# What is the most plausible concept for an uncrewed interstellar spacecraft? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [August 29, 2026, 10:32pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679 "2026-08-29T22:32:56Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![spacecadet86](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@spacecadet86](https://boards.straightdope.com/u/spacecadet86)\ **Post date:** [August 29, 2026, 10:32pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/1 "2026-08-29T22:32:56Z")
Whether it is Project Daedalus or Breakthrough Starshot, there are interstellar spacecraft concepts aplenty, but which seems the most plausible to you? ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [August 29, 2026, 10:36pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/2 "2026-08-29T22:36:12Z")
I’ve always been fond of [Starwisp](https://en.wikipedia.org/wiki/Starwisp), but I don’t know enough to say whether it’s more plausible than the others you mention. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [August 29, 2026, 10:46pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/3 "2026-08-29T22:46:03Z")
FQ isn’t really the right subforum for this, but do you mean what propulsion will we use, or what will the non-human crew be like? ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [August 29, 2026, 10:50pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/4 "2026-08-29T22:50:12Z")
Given that it already exists, the most plausible one is Voyager. > **[It's official: Voyager 1 is in interstellar space, says NASA](https://www.csmonitor.com/Science/2014/0708/It-s-official-Voyager-1-is-in-interstellar-space-says-NASA)** > > Data from Voyager 1 indicates that the spacecraft has exited the heliosphere, a bubble of plasma blown out by the sun. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 29, 2026, 11:57pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/5 "2026-08-29T23:57:42Z")
[Moderating] There is factual information available, but you’re right that the question is ultimately speculative. Moving to IMHO. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [August 30, 2026, 12:25am UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/6 "2026-08-30T00:25:48Z")
None of our current concepts are even remotely plausible. If you mean “Which science fiction author came up with the best-sounding technobabble?” that’s an entirely different question. As with your last question about spacefaring, you may as well ask the folks who were building sailing ships for Christopher Columbus what’s their best concept for a powered airplane with intercontinental range. Any answer they might give would be nonsense versus what actually will be invented centuries hence. That’s how far along we are on interstellar spacecraft. ---
**Author:** ![griffin1977](https://avatars.discourse-cdn.com/v4/letter/g/977dab/32.png) [@griffin1977](https://boards.straightdope.com/u/griffin1977)\ **Post date:** [August 30, 2026, 12:47am UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/7 "2026-08-30T00:47:15Z")
The idea of laser powered tiny craft always seemed pretty plausible to me. A tiny (nano technology based, but nothing to crazily beyond what we can create now) space craft with no fuel on board powered by an external laser pointing at it (from outer space not the surface of a planet). The maths of getting to a significant percentage of light speed are quite reasonable, and don’t require stupid amounts of energy. It’s not something thats going to happen in the next few decades but it’s not a completely ridiculous thing for humanity to build one day, if we avoid wiping ourselves out. ---
**Author:** ![Roderick\_Femm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/roderick_femm/32/14875_2.png) [@Roderick\_Femm](https://boards.straightdope.com/u/Roderick_Femm)\ **Post date:** [August 30, 2026, 3:45am UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/8 "2026-08-30T03:45:42Z")
David Brin’s novel _Existence_ posited small solid-state crystal objects with personality downloads (not just messages, but actual personalities) embedded in them, propelled externally somehow (I forget, it’s been years since I read it) on spec, so that by sending out so many to various likely solar systems a few might hit pay dirt and that would be enough. It would of course be one-way communication only, due to the travel time. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [August 31, 2026, 1:31pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/9 "2026-08-31T13:31:07Z")
Starwisp as proposed by Robert L. Forward and modified by Geoff Landis seems the most plausible for a fast-moving constantly accelerating uncrewed spacecraft. I know it’s already been mentioned. I have doubts about anyone ever constructing the massive batteries of lasers/masers needed to push this thing along. And, of course, it would be disastrous if it ever collided with any interstellar matter, no matter how small. Sending out a starwisp-like device ushed only by light pressure from the sun is more likely to get built. Nobody is going to waste time, effort, and money on building huge broadcast systems to goose a wisp along – they’d want that power for applications at home. But I could easily see people building multiple sun-pushed wisps and sending them off in all directions. They’d keep accelerating without any added effort from us, and would soon outpace any items we propelled into space with a fixed speed, or with short-lived propoulsion systems that must eventually die. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [August 31, 2026, 5:37pm UTC](https://boards.straightdope.com/t/what-is-the-most-plausible-concept-for-an-uncrewed-interstellar-spacecraft/1032679/10 "2026-08-31T17:37:29Z")
To begin with, an unmanned interstellar probe has to be entirely self-reliant. It has to have something like a nine-fold-redundant computer system, with a rather large read-only library of information about the kinds of things we find interesting, so that it can decide what it should be observing. Because, at a distance of just one Pm, it would be two months of back-and-forth communication delay.        Hence, it would essentially be a broadcast-only probe: it would not require a large receiving dish, because it would just be independently doing its thing and sending us data. And with huge amounts of time on its waldoes, its processing speed is not all that important: the intelligent logic can be handled by basic processors rather than SC-type accelerator modules.        Power is kind of an issue. Yes, V’ger has been running for half a century on RTGs, but the power level has been in decline, and RTG power is steady: it cannot be turned off or down, it just gets used up at a constant rate. But, interstellar space is a busy place, full of huge cosmic ray flux, which, in theory, the probe might be able to harvest for power. This is probably an area worth study, if we want to send probes out that far.        What seems to me to be the biggest problem is signal spread. At a Pm, the signal we would be getting back would be incredibly weak. If we want it to make the 40Pm to Alpha Centauri, would we even be able to pick the probe’s data out of the noise of space using a global VLA system? This is pretty important, because, if we want to spend trillions of quatloos to send these things out, we want to be able to hear what they have to say. This is another very important area that needs work.