The Back Porch
The Back Porch
You Brought Your Machete, Right?
By
Johnathan W. Carson
Originally published July, 2026
When you're designing hardware, sometimes you'll encounter designs that are just easy. Everything seems to fall in place with virtually no effort from you at all. Other times, you'll encounter designs that fight you every step of the way. They extract blood. They make you pay dearly for every inch of ground you manage to claw away. When you encounter one of those latter designs, the only advice I can offer is this: stick with it. As long as you’re making at least some progress, keep plugging away at it. Now, I've got to ask...you did develop at least three fundamentally different concepts before starting this, right? If not, now is a good time to go back and revisit that step. If you’re still convinced that this is the right design, keep working at it. Eventually, you will hack your way through this jungle and find yourself at the other end. You’ll either figure out a way to make this work, or you’ll find a better approach. Either way, you will get there.
Throughout your career you will encounter these extremes time and again. I know I sure have. The funny thing is, those easy designs are satisfying, but they're rarely the ones you remember years later. The difficult ones become your teachers. By the time you've fought your way through them, you're a better engineer than when you started.
One example of this that comes to mind is a flexure I designed for ECOSTRESS. We had to literally scrap together a scan mirror for that project (which is another story altogether). This scan mirror had a drive motor on one side and a support bearing on the other end of the shaft. That support bearing had to be held very rigidly in the radial direction, but it had to be fairly compliant in the axial direction. Because this was an optical instrument, it couldn’t tolerate any discontinuities, so simply allowing the shaft to slide in the bearing bore was not an option. I decided a flexure was the right way to solve this problem. So a flexure that’s stiff radially and soft axially sounds simple, right? It was anything but. Every time I made a change to meet the axial requirements, I ended up reducing the radial stiffness to unacceptable levels. When I increased the radial stiffness, it ended up pushing the axial stiffness beyond what could be tolerated. Oh yeah, and of course this had to fit the existing hardware and be machinable, so that added even more layers of complexity. This felt like an endless loop, but eventually it came together. It wasn't an elegant design, but it met every requirement. That flexure eventually flew to the International Space Station, where it's still quietly doing its job.
Takeaways
Persistence is a virtue—but only after you've convinced yourself you're climbing the right mountain. Knowing when to quit and when to keep going is difficult, but it gets easier with experience.
Sometimes the best design isn't beautiful or elegant. Sometimes it's simply the one that satisfies every requirement.
The designs that fight you the hardest often teach you the most.
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