The first five minutes the crew is shaking uncontrollably, but trying to maintain their cool, during takeoff. The crew begin to get adjusted to the habitat, getting themselves settled. Before long, the commander/pilot Marina sees some blood on the floor, looks up, unscrews a panel, discovers a stowaway (Michael), bleeding badly, who is larger than the space accommodates, and he quickly falls down on top of her, breaking her arm. Some equipment behind his body in the compartment appears damaged. The crew wonders if he stowed away intentionally, but this plot point is never answered; he claims he does not remember and someone would have had to screw the panel down from the outside after he was 'in' in any case. Zoe, the doctor, sews him up, with help from David, the scientist. The stowaway is somewhat hysterical upon regaining consciousness, having left his disabled (we never learn exactly how) sister behind alone, on Earth; as a result of his reaction, the crew decides he did not stow away on purpose. There are a few brief scenes where Michael eats with the crew and works alongside David, though he is clearly not qualified to be aboard a space ship as an astronaut.Michael is the largest person on board, and Hyperion (the NASA alternative/private space company) is not able to figure out how he got on board, nor how to fix the oxygen scrubber that was permanently damaged by the stowaway's body, he used up extra fuel and oxygen in takeoff that was not planned for, and there are NO replacement parts. Marina asks David to work on increasing his algae project, using up all the resources that were intended for his research project on Mars, to try to produce enough oxygen for even three of them to survive without the scrubber. Concurrently, Marina tries to get Hyperion to come up with a solution (besides offing Michael) and they (with all the world's best minds) can't come up with anything that would allow them to survive the journey. Zoe wants to give Michael extra time while they try to find a solution anyway, David and Marina do not, but they compromise on 10 days, and are ordered to tell Michael nothing. Frustrated at the life threatening risk Michael's presence poses to all the lives of the approved astronauts, David comes up with a lethal injection and offers it to Michael, with an explanation. But Zoe finds Michael, trembling with the injector, and stops him from doing it. She accuses David of not caring, but David (who has a wife at home) has sacrificed ALL of the raw material for his scientific mission for two years in the hope of keeping them all alive, and half of his algae died. He asks what she has done. The other half of the algae dies and there is now only enough oxygen for two people to survive. The commander orders Zoe and David to go out in space (Michael can't physically do it, for lack of training; it does look extremely difficult and something that would take a long time to learn to do well) They try to walk down long cables hooking the main spacecraft to the rocket which launched them off, in the hopes of filling tanks two tanks with remaining liquid oxygen from the launch craft. Each tank can hold liquid oxygen for one person for the whole trip. Zoe succeeds in filling the first tank, and is working on the second tank, but SOLAR STORM! They have to rush back or die from radiation. They rush back and the first tank, which is in no way tethered to Zoe flies off into space just as Zoe and David make it back aboard. The oxygen tank on the launch craft is leaking and Marina says the solar storm will last five hours. Zoe volunteers to go back and fill the second tank. If she succeeds she can save the three remaining astronauts, as she would die due to the radiation. She makes it down, fills it up, brings it back up, then dies of solar radiation..