I share your reservations Stephen. Of course, if the Chinese actually state that they have a working device I wanted to know the details. Strange things do happen on occasion.
Dave -----Original Message----- From: Stephen A. Lawrence <[email protected]> To: vortex-l <[email protected]> Sent: Wed, Dec 28, 2016 1:43 pm Subject: Re: [Vo]:EM Drive need not be outside the spacecraft Just to point something out -- the EM drive obviously doesn't need to be outside the craft to work, since it doesn't eject mass. Furthermore (and consequently), it violates conservation of momentum, conservation of angular momentum, conservation of energy, and conservation of mass. While data trumps theory, this doesn't seem like the most likely explanation of the effect to me. Gedanken: Put an EM drive in a box. Attach it to a wire. Attach the other end of the wire to a pivot (like one of those old gas powered toy planes people used to have before the days of radio control). Let the box with the EM drive go. It will accelerate in a circle, around the pivot point. Power consumption inside the box is presumably constant. Power generated varies in proportion to the speed of the box (power = force * velocity). So, at some point it'll be generating more power than it's consuming. And there's the violation of CoE. (With a bit of cleverness you can turn it into a Type I perpetual motion machine.) Meanwhile it's going lickety split around the pivot, with increasing angular momentum; with no mass ejection there's no compensating decrease anywhere else. There's the violation of conservation of angular momentum. And as its velocity increases, its mass increases as gamma*m. There's the violation of conservation of mass. And violation of linear momentum is obvious. On the other hand if it doesn't work, then all that's being violated is the assumption that the handful of extremely delicate high precision experiments that have been done to show the effect were not somehow botched. I'm not holding my breath on this one. On 12/28/2016 02:02 AM, David Roberson wrote: Russ, Can you verify that the Chinese actually have a functioning EM drive on their space station. Also, how much thrust are they claiming? Finally, is that device or group of devices capable of maintaining all of the orientation required for the station? Dave -----Original Message----- From: Russ George <[email protected]> To: vortex-l <[email protected]> Sent: Tue, Dec 27, 2016 3:45 pm Subject: [Vo]:EM Drive need not be outside the spacecraft A curious facet of the EM drive, such as the one now operating on the Chinese space station is that it need not be on the outside of the spacecraft, it’s thrust is independent of the position and surrounding matter. This enables all manner of interesting spacecraft geometries.
