Question: is field propulsion possible?

Martin McCoustra answered on 5 May 2025:

If you mean that the spacecraft doesn’t carry propellant to change it’s flight path then yes… we have technologies that can do that. Indeed, the flight the the Voyager space probes which have no left the Solar System is governed only by the interaction of the spacecraft with the gravitational fields surrounding it and has been such since pretty much their law in the 1970s. Another technology that we currently have and could use is a solar sail… which relies of the light field emitted by our star to propel it.