Sizing Up the Daedalus Interstellar Spacecraft

astroengine writes "How big would an interstellar spaceship need to be? New artwork of the British Interplanetary Society's 1970's Project Daedalus by the non-profit organization Tau Zero Foundation gives the impression that the fuel economy for a nuclear pulse propelled vehicle might be a bit steep."

Comments

Spaceship?

[stjobe]

Wouldn't "space probe" be more accurate? I don't believe it was ever intended to be manned.

Re:Spaceship?

[geogob]

But... I was told that 2 was enough?!

Re:Spaceship?

[careysub]

And if it were to be manned it wouldn't be a return trip so to allow for a sufficient genetic variation the crew needs to be at least 1600 individuals.

Otherwise the risk of genetic degradation would be too great.

Depends on what "too great" means. The Hutterite community in North America, a closed religious community, was founded around 1700 with a founding population of about 400 that was already highly inter-related (compared to world-wide human genetic diversity) and has now increased to 50,000. Genetic studies do show a measurable penalty in fertility and fitness with this high level of inbreeding, but the community is doing quite well nevertheless.

What is more there is evidence of major human populations developing from even smaller founder groups PLoS Biology, June 2005, On the Number of New World Founders: A Population Genetic Portrait of the Peopling of the Americas asserts that "Taken together, the analyses in this study suggest a recent founding of the New World Amerind-speaking peoples by a small population of effective size near 70"

Now the lack of diversity in the immune system of the American Indians later led to an epidemiological calamity when diseases from the Old World were imported 10 or 15 millenia later, but this is an avoidable hazard for interstellar colonists.

But the key difference with a space mission is that there is much we can do to avoid genetic disorders and promote genetic diversity:
* Select colonists (or colonist couples) for genetic diversity,
* Use sperm/ova banks to import gentic diversity,
* Use genomic screening to screen out lethal genes (which can be applied in a number of ways).
These techniques can make inbreeding problems go away entirely.

From the article: A major drawback

[Suki I]

Or maybe not so major of a drawback.

Says it would zoom past Barnard's Star in 50 years at 12.5% the speed of light because it is not designed to go into orbit. So, it is just getting a quick look there and everyplace else it travels. By the time this thing could be built, sensor technology might be up to the task.

Re:From the article: A major drawback

[Onuma]

We could just harpoon & tow-cable the leg of Barnard's Star as we swoop by...

Think Positron Engine Drive

[tyrione]

WSU Positron lab: http://www.cmr.wsu.edu/facilities/webster_547

W.M. Keck Lab

This article and video explains their research: http://wsutoday.wsu.edu/pages/publications.asp?Action=Detail&PublicationID=14531&TypeID=1

Re:Think Positron Engine Drive

[wagnerrp]

Antimatter reactions are ridiculously energetic, with an energy density of some 90PJ/kg. The problem is that there is no known naturally occurring source of antimatter, we have to produce all that we want to use. That makes it nothing more than a battery technology. Add in the inefficiencies of antimatter production, and you're talking about energy requirements equivalent to centuries at our current global consumption rate just to get into orbit. Finding a way to densely store the stuff is just one of many very difficult problems that need to be solved.

Re:Space and Sails

[Lumpy]

So then what do you do when you pass the heilopause and you no longer have a solar "wind"?

Honestly a redesign using ion engines of today would make a different craft. Plus it would allow the craft to not just speed on by in a ballistic trajectory, but even start breaking and enter a orbit that would allow the craft to stay and radio back info.

It can be electrically powered by Nuclear reactors, and as each one get's past it's 20 year lifespan you jettison it making the craft lighter. Ion engines already are producing impressive thrust for the age of the technology. An unmanned interstellar probe moving at 12% the speed of light, assuming it does not plow into something out there is a very feasible project and could gather scientific data the entire way. Although the Doppler effect on communications would be interesting. But research into really measuring time dilation could be done as well.

Sadly, we are far more interested in killing each other. It's more important to fund the war machine than the thinking machine.

Re:Buyer's remorse

[cowboy76Spain]

Yeah... but building it will be one of the ways of improving such technology (and every other way of improving the technology costs money, too).

Re:Automation has a long long way to go

[Sockatume]

I think you'll find that we can do that, if by "we" you mean the human race. IKAROS has passed Venus, and is still going strong.

Daedalus class

[rossdee]

I thought the Daedalus incorporated a lot of Asgard technology, including Hyperdrive and site to site beaming ability. It would be very useful to have since it can go to other nearby galaxies (Like Pegasus)
Heres some info: http://stargate.wikia.com/wiki/Daedalus

Re:Nuclear fission propulsion

[stjobe]

Freeman Dyson published a paper called "Interstellar Transport" (Physics Today, October 1968, p. 41–45) on how to build an Orion spaceship to get to Alpha Centauri, so yes, it could carry enough fuel for interstellar travel. Your other two points are correct though.

I strongly disagree

[captainpanic]

Oddly enough, I was reading up on possible interstellar probes just a few days ago.

Anyway, getting to another star system is just simply such a huge task. Take for example Daedalus' design -- the economics of building such a vehicle today are such that even if we had the political willpower to do so, it would just cost so much that it would soak up our global economic output for a very long time, possibly centuries.

If we were to just wait 100 years or so, I'd put money on new physics being discovered which would allow an interstellar mission to be constructed for a tiny fraction of the cost of Daedalus (or Icarus), be completed in a fraction of the time, and have enormously increased capabilities (e.g. stopping at the target star, making a return journey, or even carrying Astronauts).

It's an interesting study, but totally impractical today. We need a better understanding of the universe before we should even give serious thought to attempting this -- it doesn't pass the back-of-the-envelope test.

It's not completely absurd. The projects that mankind undertakes today are enormous (in fact, there are multiple things that are way more expensive or complicated than this Daedalus spaceship). Take for example the entire road system of the world, including all rural roads, cities, traffic lights, cars, trucks, and whatnot. It's been an enormous undertaking - yet we don't mind rebuilding it entirely every decade because we don't like bumpy old asphalt or old cars.

The ISS, with a weight of nearly 400 tons, and measuring 50x100 meters shows how much is possible for a relatively small-scale human project. All our civil achievements show how much is possible for the large-scale human projects. We don't mind changing the entire surface of our planet.

We humans look at cost/benefit estimates. If the costs are high, we don't mind, as long as the benefits are there.

The problem therefore with the Daedalus is not that it's not possible. It is that it just does not have enough benefits for mankind to invest the time, effort and resources in it.

Re:I strongly disagree

[Nethemas the Great]

In singular perhaps, but not in aggregate. US DoD funding for one year dwarfs the ISS. I personally would rather invest in something that can pay dividends even if the payout is some distance off. The slaughter of man and the destruction of infrastructure doesn't fit that bill. Stop making swords, start making pens, and go put the savings to productive use.

Re:HOW DO I VIEW ALL COMMENTS WITH NEW SLASHDOT?

[Fnkmaster]

You switch to D1 instead of the stupid D2 discussion system by clicking on Account while on the main page. D1 actually lets you view more-or-less all the comments for most stories.

Then fix up the D1 system by creating/editing userContent.css (assuming you are using Firefox) in your profile/chrome directory:

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