Slashdot Mirror
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."
But... I was told that 2 was enough?!
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).
Why can't
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.
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
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.
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.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj