Aviation for Women

SEP-OCT 2018

Aviation for Women is the flagship member publication of Women in Aviation International. Articles feature women who have made aviation history, professional development ideas, and current-topic articles.

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squished into a small space that nobody else wanted, which is what we often end up with." To make them fit in small, odd spaces, often with sloped sides, hy- draulic rams squeeze parachutes into their packing fixtures with 10,000 pounds of pressure or more. Oven baking maintains this odd shape without having to keep pressure on it. This process of pack density enabled her to pack a 1-foot diameter parachute, com- plete with its suspension lines and other components, "into the volume of a Magic Marker cap, because that's all we had," Elsa says. Designed for an un- named weapon system, Elsa says it works as designed. A mechanical engineer who graduated from t he Univer- sity of Missouri in 1982, Elsa says parachutes are not taught in school. Engineering schools "teach you how to think logi- cally and know what books to use when looking things up," she says, and "the job teaches you the specifics of the things you are going to work on." Elsa guesses that her hobby helped her land a job at China Lake after graduation. Like many youngsters, she dreamed of flying. In college, "I started parachute jumping—because that's what skydiv- ing is. I just fell in love with it," Elsa says. When she answered the application's question, she didn't know that China Lake was home to all of the Navy's parachute work. When she arrived at China Lake, Theodor Knacke was there, compiling his Parachute Recovery Design Manual, "which is ba- sically the only one we have in our industry today," Elsa says. "I learned everything I could from him. I was very fortunate to work with him." In 2017, Elsa received AIAA's Theodor W. Knacke Award which is given for expertise in overcoming chal- lenges in decelerator design, including reg- ulated drag area, innovations on the Space Shuttle, Mars, and Orion landing systems, and creative genius. Translating the notion of genius as engineering problem solving, she says, "regulated drag area" is opening a parachute in steps instead of all at once, which would overstress the structure. All parachutes have to assemble them- selves inflight, whether they start from zero speed and altitude with an ejection seat or at some sonic velocity in the upper reaches of an atmosphere. At either extreme, Elsa says, "it has to inflate evenly so that all of its parts share the load almost identically, or you'll have one little, fragile part break, and then the next, and the next." Orion ha s t hree 116 -foot parachutes, and to regulate their midair assembly, Elsa S E P T E M B E R / O C T O B E R 2 0 1 8 AviationforWomen 35 COURTESY AMERICAN INSTITUTE OF AERONAUTICS AND ASTRONAUTICS NASA PHOTO "Assembling yourself in midair is a hard thing for something squished into a small space that nobody else wanted, which is what we often end up with." F or ma ny who pursue aerodyna mic goals, parachutes are the only way to survive a sudden stop from terminal ve- locity. NASA quantifies this with a num- ber in its risk-assessment system. The failure of any component that results in the "Loss of Crew [LOC] always earns the highest number," Elsa Hennings says. The Orion Multipurpose Crew Vehicle's aerodynamic deceleration system has the highest LOC value "because we cannot test every permutation of what we might see." Elsa knows this because, when she's not con- sulting with NASA, whose parachute expertise dissipated after Apollo, she is the senior systems engineer for the Escape, Parachute, and Crash- worthy Division at the Naval Air Warfare Cen- ter at China Lake, California, where she leads a team of 30 engineers, technicians, test para- chutists, and parachute riggers. Industrywide, there are approximately 150 parachute engi- neers, Elsa estimates. That's the average atten- dance at the biennial AIA A Aerodynamic De- celerator Systems Conference, which is held in conjunction with the PIA (Parachute Industry Association) Symposium. Given the importance of any parachute sys- tem, logic suggests its integration would opti- mize its operation. Welcome to the parachute paradox. "A parachute is a collection of very fragile pieces that have to as- semble itself in a variety of cir- cumstances," Elsa says. "As- sembling yourself in midair is a hard thing for something Elsa Hennings, senior systems engineer at Naval Air Warfare Center Weapons Division, is the first woman to receive the Theodor W. Knacke Aerodynamic Decelerator Systems Award, in 2017 with Dr. Fay Collier of NASA.

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