use up all the oxygen. Bob, ever reserving his right to act at discretion, secretly prepares a dose of sodium pentathol to use on Valkerie after she has sedated Kennedy. But at the last minute, Valkerie tells him that she forgives him for not trusting her. He cannot bring himself to rebel against Valkerie, and so allows her to sedate him. Another disaster--and eventual landing Valkerie now faces a problem with which she almost cannot cope: total isolation, with no one to converse with—not even Houston, because she must power down the radio to conserve energy. She spends most of the time in prayer, but mostly crying out to God to "send her an e-mail" and give her a reason to believe. As the ERV continues its approach, Valkerie asks for and receives permission to revive Bob so that he can help her pilot the habitat to a rendezvous with the ERV. Unhappily, the ERV is approaching far too fast. Valkerie's attempt to match velocity with it ends in failure, and worse—she uses up more fuel than they can spare. With the ERV speeding past the habitat, Bob and Valkerie suddenly remember that the ERV carries a crew re-entry vehicle with its own engine. They issue orders to detach it from the ERV and bring it to a slow rendezvous—and then Valkerie makes another spacewalk to cut loose its oxygen tank and bring it aboard. Bob, in turn, receives instructions to build a Sabatier scrubber—an ultra-low-power device for removing carbon dioxide from the ship's air. They then reawaken Kennedy, who must regain his strength to perform the landing—and then decide that the only way they can land is to abandon the original mission profile calling for a Martian orbital capture, and instead dive straight down to the Martian surface. This is an incredibly risky maneuver, one which they almost do not complete because they are about to use an aerobrake deployment system that is non-functional. (Another failure of trust is responsible for this predicament, which they avoid only by some last-minute deduction of NASA's true intentions.) They intend to land in a camp that previous missions have already established—but they end up landing too far away. However, they manage to pool their remaining oxygen to give to Bob and Kennedy, so that they can retrieve a pressurized powered rover to rescue Valkerie and Lex. When the men return, they find