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47-year-old Voyager 1 fired up thrusters it hasn't used in decades

cnn.com

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Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#12

Post by throw310822 »

floppiplopp wrote: post #11
stevage wrote: post #7

Multiple puffs of hydrazine every day to keep the craft stable, for more than 50 years? How big are these tanks?

100 kg apparently, supposedly providing fuel until 2034. Those are just very small puffs.

About 680 thousand puffs so far (40 x 365 x 47). Also, "When the team initially switched Voyager over to the trajectory correction thrusters six years ago, the tube opening was 0.01 inches (0.25 millimeters) across".

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#14

Post by irjustin »

I'm so surprised it needs so many puffs per day (40?!) to keep the aircraft oriented at earth in space the vacuum of space where there's so much... vacuum.

When I started the article I figured they'd correct for orientation once every 2 weeks or so.

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#16

Post by rob74 »

irjustin wrote: post #14

I'm so surprised it needs so many puffs per day (40?!) to keep the aircraft oriented at earth in space the vacuum of space where there's so much... vacuum. When I started the article I figured they'd correct for orientation once every 2 weeks or so.

I guess it's not as much "orienting it in the right direction and then just keeping it that way" as it is a constant to-and-fro - the thrusters are probably not precise enough to keep it oriented towards earth, I imagine the range is extremely narrow by now?

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#17

Post by akira2501 »

yashg wrote: post #6

A radio signal takes more than 22 hours to reach Voyager 1. And it would take the same to get a response back. Incredible. And imagine the patience needed to send commands and wait for the outcome on the part of the engineering team. You can't afford to send a wrong command and have the luxury of undo. Also, I wonder how many generations of engineers must have worked on the project by now.

You characterize every single piece of equipment on platform so you can do somewhat accurate simulations. The shuttle flew most of the critical phases of their missions on the ground before ever uploading the code into an actual shuttle computer. The simulation system was continuously updated with real world performance information so it's accuracy continually improves.

You also have a command processor on the spacecraft side. It will have some of these characterizations present as limits on command authority. Commands sent without override that exceed these limits will be ignored, possibly cancelling the entire sequence of dependent commands. You can demand that these limits be ignored but this obviously requires you to specify it redundantly in the message set.

Should anything happen your flight software is generally going to go into a recovery mode. Voyager will try this 4 times after a period of no commands triggers a watchdog. This will switch on different radios while keeping them oriented towards the Earth in a constant effort to reacquire the command signals.

Should this process fail a backup flight software mode will then activate which performs basic mission functions on a continuous loop so whatever continues to operate on the spacecraft will transmit it's data automatically back to the Earth at it's highest power setting.

Voyager was a continuation of some of the Viking hardware and flight systems.

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#18

Post by tannhaeuser »

yashg wrote: post #6

A radio signal takes more than 22 hours to reach Voyager 1. And it would take the same to get a response back. Incredible. And imagine the patience needed to send commands and wait for the outcome on the part of the engineering team. You can't afford to send a wrong command and have the luxury of undo. Also, I wonder how many generations of engineers must have worked on the project by now.

> Also, I wonder how many generations of engineers must have worked on the project by now.

Would've expected the generation raised on punch cards to be ideally suited for this kind of stunt, having learnt the hard way about the turnaround time for a bug (Donald Knuth quote about proving programs correct comes to mind), so I'd expect mission control, operators, and coders to be well in their 70s at least? Whereas tiday we hardly can write a single line if code without our AI overloads introducibg typos and not-fo-subtlr bugs.

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#19

Post by akira2501 »

irjustin wrote: post #14

I'm so surprised it needs so many puffs per day (40?!) to keep the aircraft oriented at earth in space the vacuum of space where there's so much... vacuum. When I started the article I figured they'd correct for orientation once every 2 weeks or so.

That's a 90 minute cycle time. It's outside the heliosphere now so the Solar winds are no longer a nearly constant force in a single direction. So it experiences more "turbulence."

Re: 47-year-old Voyager 1 fired up thrusters it hasn't used in decades

#20

Post by irjustin »

rob74 wrote: post #16
irjustin wrote: post #14

I'm so surprised it needs so many puffs per day (40?!) to keep the aircraft oriented at earth in space the vacuum of space where there's so much... vacuum. When I started the article I figured they'd correct for orientation once every 2 weeks or so.

I guess it's not as much "orienting it in the right direction and then just keeping it that way" as it is a constant to-and-fro - the thrusters are probably not precise enough to keep it oriented towards earth, I imagine the range is extremely narrow by now?

Then the 0.035mm would be a benefit! more puffs!

I clearly have no idea what I'm talking about.

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