Author Topic: Voyager 2 Contact  (Read 8215 times)

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Offline Brumby

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Re: Voyager 2 Contact
« Reply #25 on: November 07, 2018, 04:29:32 am »
Armchair "engineering":            (my bad)
One of these faults will be receiver drift and the test would be to send commands at different frequencies and see if there is a response.

Real engineering:
JPL does not send multiple frequencies, they actually calculate the shift based on probe temperature and some other parameters they observed during the pre-encounter phase.

How real engineering is done:
Quote
Even firing the maneuvering thrusters or switching on/off another instrument causes a known shift in the receiver frequency and a specific settling time.
As for the issue itself, JPL engineers modeled the issue locally and came to the conclusion that the fault is a defective capacitor in the receiver frequency tracking feedback loop.  That matched the observed characteristics of the receiver and has allowed them to hit the receiver's center frequency essentially every time since the first encounters.

As I said ... there' no magic in it.
 

Offline imo

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Re: Voyager 2 Contact
« Reply #26 on: November 15, 2018, 08:44:46 pm »
Interesting reading on various JPL's magics:
https://descanso.jpl.nasa.gov/DPSummary/summary.html

Article 4 on Voyager telco systems:
https://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf
« Last Edit: November 15, 2018, 08:49:38 pm by imo »
 
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Offline Beamin

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Re: Voyager 2 Contact
« Reply #27 on: December 02, 2018, 04:00:07 pm »
https://en.wikipedia.org/wiki/Voyager_2

Since early days, the probe has been operating on its backup receiver; the primary blew its power fuse for uncertain reasons.  JPL does not send multiple frequencies, they actually calculate the shift based on probe temperature and some other parameters they observed during the pre-encounter phase.  Even firing the maneuvering thrusters or switching on/off another instrument causes a known shift in the receiver frequency and a specific settling time.

As for the issue itself, JPL engineers modeled the issue locally and came to the conclusion that the fault is a defective capacitor in the receiver frequency tracking feedback loop.  That matched the observed characteristics of the receiver and has allowed them to hit the receiver's center frequency essentially every time since the first encounters.


I knew I heard dave say "bad cap" in the video. Even the most technologal thing we could invent billions of miles away and still I can hear the internet saying "Did you change the caps in it? Its probably a bad cap. All those wax caps have gone bad by now." Aliens will find it try to play the record and another alien will tell him to change the caps and it will work. I guess it's better then people saying "check the fuse" the general public has moved to the 2nd most common point of failure. A few more years and "Did you check your voltages? I bet you could find the problem if you checked your voltages" Thou shal check voltages sayeth the armchair engineer and youtube alumni.
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