Although Kennedy is hit, he survives, Jacqueline Kennedy taking the fatal bullet. Kennedy's injuries, however, force him to relinquish his office to Lyndon Johnson and act as a cheerleader for the space program he began as president. The space program then continues much as in our world, including the landing of Neil Armstrong and Joe Muldoon on the Moon on July 20, 1969. Baxter's changes come slowly, as if to say the inertia of history must be taken into account. Eventually, Nixon, at Kennedy's urgings, chooses a Mars program instead of merely the shuttle program he chose in our timeline.
Voyage is an epic.
As such, it has a large cast of characters,both real and fictitious. It also spans a period of time from 1963 to 1986. Unfortunately, Baxter chooses to jump back and forth through time to tell his story. A scene from the Ares launch in 1985 will be sandwiched between scenes of Armstrong and Muldoon on the Moon in 69 and Apollo 13 in 70. At times, this causes a disjointed narrative, leading the reader to pause in order to figure out the sequence of events, identities of characters or a character's age at the time something occurs.