The Exodus Effect vs. Known EHD Physics

A small, independent physics sanity-check of the Exodus Effect — the propellantless drive that Charles Buhler / Exodus Propulsion Technologies described on the Danny Jones Podcast (July 2026). Their claim: ~10 mN of thrust from a cm-scale ~760 mg device at 30–40 kV, said to be sustained in a vacuum chamber and to persist after power-off, and framed as a working version of Quantized Inertia that violates Newton's third law.

This project builds the standard, peer-reviewed model of electrohydrodynamic ("ionic wind") thrust and asks: how much of that is explained by ordinary physics, and exactly where does the claim require something new?

What this is: a quantitative yardstick — what ordinary ionic wind predicts, using published EHD literature (MIT's Nature 2018 solid-state aeroplane, which flew at ~40 kV, as the anchor baseline). What this is not: a lab replication, a measurement of Buhler's device, or an endorsement. No hardware — pure numerical computing.

The one-line finding

In air, ~10 mN at ~40 kV is unremarkable ionic wind — it's the exact voltage regime the MIT plane flew on, and needs only 50–400 µA of corona current, at a thrust-to-power ratio (0.6–5 N/kW) at or below the known 5–15 N/kW ceiling. Nothing anomalous. The claims that would be anomalous are the ones about vacuum: Paschen's law says a corona at a cm-scale gap and 40 kV cannot even self-sustain below ~10–80 Pa, so the model predicts 0 mN at any real vacuum-chamber pressure. If Buhler's ~10 mN truly holds in hard vacuum, ordinary ionic wind is falsified for his device — so his case stands or falls entirely on a thrust-vs-pressure curve, which the public accounts never show.

And "thrust persists after power-off" is outside this model entirely: ionic wind stops the instant the field is removed. A force that outlives the power is the classic signature of a measurement artifact (thermal, dielectric charge decay, balance settling) — the failure mode that sank the EmDrive/Eagleworks results.

And the "but any thrust adds up over time in space" argument? Correct in principle (~10 mN would give a small craft 3–13 km/s of Δv per year) — but the ionic-wind thrust hits its Paschen cutoff at ~55 km altitude, ~45 km below the Kármán line. Realized thrust in orbit is 0 mN, so accumulated Δv on any space mission is 0. The argument integrates a number that is zero everywhere you'd actually fly.

Run it

pip install -r requirements.txt
python src/compare_claims.py

This runs the whole pipeline: validates the model against the MIT baseline, generates the pressure-scaling and comparison plots, and writes the report.

Outputs (in output/)

• pressure_scaling.png — thrust vs. chamber pressure, with the Paschen discharge cutoff marked (the core discriminator).
• paschen_curve.png — the Paschen breakdown curve for air; its left branch sets the vacuum-side cutoff used in the thrust model.
• claim_comparison.png — the claim vs. the known-physics band, and what it becomes in vacuum.
• sensitivity.png — how the in-air verdict holds up as μ and voltage vary.
• mission_integration.png — the "it adds up over time in space" argument vs. where the thrust actually goes to zero (altitude / pressure profile).
• report.md — full write-up: model, assumptions, MIT validation, verdict.

Layout

ehd-thrust-verification/
├── README.md
├── requirements.txt
├── data/
│   └── reference_literature.json   # cited baselines + the claim under test
├── src/
│   ├── ehd_model.py                # F = I·d/μ core model + MIT validation
│   ├── pressure_scaling.py         # thrust-vs-pressure + Paschen cutoff
│   ├── sensitivity.py              # sweep over μ and voltage
│   ├── mission_integration.py      # "adds up over time" vs altitude/pressure
│   └── compare_claims.py           # runs everything; writes report + plots
└── output/                         # generated plots and report land here

Citations

• Xu et al., Flight of an aeroplane with solid-state propulsion, Nature 563, 532–535 (2018).
• Masuyama & Barrett, On the performance of electrohydrodynamic propulsion, Proc. R. Soc. A 469:20120623 (2013).
• Gilmore & Barrett, Electrohydrodynamic thrust density using positive corona-induced ionic winds for in-atmosphere propulsion, Proc. R. Soc. A 471:20140912 (2015).
• Paschen's law — standard gas-discharge physics (constants for air converted from Raizer, Gas Discharge Physics).
• Claim under test (not peer-reviewed): Charles Buhler & co-founder Andrew, Exodus Propulsion Technologies, Danny Jones Podcast (published 2026-07-02); The Debrief, "NASA Scientist Says Patented 'Exodus Effect'…" (2026); APEC presentations (2024–2026). The patent number "WO2020159603A2" from the original podcast summary is unverified and may be incorrect.