The probe encountered Pluto at a distance of $4\mathrm{.}6$ billion km from Earth, fom where it transmitted a series of $312\mathrm{.}5$ kB images back to earth using binary PSK modulation with a carrier frequency of $8\mathrm{.}438$ GHz $($NB a kB is a thousand bytes, and one byte is $8$ bits$).$ Due to the distance involved and the limited power on board, the data rate was limited to approximately $1$ kbit$/$sec$.$