Tuesday, June 28, 2011

Earth's 100 Year Starship Project

Since January of this year, DARPA and NASA have finally been "publicly" talking about their 100-year starship program.

The scope of a program for such a starship implies just that; it's mission would surpass all interplanetary exploration, pushing far beyond our solar system into the great void of interstellar space.
They’ve held a symposium, put out an official Request for Information (RFI) looking for ideas about how a long-term human mission to boldly go out to the stars could possibly happen, they have an official website and have just put out a request for papers for a public symposium that will be held this fall in Orlando, Florida.

It appears they are serious about this.

However, contrary to what the title of the project might suggest, it’s not so much about actually building a starship that could accomplish such a long distance journey, but more about solving all the various technical, medical, sociological and economic problems; so that one day – perhaps in a 100 years or so – we actually could build one and humanity could head for the stars.

Ultimately though, the broader challenge for such a project would in fact be to launch a new breed of pilgrim on a journey that would span many lifetimes. The biggest initial problem to solve is coming to terms with an acceptable propulsion system. That will determine the time span and all other mission specifications. But, we are not likely to invent a "warp drive" anytime in the next few centuries. Sorry Star Trek fans.

So we won't be approaching anything like light-speed in the foreseeable future. The closest warp speed number might be more like Warp Factor 001. Theoretically, a warp drive might be possible (see the Alcubierre drive in my earlier post) in the distant future, but we would need to also invent technologies far advanced of anything we can currently foresee.

Thus, the closest star, at 4.2 light years away from Earth (a distance of 4.2 years at a speed of 186,000 miles/sec), might be reachable in a few hundred years. Even at a terrific one 10th of light-speed (18,600 miles/sec), it would take nearly a century to bridge interstellar space to the closest star system beyond our Sun.

In fact, we already have two unmanned starships (Voyager 1 and 2 both launched in 1977), already well on their way to entering interstellar space and soon they will be reporting back, for the first time in human history, what lies beyond the heliosphere. That is the bubble of space surrounding our solar system, still influenced by particles from our sun's solar wind and magnetic field.

Both Voyager spacecraft are now traveling at speeds over 3 AU per year, nearly 280 million miles/year (1AU=distance from the Earth to the Sun), or roughly 53 miles/sec in their sprint to cross into the interstellar medium. Voyager 1 is estimated to pass out of the heliosphere anytime between now and 2014. But they are not currently being driven by any propulsion system.

A manned starship would no doubt continue to accelerate, achieving many times the velocity of either Voyager spacecraft. Assuming we could even achieve a 10th of light speed in a manned starship, we would also need to begin decelerating at some point in the journey. That will also add time.

So at the very least, with our highest hope for speed over distance to another star, humans would need to last almost 200 years to fulfill the dream of reaching another potential exoplanetary system, realizing the hope of finding another habitable Earth-like planet.

In my next post, we'll explore what such a starship might look like, what life would be like on board and what sort of people would volunteer to go on a journey where only their children's children might ever see the dawn of a new sun.

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