# negative mass propulsion

Negative mass propulsion is a hypothetical propulsion system based on the juxtaposition of ordinary
positive mass and negative mass. In theory,
such a system would be able to provide continuous thrust, without violating
the principles of conservation of momentum or energy. It would require no
input energy and no reaction mass.
Workability of the scheme, however, hinges on the existence of negative
mass and also on negative mass having negative inertia.
The combined interactions of the two types of mass would then result in
a sustained acceleration of both masses in the same direction. The concept
of negative mass was first considered in depth by Herman Bondi^{1} in 1957 and revisited in the context of interstellar spaceflight by Winterberg^{2} and Robert Forward^{3} in the 1980s.

### References

1. Bondi, H. "Negative Mass in General Relativity," *Reviews of Modern
Physics*, Vol. 29, No.3, July 1957, pp. 423-428.

2. Winterberg, F. "On Negative Mass Propulsion," International Astronautical
Federation, Paper 89-668, 40th Congress of the International Astronautical
Federation, Malaga, Spain, Oct., 1989.

3. Forward, R. L. "Negative Matter Propulsion", *Journal of Propulsion
and Power* (AIAA), Vol. 6, No. 1, Jan.-Feb. 1990, pp. 28-37.