[AcerbicZero]

I'm disappointed that it even as it become very obvious we were going to continue gathering useful information from Voyager 1/2 and yet no follow on missions have been launched.

I suppose the idea is that there is more to be gained via specialized missions inside the solar system, compared with new long running extreme range probes, but you would think there might be some value in starting to send a chain of probes out, so that communication can be maintained even further.

[azernik]

Voyagers 1 and 2 took advantage of a fleeting phenomenon - an alignment of all the outer planets that allowed successive gravity assists, and so let us send probes out to those planets and then on to escape velocity with a very small launcher/budget. These come around every 175 years, so the next point at which solar system escape will be that easy is around 2150.

https://en.wikipedia.org/wiki/Grand_Tour_program

All the ideas thrown around for follow-on missions have relied either on very powerful boosters (on the scale of SLS), smaller probes (New Horizons, a bit over half the size of the Voyagers and on a much lower-energy trajectory, despite a more powerful launcher), or an Oberth maneuver close to the sun in a very challenging thermal and radiation environment.

[CDSlice]

The problem is we can't launch another Voyager mission. The Voyagers took advantage of the planets being aligned in just the right way to allow them slingshot through the outer solar system. This won't happen again for another 100 years or so.

Now we could design probes that are just for going into interstellar space but it would be a hard sell when you are competing against missions like sending a drone to Titan. Even the New Horizons mission to Pluto barely made it through NASA's project selection process and IMO expanding our knowledge of Pluto is more valuable (and sellable to the public) than a mission to literally nothing.

[adventured]

New Horizons can and may do exactly that.

http://pluto.jhuapl.edu/Mission/2019-Onward.php

"Future New Horizons extended missions, if funded by NASA, could explore even farther out. The spacecraft is on an escape trajectory from the Sun, traveling about three astronomical units per year. Moreover, New Horizons and its payload sensors are healthy and operating perfectly. The spacecraft has enough power and fuel to operate into the mid-2030s or longer, perhaps enough to reach the boundary of interstellar space."

[RosanaAnaDana]

Yeah but what do you even do out there with the sensor payload it has? Its imaging devices really aren't structured for deep space remote sensing. They were built to image planet and planet sized objects.

[toyg]

The cynic in me thinks that there is little marketing value in throwing probes into the void, whereas landing and taking pictures of “the new frontier” can be sold to the (taxpaying) public more easily.