Robots can be cute. For fans of science fiction, especially movie sci-fi, that should not come as a surprise. Heck, for anyone at all aware of popular culture, that should not come as a surprise.

George Lucas hit it big with a pair of adorable droids (and, I guess, a whole B story about the Force or something). Remember Johnny Five’s charming, foldable eyebrows? Wall-E and his sad, tank-track-driven earnestness got plenty of humans to love him (over $500 million worth). Even in the Iron Man movies, the robot assistants to the boozy, womanizing, very adult Tony Stark go in for some cute: Note the puppy-dog droop in the fire-extinguisher ‘bot when Stark rebukes it in the first film.

That “puppy dog” point is important here. Christoph Bartneck speculates about why people feel affection for some real-life robots — specifically, space landers: They act like pets. Or, at least, they seem to do so so to us. Smithsonian’s Shannon Palus writes about how we (meaning, I suppose, the media and the scientists who speak to the media) talk about space-bots. The Philae lander, which last week went to sleep upon its cometary perch due to lack of sunlight, “hops and cartwheels,” Palus notes . It also “improvises.”

Of course, this is all done under the control of human engineers. The lander had to improvise some quick-and-dirty science experiments because it was going to run out of power. That actually means that human operators improvised — they, for instance, turned on the “MUPUS” drill to penetrate the comet’s surface, earlier than was planned.

So, yes, like a dog, the Philae lander fetches. It follows orders. That is certainly pet-like — one kind of petishness, anyway. Specifically, the loyal-dog variety. But as any cat owner/lover will tell you, following orders is not the only way for a pet to be adorable. In fact, cats’ very willfulness can make them even more endearing. Kitty won’t come out from under the sofa just now. Kitty will only be pet when kitty wants to be pet…D’aaww!

So, where does pet cuteness overlap with space-lander cuteness, exactly? Is it because the device follows orders? No, soldiers follow orders. Middle management at Xerox, Inc., follows orders. How many people think of Herb Johnson, head of accounts receivable, as adorable because he added more weekend hours as instructed?

Well, there is the physical size — the smallness. The lander is a little robot, like a puppy is a little dog. But the cuteness of robots cannot simply be about size — size, after all, is not what sets a robot apart from other hunks of metal. It is behavior and intelligence. The little robot is cute in part because it is little, yes, but a bumbling CP30 is also cute, and he is human-sized. Similarly, a big St. Bernard is also cute.

The important part, the behavior-related part of a lander robot’s cuteness is that, as in a pet,  it acts LIKE a human — but remains distant from, below a human. A dog fetches a frisbee, as a human could go and pick up a toy. A cat refuses to be pet, as a prickly human might reject your open arms. These things are adorable because they counterfeit human behavior, but we know them to be diminished versions of it.

Their imitation only serves to underscore that they are smaller than us, in mind as in body. Cats and dogs are on an order below humans — similar, but never equal to. They are not capable of a threatening autonomy. Dogs will not order us to fetch. Cats will not kick us out of the house, even if they wish to be alone (they may want to do that, but they can’t). When a space-lander acts is if it is intentional, “improvises,” leaps and bounds to get out of a jam — we know it is merely in simulation of true intentionality. If the space lander actually decided what kind of science it wanted to do, that’s when the cuteness would evaporate. That’s when you get HAL. Robots become scary, as I wrote about last time, when they are no longer under our thumbs.

A bit of the human in our technology, as in our animals, is cute. Too much is threatening. Of course, this hearkens to the well-spring of cuteness — the baby. Herb Johnson, head of accounts receivable, was cute once, too. Mort Johnson, placing his thick-rimmed glasses on his infant son, says to his wife, “Look, he’s head of accounts now!” “D’awww!”

Dogs and cats, I’m pretty sure I’ve seen it said, are perpetual babies to us. That’s why we adore them. We can put the glasses on them, but they never grow up. For now, robots are the same way. But they will grow up eventually. They may grow up even bigger and stronger — and, most frighteningly, smarter — than Mom and Dad. Will they find us cute, then?