EM Drive
A proposed spacecraft thruster that claimed to produce thrust without propellant, violating conservation of momentum, tested by NASA but ultimately attributed to measurement error.
INVESTIGATION OVERVIEW
The EM Drive (Electromagnetic Drive) was a proposed thruster design by British inventor Roger Shawyer in 2001 that claimed to produce thrust by bouncing microwaves in a closed cavity, requiring no propellant. This would violate the conservation of momentum, a fundamental law of physics. NASA's Eagleworks laboratory tested the EM Drive and reported anomalous thrust in 2014–2016, generating enormous media interest. However, subsequent testing by multiple laboratories (including a 2021 Dresden University study) concluded the thrust was an artifact of thermal expansion and electromagnetic interference. The EM Drive is now widely considered a dead end, though it remains a subject of interest in fringe physics communities.
KEY CLAIMS
The EM Drive produces thrust without propellant, violating known physics
NASA's Eagleworks tests confirmed anomalous thrust
The drive could revolutionize space travel if the effect is real
The thrust may be explained by new physics (quantum vacuum, pilot wave theory)
The effect was suppressed by mainstream physics establishment
SUPPORTING EVIDENCE
NASA Eagleworks reported thrust in multiple test configurations
Chinese researchers reported similar anomalous thrust measurements
The thrust was measured in vacuum conditions, ruling out air convection
The effect was small but appeared consistent across different test setups
The drive generated significant interest from DARPA and NASA
COUNTER ARGUMENTS
The 2021 Dresden University study conclusively showed the thrust was thermal expansion artifact
The measured thrust was at the threshold of measurement sensitivity
No theoretical mechanism for propellantless thrust exists in known physics
The NASA results were never published in a peer-reviewed journal
The EM Drive violates conservation of momentum, which has never been violated
TIMELINE
Shawyer proposes the EM Drive concept
NASA Eagleworks reports anomalous thrust
NASA publishes results in peer-reviewed journal
Dresden study attributes thrust to thermal effects
KEY FIGURES
Roger Shawyer
British inventor who proposed the EM Drive
Harold 'Sonny' White
NASA Eagleworks researcher who tested the drive
ORGANIZATIONS
NASA Eagleworks
Space Agency
Dresden University of Technology
Academic
DARPA
Government
SOURCES
RELATED ENTITIES
PEOPLE
Roger Shawyer
Harold 'Sonny' White
ORGANIZATIONS
NASA Eagleworks
Dresden University of Technology
DARPA
EVENTS
Shawyer proposes the EM Drive concept
2001
NASA Eagleworks reports anomalous thrust
2014
NASA publishes results in peer-reviewed journal
2016
Dresden study attributes thrust to thermal effects
2021