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Just wondering, is voyager going at the maximum speed we could we realistically go today or would a newer craft be able to exit the solar system faster? would t

by nkassis 16y ago

Just wondering, is voyager going at the maximum speed we could we realistically go today or would a newer craft be able to exit the solar system faster? would that even be useful to science?

hugh3 16y ago
Well, rocket technology hasn't really advanced all that much since Voyager was launched. We could certainly send a faster probe out by spending more money to build a bigger rocket. On the other hand, they could have done so back then, as well. On the other hand, Voyager picked up an awful lot of its speed not from its initial launch but from slingshotting around the various planets it visited -- essentially picking up some free energy at the cost of infinitesimally perturbing the planet's orbit. If our goal was to send a probe out of the solar system as quickly as possible, we might be able to do a better slingshot than was done back then. On a third hand, Voyager 2 benefited from a rather fortuitous arrangement of planets which enabled it to visit all four giant planets and presumably pick up some momentum from each. This kind of configuration only comes around once every few centuries so if we launched it now then it would have to miss some planets. I don't know how much of an effect this would have; did the Uranus/Neptune visits "pay for themselves" momentum-wise? (Edit: I looked it up and apparently not, because Voyager 1 which skipped the last two planets is further out and travelling faster than Voyager 2). One thing we can do now which we couldn't do back then is build a good ion drive. A probe with an ion drive and a nuclear fuel cell could keep accelerating for many years, so it would probably be able to outpace Voyager eventually. So in conclusion, if we wanted to build something faster than Voyager I think we probably could. But in answer to your second question, no, I don't think it would be very useful to do so. There's not much that's particularly interesting beyond the solar system. We're still keeping Voyager alive because we might as well, but sending another probe out there with it would be a fairly low priority for missions.
- bkudria 16y ago
  With your three hands you clearly support the "Aliens messed with it" theory.
  - Qz 16y ago
    Or he's read The Mote in God's Eye/The Gripping Hand.
  - rbanffy 16y ago
    That will be Voyager 6, after it falls into a black hole and ends up being rescued by machines.
rbanffy 16y ago
If you want to go to away fast, you could ride an ion engine. It gets you faster for the same mass than chemical rockets can. The concept was tested on the Deep Space 1 probe with great success. IIRC, a Vasimir engine (a variation on the ion theme) will be tested on the ISS. Ion engines are pretty much off-the-shelf (or, as much off-the-shelf as deep-space probe propulsion go) now. Another alternative (that still would require some work) would be a solar sail, to be deployed after the probe uses the Sun as a gravity assist. You could, conceivably, use both. You would shot the probe towards the Sun with ion engine on. Ideally, it would reach escape velocity from the Sun during this first leg. When passing close to the Sun, it would deploy the solar sail and get as much impulse from that as possible - discounting the sail mass, it's essentially free. When the solar sail is spent (it's a very thin foil, degrades and becomes less efficient as it gets farther from the Sun) the probe jettisons it, turns on the ion engine again and rides it until all the propellant is spent. That should give it some serious speed. Mind you, speed was not Voyager's priority. Voyager 1 and 2 were great sightseeing tours of the outer solar system. The fact they still work is a testimonial of the genius of those who built them.

by nkassis 16y ago

Just wondering, is voyager going at the maximum speed we could we realistically go today or would a newer craft be able to exit the solar system faster? would that even be useful to science?

hugh3 16y ago

Well, rocket technology hasn't really advanced all that much since Voyager was launched. We could certainly send a faster probe out by spending more money to build a bigger rocket. On the other hand, they could have done so back then, as well. On the other hand, Voyager picked up an awful lot of its speed not from its initial launch but from slingshotting around the various planets it visited -- essentially picking up some free energy at the cost of infinitesimally perturbing the planet's orbit. If our goal was to send a probe out of the solar system as quickly as possible, we might be able to do a better slingshot than was done back then. On a third hand, Voyager 2 benefited from a rather fortuitous arrangement of planets which enabled it to visit all four giant planets and presumably pick up some momentum from each. This kind of configuration only comes around once every few centuries so if we launched it now then it would have to miss some planets. I don't know how much of an effect this would have; did the Uranus/Neptune visits "pay for themselves" momentum-wise? (Edit: I looked it up and apparently not, because Voyager 1 which skipped the last two planets is further out and travelling faster than Voyager 2). One thing we can do now which we couldn't do back then is build a good ion drive. A probe with an ion drive and a nuclear fuel cell could keep accelerating for many years, so it would probably be able to outpace Voyager eventually. So in conclusion, if we wanted to build something faster than Voyager I think we probably could. But in answer to your second question, no, I don't think it would be very useful to do so. There's not much that's particularly interesting beyond the solar system. We're still keeping Voyager alive because we might as well, but sending another probe out there with it would be a fairly low priority for missions.

bkudria 16y ago
With your three hands you clearly support the "Aliens messed with it" theory.
- Qz 16y ago
  Or he's read The Mote in God's Eye/The Gripping Hand.
- rbanffy 16y ago
  That will be Voyager 6, after it falls into a black hole and ends up being rescued by machines.

rbanffy 16y ago

If you want to go to away fast, you could ride an ion engine. It gets you faster for the same mass than chemical rockets can. The concept was tested on the Deep Space 1 probe with great success. IIRC, a Vasimir engine (a variation on the ion theme) will be tested on the ISS. Ion engines are pretty much off-the-shelf (or, as much off-the-shelf as deep-space probe propulsion go) now. Another alternative (that still would require some work) would be a solar sail, to be deployed after the probe uses the Sun as a gravity assist. You could, conceivably, use both. You would shot the probe towards the Sun with ion engine on. Ideally, it would reach escape velocity from the Sun during this first leg. When passing close to the Sun, it would deploy the solar sail and get as much impulse from that as possible - discounting the sail mass, it's essentially free. When the solar sail is spent (it's a very thin foil, degrades and becomes less efficient as it gets farther from the Sun) the probe jettisons it, turns on the ion engine again and rides it until all the propellant is spent. That should give it some serious speed. Mind you, speed was not Voyager's priority. Voyager 1 and 2 were great sightseeing tours of the outer solar system. The fact they still work is a testimonial of the genius of those who built them.