The SLS’s 212-
foot rocket core
stage, en route for
testing at NASA’s
Stennis Space
Center.additional testing, as well as investments in man-
ufacturing that will generate overall savings. That’s
still a lot of money for engines that will only be used
once before being discarded into the ocean.
Dealing with an expendable launch system is new
for the SSME veterans at Aerojet Rocketdyne, where
the primary design and manufacturing ethos had
changed from reuse to cost reduction. Company
facilities in California and Florida are creating legacy
engine components using 21st-century manufactur-
ing techniques, like laser printing, to reduce the time
needed to make and quality-check engines. “The
main things we’re working on right now are retaining
reliability and making it less expensive,” Bradley says.
The new RS-25s will only be fired during one
test and one launch, so the engines won’t have the
chance to develop those personalities that come
from contact with maintainers.
The engine’s return on a one-and-done rocket
makes for an emotional, bittersweet return. “I was
sad to see my children go, but they’re going off to
college now,” Muddle says.ON JANUARY 28, 2021, AN RS-25 DEVELOPMEN-
tal engine fired for a full duration, the entire 500
seconds it takes to vault Orion into orbit. Bradleywent to Stennis Spacef light Center in Missis-
sippi to work the test—familiar ground for the now
high-ranking executive engineer.
The visit triggered memories of the first rocket
engine test Bradley observed as a fresh Aerojet
hire at the same location. He watched from the
roof of a building just a quarter mile away from
where the engine roared to life, assaulting his ears
and spreading shock waves through his chest. “My
thought at that time as a young engineer was:
‘How does that thing stay together?’” Bradley says.
Watching the RS-25 flare to life in January
2021, thundering well past the original limits
of its design, reignited those memories. “I’ve got
to admit that during the last single engine test, I
had the same thought,” he says. “I’ve been in this
business for a long time, but the amount of power
that we’re harnessing—I just never take it for
granted.”
The SLS is scheduled to make its maiden voyage
sometime this year, carrying an Orion capsule with
an instrumented mannequin in the seat where
astronauts will one day sit, and Bradley plans to
see his old friend fly again.
“I’ll probably have a job to do,” Bradley says.
“But I’m hoping I can sneak outside three min-
utes before the launch and watch it with my
eyeballs.”May/June 2022 57CO
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