Every Viking activity was framed in time. Weekly reports indicated tasks accomplished, and deadlines projected through the next few months. In conference rooms regularly updated calendars documented the days to launch, as well as hundreds of intervening events.
This emphasis on time was dictated by the nature of the journey to Mars. Approximately every two years Earth and Mars draw side by side in their respective orbits, an event known as an opposition. For a period of only a few months just before opposition, the conditions are favorable for a spacecraft to spiral out from Earth to Mars. For all other times, the thrust of the rockets is inadequate. For this reason, a so-called launch window can be identified years in advance.
Viking was first planned for a 1973 launch. During January of 1970, when the very existence of the mission was threatened by funding problems, it was decided to delay the launch two years to 1975, spreading the cost over a longer period. Our disappointment was shortlived. In fact, the delay was something of a reprieve. In retrospect, it is clear that the spacecraft could never have been designed and constructed by 1973 without seriously compromising both capability and reliability.
The ultimate deadline, then, was the August-September launch window in the summer of 1975. The spacecraft had to leave Earth at that time. No excuses. Another two-year delay until 1977 was unthinkable in terms of increased cost and administrative complexity.
Development of all instruments was keyed to the 1975 date. Working from that deadline backward, a cascading array of secondary deadlines was identified. A slip of a few weeks in 1971 could endanger the delivery of the hardware to the Cape Kennedy launch facility in 1975. Everyone understood the penalty. If the instruments were only half-ready, they would be flown half-ready-or not at all.
Working within these constraints was less of a burden than one might imagine. Indeed, it was an exhilarating change from our normal activity-in a university, at least-where the business of one day can be deferred to the next day, or even the next year. The Viking goals were sharp. There were no compromises, no rationalizations. Every problem required a timely solution.
Only when you move away from a project like Viking-and are no longer controlled by the calendar-do you realize the impact of that discipline. It affects you in small ways-always keeping an engagement calendar in your pocket, leaving meetings with just enough time to catch a late plane home and in larger ways-looking forward to a future where events yet to come assume the reality of the present. Now that Viking has passed, I sometimes feel adrift without those signposts stretching out before me through the years ahead.