how to slow down a spaceship using law of conservation of momentum without a collision?

[imported_Amber]

you command spaceship zero which is moving through the void of interplanetary space. using only law of conservation of momentum explain how you would slow down your ship without striking another object

 

[lexy]

If you are talking about a friction-less atmosphere/environment then you cannot. Otherwise turn the spaceship off? or however you make a spaceship stop going? but even then it would slow due to friction with the atmosphere.