The Tale

You work at a NASA Deep Space Communication antenna complex and you are attempting to receive radio signals from a spacecraft in deep space traveling at a high velocity relative to you.

You know the transmission frequency the spacecraft is using, but due to the doppler shift you will receive the signals at a (slightly?) different frequency.

Your job is to calculate the receiving frequency, otherwise you will be unable to communicate with the spacecraft.

FYI, Google "Casini doppler shift probe problem"

Definitions

The Doppler effect or Doppler shift is the apparent change in frequency of a wave in relation to an observer moving relative to the wave source. (Wikipedia)

Velocity is positive by convention if the object is moving away from the observer.

Frequency refers to the number of waves that pass a fixed point in unit time.

Wavelength is the distance between successive crests of a wave. For example a sound wave or electromagnetic wave.

Hertz (Hz or hz) is a unit of frequency of one cycle per second. (GHz short for gigahertz. It is a unit of frequency equal to one billion hertz.)

Doppler Shift Equations

Frequency

ƒr = ƒs * (1 / (1 + (v/c)))
ƒr	receiver's frequency
ƒs	sender's frequency
v	sender's velocity relative to the receiver
c	the speed of light in a vacuum 186,282 mi/sec (often rounded to 186,000 mi/sec) 11,802,852,677.165 in/sec 299,792,458 m/s m/sec 29,979,245,800 cm/sec

Wavelength

λr = λs * (1 + (v/c))
λr	receiver's frequency wavelength
λs	sender's frequency wavelength
v	sender's velocity relative to the receiver
c	the speed of light in a vacuum 186,282 mi/sec (often rounded to 186,000 mi/sec) 11,802,852,677.165 in/sec 299,792,458 m/sec 29,979,245,800 cm/sec

Note:

1. Velocity is speed and direction.
2. A more accurate value for the speed of light is
   186282 miles, 698 yards, 2 feet, and 5 21/127 inches per second. (Wikipedia)

Project #1

Write a program that will calculate the receiver's frequency using a spacecraft's velocity and sending frequency.

1. ask the user for the spacecraft's name
2. ask the user for the spacecraft's sending frequency
3. ask the user for the spacecraft's velocity relative to the receiver
   (specify the units to enter: miles/second, meters/second, miles/hour, kilometers/hour, ...)
4. calculate the receiving frequency
5. display the
   • spacecraft name (if any)
   • spacecraft velocity units
   • spacecraft velocity relative to the receiver
   • sending and receiving frequencies
   • Doppler shift (difference in frequencies)
6. loop

Voyager normally transmits data to Earth over the Deep Space Network Channel 18, using a frequency of either 2.3 GHz or 8.4 GHz, while signals from Earth to Voyager are transmitted at 2.1 GHz. (Wikipedia)

Use the current data from voyager Mission Status .

Project #2

Allow the user to set the spacecraft's velocity units. Also the units of frequency input and output (MHz, GHz, ...).

Project #3

Create a GUI for the program (if possible).

Project #4

Your are standing next a train track. A train is approaching at 40 mph and blowing its whistle at 440 Hz.

What is the frequency do you hear as it approaches and as it moves away from you?

The speed of sound, is speed at which sound waves propagate through different materials. In particular, for dry air at a temperature of 0 °C (32 °F), the modern value for the speed of sound is 331.29 meters (1,086.9 feet) per second. ( Encyclopedia Britannica)

Hertz, unit of frequency. The number of hertz (abbreviated Hz) equals the number of cycles per second. (Encyclopedia Britannica)

Using the equations above for sound, c = Speed of Sound.

What is the frequency of middle C?

Does the speed of sound vary with altitude?

FYI: Musical note