Ricochet is the best place on the internet to discuss the issues of the day, either through commenting on posts or writing your own for our active and dynamic community in a fully moderated environment. In addition, the Ricochet Audio Network offers over 50 original podcasts with new episodes released every day.
Ingenuity Delayed
A couple of months ago NASA’s Perseverance rover arrived on Mars. On the exploration vehicle was a small helicopter, the Ingenuity, intended to fly above the surface of the red planet and take photographs and other measurements. Ingenuity performed a rotor spin test this week, and an alert triggered by the craft’s on-board software has prompted NASA to delay the planned launch date for the tiny four-pound flying machine until sometime next week, or perhaps later.
I feel for the people who build these things. I write robotics and automation software, and I’m familiar with the stress accompanying every demonstration of a new automated system. I’m not a flashy programmer nor a particularly fast one, but I do write rock-solid software that does, in almost every instance, precisely what I intended it to do (though whether or not I understood the requirements correctly is another question). Even so, I’ve had my share of embarrassing failures during product demonstrations over four decades of software development, so much so that I never approach a software rollout without at least a little anxiety.
To NASA’s credit, their software quality standards and procedures are astoundingly mature. But Ingenuity is currently 15 light-minutes away from Earth: it will take off, fly about, take its pictures, and (we hope) land successfully all within a minute — and we won’t know what happened until a quarter of an hour later. Or perhaps never, depending on how it goes.
I made a decision many years ago not to write software for life-critical applications. I simply don’t want the stress. While many of the machines I program are capable of seriously injuring someone, I’ve always relied on the presence of hardware interlocks and physical barriers to prevent my software from crushing, cutting, or otherwise mangling an operator. The most recent machine for which I provided both software and electronics actually features a circular razorblade spinning at 5,000 RPM attached to the end of a pneumatically operated arm: it has a legitimately menacing aspect about it. But, again, hardware safety relays and multiple interlocks prevent anyone from getting close to the whirring knife while its motor is still powered and its arm still enabled.
I get to test my software and am often present when it’s put into production. The creators of the Ingenuity have undoubtedly tested to the best that NASA’s ample budget and their project time constraints allowed. But I will be very surprised if any of the developers sleep soundly the night before the machine flies — and I’m sure that, when it does, its programmers will experience the longest 15 minutes of their lives.
Here’s hoping to a continuation of a so-far successful mission.
Published in Technology
Great post, Henry. As a non-programmer, I appreciate the non-condescending way way you explained the multiple issues involved–if only all science and engineering reporters had that gift. Anyone could understand the human issues of hesitating to casually accept life and death responsibility, morally if not legally.
My amateur’s concern: stability, not lift. I’d bet it can get off the surface, but it’s very light and could (too?) easily tip over if it lands on even a small rock.
…is ingenuity denied!
Ingenuity has a tiny scrap of the fabric from the wing of the Wright Brothers’ plane. One hundred and eighteen years – the a single beat of a hummingbird’s wing in the scale of things – from slipping the surly bonds at Kitty Hawk and droning around another planet. It’s remarkable. Humans are remarkable.
Mars has about 40% of Earth gravity, which makes flying easier, but a very thin atmosphere, which makes flying harder. I haven’t read up on what differences it has compared to Earth-flying drones. Maybe larger blades, and/or faster motors… They would be able to test in thinner atmosphere, inside special chambers. But there’s no way they could properly simulate 40% gravity.
Maybe with counterweighted tethers. Not perfect, but easy to do, and probably valid. After all, the thing ain’t going to be doing aerobatics.
How about on a depressurized Vomit Comet?
That effect only lasts about 30 seconds, doesn’t seem like that would be very useful in this situation.
Ack!!!
Several years ago I saw a table saw that wouldn’t cut off a human finger. They demonstrated it with a hot dog. Nor even a scratch. It had to do with the blade picking up and electric charge from the finger or hot dog. How they got it to stop in a split second I don’t know.
Oh there’s way more than that. It was a fine show. And Kaley Cuoco was – and still is – gorgeous. (That’s why I first started watching it, she was so good in the last season of Charmed.)
I saw that also. It’s called SawStop. It charges the blade with a low voltage. When it detects a voltage drain — as, for example, from a finger (or hot dog) touching the blade — it uses a higher voltage to melt a thin wire, which releases an aluminum block that is driven by a spring into the spinning blade. The blade bites into the aluminum block, stopping almost instantly; the energy dissipated in the action causes the blade assembly to cantilever down into the table, away from whatever touched it.
The whole thing happens in about
1/20th[correction:] 1/200th of a second. I’m skeptical that it’s practical, since some of the things one cuts on a table saw might as readily trigger the safety feature, and it’s destructive of the blade and various components of the system. I think a simple blade guard might be more practical.Then again, I’m a Luddite.
In wood shop in Jr High School, I used table saws and lathes at age 13 or so. And I still have all my fingers. Do kids get to do that now?
I’d be surprised. I remember a kid lost a couple of fingertips in shop class when I was in high school. (I didn’t see it, but everyone talked about it.) We live in a safety-obsessed, emasculated, feminized culture now: there probably aren’t many table saws in high schools today.
And you criticize people who watch sports?!!!
None of that when I was in school. But they stopped doing blood-typing in science class shortly after my years, seems like each year a couple kids found out they were adopted.
Sports are funny? I never heard that claim before.
You think people who watch sports are crazy. I think all modern comedy on American TV is stupid.
I wondered if it destroyed itself after a few stops. I guess it only destroys the blade, and I’m sure the filament wire could be replaced. Did they stop selling it, do you know?
Whenever I’m using cutting tools, I remember my old shop teacher. Introducing himself, he said I’m been working with power tools for sixty years, and — he held up his hands — count my fingers, all six of them. Uh, I mean ten of them.
I don’t know why that stays in my mind. Maybe his misstatement added more emphasis.
My late grandfather was missing a few fingers, but equipment was much safer even by the time I got to Jr High. What I remember most about the wood shop teacher was that his thumbs were both bent way back, like someone can do if they’re double-jointed, apparently from pressing down on wood most of his life.
Apparently meat-cutting is even more risky, because of the cold which makes it difficult to feel even while the saw is cutting your hand.
I think the REASONS most people watch sports, are crazy. I can theoretically imagine a non-crazy reason why someone might watch them – especially if it’s their job for some reason, like recruiters etc – but for most people it’s some kind of “when ‘my’ team wins, that’s a reflection on ME/the city where I currently live/the school I went to/etc” which is nonsense.
On the other hand, not all TV comedy, not even all American TV comedy, is the same.
I once did a newspaper cryptogram and the quote was: What kind of people watch golf on TV? Landscapers, I guess.
Well at least I don’t remember ever hearing anyone say that they followed some golfer because they went to the same school or whatever. Does anyone think that when, say, Arnold Palmer won, it meant that some city or state is great?
I wondered about that, too. I would think the blades would have to have a much greater surface area than a unit operating in Earth’s atmosphere.
Not only still available, but pretty much mandatory in maker spaces that have table saws. (If they want insurance.) Any member who triggers it, pays a “fine” for the replacement cartridge. One use destroys the rather expensive insert.
And yes, they really do work.
Meh.
Interesting. I knew they were still available, but didn’t know that people used them. I don’t think I’ve ever seen a saw so equipped.
(Incidentally, I was mistaken above: the claimed response time is 1/200th of a second — 5ms. I remembered it being much slower than it actually is.)
Or they spin at a higher RPM.