Would a sneeze by a cosmonaut in a spacesuit affect his movement?

When the cosmonaut sneezed they would start moving, and rotating, in the opposite direction, but when the sneeze hit their faceplate (ugh!) this would stop the motion. The net result is that the velocity of the cosmonaut would not have changed, but their position and angle would have.

According to Wikipedia a typical breath is 500cm$^3$ and a sneeze velocity is around 15m/s. If the density of air is about 1.2kg/m$^{3}$ the momentum of a sneeze is about 0.009kg.m/s. I weight about 70kg, so the sneeze would leave me moving at about 0.0013m/s. Lets say the faceplate is 5cm away from my mouth, then with the sneeze moving at 15m/s I'd only move for 0.0033s before the sneeze hit my faceplate (ugh again!) and stopped me. In that time I'd have moved about 4 microns.

I must admit that's less than I thought when I started this.


Cosmonaut would not budge because the force of the sneeze pushes him back and when the sneeze hits the helmet that makes a forward force, nullifying the two forces.