How fast is the probe traveling and is it traveling towards or away from Earth?

Space probes communicate with controllers on Earth using radio waves. Suppose a probe has a radiotransmitter that operates at a frequency of 388.0 MHz when at rest relative to the observer. This probe is now wandering the solar system. The signal you pick up from the probe is shifted 4.323E+4 Hz lower in frequency than the rest frequency given above. How fast is the probe traveling and is it traveling towards or away from Earth? (assume it is either traveling directly towards or directly away from Earth. You must get boths answers correct at the same time.)|||First, what is the wavelength of one cycle of each frequency? Wavelength is speed of light divided by frequency.





Second, what is the difference of length between the two wavelengths? This is the distance the craft has traveled in one cycle.





Third, what is the time of one cycle of the original signal?





In the time the craft transmitted the one cycle of the original signal, it moved a distance. The distance is the difference in wavelength.


So the speed of the craft is the distance it traveled divided by the time of one cycle.





The direction is...if the wavelength becomes longer, the craft is moving away if it id shorter it is moving toward you.





This will be an important concept to understand for relativity and Energy equals Planck's constant times frequency, so energy related to the Doppler shift. . I am a ham radio operator. I talked to the Russian Space Station MIR around 1990 and you could hear the difference in frequency as the craft came up off the horizon and back down again. We have radio software that will track satellites (even point the antenna) and automatically tune the frequency of the radio to follow for this Doppler shift.