Former NASA engineer says he’s built a machine that defies gravity: Could propellant-free space travel be possible?

A machine that can push itself through space without expelling any propellant has long been a holy grail for engineers and dreamers. Such an invention would transform space travel, but it has always faced stiff resistance from the world of physics. According to Newton, every action needs an equal and opposite reaction and most ideas that try to get around this law have been dismissed or disproved over the years. Still, new attempts surface from time to time, like this one here.

New contender for propellant-free thrust

The latest attempt comes from Charles Buhler, a former NASA engineer now working at Exodus Propulsion Technologies. Buhler’s team claims to have built an electrostatic device that produces thrust without the use of any propellant. Unlike previous designs, he says this engine can create enough force to overcome Earth’s gravity, something no earlier model has managed.

Buhler’s journey through the world of alternative propulsion began during his time establishing the Electrostatics and Surface Physics Laboratory at NASA’s Kennedy Space Center. For years, he and his colleagues experimented with different ways to achieve motion without mass ejection. Most of their prototypes delivered barely measurable results, but persistence and new approaches eventually paid off, Buhler claims. The group’s recent efforts led them to a device with an asymmetry in electrostatic pressure or a divergent electrostatic field. They believe this allows for a sustainable force on an object’s centre of mass, enabling movement upwards.

Buhler made public his findings at the Alternative Propulsion Energy Conference, a meeting ground for engineers, scientists, and enthusiasts. During his presentation and in interviews, he was clear that this project is independent from NASA and is very much a private venture.

Despite the excitement, most physicists remain cautious. The field is littered with similar announcements that failed after more rigorous, third-party checks. The most high-profile case was the EmDrive, introduced in 2001 by British engineer Roger Shawyer. For two decades, this “impossible drive” was put through a battery of tests, including some positive readings from NASA’s Eagleworks team. Later, larger-scale studies, such as one conducted at Dresden University of Technology found no thrust at all.

The main challenge for Buhler and his team will be independent verification. The wider scientific community will want to see results reproduced by other labs that use different setups, tools, and researchers. Only this sort of testing will help rule out all sources of error, from interference and measurement mistakes to overlooked explanations within existing physics. For now, the story of a propellant-less engine remains one of big ideas and just as big a need for careful testing.