Voyager probe reaches edge of solar system

[cvidler]

Originally Posted by Fortigurn

I've always been fascinated by this slingshot business, since it seems suspiciously like getting free energy, but apparently relativity steps in and preserves the conservation of energy.

Well the moment gained by the probe is lost by the planet. In the scheme of things conservation of energy is maintained, but the planet is hardly going to notice.

[OldMate]

Amazing stuff. I don't imagine that they will get near anything for a very, very, very, very long time though.

[Fortigurn]

Originally Posted by cvidler

Well the moment gained by the probe is lost by the planet. In the scheme of things conservation of energy is maintained, but the planet is hardly going to notice.

Yeah the planet is losing energy, but the probe isn't; it's going past the planet and gaining energy, traveling away from it faster than it approached. It just seems completely counter-intuitive.

[shift]

Originally Posted by Fortigurn

Yeah the planet is losing energy, but the probe isn't; it's going past the planet and gaining energy, traveling away from it faster than it approached. It just seems completely counter-intuitive.

Think of it like this:

The planet is a bulldozer, travelling at highway speed; the space craft is a super-bouncy rubber ball.

If the rubber ball is thrown at the bulldozer (from in front of it); it will bounce off going faster than it was originally travelling, and slow the bulldozer an immeasurable amount.

Now, instead of rubber we use the planets gravity as the bouncing mechanism.

[aussie-revhead]

Why would they power this down at all? Let her fly boys !!! If it is out of range then why not let it keep powering on? OK I get that the RTG generates electricity but what produces the thrust? Or is it gaining velocity purely from slingshot effect?

[shift]

Originally Posted by aussie-revhead

Why would they power this down at all? Let her fly boys !!! If it is out of range then why not let it keep powering on? OK I get that the RTG generates electricity but what produces the thrust? Or is it gaining velocity purely from slingshot effect?

No thrust, it's just coasting. Slingshot work was all done years ago.

The thrusters it has are only good enough for manoeuvring, would use up too much fuel to add any real speed.

[cvidler]

Originally Posted by aussie-revhead

Why would they power this down at all? Let her fly boys !!! If it is out of range then why not let it keep powering on? OK I get that the RTG generates electricity but what produces the thrust? Or is it gaining velocity purely from slingshot effect?

There's no net thrust. it's going as fast as it ever (?) will. the RTG runs the electronics/experiements/antennae.

There's some thrusters, but they're to keep it (the antenna) pointing back to earth, not for acceleration.

[nEBUz]

Originally Posted by aussie-revhead

Why would they power this down at all? Let her fly boys !!! If it is out of range then why not let it keep powering on? OK I get that the RTG generates electricity but what produces the thrust? Or is it gaining velocity purely from slingshot effect?

There is very little friction where it is... it doesn't need any thrust. It will just keep going... and going... and going... and going... and well you get the idea.

Eventually it might slow down a decent amount, but there's not a lot in space as far as we know

[mrbean_phillip]

Originally Posted by Smegger

It is actually an 8 track tape. I think that may be worse.

Ah, I remember those old 8-track casette players from the 70's - dad had one in the car - a Ford 351 Cleveland 4V (or, I guess, XY GT Down Under)

But yes, certainly a feat and a half to use 70's tech to have this thing still be able to transmit and be operational 35 years after launch.

But then again, nothing wrong with the electronics of the 70's, I did my Trade at a big Power Station in South Africa designed in the mid 70's...

Good, solid (state) stuff

[shift]

Soyuz is 60s tech and still going strong.
Shuttle was 80s and is gone.

[TERRA Operative]

Just 261 years until we meet with V'Ger.

[SLATYE]

Originally Posted by shift

Soyuz is 60s tech and still going strong.
Shuttle was 80s and is gone.

That's the way things go. Some things last forever because nothing else can compete with them; others die out after a little while because something better comes along or it becomes impossible to keep them running.

The closest US equivalent to the Soyuz is probably the Delta, which has been around for even longer but hasn't done anywhere near as many flights. The Russian equivalent to the Shuttle is of course the Buran, which was terminated by the end of the USSR.


The important thing about stuff like the Voyager probes is that mistakes cannot be fixed. With the Soyuz or Delta, if something breaks then you change the design for the next launch. It's certainly not a good thing, but it'll be resolved pretty soon.

If Voyager 1 broke down ten years into its mission, it's not something that can be fixed. Even if they had the money and inclination to launch a replacement, they would have lost ten years. The fact that it worked so well the first time is very, very impressive. We've seen something similar with the Opportunity rover on Mars, which refuses to die despite having already survived for more than thirty times its intended lifespan.

[spludgey]

Originally Posted by Sankari

How fast is it travelling, and when can it be expected to lose momentum?

Not sure if you're serious or not. Either way, the answer is: It won't.
It would only lose momentum if it hit something, but since there are no atoms where it is now, it just won't slow down.

[SuzyCreamcheese]

Originally Posted by spludgey

Not sure if you're serious or not. Either way, the answer is: It won't.
It would only lose momentum if it hit something, but since there are no atoms where it is now, it just won't slow down.

The sun has a gravitational effect on the probe. Which is why it slows down over time.

Atoms do exist in interstellar space, just at a very low density (otherwise it would be a perfect vacuum), it would have an effect, just a very minor one.

[aussie-revhead]

If the probe has travelled beyond the reach of solar wind from our sun then do you think it still has a gravitational influence?