Hello All! Hope all is well.
I was reading about the Voyager Space probe sent into space about 35 years ago.
Under the "Future of the probe" section in Wikipedia It says in the year 2015 they will terminate the Data Tape Recorder (D TR) operations (limited by ability to capture 1.4 kbit/s data using a 70 m/34 m antenna array. This is the minimum rate at which the DTR can read-out data.)

Why would they have to terminate the DTR due to a minimum rate? There seems to be something problematic about the data being read out slower than normal.
Can some one shed some light as to why a slower data rate would be a problem?

Thank You

 

My understand is that the DTR operations will be terminated due to power restrictions on the spacecraft due the Plutonium fuel source decaying.

4. Modifications In Response to Electrical Power Limitations
Radioisotope Thermoelectric Generators (RTGs) provide electrical power to the Voyager spacecraft. Due to the radioactive decay of the Plutonium fuel source, the electrical power provided by the RTGs is continually declining. The current rate of decay is approximately 4.2 watts per year. Because of the continual decline in the amount of power that is available, it is necessary to periodically reduce power consumption in order to maintain an adequate power margin. This is accomplished by turning off spacecraft power loads.

http://voyager.jpl.nasa.gov/science/thirty.html

 

It sounds like it will be too far away to maintain a 1.4 kbit data link with the power and antennas available (energy per bit and all that), and that since that instrument can't be set to output at a lower rate it will become unusable.

 

We could still maintain the 1.4kbit link at that distance but because it's out of the heliosphere shockwave the Plasma Wave Subsystem (PWS) that uses the DTR is less important than the fields and particles data acquisition capability that needs to be maintained for the longest time possible.

As usual Wikipedia is incomplete as the complete line in the NASA documents says about the DTR shutdown.

* Limited by ability to capture 1.4 kbps data using a 70m/34m antenna array
In order to maximize the duration of the fields and particles data acquisition capability.

As the reason.