Exodus...evacuation Earth!

One of the reasons its been suggested we undertake interstellar travel is that this old Earth may someday become inhospitable to the human race. Possible reasons for leaving earth include eco disasters, all out nuclear war, or asteroid impact. Science fiction stories have been written about this subject as have numerous magazine articles that talk of an Earthly evacuation as being a reason to set off for the stars.

 

What is the reality? Is this something we can actually do now, or in the near future?

 

Like a scenario for shooting nuclear waste into space or the Sun, a lot more wishful thinking than science would seem to be at work here. As in the nuclear waste disposal scenario...it is a case of "Inadequate logistics". The term "Inadequate logistics" describes not being able to move nearly enough material...or in this case, people and material into space to actually colonize another star system within a reasonable amount of time. If we detected an incoming asteroid too large to deflect or destroy. That detection could come just a few years before impact. Even with a crash program, this is not enough time to evacuate thousands or millions of people from earth. The spacecraft required for the evacuation would have to be parked at some distance from earth to avoid getting hit by pieces of an asteroid after impacting earth. The only viable solution is selecting the top people of the human race to make the journey and leaving the rest to die. Something like 3,000 people minimum would be required to assure reproduction of generations of them in the event the nearest earth analogue is tens of light years away. Not to mention the feeding and life support required for such a large, space borne population. This has many thorny social implications as one with even a small social conscience might expect. Consider that in just over half a century of human space exploration thus far, less than five hundred people have journeyed into space. The reason for this, not enough seats and frequent flights. The Shuttle averaged roughly five or six flights per year over it's lifetime.

 

Soyuz or Shenzhou flights are less frequent and carry three persons maximum.

 

Russia and China are currently the only Countries that can send human into space after almost half a Century. The US having dropped out supposedly temporarily upon retiring the space shuttle. The highest human flight rate ever sustained was by the shuttle in 1985 at 9 flights. China had talked of sending their first men into space for almost two decades, and then finally did so starting on October 15, 2003. Their next mission was launched October 12, 2005 followed by a few more. At this rate, they will by no means, be sending Taikonauts  up en masse, much less sending escaping earthers away from danger. An American named Burt Rutan through his company Scaled Composites, sent humans to the edge of space for the first time on June 21, 2004. Two competitive flights for the "X" prize were made on September 29th and October 4, 2004 respectively. While Burt Rutan won the Ansari "X" prize of $10 million USD, his is nowhere near being a solution to the "Exodus" problem. Especially considering his early efforts did not achieve orbit. However, his goal is space tourism through Virgin Galactic, headed by CEO Richard Branson. As of 2016, they are recovering from an October 31, 2014 accident involving the loss of the "X" prize follow on craft, Space ship 2. Other companies such as Space X, have yet to send humans to low orbit. With a world population that will probably well exceed a hundred billion by the time humans develop interstellar travel, even the most extravagant concepts could not be expected to keep up with the population growth. And the fact that the "Population curve" is far ahead of the "Sending people into space curve" is no help. Even commercial air travel, if thought of as space travel seems inadequate. Had space travel achieved the ability to move millions into space each year, it would still be a daunting task and require a decade or more minimum to move the majority of Earths human population off Earth. To say nothing of animals such as livestock that humanity has always relied on for food and other products. Consider the interstellar travel concept I portrayed in "Human Space Flight and Beyond" which takes place very optimistically in the near future relatively speaking. That is, about a century and a half or so from now. Initially. each ship has the population of a small town on board. About 4,000 people in the case of Starship Centauri at L4 departure. And its not as though the starship could move significant numbers by frequently turning around.

 Starship Centauri enters the Alpha Centauri system, illuminated as it passes in front of the "B" star. The habitable portion of the craft is housed within this tiny asteroid.

One starship with up to 4,000 people on board, would be able to make only ten round trips per century at near light speed. This to move only thirty thousand persons or so per century, assuming more ships are not built to expedite the task. Not to mention the relativistic effects of near Speed Of Light (SOL) travel which makes return trips to Earth useless anyway. Of course, those who made the initial journeys would begin populating the hypothetical Alpha Centauri Planet one (ACP-1 or Destin) and unlike our early pioneers, they would presumably benefit from the advanced technology expected. It would probably be better to simply put populations of small towns, even cities inside huge near Earth space structures such as those once proposed by Gerard K. O'Neill.

Huge space colony concept similar to that proposed by Princeton University Professor Gerard K. O'Neill. This concept was dated June 11, 1976. Image courtesy NASA.

In my own concepts (A few shown here), I didn't require the original expedition return to Earth. The starship was intended to sustain them in the event they found Destin to be too harsh for human habitation or in the event they couldn't populate Destin to begin with.

As mentioned above, the ship, or rather forward end, is roughly
the size of a football field.

Aft view of the conceptual craft. These images are from a graphic novel I did a decade ago. The proposal was shown in response to Betelgeuse going supernova in December 2016. Of course, I do not expect Betelgeuse to go supernova on that date. I just used it to show what a supernova in our backyard would be like. For story purposes, it wasn't a full blown supernova event.

When people write or discuss Exodus earth type plans, its not known for certain  whether they are aware of the tremendous logistical and social problems involved. Those problems are usually not part of these discussions. Or perhaps they have no problem with the social implications of deciding who should be part of the evacuation of Earth, and who should be left behind. I recall one Sci Fi movie made in the late fifties or early sixties that did cover the logistical problems somewhat. It was probably the movie "When Worlds Collide". The only realistic interstellar exodus scenario I can imagine is one taking centuries and sending starships to numerous destinations, never to return to Earth. Closer to home, simply moving into O'Neill habitats scattered throughout near Earth space seems to be a more realistic solution for evacuating large numbers of people in relatively short time frames such as a decade or so. These habitats could theoretically be built like building a ship inside a bottle, but inside of hollowed out asteroids instead. This could avoid supernova and solar radiation. Terraforming planets such as Mars has been proposed as a solution to the problem of earth facing an imminent disaster. Problem is, terraforming a planet could take centuries to complete. It would appear we've been terraforming Earth for two centuries now. Only we call it industrial pollution and human made climate change. We have no idea where that will lead. For now and the foreseeable future, the idea of an exodus to an earthlike world in a nearby star system is still very much the realm of science fiction.