"All stop"

Captain Picard's Hair · Tue Feb 12, 2008 10:22 pm

Trying to move on after the recent events...

I've just seen Tom Paris, engaging in battle in a shuttle, pulling the old "come to a stop and get behind the chasing ship" trick. We've debated the sub-light acceleration rate in Starfleet ships, but how about deceleration (or, acceleration in reverse for physicists)? We've seen captains order "all stop" a number of times and as far as I can tell, it's assumed that the ship stops virtually instantaneously! How this is done without forward-facing engines is a mystery, but if we are to believe what seems to be implied, than Starfleet ships have the ability to decelerate at a bewildering rate. Of course, this is an extreme example of the importance of the inertial dampers.

Captain Picard's Hair · Tue Feb 12, 2008 10:35 pm

Of course, if they can accelerate in the reverse direction at this rate, then they should be able to do it in the forward direction pretty well, too...

Sionnach Glic · Post by **Sionnach Glic** » Tue Feb 12, 2008 10:38 pm

Maybe the impulse engines can also 'pull' the ship to a stop as well as 'push' it to hight speeds?

And as for having 'all stop' in the middle of space.....

I like to think of it as 'stopped, relative to the nearest star'.

Post by **Captain Seafort** » Tue Feb 12, 2008 10:41 pm

Or rather, "relative to the dominant gravitational field", since stopping relative to a star might cause problems with planets, moons, etc in the vicinity.

Captain Picard's Hair · Tue Feb 12, 2008 10:41 pm

Well, impulse speeds could only be given relative to a specified frame of reference too, so there's nothing really new there in terms of defining "all stop." Trek has ignored this, but we'll have to assume that it's so.

Sionnach Glic · Post by **Sionnach Glic** » Tue Feb 12, 2008 10:41 pm

Yeah, that might be a better idea, Seafort.

Post by **Captain Seafort** » Tue Feb 12, 2008 10:44 pm

Captain Picard's Hair wrote:Well, impulse speeds could only be given relative to a specified frame of reference too, so there's nothing really new there in terms of defining "all stop." Trek has ignored this, but we'll have to assume that it's so.

It depends on what "impulse" actually refers to. If it's acceleration rather than speed then I don't believe a reference point is required.

Blackstar the Chakat · Tue Feb 12, 2008 11:04 pm

I think All Stop may refer to relative inertia.

mlsnoopy · Post by **mlsnoopy** » Wed Feb 13, 2008 8:48 am

If the impulse engine is able to decrese the mass of a ship than it could also increase the mass of the ship. And there by decreasing the speed.

Post by **Graham Kennedy** » Wed Feb 13, 2008 9:30 am

This is a lovely explanation of something in ST III. When the Excelsior's engines go belly up during the chase of the Enterprise, the ship visibly slows down. In reality it should keep going at constant speed with no engines.

But if you assume that the mass lightening effect was at work as it accelerated in the first place, then when the engines shut down the ship would presumably return to normal mass, without a change in kinetic energy - so it would indeed be expected to slow down.