Breakthrough Propulsion Physics Program - Pitch and Bias

Pitch and Bias

One proposed method of achieving a diametric drive, or possibly a disjunction drive, which was studied in the BPP was called the pitch drive. This has been described as involving a hypothetical disjoint field which would eliminate the need for the field to be generated on the spacecraft itself.

One specific proposal for such a pitch drive was called the bias drive. According to this proposal, if it were possible to locally alter the value of the gravitational constant G in front of and behind the craft, one could create a bias drive. While the gravitational constant is a fundamental physical constant in general relativity, the Brans-Dicke theory of gravitation does in a sense allow for a locally varying gravitational constant, so the notion of a locally varying gravitational constant has been seriously discussed in mainstream physics. It has been claimed that one problem with the concept of a bias drive was that it might create a singularity in the field's gradient located inside the vehicle.

The bias drive and pitch drive is expressed qualitatively in mathematics as :

and

respectively.

where :

is the Gaussian distribution over dimensionless

is the magnitude of hypothetical pitch drive effect

is the magnitude of hypothetical bias drive effect