Sleeper ships are a viable means of interplanetary travel, but they are most commonly associated with star ships. Sleeper ships have been seen or mentioned in many science fiction sources, including the original Star Trek episode "Space Seed," the original Planet of the Apes movie, the Alien movies, the early 90’s TV series Earth 2, the novel A Deepness in the Sky by Vernor Vinge, in "Known Space" stories by Larry Niven, and many others.
A sleeper ship is a "low C" option of interstellar travel. Low C (C standing for the speed of light) options assume that obtaining significant fractions of light speed are either impossible or highly impractical, and astronauts must consign themselves to voyages of centuries or millennia.
Basically, the crew of the ship spends most of the many decades in transit in suspended animation, where they age very slowly or not at all. Their physical condition is monitored by computer and they will eventually be awakened at their destination by automated ship’s systems. Exact methods for suspended animation will be discussed in a future article, but include techniques such as cryonics, chemically induced hibernation, fluid replacement, cryogenic suspension, nanotech restructuring, or combinations thereof. The length of a voyage may not be limited by the technology of the stardrive but by how long the human crew can safely remain in suspended animation without risking permanent medical complications.
Sleeper ships are usually associated with low C drive technologies, such as fission rockets, fusion rockets, simple antimatter rockets, and simple lightsails. However, they can be used with just about any form of interplanetary or interstellar propulsion, as the suspended animation process is assumed to consume less shipboard resources than an active human being who will need a constant supply of air, water, food, and other consumables. A good example of this is the ships of the Alien movies, which use suspended animation as a matter of course despite the presence of FTL drives. Suspended animation may also be used as a "cheap" means of interstellar passage on more sophisticated ships, as per the Traveller universe, where a "Low Passage" in cryogenic suspension is the cheapest means of buying transport on the FTL ships that travel between star systems. Another option is the sleeper ship "lifeboat"--if a larger, more advanced starship runs into trouble deep in the vast voids between the stars, small sleeper ship subcraft can serve as a means of getting the crew to a habitable system despite the vast distances involved.
Depending on circumstances, it may not be wise to have the entire crew in suspended animation for the entire voyage. Individual crewmembers may have to be awakened for rotating ‘watches’ while the rest of the crew sleeps so they can monitor sysetsm and do routine maintenance. For example, on a ten year voyage with a crew of twenty, two crewmembers at a time would spend a year awake to tend to the ship. On very long voyages of centuries or more, the ship would have to run on automatic for most of the time, with the crew being only occasionally awakened for brief periods for routine maintenance or emergencies.
|A suspended animation cryopod from the movie Aliens. Image (c) Twentieth Century Fox.|
Engines of Creation by K. Eric Drexler
A Deepness in the Sky by Vernor Vinge
On the Web:
Sites on suspended animation, cryogenic suspension, and cryonics science:
http://www.ibiblio.org/astrobiology/index.php?page=future03http://www.cryonet.org/cgi-bin/dsp.cgi?msg=10201 http://www.halfbakery.com/idea/Suspended_20Animation http://www.cryonics.org/ http://www.cryonet.org/ http://www.crystalinks.com/hibernation.html
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