I'm Bradley Tyree,
and I'm a NASA test operations engineer
here at the A-1, Fred Hayes Test Stand.
From a really young age, I was interested in Space,
and I can remember being in elementary school
and doing like the Solar System,
science projects and things like that.
Also, my great grandfather worked out here for
Rocketdyne and Rockwell and Boeing as they changed
names throughout the years from the sixties,
seventies and even into the early eighties.
So he had a direct part, a direct part that he played
with the Space Shuttle Main Engine program.
I have pictures of him working on the engine,
working at B-2, you know, back when it was
more just like a skeleton.
And so that's really interesting.
And that was really fun, you know, growing up,
hearing all these stories, and seeing the pictures
of him working on the old rocket engines
and things like that.
So I never thought I would
see myself at Stennis Space Center.
But as I came up and I was started going to college
and studying aerospace engineering, I realized,
wow, I could really do, I could follow in his
footsteps, you know, and do the same kind of work.
I never pictured myself doing that,
but so I've always been interested in it.
And that's how I guess I found myself here.
As a NASA test operations engineer,
one of the roles that we have to perform
is the role of the test conductor,
and the test conductor is the vessel
at which all of the operations
on the stand has to be coordinated through
for testing the rocket engine.
So as a test conductor, this was never something
that I saw myself doing whenever I first started
at Stennis Space Center.
I kind of remember sitting in the back of the room
and thinking, wow,
that person up there is important.
So as the test conductor, you're responsible
for dozens and dozens of different technicians
and engineers, operations.
They are all counting on you to know what's
happening on the stand at all times.
You're responsible for knowing the valve
positions from level one to level ten and what
systems are pressurized and what systems aren't.
And people are looking to you to tell them when
and where they can perform their job.
And so there's a lot of responsibility and there's
a lot of pressure on the test conductor.
You know, sometimes you're having
five or six conversations at one time
with five or six different people simultaneously.
So it can be stressful,
but it's also very exciting.
On a typical test day, the test team arrives
at the control center around 5 a.m.,
so we start preparing the facility for calibration.
Right?
We have to make sure everything
is reading accurately and precisely
because we're going to be reading
all of this data back and conveying it
and sending it out and processing it.
We have a lot of analysis that happens.
So the team arrives, and everybody
starts getting on station.
We have transfer engineers for the different
propellants that goes to the rocket engine.
We have data engineers, video engineers, you know,
technicians start getting on station
on the test stand, and we start, everybody gets,
starts falling into place.
That's all day long, 12 plus hours.
Right?
You're on, you're in the chair,
and you're coordinating all these
different activities, and you have all these
different conversations happening.
You have all these systems you have to monitor
and data you have to watch.
All these things are happening,
and test day is just a giant adrenaline rush.
Right?
So you're building up and you've got
all these operations and then, you know,
1-O'clock, 2-O'clock happens and here it comes.
You're getting ready to hit that button
to start that engine.
That's, it's like being at the top
of the roller coaster. Right?
You're right there at the peak.
And you're ready to hit the button.
You hit the button
and that rocket engine starts firing.
Now you're on the roller coaster and
you're just holding on. Right?
You're watching all these different data systems.
You're watching temperatures and pressures
and all of the things are happening,
you know, in that 500 seconds.
One of the more important things
about being a test conductor is how the team
is integrated into that role.
Right?
So the test conductors job can be much easier
if we've got a really knowledgeable,
trained test team. Right?
And so everybody can take their specific
individual systems and relay that information
to the test conductor and the test goes smoothly
when you're getting lots of thumbs up
from the test team. Right?
It helps to have a team
that's on their game all the time.
Today, we'll be testing the RS-25 engine,
which is used to power the Space Launch System
on the Artemis missions.
These RS-25 engines are space shuttle main engines
that have gotten new, upgraded parts.
We've used things like 3D printing,
we've got different manufacturing techniques,
and so we're testing these engines as
part of a certification series right now.
And this series will prove and
provide data useful for future Artemis missions
and future rocket engines.
Here at NASA, we talk about
testing like you fly, and a typical RS-25 test
runs for about 500 seconds because
500 seconds is about how long it takes
for the Space Launch System
from the ground to reach orbit.
So you might think, you know,
why is this test going so long sometimes?
And that's because we're testing like we fly.
You know, we want to make sure that we hit
all of the same parameters that we would need to hit
in a launch day situation.
During today's engine test, you'll notice
the rocket engine gimbal or in other words,
it'll pivot around the central point.
Right?
This gimballing is used during flight
to control and to stabilize the rocket
as it reaches orbit.
We want to use the gimballing to control the
trajectory of the rocket as it reaches orbit.
During the test we'll take this gimballing,
and we'll take it as far as it can go.
Right?
To simulate any kind of conditions
it might experience during a flight.
One of the cool things about the rocket engine
test that most people don't know about
is that we actually take the rocket engine
past its limits, past any parameters
that it might see during a flight.
Right?
We take it to a higher power level,
to higher pressures, and
we gimbal this engine to higher angles of attack
than it would probably see during a launch,
during a flight situation.
And that's because, you know,
if I was an astronaut on board this rocket ship,
I would want to know that this thing's been tested
to its absolute limits. Right?
It needs to be able to perform
more than it's designed for.
And so that's the whole point of us
doing these rocket engine tests.
The RS-25 engine uses liquid oxygen
and liquid hydrogen
as the propellants for the engine.
We use liquid hydrogen because liquid hydrogen
has the highest specific impulse
or efficiency of any other substance.
It's extremely hazardous,
and it's extremely hard to control.
Liquid hydrogen has to be at temperatures
more than -420 Fahrenheit.
So it's a hard to handle propellant,
but you get the most bang for your buck
out of liquid hydrogen.
And I think that's what we'll continue to use
on all of these heavy lift space systems.
As you're watching today's test,
you'll probably notice this great white plume
exiting from the rocket engine exhaust.
Right?
And there's a myth that, that this plume is smoke.
It's actually water vapor.
So the two propellants that we use
in the rocket engine are made up of liquid oxygen
and liquid hydrogen, which forms H2O.
So you've got this extremely hot exhaust gas
coming from the rocket engine.
Right?
Thousands of degrees.
Meanwhile, we're pumping thousands and thousands of
gallons of water at the rocket engine exhaust to
help cool the structure as the exhaust is being
directed through the deflector and then out.
The atmosphere in the test control center on test day
is very relaxed at first. Right?
Everybody's coming in.
They got their cups of coffee,
everybody's getting on station,
and we're starting to monitor data.
Well, as we bring up systems,
you can kind of feel the tension build in the room.
Right?
It slowly gets quieter and quieter as you approach
that test, that launch or that engine start button.
So as we're going, you know, we're building up
the tensions, getting thicker almost.
You can feel it in the room.
And then I would say that 30 minutes before you
start the engine, it's very quiet in here.
Right?
And a lot of things are happening.
We have a lot of operations
that have to happen in those final 30-,
15-, 6-, 1-minute call outs
that we have in our test countdown.
Test day, there's nothing like test day.
Right?
And of course, there's all the time
and work that goes into test day.
But there's nothing like test day.
It doesn't feel like work at all.
It feels, it's very fun.
It's exciting. It's challenging.
It, it's dynamic. Right?
A lot of things are happening all at once.
And that's, I would say that's true for anyone in
the control room, anyone involved with tests.
I don't think it's just test conductor, your
transfer engineers, your instrumentation engineers.
I'd like to think that they're also feeling that,
that feeling. Right?
It's like it doesn't feel like work.
I'd say we have probably the coolest job.
Some advice I have to maybe, you know,
some of the younger generation
that's getting interested in some of this work
and thinks, man, I'd like to do that someday.
My advice would be to don't sell yourself short.
Don't think that you can't.
If I was to meet myself ten years ago,
there's no chance that ten years ago me
would have thought I'd be where I am today.
So I'd say my biggest piece of advice,
just don't, don't stop.
Don't give up. Right?
Keep learning. Keep trying.
You can do it.
And if I can do it, anyone can do it.
That's my advice.
(engine rumbling)