Over the weekend, SpaceX successfully launched their 5th (fifth!) Falcon 9 and Dragon capsule to resupply the ISS. Company news with some photos is here.
This was the primary and most important criteria for the mission–to resupply the International Space Station. But of course, I and millions of other people were eager to learn the results of their attempt to land the first stage on a floating ocean platform.
According to Elon Musk, the control fins ran out of hydraulic fluid just before touchdown. This fluid is what drives the control mechanisms–changing their position to direct the rocket thrust in the right direction. I don’t know what their failure and safety modes directed would happen next (probably cutting all signals to use the rockets). But the end result was a hard landing. Or splash–I’m not sure which yet, depending on how close to the platform they actually were.
This situation brings me back to graduate school in Penn State University. My advisor, Dr. Mark Maughmer, used a very descriptive and memorable analogy to describe the science and art of aerospace design. (He is a world authority on winglet design, by the way. The evolution of sailplanes and then commercial aircraft to use winglets as a standard configuration item can be traced to his efforts. He also flies sailplanes and plays a mean game of racquetball.)
Anyhoo…aerospace design is a constant challenge of balancing and optimizing a large number of constraints, variables, and objectives. He describes it as trying to squeeze a lump of JELL-O in your hands. Squeeze too hard in one area, and some of it will squirt out on the other side. Just when you think you have a stable, clean solution…oops, some of it starts leaking out somewhere.
For SpaceX on this latest flight, running out of hydraulic fluid was their bit of JELL-O that oozed out first. (Making this more complicated, this JELL-O can be oozing in or out to cause a problem. Because in this case it wasn’t too much hydraulic fluid, it was too little.)
In this sense, any complex engineering and design project is like squeezing JELL-O. It’s not just in rocket science.
We can even think bigger than that. Every time I hear the famous line from Forest Gump, I want to say, “No, life isn’t like a box of chocolates. It’s like squeezing JELL-O!”
One geeky technical term and discipline for this, BTW, is MDO: Multidisciplinary Design Optimization. Maybe that’s your calling in aerospace.
Put this mental image in your head the next time you tackle a complex problem and you’ll be thinking (and working) like a rocket scientist.