Measurement & replication
Make the signal survive.
Calibration, thermal drift, magnetic interactions and analysis choices determine whether a force can be interpreted. Null tests place useful bounds on defined claims.
Which control distinguishes the candidate from its strongest ordinary explanation?
Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum
Reports a small force signal from an asymmetric radio-frequency cavity and documents a vacuum test campaign. It is a useful historical case for examining how a claimed propulsion signal must be tested against systematic effects.
High-accuracy thrust measurements of the EMDrive and elimination of false-positive effects
Shows how thermal expansion, center-of-mass shifts, and magnetic interactions can imitate small thrust. The tested cavity configurations yielded no anomalous force above a 10–30 nN noise level across the reported frequency scans.
Recommended Practice for Thrust Measurement in Electric Propulsion Testing
Details design, calibration, drift handling, analysis, and uncertainty reporting for pendulum thrust stands. It distinguishes sensitivity, repeatability, accuracy, and resolution, which should remain separate in the company's test reports.
Force Calibration Via Electrostatics
The authors describe how electrical and length measurements realize micronewton forces with SI consistency. Comparisons between electrical and deadweight forces demonstrate a traceability route and motivate independent calibration of a candidate propulsion experiment.
Thrust measurements and evaluation of asymmetric infrared laser resonators for space propulsion
A dedicated balance tested asymmetrical laser resonators, reflective cavities, and fiber-optic loops at nanonewton sensitivity. No net thrust was resolved for those devices, making the paper directly relevant to claims that cavity asymmetry or resonant enhancement alone creates propulsion beyond ordinary photon recoil.
Milligram mass metrology using an electrostatic force balance
Uses a concentric cylindrical capacitor to link electrical and length measurements to reference force. Weighing experiments illustrate how a small-force measurement can have a traceability chain instead of relying on nominal sensor resolution.
Removal of zero-point drift from AB data and the statistical cost
Analyzes alternating measurements of two configurations and removal of polynomial zero-point drift. It explicitly treats the statistical uncertainty introduced by drift filtering, helping distinguish a corrected estimate from an artificially clean trace.
Zeptonewton force sensing with nanospheres in an optical lattice
Uses a standing-wave trap and feedback cooling for long-duration measurements of small forces. Moving a sphere between known optical-lattice positions calibrates displacement, providing a route that also works for neutral particles.
Charge-Induced Force Noise on Free-Falling Test Masses: Results from LISA Pathfinder
Measures coupling between test-mass charge and stray electric fields in flight. Charge management and field compensation suppress a conventional source of acceleration noise that could otherwise obscure a weak-force experiment.
Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results
Reports free-fall performance across a frequency band and separates low-frequency behavior, residual-gas noise and interferometer readout noise. It is a model for reporting spectral performance instead of one context-free sensitivity number.
Increased Brownian Force Noise from Molecular Impacts in a Constrained Volume
Finds that a nearby enclosure can increase residual-gas damping and associated force noise. Two different torsion-pendulum arrangements and numerical modeling demonstrate why chamber geometry belongs in the measurement model.