6 replies to this topic

[Guyverman1990]

HI guys,

I'm just wondering what planet in what nearby interstellar star system would be the first for humans to set foot in and/or colonize. Would it be the Gilese, Kepler or Alpha Centauri?

What do you guys think?

[Craven]

If there will be one it most likely would be "transhumanned" mission
And I think we'll have answer in less than 10 years. By that time we will have pretty good idea about habitability of nearest worlds and will pick closest of the most promising ones.

[Time_Traveller]

I'd go with Alpha Centuri as it's the most closest to our solar system.

[eacao]

I'd go with Alpha Centuri as it's the most closest to our solar system.

The hard part of an interstellar mission is accelerating. After that, you can cruize for as far as you need to. If you could get a vehicle up to a sizeable fraction of the speed of light, why go to Alpha or Proxima centauri. Proximity isn't everything. A mission that resource and energy intensive is more likely to go to a star 20ly, maybe 30ly away if there is a habitable planet orbiting.

[Craven]

Yeah.. but it still takes time, even at subluminal speeds Alpha Centauri will be ~6 year trip, stars 20ly. It's months till you can accelerate to accurate speed. And if there are no interesting planets in Alpha Centauri, then why go there? Why send humans. And I say - I believe we'll never send homo sapiens outside Solar system. It'll probably be transhuman beings.

[Italian Ufo]

I agree with Craven, it would be sadistic for humans to go there

[wjfox]

From SentientDevelopments.com (currently unavailable, so here's Google's cache of the page)

http://webcache.goog...n&ct=clnk&gl=uk

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Study: Interstellar Travel Not Possible Before 2200

According to a recent paper put out by Marc G. Millis, humanity will not meet the energy requirements for an interstellar trip for at least another two centuries. Millis is the former head of NASA's Breakthrough Propulsion Physics Project and founder of the Tau Zero Foundation which supports the science of interstellar travel.

He bases these calculations on 27 years of historic energy trends, societal priorities, required mission energy, and the implications of the Incessant Obsolescence Postulate (where newer probes pass prior probes).

Millis considers two possible missions: launching a minimal colony ship where destination is irrelevant, and sending a minimal probe to Alpha Centauri with a 75 year mission duration. In the experiment, the colony ship is assumed to have a mass of 10^7 kg, and the probe 10^4 kg.

The first mission is a human generation ship of 500 people on a one-way journey into space. He assumes that such a mission would require 50 tones per human occupant and that each person would use about 1000W, equal to the average amount used by people in the US in 2007. From this, he estimates that the ship would need some 10^18 Joules for rocket propulsion. That compares to a shuttle launch energy of about 10^13 Joules.

The second mission would be a 71 year journey by an unmanned probe headed for Alpha Centauri which is just over 4 light years away. Such a ship would be some three orders of magnitude less massive than a colony ship so it would require considerably less energy.

"It is found that the earliest interstellar missions could not begin for roughly another two centuries, or one century at best," writes Millis, "Even when considering only the kinetic energy of the vehicles without any regard for propellant, the colony ship cannot launch until around the year 2200, and the probe cannot launch until around 2500."

Problems I have with this paper:

• Millis's extrapolations assume a linear progression of available energy density; technological development is showing a strong tendency to progress non-linearly
  
• He assumes that there won't be a "wild card" type breakthrough in propulsion technology and energy extraction; it's not unreasonable to assume that there will be a sudden breakthrough that could serve as a significant game changer
  
• His 500 passenger colony ship is ludicrous; biological humans won't be making such a journey, and most certainly not 200-500 years from now