Gravity and vacuum are not mutually exclusive - you always have to deal with gravity forces, although they become negligible pretty quickly when you get into and then leave orbits.

As to the specific claim, I suspect that the experiments they are currently doing (in vacuum chambers on earth) have gotten to the point that they are measuring the propulsion system producing more thrust than it's own weight (T/W >1), which would technically be enough thrust to overcome gravity. Even if it wasn't practically useful for actually getting to orbit, that amount of thrust on a reactionless motor would be incredible, and would totally unlock the solar system for us.

[–] [email protected] 8 points 3 months ago

And now it makes sense. Thank you!

[–] [email protected] 3 points 3 months ago

they become negligible pretty quickly when you get into and then leave orbits.

You're not wrong, but it's worth noting that in low earth orbit (e.g. typical ISS orbiting altitude) earth's gravity is still 90% as strong as at sea level. Astronauts on the ISS are weightless not because they escaped earth's gravity, but because they're continuously falling.

[–] elbarto777 0 points 3 months ago

it’s own weight

its* own weight.