The First Space Colonists: A Permanent Home Away From Home?

The International Space Station's long-duration crew doubled to six Friday, when a Soyuz TMA transport arrived with three new inhabitants. And life will get even more crowded onboard the orbital outpost next month, when shuttle Endeavour is scheduled to deliver six temporary visitors, plus a replacement crew member for the station.

Expanding the full-time crew was an important and long-delayed milestone for the space station program that should allow the astronauts and cosmonauts to devote more time to science and less to assembly work and housekeeping. But the crew count is not as interesting to me as another overlooked detail: Humans have now lived and worked in Earth orbit continuously for eight years and seven months -- 3,134 days and counting as of Sunday.

This extended occupation began on Oct. 31, 2000 -- perhaps a date that will matter in future history books. That's when a NASA astronaut and two Russian cosmonauts blasted off in Kazakhstan to open the space station for business. One of the three crew members, Sergei Krikalev, is pictured above during that mission, watching shuttle Atlantis approach for an early 2001 visit. In a career that included six different space missions, Krikalev spent 803 days circling the Earth -- more than anyone else to date. The record for a single space flight is held by fellow cosmonaut Valeri Polyakov, who spent 438 days on board the Soviet/Russian space station Mir in 1994 and 1995.

If not for a 14-month gap (from August 1999 to October 2000), the beginning of ongoing human settlement of space could be dated more than a decade earlier -- to Sept. 5, 1989, when the Soviet Union commenced what would turn out to be 10 years of continuous operations on Mir.

But does continuous mean permanent?

Perhaps the long-term missions to the International Space Station and to Mir before that will be remembered as the beginning of humanity's extraterrestrial colonization. Or perhaps they will turn out to be more like L'Anse aux Meadows, the location of an 11th Century Norse sailing camp that was rediscovered by archeologists in 1960. This admittedly Eurocentric example offers a useful distinction: The temporary Norse settlement in what is now known as northern Newfoundland predated the voyages of Christopher Columbus by half a millennia, making it Europe's earliest known toehold in the New World; but permanent European colonization of the North American continent would not begin until centuries later.

The timeline for the next major phase of human migration will likely be measured in similar increments.

(Photo above from NASA)