What happened to the Kings of Infinite Space, as J. G. Ballard ironically called them? They were, as Ballard said, "dull men, living examples, incidentally, of that wooden characterization for which science fiction writers have always been criticized." Did they feel nothing? I think it was Gus Grissom, who died in the Apollo fire, who was once asked how he felt, and replied How would you feel when you know you're sitting on the results of the lowest tender received by NASA? They must have felt something.

Stephen Baxter's VOYAGE brings all these together, re-writing history with a focus on the technology. Shot but not killed in 1963, after Kennedy retires the same line of American presidents who have lead the USA make a slightly different series of decisions about the space program. The slight difference is that the Apollo program becomes not the space shuttle, but a journey to Mars. It was Richard Nixon who decided what would happen to Apollo (he needed the money to fight on in Vietnam), and somehow in Baxter's timeline he manages to find the money for both: the ideal of the Mars voyage does little to inspire peace and both the Vietnam war and the Cold War go on as they really did. The departures of Mars explorers in late 1996 (or unfortunate non-departure in the case of the Russians) was a late attempt to use the "Mars window" which aligns with Earth at long intervals. Far better would it have been to launch forth in 1985. It was 1971 when Nixon wrote his fateful document - in reality it ended the Mars program, in VOYAGE it begins it. NASA would have fourteen years to prepare for the three year journey. That is, would have only fourteen years.

VOYAGE is a series of interlinked stories, cutting between the three astronauts on their journey out, telling their life stories in-between, and describing the history of NASA and the proving missions on the way. This third element of the story makes harrowing reading - the internal politics, and struggles of the contractors and sub-contractors. Not Rockwell or Martin or Grumman, but Columbia Aviation, a fiction. But Columbia can only put forward their idea - give NASA the simplest copy of what they've already had - after the failure of Apollo-Nerva. In reality Nerva was the atomic powered rocket which never got off the test beds in the Nevada desert, but in test orbit in alternate December 1980, the reactor blows, three astronauts lying above it. One of those men, Jim Dana, knows he will die, but he has always wanted to be part of the space program, as his father has been a rocket scientist before him.

In Baxter's plotting, the Dana family are minor but essential, because it is Dana Senior who has recognised that the mission can slingshot off Venus on its way to Mars, and it is Columbia Aviation's recognition of this additional use of free energy that allows them to put in their lowest bid. It is a remarkable conception in the writing, that a scientific curiosity can be used as an accountant's device to rig a bid, and yet sustain a major part of the plotting. The character who uses it, J K Lee, is more dubious, a stereotypically driven business tycoon cracking up, but that should not detract from Stephen Baxter's skill in merging science and fiction here.

Remarkably, what I have not done is point out that the central character of VOYAGE is a woman. I will leave her discovery to you.