Re: How does a DST work?

I am sorry that I have been unable to find out what a DST is.  
Unfortunately, when you perform a search for DST on a web search engine you 
get hundreds of hits, but DST is a very common acronym, and I could not 
find anything about a reactionless drive mechanism.  If you search for 
reactionless drives you do find some web sites that refer to things that 
sound like the DST you refer to.  Web sites to check out are:
http://www.open.org/davidc/
http://www.spacedrives.org/

I looked at these and could not figure out how they were supposed to work.  
I very much doubt that Newton’s third law would be violated by any of these 
devices.  These devices seem to be ordinary mechanisms that involve complex 
rotating parts  Conservation of momentum is very well tested.  In order for 
such a fundamental law to be broken you would probably need to have 
conditions that were very extreme in some respect.  For instance, at very 
high energies the laws of physics that we know may be shown to be 
incomplete.  

Every know and then are entire view of what is possible changes.  Einstein 
was able to show that our basic concepts of space and time fell apart when 
relative velocites got to be comparable to c, the speed of light.  However, 
for velocities small compared to the speed of light, the special 
relativistic effects of Einstein are very small, and Newton’s laws of 
motion are very nearly exact.  When velocities are not limited to being 
small compared to the speed of light, Einstein’s generalization of Newton’s 
laws still require conservation of momentum.

So while it may be that momentum is not always conserved, it certainly 
appears that in the corner of the universe we inhabit, with the energies 
that are accesible to us, and with the four fundamental  forces that we 
have found, momentum is conserved.

I hope this has been of some help.