Poul Anderson is, and mayhaps always will be, the speculative fiction writer who most integrates myth and legend into fantasy and science fiction. The former relatively easy given myth and legend are typically already half fantasy, the latter is the more difficult given one of the aims of science fiction is believable futuristic extrapolation. Failing spectacularly with The High Crusade (a novel that sees Medieval knights take a space ship to another planet to fight blue-skinned aliens), his 1970 Tau Zero is a more subtle mix. While lacking in fully humanized characters, it nevertheless captures the ideal of a mythological journey in hard sf form.
Tau Zero is the story of a group of fifty astronauts on a mission to a distant star system. The journey planned to take five years subjective time, thirty-three years actual time, the group know they are leaving their loved ones behind for good; the Earth they will return to in sixty-six years will be in differing circumstances. Their ship, the Leonora Christine, the most sophisticated, technologically advanced space craft ever assembled by humanity, is capable of accelerating the vessel to near light speed with its massive Brussard ramjet. Blast off going off without a hitch, when the ship flies through a nebula, however, a wrench is thrown in the works. The gas pedal essentially stuck to the floor, the astronauts must find a way to remove the figurative wrench as they inch closer to light speed and further from the reality they are most familiar with.
Tau Zero operates at two surface levels and one sub-surface. The science surrounding the Leonora Christine, as well as astrophysics at large, play a significant role in the narrative. Anderson takes small breaks to explain various technicalities and pass along bits of knowledge relevant to theoretical space flight. Characters occupy the other significant portion of the narrative. Relationships formed and broken, much of the story is the interpersonal interaction amongst the crew, which, in politically correct form, contains the token ethnic representatives, Swedish most prominent among them. The vast scale of the venture combined with the human expectation and reaction to the events which occur forms the subtext: a people caught in an expedition beyond their ability to immediately influence. Or, in other words, a boat caught in a storm on a journey to a place none can predict. With Anderson’s penchant for Norse myth, there are parallels. The connection to myth likewise offers an explanation for limit of one, sometimes two dimensions of the characters.
Not fully fleshed, the main issue with Tau Zero is the lack of realism and empathy generated by Anderson’s descriptions of humanity. Many of the characters archetypal rather than real, it wouldn’t be a problem were the narrative to have maintained a mythic tone—as Anderson successfully does with many other of his stories, e.g. The Broken Sword. Attempting realism yet not wholly succeeding, the result is a juxtaposition of tone: somewhat exaggerated characters attempt to convey realistic emotion and behavior. This gap becomes particularly obvious as, among the several facets of humanity Anderson attempts to portray, one is the most difficult subject to capture realistically on the page: love and relationships. Lingrid and Reymont, for example, mostly feel as through they are going through the motions of getting together, breaking up, etc., rather than innately involved as living, breathing humans. Had Anderson kept his character profiles simpler (like real myth), the balance of science and plot would have been more effective. As it stands, the attempt at realism falls mostly flat.
In the end, Tau Zero is the straight-forward story of a crew of astronauts who embark on an interstellar journey aboard a highly technically conceptualized spacecraft. Part hard sf and part legend, the human stories do not color fully and would have been better as pale representations. But the journey they undertake—and are taken on—is all the stuff of legend, literally.