As probes that we build travel farther, won't more problems occur? For example, as the nuclear energy thing (RTG) it goes on gets weaker over time. Or, solar panels will receive less light. Or even, the delay between Earth and the satellite communication. Are there any probes that address some of these issues? Are there any planned probes in the future to go interstellar?

  • $\begingroup$ By definition satellites won't go interstellar because the whole point of a thing-that-orbits-another-thing is that it orbits-another-thing. Do you mean a probe? $\endgroup$
    – slebetman
    Mar 7, 2016 at 8:11
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    $\begingroup$ @slebetman yeah but to be even more pedantic, voyager is orbiting the galaxy. XTImpossible: The issue with your question is that it is actually very broad. A probe designed to go 200AU would be different as one designed to go up to 1000, then different than one designed to go 1LY away, etc. Depending on how far you want it to go, our current technology might scale. Just not to infinity. $\endgroup$
    – Antzi
    Mar 7, 2016 at 16:23
  • $\begingroup$ bbc.com/news/science-environment-36025706 $\endgroup$
    – Steve
    Apr 12, 2016 at 20:20

1 Answer 1


As satellites travel further from the sun, available solar energy decreases proportional to the square of the distance. This means that satellites we build for much operation past Mars require supplemental energy sources, such as thermonuclear generators.

Right now, if we were to build something for interstellar travel, we'd either need a fission reactor onboard, a very, very large thermonuclear generator, or very deep sleep cycles. We'd also need a mechanism for generating the required thrust, and a way to shed it upon arrival at a target. The short answer: we're not quite ready.

I'm not aware of any planned or even announced interstellar satellite or probe missions.

  • $\begingroup$ "I'm not aware of any planned or even announced interstellar satellite or probe missions." Voyager 1 exited the heliosphere in August 2012, and is considered to have entered interstellar space. Does that count? $\endgroup$
    – user
    Mar 7, 2016 at 10:46
  • $\begingroup$ @Michael: True, but Voyager's interstellar mission was not a primary mission objective. More a happy accident that it still works after 4 times the original planned mission length. $\endgroup$
    – Hobbes
    Mar 7, 2016 at 12:23
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    $\begingroup$ @MichaelKjörling I'd say it is more accurate that Voyager is in 'interstellar space', but it was never designed to be operational in interstellar space, let alone 'travel to another star', which can be implied by some uses of 'interstellar'. It happens to be operational therein, but that wasn't the intentions during construction. $\endgroup$
    – Ehryk
    Mar 7, 2016 at 16:42
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    $\begingroup$ @Puffin Icarus Interstellar's current goal is to lay the technological framework that enables interstellar travel, and are not (yet) planning or announcing any interstellar crafts or designs. $\endgroup$
    – Ehryk
    Mar 7, 2016 at 16:45
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    $\begingroup$ I wouldn't even say that Voyager is on an interstellar mission, at least not yet. It is about 1/500th of the way to the outer Oort cloud. $\endgroup$ Mar 8, 2016 at 1:08

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