Highways Into Space: A first-hand account of the beginnings of the human space program by Glynn S. Lunney

was also selected as a Flight Director in January 1966 in the middle of the Gemini flight phase. We managed both jobs until March 1968 when we were both transferred to a new Flight Director Office as Apollo approached. It is up to the FDB-ers to say whether this organization arrangement was a problem or an opportunity for them. With Cliff and I not available for assignment to any flight dynamics console positions, I would wager on opportunity. But, I get ahead of the story.
     

Moving Towards Operations
    My assignment as the Flight Dynamics Officer at Bermuda was a great opportunity to gain experience in what flight operations was becoming. The Bermuda station was in an excellent location to evaluate trajectory conditions after engine cutoff. At this point, it will aid in understanding to review the general subject of the launch phase and the abort (escape) modes available to the operations team.
    The Atlas launch vehicle was selected for the Mercury program on the basis of its stage of development and its lift capability. Probably, the most significant reason was that it was the only national system available to perform the mission on the planned schedule. I was amazed at the design of this launch vehicle. The structure of the vehicle was basically two compartments containing kerosene and liquid oxygen respectively, separated by a common bulkhead. The overall structure was a very thin sheet of aluminum fairly close to what we know as aluminum foil. The vehicle structure was so light that it had to be pressurized with a gas like nitrogen for most of its life on the ground. The internal pressure is what gave it shape, form and whatever rigidity it had. Yes, it was like a high-tech balloon. It was equipped with three engines in a horizontal row at the aft end. Like other rockets, it employed some degree of staging but it only dropped off the two outboard engines, no tankage. The vehicle continued under the thrust of the middle engine, called the sustainer engine, until commanded to be cut off by the guidance system. Unlike all successor orbital launch vehicles that have onboard inertial guidance systems, the guidance was performed by a ground-based tracking and computing system at the Cape, known by its suppliers – GE (tracking) and Burroughs (computer for guidance).
    Various factors combine to make the launch phase a very critical period of flight – booster reliability (about fifty percent in those years), short reaction times, high rates at which some failures develop, the catastrophic consequences of some malfunctions, limitations of the escape systems and techniques – to name some of the most obvious. I had the sobering experience of reviewing most of these films of launch vehicle failures. They stay with a person for life, just like the Challenger videos do.
    The function of range safety (i.e. the protection of personnel on the ground, property and facilities) is discussed elsewhere in the Mercury Redstone experience and was a good starting point to begin to conceptualize how to protect the spacecraft and crew. Range safety required an onboard destruct system, basically a shaped charge running the length of the tanks and on both sides of the vehicle. The concept was to stop the propulsion and disperse the propellants so they did not land in a concentrated mass. For staged vehicles, they required a hot wire type system between stages to fire the destruct system in case of the stages separating in an uncontrolled fashion.
    In the case of Mercury, the spacecraft was equipped with an escape tower, which was designed to separate the spacecraft from the launcher quickly enough and to a sufficient distance to survive the fireball created by the vehicle being destroyed by the range safety destruct system. There was a small delay of three-and-a-half seconds built into the system such that the command first alerted the crew and then delayed the actual destruct function to give the escape system opportunity to propel the