In six weeks we’ll know whether NASA’s elaborate process for landing Curiosity on Mars works. The landing process is worthy of Rube Goldberg, with the last step being a sky crane (really!) since firing the rockets near the surface might damage Curiosity (so will dropping it with the sky crane). Since it’s a huge hunk of money, plus opportunity for a lot more surface exploration of Mars naturally I hope it works, but I would be surprised to learn it didn’t. Mars eats probes, or at least it seems that way (we send some many we may simply have statistically significant sample size showing landing unmanned probes is hard) and unfortunately the odds are too high that Curiosity could join the list.
But why even do this after some much success with the airbag landing system used for the Rovers. Well, Curiosity has undergone the usual bloat (plus nuclear powered, somehow that always sneaks in) of any manmade object so it’s too heavy to be landed with the airbags.
And this is my point. We just can’t leave successful designs alone, we have to “improve” them, which rarely means simplifying and usually means bloating them (e.g. Windows). And despite frequent evidence that small (and numerous) is better, at least in the U.S. we just love big and complex, quite possibly because these also mean expensive. The U.S. auto companies only know how to get decent margins from large, heavy, gas-guzzlers, because they only associate small with cheap and low margins (and now, so does the public because anything small they make is junk).
But OTOH look at digital technology (the actual hardware). There, most of the time, small is beautiful and cheap is good now. When we need power we takes lots of small cheap things (chips, servers, disk arrays) and combine them together instead of going off and spending a fortune building some single “super” computer (or giant disk or whatever). Small, cheap, plentiful are the words that make digital technology work.
But there is still just something in the American DNA that loves big. And so NASA went big with Curiosity. Sure, it’s got all kinds of fabulous capabilities, maybe even some that are actually needed. But, did I mention, it’s big. And big has lots of drawbacks, certainly the complex landing system, but also big big big price tag which means we don’t get many of these.
Now I saw a fanciful idea once, but one that might actually work. Build digital “tumbleweeds” to send to Mars. Small lightweight and rugged devices with all the miniaturized surveillance stuff we’re putting in battlefield drones on some sort of inflatable sphere that is optimized to catch the wind gusts and see a bunch of these things (so some crash or break) and let them roll around and collect data. For the same bucks as Curiosity we might be able to have hundreds of them and by pure chance, as the Rover’s have shown, a few might survive longer than Curiosity. [If you think the tumbleweed idea is crazy, remember the Rovers landed in essentially a crash protected by airbags and that worked fine.]
But masses of cheap probes just doesn’t seem to fit the American profile (or really any of the space powers, they all like big). So Curiosity wasn’t just 50% bigger than the Rovers, it jumped in size, weight and cost by huge factors (if we’d had a bigger boaster we probably would have made it aircraft carrier sized). Yes, there is always another instrument to add it to (raising power requirements, raising the complexity (and reducing reliability) of its drive system). And if it lands and if it doesn’t get stuck in the sand and if all the instruments work it will do some science a Rover can’t do. But all that complexity really increases the risk of just scattering the debris of some very expensive hardware in yet another crash site on Mars.
Or, maybe I’m over-complicating the problem. Big means more budget spent to more aerospace contractors – couldn’t be that simple, could it?