# Is it possible to build a space drive that doesn't expel reaction mass?
**URL:** https://boards.straightdope.com/t/is-it-possible-to-build-a-space-drive-that-doesnt-expel-reaction-mass/159838
**Category:** Factual Questions
**Created:** [March 8, 2003, 2:15am UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-space-drive-that-doesnt-expel-reaction-mass/159838 "2003-03-08T02:15:45Z")
**Posts on this page:** 3
**Page:** 2
### Author:  [@Thaumaturge](https://boards.straightdope.com/u/Thaumaturge)
#### Post date: [March 10, 2003, 5:54am UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-space-drive-that-doesnt-expel-reaction-mass/159838/21 "2003-03-10T05:54:06Z")
> [@](#):
>
> \*Originally posted by scr4 \*
> \*\*
> As for artificial gravity, there’s no reason to think it’s possible. Relativity doesn’t allow for it. \*\*
Erm…relativity is quite mute on the subject of whether or not artificial gravity is possible or not. Quite simply we do not know.
One way to propel a ship to a good fraction of the speed of light that is doable with today’s knowledge is with a microwave laser generated from a solar power station in orbit. The beam would shine on a microwave reflective carbon mesh and accelerate it to high speeds. The ship doesn’t have to carry any fuel, and thus is far easier to accelerate. There’s a rather good article on it in the Jan/Feb issue of _the Planetary Report_. Not having to carry around reaction mass makes the mission much easier.
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### Author:  [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)
#### Post date: [March 10, 2003, 12:25pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-space-drive-that-doesnt-expel-reaction-mass/159838/22 "2003-03-10T12:25:39Z")
I’m surprised nobody’s mentioned this yet, but legendary author/editor John Campbell was a firm believer in The Dean Drive, a supposedly reactionless drive system that didn’t require you to throw reaction mass out the back. Campbell was a truly fascinating person – he knew and anticipated some of the great scientific inventions and events of the 20th century, yet he believed in the Dean Drive, the Hieronymous Machine, ESP, Psionics, Dianetics/Scientology, and “critical action time” physics. A weird mixture of up-to-daye science and pseudoscience.
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### Author:  [@Urban\_Ranger](https://boards.straightdope.com/u/Urban_Ranger)
#### Post date: [March 10, 2003, 2:08pm UTC](https://boards.straightdope.com/t/is-it-possible-to-build-a-space-drive-that-doesnt-expel-reaction-mass/159838/23 "2003-03-10T14:08:26Z")
> [@](#):
>
> \*Originally posted by Q.E.D. \*
> Wow. Is there a record for the longest time between double-posts? If not, I nominate **Urban Ranger**!
Rats! 😛
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