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Comment by maxlin | Hacker News Reader

This is so cool. Wonder why they wouldn't just use telephoto lenses an some small caliber gun for this though

Take it from someone who grew up among gun-happy USA-ians and stupidly fooled around with guns in their youth: Don't shoot tires. Not even an old economy tire left from the target car someone dumped in the abandoned gravel pit. Eventually you may hear a zip going the other way, and it might break your buddy's car window behind you and he'd be super mad and want you to pay for it. [0]

All rounds that don't embed will hit something downrange, for somewhat arbitrary values of "downrange" expressed in terms of angle and retained energy. A core principle of firearm safety is that you only get to pick a round's first target, the round picks the rest. And that's why airports and space centers are generally considered by experts to serve poorly as firing ranges.

[0] it's some kind of miracle that we survived to adulthood

I think because they wanted to let the air out gradually so they could inspect the tire afterwards, they weren't interested in tearing a big hole in it from a high velocity projectile. They even started with a hollow drill bit, but decided that wasn't needed.

They used the camera on the tank to pre-inspect the tire before deflating it, which would have given them close ups and angles of view that wouldn't be possible with just a distant telephoto lens.

And for only $3000, it was probably much cheaper to build this than to put in place all the range safety procedures they would have needed to shoot it.

This comment hurts my head.

How come? If the idea is to be capable of inspecting the tire, then puncturing it if it's deemed a time bomb, why wouldn't this do the same?

The tire is risky in the first place because people are around, making shooting a gun off a bit tricky in terms of safety.

A gun is not a bomb. It is a reasonably precise tool. If the point is to puncture a wheel, and there is one guy at NASA who isn't bloody blind, I really don't see how this becomes less safe from the tire exploding anyway.

If you read the article you’ll find that the device successfully punctured many tires WITHOUT any explosion.

I'm sure that there exists a real reason, but I choose to believe that it's because NASA is made of engineers, and engineers are by nature not practical people. They want to design a solution, not find a solution.

If they'd asked the technicians then they would've landed on Steve with his target rifle, or just a plate with a few spikes in it to drive the wheel over. Y'know, simple, straightforward, and absolutely no drawings required.

Might be true lol. NIH (Not Invented Here) syndrome with the first part of "if it's not even invention, it's a worthless solution"

NIH doesn't describe this. They bought a model tank from a hobby shop and strapped a drill to it. For an organization plagued by accusations of excessive costs, this is downright cheap. NIH would involve a purpose-built rover to the tune of millions of dollars.

The point isn't to puncture the wheel, it's to measure the exact failure modes. They know if they puncture the wheel, it will burst.

A drill, for example, tells you the characteristics of exactly when and how it will lose structural integrity given a partial puncture of a given diameter and depth.

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