, certainly in situations like docking situations. Where
decisions have to be made very rapidly, and we've worked out all
those sorts of operational, handoffs and, so I think that's of
great importance as we head towards the Phase 2.
In the process of Phase 1, on STS-74,
there's an operation that, to the layman's eye, looks similar
to what you're going to do. They used the robot arm to pull the
Docking Module out of the payload bay and set it up on the Orbiter
Docking System so that it could be attached to the Mir space station.
How important is an exercise like that in setting the stage for
what you're going to do on your mission, the exercise that is
going to be so similar to that?
It is extremely similar. We will have the same sort of target
system, the same sort of centerline camera to look at that target,
we will also, eventually, not on the Node installation but on
the FGB installation, we'll be using the Space Vision System that
the Canadian Space Agency has developed. Many elements of those
tasks are very, very similar, and we certainly learned a lot from
Let me ask you to expand a bit for
us then, because one of the first highlights of this mission is
going to be when you, as the operator of the RMS, are going to
get the Node, called Unity, that you're bringing, ready for its
mating with the Zarya. Talk us through what is going to happen
and what you're going to be doing as you, go through that task.
OK. Well, first of all, in the shuttle's payload bay, in the
aft portion of the shuttle payload bay, will be the Node, and
at either end of the Node is attached a Pressurized Mating Adapter.
Now one of those Pressurized Mating Adapters, what we call PMA,
PMA-1, will be the interface between the U.S. element and the
Russian element, between Unity and Zarya. That is a fixed segment
that will never be moved in follow-on construction missions. And
so with the two Pressurized Mating Adapters, and the Node in the
middle, we will pick it up through the robotic arm with a grapple
fixture located on the Pressurized Mating Adapter number two.
We will go ahead and lift it up out of the payload bay, maneuver
it around, and then place it on top of the Orbiter Docking System.
Now with the Orbiter Docking System, because it's aft of the windows,
it's very, very difficult to tell things like pitch and yaw and
roll of the element. So we have a centerline camera that looks
straight up through the Orbiter Docking System that we actually
put on orbit, on the first day we go ahead and install this camera.
Then on the end of the Pressurized Mating Adapter is a target,
and that target is so accurate that if you're, say, .2 degrees
off in pitch, you can tell by looking at this target. It is the
same target they have used to dock with the Mir, so we have a
lot of experience with this and, feel pretty confident that this
is a very good way to get within a very tight tolerance. About
two inches and two degrees is the tolerance of how close we have
to be, between the two elements in order to have a successful
mating. We actually won't take it all the way down to the Orbiter
Docking System. We will take it four inches apart, separation
between hardware to hardware, so the petals will actually overlap,
but the rings themselves will not be touching. And then our Commander,
Bob Cabana, will fire the jets on board the orbiter to provide
some thrust to close the gap between the two segments.
Why is the mating of those two elements
to be done by forcing the shuttle up into it rather than you,
at the control of the arm, placing it down?
This is the same element that is used to dock the shuttle with
the Mir; interestingly enough it's the same designer who designed
the Apollo-Soyuz docking mechanism-it's basically an Apollo-Soyuz
docking mechanism kind of turned inside out. And it's a very robust
structure but it does require some closure rate, some force, to
activate the latches and so forth, in the docking system.
A force that you don't want the
arm to try to have to create?
Let's, move ahead from that point:
you've successfully grappled Unity and it's now in place on the
Orbiter Docking System. The next highlight comes as Bob Cabana
flies Endeavour to a rendezvous with the Zarya control module
while you, standing by prepared to grab it out of the sky as you
go by; tell us, tell the story of how that is going to transpire?
Well, the first thing is because the day prior we did put the
Node and the two Pressurized Mating Adapters on top of the Orbiter
Docking System, we now have no aft view into the payload bay;
that's all we see out the window is these elements. So that's
one of the first problems we have to overcome is that almost for
the first time, when we're trying to grapple a free-flying payload
or dock with a free-flying payload, we don't have visual contact
with it out the window. So we're going to be greatly relying on
the cameras in the shuttle payload bay. We have two what we call
keel cameras, which are located in the bay looking straight up.
We also have, of course, the four normal orbiter payload bay cameras;
we have a camera on the end of the arm, the end effector, and
we will also use that to look at the FGB as it comes down. My
role during the rendezvous is to assist the Pilot and Commander
with all the rendezvous burns: they're also very complex, it's
not like, any rendezvous we've ever done before because we have
this 25,000 pound mass mated way down at the Orbiter Docking System
we are greatly constrained on the way we fire the jets and the
way we fire the Orbital Maneuvering System engines on the shuttle,
otherwise it puts too much stress at that interface, and so it's
a very, very complex rendezvous. So I'm backing up the Pilot and
Commander, I'm timing between the thruster firings; we're constantly
monitoring the data coming in to the rendezvous radar and so forth.
About seventy feet out my role changes, and I go to the back and
Bob and I talk back and forth and decide when in fact it is stable
in the end of the end effector view, stable enough to go ahead
and move the arm over and to grapple the, grapple fixture on the
The next step, maybe one of the
more interesting things that is going to happen, is to try to
put the Zarya together with the Unity, and as you've mentioned
this is going to be an exercise where you don't have an eyeball
view of where you're working. What's the plan? How do you overcome
Well, one of the first problems is, again, we have this Node
and the two Pressurized Mating Adapters and we have to put Zarya
on top of that, so it's already stretching about forty feet out
of the payload bay. Because of the limitations of the robotic
arm we can't just drive the robotic arm all the way up and move
it forward, so as we come forward we kinda have to move it up.
And so one of the first things we're going to do is we're going
to retract that ring for the adapter between the Pressurized Mating
Adapter and Zarya; we're going to retract it, otherwise it sticks
up another thirteen inches. That's just one more thing to kind
of overcome as we kind of stair-step up. Once we do that and we're
looking, at that interface with the aft cameras and we're watching
it with the elbow. But because the elbow camera's located on the
elbow as the arm moves that camera moves so it's kind of some
strange camera views that we have had to get used to. Once we
think it's in place, and again we have somewhat very tight tolerances.
We can be about three inches and three degrees offset between
surface to surface, in order for a successful capture. Again we're
not going to take it all the way down, we're going to take it
this time to about six inches apart before we fire the thrusters
on board the orbiter. Once we think it's in place, and we think
we're there, we're going to use the Space Vision System before
we really start moving it down to that six-inch gap, and we're
going to use the Space Vision System to acquire targets, which
are dots. It's kind of a joke in the space station program that
all the elements look like dominos because they either have targets
that are black on white or white on black. By using the techniques
of photogrammetry, you have what's called an array, and the array
may be four targets or dots, or maybe five. Then we have targets
on the other element; in this case we have targets on the Node
and we have targets on the FGB, and so the camera angle has to
be far enough away that we can acquire both of those. So as soon
as we give the Space Vision System a camera view that they like
in order to acquire both sets of targets, for me as the arm operator
that really is not very useful to me because the camera zooms
so far away that I really can't tell down to three inches and
three degrees. So it's going to be very complex to switch back
and forth between the camera views that the Space Vision System
wants to acquire their data, and then the data that we would like
to see. Visual data, through the cameras, on board the orbiter,
a much tighter zoom-in angle, so we'll be trading back and forth.
Now each time we take and move that camera, they have to go and
realign that camera for the SVS data to occur, and so it's not
just a matter of zooming the camera in and out; it's a reconfiguration
each time we do that. So we're going to stair-step it down and
check it again, and check it again. We're going to check it several
times as we come down.
How many steps of that do you, in
your simulations, do you suppose you've got to go through in order
to get within that three-inch tolerance that you talked about?
We think maybe up to three times that we'll have to do that.
One at approximately forty inches away, one at about a foot away,
and then one at the six-inch, level away. Where we'll be doing
this hand off, back and forth- SVS, the Space Vision System, says
that we're within the tolerances. Now we want to take the cameras
and verify what we're seeing. Of course the third level is the
digital accuracy of what the robotic arm is telling us because
it does provide digital data in terms of the "x," "y," and "z"
position and the pitch, yaw and roll. But sort of the, the advertised
engineering accuracy of those numbers is plus or minus two inches
and two degrees, so that's already putting us quite a bit into
our tolerance for a successful mating, so we want to be very,
very cautious and use all the available cues.
This past June, the STS-91 crew
conducted tasks of some upgrades to the shuttle's robot arm which
you're going to be using on this mission; can you explain what
those improvements are and the impact that you expect they might
have on the job you've got to do?
Actually, the upgrade was originally designed, to upgrade the
capability of the arm, to grab a mass about nine times greater
than it can currently; right now it's constrained to about 65,000
pounds. Certainly, with Zarya being around 45,000 pounds, we didn't
necessarily need those upgrades because now we have changed, in
our assembly concept, to not use the shuttle's arm to grab on
to the space station. However, what it's done is it's provided
us kind of a greater control accuracy because it was designed
to handle much, much greater masses. Now as we control the arm,
with heavy masses in the old arm, and certainly the Zarya falls
into that category of one of the heaviest things we've ever, grappled
and moved with the robotic arm, it'll give you a finer control.
You won't have as many start-up and stopping transients. We used
to have something, when you took the brakes off the arm, the arm
might move a little bit; that's gone away. So, when we're talking
about tolerances on the order of plus or minus two inches and
two degrees, like for the Unity installation, we really need that,
that tighter controls band. Most of the changes have been, in
hardware and firmware, which, controls the software on the arm.
You were the arm operator on your
first spaceflight, the retrieval of the EURECA satellite back
in 1993…different than what you're going to do now but, again,
to the layman's eye, there seem to be some similarities. Talk
about the operations of grasping two satellites like that, and
how some experience in your own past has helped you prepare for
I learned from a great one and that was G. David Low, and, G.
David Low, was the primary arm operator on a flight for the retrieval
of EURECA. I was the primary arm operator for the EVA operations,
where we moved the EVA crewmembers because it was G. David himself
on the end of the arm. One of the things I learned from him was
to question everything, to be prepared for any possibility, even
though you may train in scenarios where the end effector camera's
non-operational. The arm is broken down to what we call direct
mode where you're applying a direct electrical impulse to each
of the individual joints and it's a very painstakingly long process
to move the arm joint by joint by joint. He taught me to question
everything and to make sure that we're fully prepared so I would
say that's one of the things in having flown previously, particularly
as the arm operator, is to constantly be looking ahead: what other
cues can I gain from other camera positions? Are there any things
that we can look at in the labs here at the Johnson Space Center
to better prepare us for the mission? Perhaps there's a different
camera view that we can look at something as simple as a handrail
on Zarya, and we can use that as sort of a boresighted cue to
determine our pitch and our yaw and our roll. So I think, certainly
having that experience has helped a little bit.
After the successful mating of these
two pieces of hardware, there are three spacewalks on your mission
and you're to be the arm operator standing by for all three of
those. What tasks might you be called upon to do with the RMS
during these three spacewalks?
We are going to use the arm from start to finish of all three
of the EVAs. We have trained to have one crewmember on the end
of the arm at all times during the EVA. Basically what that does
is provide a very stable work platform for them to perform the
multitude of tasks. All the electrical connections of which there
are over forty that they're going to make between the modules;
handrail installations…, sometimes people say, "Well, why are
you going to install a handrail in orbit? Why don't you just put
it on on the ground?" Well, the Node, or Unity, is so large and
so wide that it couldn't fit in the payload bay of the shuttle
had we put all these appendages on, so we literally have to wait
'til we're up in space to add some additional handrails so that
the EVA crewmembers have a translation path along their elements.
After these two pieces are mated
and in the midst of the spacewalks that we've talked about, you
and your crewmates will be among the first group of people who
will go on board the International Space Station; what are your
thoughts about occupying that spot in history?
As just a tremendous, pleasure to be afforded the opportunity
to do that. Never in my wildest dreams did I think I would be
on this particular mission. Actually when the mission, started
we weren't even supposed to go inside the elements. So that came
along a little bit later that "Hey, we really need you to go inside
and install the Early Communications systems" and some things
that came along later, and so it's just a tremendous, pleasure
to be afforded that opportunity.
Have you folks decided which one
of you will get to be the first to go inside?
Well, the ingress crewmembers are Bob Cabana, the Commander,
and Jerry Ross MS1, and so, Bob, being the Commander, will probably
be the first one through the hatch, and as well he should be.
Presumably, entering the International
Space Station-entering Unity and then Zarya-is not as simple as
opening a hatch and floating inside; describe for us what it is
that you do to prepare to enter these different pieces of the
One of the first things that makes it so complex is that all
the modules are at different pressures, and so we have to, step
by step, equalize the pressure between the modules before we open
up the hatches. Each of the pressures is completely different
and so, at any given phase of the flight, one module may be a
completely different pressure than another module so, that's part
of the pre-ingress activities, is to perform all the environmental
control system, operations to equalize the pressure. One of the
other things we have to do is is simply accumulate all those pieces
of equipment and tools that we're going to take from the shuttle
into the space station. One of our tasks will be to make sure
that we don't start mixing up the pieces: we don't want to take
any tools into the space station and leave them behind and shut
the door and then not be able to fix an orbiter problem. Nor do
we want to come back with anything that the station launched with,
and so, the transfer operations and tool control become very important
as we go through these exercises.
It's a whole day's worth of activity
that's timelined for you folks inside the station. Can you help
us understand also the setup of some Early Communications equipment
that is going to be put there for the first Expedition crew to
use. Talk about what you have to do with that and your plans for
that first day inside the station.
Well, the first day comes after the second EVA, and one of the
things that they're going to do on the second EVA is to install
communications antennas on the outside of Unity and then hook
up the electrical connections on the outside of the module. Then
when we ingress, and again it will be Bob Cabana and Jerry Ross,
will be installing the Early Communications equipment. Actually
what they'll be doing is using the electrical interfaces that
would normally be used for the control systems to the Common Berthing
Mechanisms to dock other pieces to the station eventually. So
this is kind of an interim fix to communications, particularly
for the early long-duration crewmembers. One of the other things
we're going to be doing is, in order to withstand launch loads,
they have to really snug-down all the bolts inside. Rick Sturckow,
the Pilot, and I are going to be tasked with, currently, removing
774 bolts, out of the Node, many of which are non-captive. Of
course as you might imagine that's kind of a problem on orbit.
So we're really hoping that our electrical drills are operating
properly. So most of that time we're going to be doing, some early
maintenance procedures-removing bolts, taking a look at the filters,
preparing some filters, installing some things in the rack, the
one rack that's already in the Node.
We've talked about what you folks
are going to do in terms of preparing the Unity node and grappling
and mating it, the Zarya, to it, all the tasks that are required
in three spacewalks. That's just the first assembly mission for
the International Space Station. How critical is any one step
in this whole process? Does the whole assembly sequence get thrown
out of whack if STS-88 doesn't do each and every thing that's
on the list?
No, not at all. And, in fact, many of our tasks that we're doing
we sort of call "get-ahead" tasks for follow-on flights, like
the 2A.1 mission that follows us and so I wouldn't say that any
one task, in and of itself, would cause a grinding halt, to the
program. Certainly if you had problems installing one module to
another, we probably would have to realign the mission priorities
on the next mission. Certainly it is a "building block," effort-
we are counting on each of the preceding missions to do their
task in order for the follow-on missions to pick up their assembly
task and follow on. But certainly I think there's enough cross-training
within the office that if something did not occur, that we would
just change the mission priorities on the next mission.
If then as Endeavour undocks from
the International Space Station, for the first time, and recedes,
as you start your trip home, what will have had to have happened
for you to consider the mission a success?
Well, hopefully we are leaving it with Unity mated to Zarya,
and all the electrical connections mated, the Early Communications
system checked out and operational, and the computer systems checked
out and operational.
Let's go away from 780 nuts and
bolts that you've got to remove, …more of a philosophical approach.
You've undoubtedly had time to be philosophical about the part
that you're going to play in this and the International Space
Station itself: what in your mind is the meaning of this contraption
to the future of space exploration?
I think it's the next natural progression in spaceflight. As
I said, we have taken the shuttle to great places, we have done
great thing, things with the space shuttle; certainly, the space
shuttle will be the workhorse of building the International Space
Station. But the International Space Station will truly give us
this international platform to learn to work together in space,
to give us a platform, a orbiting platform, for long-duration
scientific investigations, and I just don't think that there's
any replacement, I think it's the next natural progression. I
think if we fully intend on going to Mars in the future we have
to better understand physiology, and we really need long-duration
spaceflight in order to do that.
Well, with that said then, with
that in mind…the International Space Station is that important;
STS-88 is the first mission to begin assembling that critical
piece to the future; how would you like history to view STS-88?
Hopefully as a success. We would like to consider that when
we undock, as I said, we look back and we're looking back at Zarya
attached to Unity, that all the systems are up and operational,
and that we're ready for the next mission to come up and do their