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Voyager 1 Officially Exits Our Solar System
An anonymous reader writes "A new study released today (abstract) indicates that the Voyager 1 spacecraft has become the first man-made object to exit our solar system. Instrumentation data sent back to NASA indicate the historic event likely occurred on August 25, 2012, evidenced by drastic changes in radiation levels as the craft ventured past the heliopause. What remains to be seen, however, is whether Voyager 1 has actually made it to true interstellar space, or whether it has entered a separate, undefined region beyond our solar system. Either way, the achievement is truly monumental. 'It's outside the normal heliosphere, I would say that. We're in a new region,' said Bill Webber, professor emeritus of astronomy at New Mexico State University in Las Cruces. 'And everything we're measuring is different and exciting.'"
Update: 03/20 20:44 GMT by S : Reader skade88 points out that the JPL Voyager team is not so sure: "It is the consensus of the Voyager science team that Voyager 1 has not yet left the solar system or reached interstellar space. In December 2012, the Voyager science team reported that Voyager 1 is within a new region called 'the magnetic highway' where energetic particles changed dramatically. A change in the direction of the magnetic field is the last critical indicator of reaching interstellar space and that change of direction has not yet been observed." So we'll probably be hearing about this again in a couple years.
You did really well.
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What I don't understand is why the linked stories don't mention how big a change in radiation was experienced. Are we talking 10%, or a factor of 10? How about a curve while we are at it -- could be it is gradual, could be sharp, could be a hockey stick -- curve us please.
I come here for the love
Sorry if this sounds dumb to some of the astronomy cracks, but from what I gathered so far from astrophysics is that there are different speeds for leaving the "area" of a body. IIRC it is called the sphere of influence, where a certain celestial body is the one that affects me the most. Like here on Earth, obviously, it's that planet, despite the Sun being a LOT bigger and hence having a lot more gravity, but since I'm sitting on that rock, Earth is it for me. Now, when thrusting away from Earth, at some point I leave its SOI and the Sun will take over as the main body defining my "main body" towards I move relatively. And provided I do not end up in the SOI of any of the planets or moons in our solar system, that's how it's going to stay until I am so far away from the sun that something else will be my frame of reference.
So wouldn't "leaving the system" technically require exactly that? That I enter another body (or bodies) sphere of influence? And, another thing, does Voyager actually have enough push to leave the system for good? As far as I know it does take quite a bit more oumph to leave the Sun's SOI than Earth's.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
The fact that this was launched in 1977 and is still operating 36 years later -- 33 years after its primary mission (Jupiter, Saturn encounter) ended in 1980 -- is an achievement in itself and testament to its design and build quality. According to Voyager 1 the 3 RTGs (radioisotope thermoelectric generators) on Voyager 1 will continue to provide sufficient power for some operations until around 2025.
It must have been something you assimilated. . . .
Carl Sagan wrote a lot about the Oort cloud. It would be nice if we could get first-hand evidence of it. Unfortunately the nuclear power supply on Voyager will run out long before anything like that would be remotely possible.
I think the interesting question is, what would constitute evidence of the Oort cloud's actual existence? Every textbook and Wikipedia article I've read still describes it as a theoretical construct.
But yeah, it took us 40 years to get out to 130 AU, and astronomer's talk about comet dust being out as far as 50,000 AU. A humbling thought to be sure.
Voyager 1 won't escape the Oort cloud (really the outer Oort cloud) for another 14,000 - 28,000 years. (Probably due to running out of power in the next 10 to 15 years.)
Perhaps I have misinterpreted your statement, but are you aware of Newton's First Law of Motion? Voyager has no need for power to continue its journey; running out of power will have no effect on its velocity.
My guess is that, aside from attitude adjustment, Voyager hasn't fired its thrusters since its encounter with Titan in 1980.
Voyager was launched at an almost optimal time for gravitational slingshots, so that resource is already tapped out. If I recall correctly the planets won't align like that again until sometime next century and it still wouldn't go faster. In fact that was what gave it most of the speed so we need a lot better propulsion go get anywhere.
I hadn't heard of this so I looked it up. It turns out that the "Grand Tour" was for Voyager 2, which received gravity assists from Jupiter, Saturn, Uranus, and Neptune. It's true that those four won't be in a similar alignment until the next century, but Voyager 1 only received gravity assists from Jupiter and Saturn (and Titan). I haven't done the math or anything, but those two should line up at least a couple times each century (see the Cassini trajectory).
Some dumb, back-of-the-envelope calcs with existing tech: assuming a 50 mN Xenon ion thruster that can run continuously for 3.5 years (NASA's NSTAR did this) spacecraft, right now we can add about 11 km/s to a 500 kg spacecraft per thruster. New Horizons is 478 kg, so I figure 500 kg is a decent guesstimate (it would need a much bigger RTG to run even a single ion thruster for that long, though). Also, New Horizons will be traveling 13 km/s when it reaches the same distance as Voyager 1 with only a Jupiter gravity assist, so even with a less-than-optimal gravity assist I think we can easily beat Voyager 1's speed (turning on the thrusters after the last gravity assist, of course). It would still take us decades to pass it, but we could.
Still, that wouldn't take us to the Oort cloud in any decent amount of time. If we used a different nuclear fuel with a longer half-life we could stretch our ability to power it, but probably at the cost of peak power.