powers of the Mandate are the Earth-Moon Union (which is apparently American-dominated), the Martian Reich, the Jovian Soviet, and an unnamed Chinese regime on Venus; the Earth-based Interplanet conglomerate, which holds a century-old uranium monopoly, is a de-facto fifth power, and largely controls the government of Earth. The Mandate, whose capital is located on the asteroid Pallas, had been established in 2171 by the peace treaty concluding a nearly ten-year war started by the Martian Reich, which saw all of Earth's colonies except the Moon gain independence. The more moderate Venusians and Jovians had invited Earth to join the post-war Mandate to counterbalance hard-line Martian influence, but the asterites - despite having fought on the rebel side in the hope of establishing their own independent High Space Union - were betrayed by their former allies at the conclusion of the war. Plot "Collision Orbit" begins in early 2191, as the sleepy asteroid Obania is suddenly menaced by a smaller rogue asteroid after a random seetee collision alters its orbit. Spatial engineer Jim Drake, tugboat pilot Rob McGee, and young heiress Ann O'Banion try to divert the asteroid - which they name Freedonia - which would enable them to claim it in recompense and use it as a laboratory for Drake's seetee experimentation. The attempt to install a paragravity engine at the center of Freedonia fails due to bad luck and economic sabotage by Mandate authorities, but in the end Jim succeeds by steering a mass of anti-iron into a borehole, where the resultant matter-antimatter reaction can faction as an improvised rocket. The Mandate recognizes Drake's claim, and his son Rick - impressed by his father' success and angered by Mandate action joins project - joins the family business. "Minus Sign" begins in March 2191, immediately after the conclusion of the preceding story, but switches viewpoints to Rick Drake, also a spatial engineer and a rising star with Interplanet. Angered and disillusioned by the Mandate's treatment of his father, he joints Drake, McGee and Drake as a partner, just in time for a race against a Mandate science expedition to unlock the secret of a seetee asteroid exhibiting anomalous properties. In "Opposites—React!" a contraterrene alien artifact is discovered, and competing parties race to reach it and learn its secrets. The plot of the later book version differs somewhat from the magazine version, particularly in incorporating the speculation that time might run