MAN: This morning we have sort of a unique event going on.
We're gonna have a reboost,
where we're gonna fire the engines
on the aft end of the space station
to increase our velocity in orbit around the Earth,
about one meter per second or so.
So not a lot, but enough to -- to raise our orbit a little bit
and to prepare for a coming Progress supply ship,
as well as the space shuttle shortly after that.
Now, some of you have asked why we need to do a reboost --
Do we stay in orbit, and questions like that.
The answer is there is a small amount of drag here
even 200 miles above the Earth.
And they say it's from atomic oxygen,
so there's a very small amount of oxygen
present out there in the vacuum of space,
and so it's not a 100% vacuum.
And those atoms
cause a finite amount of drag on the space station,
so over a period of time, we slow down,
and our altitude over the Earth decreases.
So, due to that
and also due to the requirements of rendezvous
of spacecraft like Progress and shuttle,
we need to adjust the orbit --
usually increase it periodically.
And we're gonna do that this morning.
I'm gonna try to give a demonstration
while it's happening
so that you can see the acceleration from the engine.
So, let's head down to the Russian segment
and prepare for that.
Okay, here we are down in the Russian segment
in the service module.
And we don't actually operate the reboost here on board.
The ground programs it,
and then the computers on board execute the reboost.
But we have insight into the parameters coming up,
and it looks like we're programmed
to do a 2.7-meter-per-second increase in our Delta-V.
When the engines fire, we will experience a small acceleration,
not a whole lot,
but it will be 0.0185 meters per second squared.
And I'm gonna try to demonstrate that
at the time of ignition and during the burn.
Now, the way I'm gonna demonstrate the acceleration
that comes during the reboost is by using this camera --
800-millimeter lens, so it's -- it's pretty massive, actually.
And you can see I can float it here,
and there's no reboost going on right now,
so the camera's not gonna go anywhere.
It's just gonna slowly drift due to the ventilation
or -- or if I put any velocity into it,
it'll drift out of the scene,
but I'm gonna try to hold it here steady,
and you can see that it stays very steady.
That's gonna be different
at the point of ignition entering the reboost,
and we'll see that here in a few minutes.
Okay, we have about 40 seconds or so before the burn starts.
Again, we're in weightlessness right now,
and there's no accelerations --
virtually no accelerations on us,
and you can see I'm floating this camera right here,
and it's not going anywhere.
That's gonna change here in just a little while.
Let's see.
Looks like we have about 20 seconds to go
until the scheduled burn time.
There's my camera. I'm setting it up for ignition.
Here it goes.
It actually came a little bit early.
Now watch the camera accelerate toward you.
There it goes.
I'm gonna reach out and grab it
and bring it back into view here.
And I'm holding it.
I'm actually feeling the acceleration.
I'm gonna let go again.
And here it goes. It's gonna take off.
I'll try not to let it hit you.
Just gonna miss you.
[ Radio chatter ]
The burn is still going on.
I'm gonna let go again. Here it goes.
[ Man speaking native language ]
The burn is continuing.
Again, I'll demonstrate it one more time.
I'm just gonna have the camera. I'm gonna let go.
It's gonna begin to accelerate toward you.
Now, what would happen if I let go myself?
Okay, I'm gonna let go now.
And here I go, drifting back toward you again.
So the acceleration applies to me, too.
[ Engine turns off ]
Ah, and there I could hear the engine cut off.
So the burn is complete.
We have reached our 2.7 meters per second
that we desired.
And now, if I let go of the camera, it's not going anywhere,
so the burn is over.
Reboost complete.
We'll stay in orbit for a little while longer.