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> "the antenna on the spacecraft had been pointing two degrees away from the Earth [...] left it without the ability to receive commands or transmit data [...]

> "the antenna on the spacecraft had been pointing two degrees away from the Earth [...] left it without the ability to receive commands or transmit data [...] NASA reckons the situation is temporary [...]" I wonder how it's temporary. Does the probe have a re-targeting function? The answer is in the original statement: > "Voyager 2 is programmed to reset its orientation multiple times each year to keep its antenna pointing at Earth; the next reset will occur on Oct. 15, which should enable communication to resume. The mission team expects Voyager 2 to remain on its planned trajectory during the quiet period."

williamdclt 3y ago
I wonder why the reorientation is so infrequent? Is it a long process or a strain on hardware that you wouldn't want it to happen every day or even every month?
- Dalewyn 3y ago
  Reorienting requires using a reaction wheel or propellent to move yourself. Propellent is finite, so you want to use it as rarely as possible. A reaction wheel is by itself infinite (assuming it doesn't break), but eventually it saturates and you need to desaturate it, which basically means spinning the wheel the other way while spending propellent to maintain position. All of this is to say, reorientation is an expensive process especially if refueling isn't an option.
  - Dylan16807 3y ago
    Reaction wheels only saturate by absorbing external acceleration, though. You can reorient as much as you want with a reaction wheel, and the only cost is electricity.
  - curiousObject 3y ago
    >reorientation is an expensive process That’s true, but a failsafe automatic reorientation mode after two weeks with no communication from Earth might be a useful feature
    - jjk166 3y ago
      On the timescale of decades, does a 2 week vs a 10 week waiting period make much of a difference?
      - curiousObject 3y ago
        >On the timescale of decades, does a 2 week vs a 10 week waiting period make much of a difference? I agree. It probably doesn’t make much difference now. There are very unlikely to be any important data that will be lost. The mitigation process they already implemented seems prudent and sufficient During earlier parts of the mission, like planetary encounters, it would make a difference. Even a two week wait could be much too long in those circumstances.
        jjk166 3y ago
        Presumably during encounters the probe was in a different control scheme to keep its instruments pointed at the planet, as opposed to keeping its antenna pointed at Earth.
- rvnx 3y ago
  It costs fuel to reorientate
- csunbird 3y ago
  In addition to the points made by sibling comments, there is always a chance something going wrong in the reorientation, so you do not want to do this more than necessary

williamdclt 3y ago

I wonder why the reorientation is so infrequent? Is it a long process or a strain on hardware that you wouldn't want it to happen every day or even every month?

Dalewyn 3y ago
Reorienting requires using a reaction wheel or propellent to move yourself. Propellent is finite, so you want to use it as rarely as possible. A reaction wheel is by itself infinite (assuming it doesn't break), but eventually it saturates and you need to desaturate it, which basically means spinning the wheel the other way while spending propellent to maintain position. All of this is to say, reorientation is an expensive process especially if refueling isn't an option.
- Dylan16807 3y ago
  Reaction wheels only saturate by absorbing external acceleration, though. You can reorient as much as you want with a reaction wheel, and the only cost is electricity.
- curiousObject 3y ago
  >reorientation is an expensive process That’s true, but a failsafe automatic reorientation mode after two weeks with no communication from Earth might be a useful feature
  - jjk166 3y ago
    On the timescale of decades, does a 2 week vs a 10 week waiting period make much of a difference?
    - curiousObject 3y ago
      >On the timescale of decades, does a 2 week vs a 10 week waiting period make much of a difference? I agree. It probably doesn’t make much difference now. There are very unlikely to be any important data that will be lost. The mitigation process they already implemented seems prudent and sufficient During earlier parts of the mission, like planetary encounters, it would make a difference. Even a two week wait could be much too long in those circumstances.
      - jjk166 3y ago
        Presumably during encounters the probe was in a different control scheme to keep its instruments pointed at the planet, as opposed to keeping its antenna pointed at Earth.
rvnx 3y ago
It costs fuel to reorientate
csunbird 3y ago
In addition to the points made by sibling comments, there is always a chance something going wrong in the reorientation, so you do not want to do this more than necessary