Saydean Zeldin

Saydean Zeldin

Software Engineer and Programmer

Saydean Zeldin joined the Instrumentation lab in 1966 as a software engineer and programmer for the Command Service Module, reporting to Fred Martin. Apollo 8 was her first mission, the command module guidance system her primary contribution. Before moving to the Boston area, Zeldin was an engineer at the GE Space Sciences Lab in King of Prussia, PA, where she studied the effects of high temperature air to distinguish the pattern surrounding missiles as they reentered the atmosphere to determine if they were friend or foe.

As a software engineer, Zeldin used the sophisticated algebraic programming language developed by Hal Laning to simulate the space environment in order to test the effects of the on-board instructions of the Apollo Guidance Computer (AGC). The simulation language had the capability to directly enter matrix and vector notation, a process that took 3 punched cards for every line – one for the superscripts, one for the main part of the equation, and one for the subscripts. Tricky to set up, but beautiful when printed. As a programmer, she used the Interpreter developed by Charlie Muntz to formulate the on-board instructions the astronauts would use for engine burns, navigation, and re-entry. Boxes and boxes of punched cards. The discarded ones were recycled into card “sculptures” by her 3 daughters when they visited the lab after attending MIT’s day camp in the summers.

In the early 70's Zeldin began working on a project to analyze the Apollo software effort. It was one of the first large scale software system analysis efforts. The results of that analysis led to formulate a theory named “Higher Order Software” that could produce more reliable software. The results were published in the first issue of an IEEE journal dedicated to software engineering. 

In 1985, Zeldin served as co-founder and President of the software company Touchstone Engineering. In the early ‘90s, she joined the software company Mercator Inc., eventually becoming Chief Technology Officer. She is currently retired, hiding out in Down East Maine.