Thomas Mueller is an American aerospace engineer and rocket engine designer. He was employee No.1 of SpaceX and is the founder and now CEO of Impulse Space.

Mueller is best known for his engineering work on the Merlin, Draco, Super Draco and TR-106 rocket engines. He is considered one of the world's leading spacecraft propulsion experts and holds several United States patents for propulsion technology.

In 2002 Mueller joined Elon Musk as the founding employee of SpaceX. As Vice President of Propulsion Engineering and subsequently CTO of Propulsion at SpaceX, Mueller led the team that developed the Merlin 1A and Kestrel engines for the Falcon 1, the first liquid fueled orbital rocket launched by a private company; the Merlin 1C, Merlin 1D and MVac engines for the early iterations of the Falcon 9 launch vehicle; the Draco thrusters that provide the attitude control thrusters for the Dragon spacecraft and the SuperDraco storable-propellant engines used to power the capsule launch escape system. Dragon was the first spacecraft launched by a private company to dock at the International Space Station. In 2014, Mueller transitioned engine development to the SpaceX Propulsion Engineering team and in 2016 he moved into the role of Propulsion CTO. In January 2019 he became Senior Advisor (Part-Time). Tom Mueller announced that he retired from SpaceX on November 30, 2020.

Mueller founded his own company, Impulse Space in September of 2021. The company develops chemical rocket engines, space tugs for moving satellites on-orbit, and planetary landers to deliver payloads to Mars.

Science, Technology, Engineering, Aerospace Engineering Space,