| Ed
Lu | 
NASA
ISS Science Officer Ed Lu | | Related
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Expedition
7
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Next
The
Soyuz Ride
Greetings
Earthlings! I've always wanted to say that. Now that things
are beginning to settle down here a bit, I wanted to tell
you a little bit about what life is like up here on ISS, and
some of the things that make this such a special place.
Let me
start from the beginning: how we got here. We launched a little
over 2 weeks ago from the Baikonur Cosmodrome on a Russian
spaceship called a Soyuz TMA. It is the latest in a series
of spacecraft based on the design of the spacecraft that the
first man in space, Yuri Gagarin, first flew into space over
40 years ago. In fact, we launched from the very same launch
pad that Gagarin launched from!
Launch
day, April 26th, started for Yuri and I at 1:30 in the morning
when we woke up, quickly dressed and ate breakfast, and were
met by a horde of well wishers at our room. After all the
obligatory nice words, we had the Russian traditional moment
of silence before setting off on our journey. On our door
were signatures of all the cosmonauts who stayed in this room
before launch, dating back to the Apollo-Soyuz mission in
1975 (Leonov and Kubasov stayed in our room). I remember watching
that mission on TV back in Webster, NY, at my friends Kevin
and Mark's place with the neighborhood kids. Now it was our
turn to sign the door. We then boarded the bus for the drive
out to the launch area. Once there, we suited up and pressure
checked our suits, then at the appointed hour marched out
to report to the commanding officer of the Cosmodrome that
we were ready for launch. Then it was back on the bus to head
to the launch pad. The sun was just coming up, and crowds
of workers were standing along the road waving and saluting.
At the
launch pad, we wave to everyone before getting on the elevator
to the top. I see Christine and my brother Rick there waving,
and I flash them the Shaka sign before heading up. For those
of you who have been to Hawaii, you know what that is, and
for those of you who don't know what it is, you should immediately
get on a plane and go to Hawaii to find out! Once at the top,
we literally crawl on our hands and knees through a hatch
in the side of the shroud into the Soyuz.
From
there, we lower ourselves down into the descent module, which
is basically the cockpit. In our bulky pressure suits it is
difficult to maneuver into the seats and buckle up -- the
two of us plus the load of cargo in the right seat fill most
of the cockpit. The Soyuz is a small, simple spacecraft --
your basic no frills reliable ship. It was designed to do
one thing, fly humans to and from an orbiting space station.
That means it doesn't need to be large, just large enough
to hold the cosmonauts and their equipment for however long
it takes to rendezvous and dock with a space station -- which
happens to take 2 days. My seat, as the flight engineer, is
on the left, and Yuri sits in the commander's seat in the
middle. We each have electronic displays in front of us that
we can use to call up a variety of different computer displays
so we can issue commands or look at status displays from the
onboard sensors. Spacecraft are a bit like humans in that
there are leftover characteristics from old designs that have
remained but no longer serve a purpose, like your appendix
or your tonsils. In the case of the Soyuz, even though there
are new electronic displays, the commands are still sent using
a matrix of commands where you specify the row and column
number. This is simply a holdover from the previous Soyuz
design, which had mechanical switches arranged in rows and
columns. Now, on the high tech computer display, there is
a picture of the old mechanical design, which you use to issue
commands! The same is true of the new electronic displays
in the Space Shuttle -- we have recreated pictures of the
old displays on our new advanced displays. In both cases the
engineers realized that it was simpler and more reliable to
make gradual changes, rather than to do a complete redesign.
It's kind of like biological evolution, but for spacecraft.
Once
we have strapped in, we check to make sure the hatches are
sealed tight by slightly over-pressurizing the Soyuz and waiting
to see if the pressure drops. We do a quick check of all our
radios and communications equipment, then we settle in for
the roughly 2-hour wait until launch. Talking to us from the
bunker is our Soyuz simulation instructor, Andrei Kondratyev,
who will be our capcom (that's what we Americans call the
astronaut who talks to you from Mission Control) during the
launch phase. It is reassuring to hear his voice, since we
have heard it so many times before in the simulator. The two
hours go quickly, in spite of the fact that we are strapped
into a rather tight spot and there is no place to straighten
our legs. Because of our busy training schedule, this is about
the first quiet moment we've had in almost 2 months! I actually
fell asleep for a little while.
A few
seconds before liftoff, the engines are fired up and you can
feel the vibration. It makes a dull roar in the cockpit, but
it isn't really that loud. The actual liftoff is smooth, and
the G forces pushing you into your seat due to the acceleration
gradually build up over the first few minutes. The first stage
is much smoother than in the Space Shuttle, which really rumbles
as it takes off because of its two huge solid rocket boosters.
At a little before 2 minutes, the emergency escape rocket
is jettisoned because it is no longer needed. At this high
altitude and thin air, we no longer need such large rockets
to escape from the rocket below us if there was an emergency.
I can feel a thud as it shoots off the top of the Soyuz. A
few seconds later, the 4 small first stage boosters surrounding
the main body of the rocket are jettisoned, and there is an
immediate drop in acceleration from about 4 Gs to maybe 1.5
or so. For those of you who don't know, when we say 1 G, that
is the force of your normal (on the ground) weight. 4 G's
means 4 times your weight.
At about
2 and a half minutes, we are above almost all of the atmosphere,
so we no longer need the launch shroud which protects the
Soyuz from aerodynamic forces at low altitude. At this point
the shroud is just dead weight, so it too is jettisoned. Before
that, there is nothing out the window since the entire spacecraft
is enclosed in the shroud, but when the shroud goes off the
sun comes shining in my window to my left. It is blindingly
bright, and it shines right on my face making it almost impossible
for me to either read my checklists or to even see the readings
on the control panel in front of me. I spend the next few
minutes trying to block the sunlight using my left hand and
my checklist!
On the
radio, we can hear Andrei reading to us our engine parameters
and trajectory information. Interestingly, we don't have any
displays in the cockpit with this information, I guess because
there isn't anything we can do about it anyhow. If there is
a problem, we have a launch escape system which will take
us away from the rocket, and we would just land in the capsule
under parachute. During the second and third stages, the rocket
occasionally sways back and forth, perhaps it is the engines
swiveling underneath us to control our trajectory. It is a
little unnerving because at this point the Space Shuttle is
rock solid and smoothly accelerating. When we drop the 2nd
stage, there is a momentary drop in acceleration, then you
are rapidly pushed back into your seat when the 3rd stage
lights off. At 528 seconds after launch, the 3rd stage engines
stop, and our capsule separates from the 3rd stage -- actually
it feels more like we are ejected from the 3rd stage since
it is quite a shove. Yuri has a pencil and eraser tied off
on strings in front of him, and they begin floating telling
us that we are now weightless. It is nice to be back in space!
For the
next two orbits (about 3 hours), we remain strapped into our
seats while we check out all the systems of the spacecraft,
including the motion control system. The motion control system
is basically the sensors and gyroscopes which tell the ship
which way it is pointing, the small jets situated around the
Soyuz which allow the spacecraft to maneuver, and the computer
which figures it all out. After all the checks are complete,
we orient the ship so its solar panel wings are in direct
sunlight, and we spin the ship like you would spin a bottle
on the floor so our solar arrays stay pointed at the sun.
The ship is naturally stabilized like a top, so we can then
power everything down including the jets and motion control
computer. This makes for an interesting view out the window
since the ship is rotating end over end about once every 2
minutes.
After
that, we get out of our seats, head "up" into the living compartment,
which is nothing more than an 8-foot diameter sphere attached
to the top of the descent module. There, we take off our pressure
suits and get ready for the first rendezvous maneuver. By
then, the ground has tracked our orbit well enough to calculate
how much we need to increase our speed to raise our orbit
just enough so that our docking will occur at the proper time
2 days later. We go back down into the cockpit and execute
the first engine firing to raise our orbit. We only fire the
main engine for about 40 seconds or so, enough to increase
our speed by about 50 MPH. This is only a small change in
our speed, since we are going near 18,000 MPH already, but
it noticeably raises our orbit. The ground really looks like
it is going by fast since our initial orbit is only maybe
100 miles above the Earth's surface.
By then
it is bedtime, and after a very long day I have no problem
falling asleep. We each have sleeping bags and I squeeze myself
down into the cockpit, while Yuri sleeps up in the living
compartment. The second day is a light day, with just one
orbital correction burn we have to make to touch up our orbit
based on the ground's updated calculations. Besides that we
just have to monitor the spacecraft systems occasionally to
make sure everything is going well and set up the equipment
that we will need to use if our radar system fails during
the rendezvous with the station.
The next
day is rendezvous day, and it is a busy one. Up until this
point we have relied on ground radar tracking to provide our
trajectory information so we can rendezvous with the station.
Even though the ground can accurately measure our trajectory,
there are still slight errors, so we have an on-board radar
system which will make corrections to our estimate of our
position relative to the station. For those of you who are
pilots, the system works similar to a VOR/DME at large distances,
and like an ILS for the final approach to docking. For the
rest of you that means the computer can figure out our exact
orientation with respect to the station (and vice versa) so
that it can calculate when to fire the engines, and more importantly
in what direction. I'll write more about the mechanics of
space rendezvous in a later installment.
We are
on the night side of the Earth for most of our approach, but
at a distance of about 500 meters we come around to the daylight
side. Only then is the station visible. The Soyuz has a periscope
in the cockpit, and we see the station there on the viewing
screen. Yuri remarks that it looks just like a model floating
there in space. In fact it does -- it looks just like one
of the computer-generated images we are so familiar with from
the simulator. The station looks a bit like a huge mechanical
insect with appendages and solar array wings sticking out.
We are busy checking all the data as we make our final approach
to docking, and of course we are also looking carefully at
the view in the periscope to make sure we are all lined up
properly with the docking port on the station. It lines up
perfectly, and with a thud, we dock with the space station.
Of course, more pressure checks follow to make sure we have
a tight seal before we open the hatches. We can hear Nikolai,
Don, and Sox (Expedition 6) on the other side of the hatch
knocking while we wait!
Once
we finally get the hatches open, they introduce us to our
new home, and of course after that the next order of business
is lunch!
That’s
our ship docked to the ISS.
Here’s
a photo of our launch.
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