# How long is too long for a space mission? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [May 2, 2007, 2:05pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456 "2007-05-02T14:05:04Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [May 2, 2007, 2:05pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/1 "2007-05-02T14:05:04Z")
Before the main payoff, that is. The New Horizons probe to Pluto is taking 10 years to get there. People seem happy with that; we’re getting interesting results along the way. But what if we could make our probes go even faster - would a 50 year mission to Alpha Centauri be acceptable? A 100 year mission? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 2, 2007, 2:15pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/2 "2007-05-02T14:15:02Z")
I think more than a decade is starting to stretch things, unless, like Voyager 2, you can do some other stuff on the way to the long-term part of the mission. I think people want to see results and while I would love it if someone else had selflessly prepared the way for me to see some results, I don’t feel quite so enthusiastic about preparing for something that will reap results long after I’m dead and gone. I realise that’s pretty much the definition of ‘selfish’, but there it is. ---
**Author:** ![Sal\_Ammoniac](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Sal\_Ammoniac](https://boards.straightdope.com/u/Sal_Ammoniac)\ **Post date:** [May 2, 2007, 4:32pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/3 "2007-05-02T16:32:14Z")
Actually, I think it’d be pretty cool to send a probe out with a payoff 500 years later. It would be like a time capsule – people would have forgotten about it, and would be excited by its reappearance. (Unless it’s a manned probe, that is, in which case enthusiasm would be somewhat tempered.) ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [May 4, 2007, 11:18am UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/4 "2007-05-04T11:18:00Z")
[QUOTE=Mangetout] I think more than a decade is starting to stretch things, unless, like Voyager 2, you can do some other stuff on the way to the long-term part of the mission. [/QUOTE] Consider then that a 40 year mission would fit this bill: start work in your 20s, get the results in your 60s. ---
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [May 4, 2007, 11:42am UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/5 "2007-05-04T11:42:06Z")
I think the “Daedalus” probe concept had something like a 50-year mission life. [Ah…yep.](http://en.wikipedia.org/wiki/Project_Daedalus) 12% of _c_! Woo-hoo! ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [May 4, 2007, 11:52am UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/6 "2007-05-04T11:52:17Z")
I wonder if you could use a solar sail as a braking mechanism? And you’d need something to keep it all warm. Would a RTG last that long? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 4, 2007, 12:00pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/7 "2007-05-04T12:00:56Z")
[QUOTE=Quartz] Consider then that a 40 year mission would fit this bill: start work in your 20s, get the results in your 60s. [/QUOTE] Sure, but you might have trouble getting the crumblies to fund it. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [May 4, 2007, 12:02pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/8 "2007-05-04T12:02:38Z")
[QUOTE=Quartz] I wonder if you could use a solar sail as a braking mechanism? [/QUOTE] Yes; either use the destination star’s sunlight, or if you are using a laser-driven sail make the center of the sail detach when you need to decelerate; the laser pushes the detached center ahead, and the ship and it’s remaining sail uses the bounced-back light for deceleration. Re the OP : As far as I’m concerned, it’s more of a technological question. There’s no point in a probe taking a 500 year journey to another star if it seems likely that in 50 years we’ll develop a probe that can do it in less than a hundred years. Right now, a voyage that will take longer than, say, 50 years ( number pulled out of air ) is probably wasted effort. ---
**Author:** ![BMalion](https://avatars.discourse-cdn.com/v4/letter/b/e274bd/32.png) [@BMalion](https://boards.straightdope.com/u/BMalion)\ **Post date:** [May 4, 2007, 12:34pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/9 "2007-05-04T12:34:53Z")
There’s precedence for a 5 year mission to explore strange, new worlds. ---
**Author:** ![Lunar\_Saltlick](https://avatars.discourse-cdn.com/v4/letter/l/977dab/32.png) [@Lunar\_Saltlick](https://boards.straightdope.com/u/Lunar_Saltlick)\ **Post date:** [May 4, 2007, 2:12pm UTC](https://boards.straightdope.com/t/how-long-is-too-long-for-a-space-mission/402456/10 "2007-05-04T14:12:15Z")
I’ve got three weeks vacation this year, but I might need a day or two to clean up the backyard. On the other hand, if you’re telling me I don’t have to go back to work at all, then I’ve got all the time you need.