A HeNe laser onboard a spaceship moving toward a remote space station emits a beam of red light toward the space station. The wavelength of the beam, as measured by a wavelength meter on board the spaceship, is $632.8 \mathrm{nm}$. If the astronauts on the space station see the beam as a blue beam of light with a measured wavelength of $514.5 \mathrm{nm},$ what is the relative speed of the spaceship with respect to the space station? What is the shift parameter $z$ in this case?