Launching a Truck Into Space 140
but it was a difficult challenge. “I don’t know if there’s
a single thing in that engine that has worked,” Elon said
about the early prototypes of the rocket engine. “Where
do I start? The turbo pump has been difficult, the thrust
chamber assembly’s been difficult, and all the little stuff in
between has been difficult, too.”^301
Known as the Merlin, the engine developed by Mueller’s
team became the first rocket engine produced by an Amer-
ican company in 10 years and the second rocket engine in
25 years. It seems probable that the name originates from
the bird Merlin – a small species of falcons. “The Merlin
is much more analogous to a truck engine than a sports
car engine, which is how all other engines are designed,”
Elon said. “Instead of designing it to the bleeding edge of
performance and drawing out every last ounce of thrust, we
designed Merlin to be easy to build, easy to fix and robust.
It can take a beating and still keep going.”^303
The Merlin is not an engine that cares about the en-
vironment, but that’s not an issue. “You know, rockets
contribute, essentially, 0.000001 percent of CO2 or other
emissions,” Elon said. “And unfortunately, you really need
to burn chemical propellants to get out of Earth’s gravity.
There’s no other way to do it.”^4 An electric rocket creates
thrust by accelerating beams of ions. These rockets are ef-
ficient, but the amount of thrust they produce is very small
compared to the amount produced by chemical propulsion.
Because of the low thrust, you can’t use ion thrusters to
launch a spacecraft into orbit, but ion thrusters are ideal
for propulsion when the spacecraft is in space.^294