Space-probes like Voyager etc are sent outwards towards the outer planets for obvious reasons but I was wondering if there would be any point in launching a probe vertically above or below the plane of the ecliptic? Are there technical reasons why this is not done or is just because its believed their isn’t any point?
Thanks 
Takes extra energy…and that region is largely empty. Not much point.
While it’d be nice to get a top-down, or more oblique angle view of out solar system and galaxy, it’d probably take thousands of years to get to a vantage where it’d do much good. Though I am curious how we might attempt such a thing when we depend on gravity assists and such just to reach escape velocity of our sun. I’m curious as to what sort of angular momentum we’d be fighting to launch a probe in such a way.
It seems like a slingshot around Jupiter would work pretty well - just aim the orbit under the pole, so the ejection path is “up.”
Voyager One is above the plane of the solar system, remember the famous pale blue dot picture. That is why it could image all the planets of the system.
Would Jupiter’s gravity alone be enough, I wonder? I know Voyager 2 got at least a couple. Once you veer off the ecliptic, no more assists.
Voyager One was deflected “up” by it’s encounter with Titan, it sacrificed going to Pluto for a good look at Saturn’s largest moon.
Voyager 1 is about 10 degrees or so out of the ecliptic. This really isn’t all that much. Voyager 2 is about 60 degrees. That’s a bit of a bigger deal.
As far as the probe farthest from the ecliptic, I’d wager Ulysses, which underwent a Jupiter flyby to swing its trajectory out of the ecliptic, and also back toward the sun, where it orbited the sum about 80 degrees or so out of the ecliptic. Its mission ended about 7 years ago, but as far I know it’s still orbiting.
This would be an effective way to change direction to “up”, but I don’t think you gain any speed unless you leave the slingshot heading roughly the same direction as the planet you are slingshotting around. The probe accelerates by stealing some planet’s orbital energy, and the planet has no energy in the “up” direction.
This is pretty much what inspired the question, thanks for the answers everyone. 
It has been done. Originally the Solar Polar mission was to have two spacecraft, but after cutbacks one was built. Eventually called Ulysses. Now retired, the craft was slingshotted around Jupiter into a solar polar orbit.
There is no advantage to observing from this orbit for anything other than studying the sun. The view of the galaxy or further is essentially identical.
The problem is that in order to get into this orbit you need to wipe out all the orbital velocity of the earth. Hence the need for the slingshot around Jupiter. To try it directly with a rocket would have been infeasible (or at least ruinously expensive).
The main point of sending out probes is so we can see objects from a closer range. What would be the point of launching a probe and then sending it off on a trajectory that doesn’t get any closer to a planet than it started at?
To get a different view. Solar polar was to do what its name said. See the Sun’s poles.
So there is nothing above or below the plane…is that what you guys are saying.
Nothing above or below until the next star system or galaxy?
Once you get out past Neptune there’s the Oort cloud. That’s kinda all around the solar system.
When the solar system formed, dust gathered together and started rotating. Clumps of dust tend to be asymmetrical, and this causes the clump to pick a general direction of rotation as gravity brings it all together. Over time, that clump flattens out into a disk. The planets all formed out of that disk, so all of the interesting planet-type stuff is all in the same general plane of rotation.
Here’s a fun youtube about a real to-scale model of the solar system:
It’s not like the far side of the moon, where we need to send a probe just to see something that’s invisible from Earth. Planets and other bodies in the Solar System rotate and revolve so we can point a telescope at any side of an object if we just wait.
The main factor is range. You get a much better view from a million miles away than you do from a hundred million miles away. So if you want to observe a planet and get better information, you send the probe to the planet.
Yes. All true. Except that we can’t see the poles. And we have good reason to think the poles are different enough to be worth the effort. And the effort is not small. The recent views of Saturn and Jupiter’s poles is why it is worth it. For the planets you don’t need to go wildly out of the ecliptic plane, but a polar view does cost energy, and limits the options. Using lots of gravity assists helps. For the sun it was necessary that the probe went out of the ecliptic plane, essentially by definition. So a fly past Jupiter was used to get it there. Only done once.
Adding to my own post above-
The other reason for actually going above or below is that these probes do not just take photos. They measure their surroundings. Indeed the solar polar mission didn’t actually take pictures. But if you want to measure the magnetic field, radiation, particle densities, and the like, you have to actually go there. A huge amount of planetary and solar science is not done with pictures of the surface, but with measurements of the environs. The public face of the science is usually photos. But when it comes to hard science there is much much more.
I can also imagine some wanting to test if empty space outside of the plane is the same empty as within it.