Stross dedicates Saturn's Children to Isaac Asimov and Robert Heinlein, explicitly making Saturn a homage to their stories. But Stross's choice of materials is oddly idiosyncratic: most writers would want the clarity and thoughtful ideas of early Asimov intersecting with the muscular prose and clean, externally-focused characterization of early Heinlein. But Stross instead chooses Asimov's most nitpicky rules-lawyer logic-chopping and the unbridled kinkiness and emotional prolixity of late Heinlein.
Saturn's Children, on the surface, is a retelling of Heinlein's Friday using more rigorous, Asimovian controls on the robots. It's set in a solar system, a few hundred years hence, populated entirely by a bewildering array of humanly-intelligent "emotional machines" after the human race quietly -- and awfully quickly -- died out. But this immediately runs Stross into consistency issues. His robots are raised like organic beings rather than programmed like machines -- except for the times that he needs hard-wired robotic control over them, when they immediately revert to a more Asimovian command-based system. He tries to have it both ways depending on the needs of a particular scene: his robots have psychological depth and real emotions, except when he needs someone to push a button and make them Asimovian automatons obeying unbreakable laws encoded into their very brains.
Similarly, he resorts to supernaturally effective tech when it helps his plot: there's something called a "slave chip," which works perfectly even when a robot doesn't know she has one installed, and which forces her to completely obey the person who installed that chip in her, even when she doesn't know who that person is. The slave chip clearly does not make the possessor obey everyone, and it doesn't tell the possessor that it exists or who she has to obey -- it just cuts in when the plot-appropriate person makes demands (even if that person might only be posing as the person who installed that chip).
One more related objection: robots are given their orders in plain language, conversationally. These orders are, in best Asimovian fashion, unbreakable...except that they're not clear enough to be unbreakable in the old Asimov style, so the robots must use their own best understanding to interpret and carry out those orders. And yet no robot is ever seen to be working around his orders, like a corrupt butler -- that possibility doesn't seem to even exist in this world. Freedom is an alien concept to the solar system of Saturn, as it often is in Stross's fictional worlds; he's one of our chilliest and most fatalistic writers, writing scenes where only a limited number of (unlikely to be successful) actions are ever possible.
The core issue behind all of those objections is that Stross has incorporated both the Asimovian Three Laws style of robot control and a late-Heinleinian conception of human psychology (with all the attendant requirements for lots of kinky sex of the sorts the author finds most interesting). Having two models of mind in one book is one too many. Either his robots are born and taught like humans -- possibly with some slightly different "robot" or "future" psychology invented by Stross -- or they're programmed like machines. Saturn's Children insists, repeatedly, that both of those are true -- that its characters had to grow up and learn to have their current capacities but also can be easily and quickly programmed via chips and verbal commands. That they have pseudo-human psychological damage caused by vicious traumatic experiences and push-button control of their internal states.
Saturn's Children is the story of Freya Nakamichi-47, the last-born of a line of very humaniform -- pneumatically femme-form, I should specify -- artificial organisms created originally to serve the sexual desires of humans. Sadly, Freya herself wasn't even created until after the human race died out, so her entire life has been one gigantic case of blue balls. (Saturn's Children is Stross's most sex-soaked book, but -- for good or ill -- he hasn't changed his geekier-than-thou diction, so the descriptions of sex are wrapped in elaborate technological jokes and obscure references; no one is likely to become aroused by reading this book, and the careless reader will miss half of the sex scenes entirely.)
Her name is the first, and most blatant, connection to Heinlein's Friday, but Freya's skills are nowhere near Friday's. (Stross is far more interested in incompetence, or rather the impossibility of beating experts, than Heinlein was -- but I'll get back to that later.) Saturn's Children is the story of Freya's inadvertent -- and mostly unwilling -- tour of the solar system. (There's a fascinating comparison to be made of Saturn's Children with John Varley's very similar Rolling Thunder, but this parenthesis is too small to contain it.) Freya begins the book by inadvertently insulting an aristocrat (by her very existence) on Venus, and then has to flee the wrath of her new enemies.
(Stross has the leftist Brit's irrational hatred for aristocrats -- "aristo" is essentially the word for "villain" in this book -- and all evil flows from the inevitable and unstoppable concentration of power in the hands of those nasty and unscrupulous enough to seize it and declare themselves rulers. These "aristos," though, don't seem to be hereditary -- there hasn't been time for generations of these very, very long-lived creatures -- so they're just petty dictators and kleptocrats. But those words don't strike horror into the bones of Stross's expected audience the way "aristo" does. Stross does have an explanation as to how this state of naked Darwinian competition came into existence, but it's just another example of a very familiar Stross expectation -- again, I'll come back to this.)
Freya finds love, of a sort, eventually, but, before that, she finds a series of Penelope-level travails and threats that become ever more pointed at her mental integrity and sense of self. Stross writes all of this with a seriousness of tone, and a tight focus on Freya's own roiling mental state, that keeps the reader from detaching from her torments. We're in her head throughout; what happens to her is happening to us, so it's less amusing to those of us who aren't masochists. We feel for her in the end, as she gets a happy ending that's a tad too conventional (and another Heinlein homage), but we've been wrung out by all that's happened to her before that.
Lois McMaster Bujold recently wrote that SF novels were "fantasies of political agency," and that idea can be applied to Stross. His novels and stories, almost to a one, are fantasies of bondage, and Saturn's Children is the novel where that tendency comes to its fullest flowering. Stross is a hard science fiction writer at the end of a long and gloomy British tradition, and so is obsessed with limits, with restraints: his novels are more about what can't be done than what can. The godlike Eschaton in his first novels is terrified with its own end, and enforces its loose rule on all humanity to maintain its own existence. The "Merchant Princes" novels are dense with argument, political and economic, about how people behave -- and themselves have darker, more violent object lessons in that same area. In all of Stross's novels, action is difficult and wrapped in turmoil; the inevitable end of everything is always in sight.
There's also been explicit, sexual, bondage in Stross's work as well, most notably in the "Laundry" novels and stories. It's come up in his work enough that one starts to
In Saturn's Children, Stross has made the implicit bondage of the laws of physics -- especially those old Cold Equations of space travel -- into the explicit bondage of sex: Frey is used and abused repeatedly, sometimes more consensually than others, sometimes more pleasurably than others. But the linkage is undeniable: to Freya, space travel is always about getting tied down and fucked. Even more so, the entire reason for her existence -- the reason for the existence of the entire series of organisms she is part of -- is to be inextricably bonded, body, mind, and soul, to whatever human being claims her. (All of the "emotional machines" have similar controls, but Freya's Rhea-class siblings are the most blatant: they exist to unconditionally love, and be fucked by, humanity.) Life is bondage; life is getting fucked, or fucked over, by whomever is in control. Since Freya is a sexy femmebot, her fucking is more direct than that of her less humaniform kin, but they're all fucked equally.
It's hard to read Saturn's Children as a fun romp through the solar system with that subtext dragging everything down; even Freya's eternally chipper attitude starts to pall when there's always one more scene of her being trussed, physically and/or emotionally, to suit someone else's needs. But, for readers who have tired of the same old whips-and-chains scenes, Saturn's Children opens up whole new vistas of torment and control.
The title puzzles me, I must admit: the most famous child of Saturn is of course Zeus, who escaped being devoured to kill his father and free his siblings. If the emotional machines are the children of the Titans of humanity, then there was no Zeus; Saturn died of natural causes. These emotional machines -- these children of Saturn -- live, irrevocably, in the shadow of their forbears, building what they all know instinctively know can only be an age of Silver, which will never match the Titans' age of Gold. Perhaps this is yet another example of the Strossian gloom; another height that can never be reached again, as all past energy is permanently lost and the universe tumbles on towards its eventual suffocating death.