Historical research guide · 0312 · 2010
Advanced Space Propulsion Based on Vacuum (Spacetime Metric) Engineering
Harold E. Puthoff
In one minute
This is the paper that named the field, in the version Hal Puthoff published for the space-flight community. The Journal of the British Interplanetary Society ran it in 2010, and Puthoff posted it to arXiv two years later; the same text had already gone to the Defense Intelligence Agency as one of its reference documents, and that sheet carries the whole of it. The argument is short and unusually practical. General relativity stores space and time in a set of numbers, the metric tensor, and every quantity you could measure — clock rate, ruler length, colour, energy, effective mass, the local speed of light — is tied to those numbers by fixed relations. So you can work out what an engineered region would do before anyone knows how to build one. Puthoff tabulates it: clocks inside run fast, emissions blueshift, materials behave as though hardened, effective mass falls, light bends around the craft. He calls the method general relativity for engineers.
Connection
Chapter 4 takes its name and its checklist from this paper, and this is the version a reader can cite in a journal reference — the peer-reviewed twin of the reference document, published in the aerospace literature rather than released under a records request.
From the source
The metric tensor approach is model-independent: it does not depend on knowing the specific mechanisms or dynamics that produce a spacetime alteration, only that a technology exists which can control and manipulate the metric, so the physical consequences can be catalogued ahead of the mechanism — a general-relativity-for-engineers approach.Section 2, Spacetime Modification — Metric Tensor Approach
Fixed relations tie every measurable quantity to the metric coefficients — time intervals, frequency and energy, spatial intervals, the remotely observed velocity of light, and effective mass — and Table 1 sets the natural case beside the engineered one, so that where a dense mass slows clocks and reddens light, the engineered column reads the other way through.Section 3, Physical effects as a function of the metric tensor coefficients, Table 1
A spacetime alteration can be written as an effective refractive index of the vacuum; because the velocity of light is set by the vacuum’s permeability and permittivity, generating such an index by technological means is the same thing as engineering those two vacuum parameters — the polarizable-vacuum representation of general relativity.Section 3.4, Refractive Index Modeling
The right-hand column of Table 1 amounts to a specification for an interstellar craft: superluminal motion relative to the background frame while nothing locally outruns light, material bonds strengthened relative to the environment, effective mass decreased, an accelerated internal time frame that permits abrupt trajectory changes without undue internal stress, gravity-like forces of arbitrary geometry, and lensing effects in which light bends around the craft or appears to terminate in mid-space.Section 4, Significance of physical effects for advanced aerospace craft, Sections 4.1 to 4.4
Arbitrary metrics with the desired gravity, antigravity and propulsion characteristics can in principle be postulated — the Alcubierre solution being the exemplar — but what implementation requires is determining appropriate sources for their generation, and Puthoff states that until that is met it is premature to guess at an optimum strategy or to form a critical path for engineering development.Section 5, Discussion
The way in
https://arxiv.org/abs/1204.2184How to cite it
Harold E. Puthoff (2010) Advanced Space Propulsion Based on Vacuum (Spacetime Metric) Engineering arXiv:1204.2184