Jack Crenshaw is the proverbial Jack of many trades, master of a few. He wants to share what he knows, and that’s one of the reasons this site exists.
Jack wrote his first computer program in 1956, his first dynamic simulation (for NASA) in 1959, and engineered his first embedded system in 1975. For NASA and Project Apollo, he did seminal work on the circumlunar trajectory (the now-familiar “Figure-8″ free return trajectory) and abort trajectories (fast return). He’s continuing that work to this day, for Part-Time Scientists, one of the Google Lunar X-Prize teams.
For trajectory analysis, he pioneered the use of unified two-body orbit formulations now known as universal variables. He also pioneered the use of quaternion mathematics for attitude control analysis and simulations.
Jack specializes in the application of advanced methods of math and physics to the solution of real, practical problems. He is the author of the book, Math Toolkit for Real-Time Programming and the column, Programmer’s Toolbox in Embedded Systems Development Magazine (now on line at EEtimes and linked as Embedded.com). Several years ago he wrote the on-line tutorial series Let’s Build a Compiler. You can find a wonderful update of the tutorial at Pascal Programming for Schools (PP4S). You can learn more about Jack and his views in interviews here and here.
All work and no play could make Jack a dull boy, but he’s not in much danger of that. Jack has many hobbies and interests, ranging from auto and motorcycle racing to physical sports like swimming, diving, gymnastics, and water-skiing to analog and digital electronics. He’s a music lover who was bitten by the “hi-fi” bug in 1955, He collects and repairs vintage vacuum-tube electronics, mostly Heathkits. See more about Heathkits here and here.
Jack is an animal lover. Aside from the family pets (dogs and parrots), he .has raised many wild and domestic birds, including songbirds, pigeons and doves, ducks, geese, chickens, etc. His favorite songbird is the bluejay, and his favorite water bird, the Muscovy duck. He and wife Toney have also kept and raised horses, goats, sheep, and one bull. See more about them here and here. Expect to see many stories about all these remarkable critters in this site.