March 21, 2014 4:00 AM EDT

The machines that made the Apollo program a success were, on the whole, huge. The Saturn V rocket rocket stood 363 ft. (111 m) tall. The scaffold-like gantry that serviced it measured nearly 400 ft. (122 m). The slow-motion crawler that took the rocket out to the launch pad weighed a tidy 6 million lbs. (2.7 million kg). But one of the most important machines that flew on any flight could fit in the astronauts’ hands, and weighed just 1.8 lbs. (0.8 kg)—even less in lunar gravity. It was the purpose-built, Hasselblad 500 EL camera, only 14 which ever flew to the moon, and only one of which—used by the late Jim Irwin, lunar module pilot for the July 1971 Apollo 15 mission—is known to have made it home. Once the last film canister had been removed, the cameras were supposed to remain on the surface to help shave weight during lunar liftoff.

If there’s one thing enlightened modern parents are good at worrying about, it’s how much time our kids spend in front of screens: television, sure, but laptops too, and tablets and phones. As a former senior editor at Parenting magazine and Newsweek, I’ve done my share of hand-wringing over whether to forswear all screens until my daughters turned 2, as the American Academy of Pediatrics advises. Ha, as if. Anyway, my girls are about to turn 6 and 9 now. And what I never worried enough about, it turns out, was how much my own media habits were affecting them. I’ve certainly had my concerns about how dependent I’ve become on my beloved iPhone, but surely the only person my compulsive thumb tapping was hurting was me, right? Not so fast. In March Dr. Jenny Radesky, a fellow in developmental-behavioral pediatrics at Boston Medical Center, published a study in the journal Pediatrics with the high-calorie title “Patterns of Mobile Device Use by Caregivers and Children During Meals in Fast Food Restaurants.” Her takeaway: parents spend a lot of damn time in the company of their kids while on some level ignoring them. Radesky and her team of researchers conducted an unscientific study in which they observed 55 family groups dining at fast food restaurants. Forty of the 55 included a parent who became engrossed in a mobile device during the meal. One of her researchers even saw a mother kick her child’s foot under the table when she tried to break mom’s attention away from her phone. Another little boy was swatted away for trying to lift his mom’s face away from the screen. Those were extreme examples, but the overall vibe is worrisome. Our mobile devices, she points out in her study’s conclusion, can “distract parents from face-to-face interactions with their children, which are crucial for cognitive, language, and emotional development.” But we’re all workaholics, right? We need to check that email and reply to this text ASAP, don’t we? “It's a challenge,” Radesky tells me when I get her on the phone. “I'm a full-time working mom, trying to be an academic. It's a tension so many parents describe to me.” Radesky has instituted a ritual phone-free chunk of time in her own home. She leaves work early, at around 5, to spend time with her kids, ages 8 months and 4, before they go to bed. “I put the devices away and I don't even look at them unless it's something urgent,” she says. “My bosses understand we have an unplugged zone. Then between 7 and 8, I pick everything back up to check email -- and ignore my husband.” Our kids are no dummies. They see us engrossed in our toys and it can make them feel sad or annoyed and neglected. It can make them act out. Psychologist Catherin Steiner-Adair knows this all too well. For her book “The Big Disconnect: Protecting Childhood and Family Relationships in the Digital Age,” she interviewed 1,000 children between the ages of 4 and 18 about their parents’ use of these devices. “What was really striking to me was the frequency with which kids said it's so annoying. ‘Daddy says he’s going to play with me and he's always on his computer’,” she tells me. “Children describe more poignantly at a younger age about parents’ absorption with cell phones when they’re, quote, ‘just checking’.” And of course, children model their behavior on their parents. So we can hardly be surprised that the first thing our little digital natives reach for when they’re bored comes equipped with a screen. With this in mind I decided to interview my own kids about my textual proclivities. Using a template modeled loosely on Steiner-Adair’s, I recorded our conversation on my phone -- an irony that was not lost on them. Excerpts: When we were growing up, we didn't have cell phones. We had phones attached to the wall. There were no phones in cars, no phones in restaurants, no screens at tables. What's it like being a kid growing up with phones everywhere? C, age 5: It feels boring. I think it's kind of sad that you're checking your phone all the time. And we really don't get to play with you that much on weekends. What about when I say, "oh I'm just checking?" C: You check for a long time. What does it make you feel when you’re trying to talk to me and I check my phone? F, age 8: It makes me feel annoyed C: It makes me feel bad because when you say, 'go on, I'm listening,' I think you're not listening. Do you feel like I check my phone too much? Both: Yes I'm glad you told me that though it makes me sad. So what can I do differently? F: Check your emails and texts when we're asleep. What do you think of the rule about no phones at the dinner table or at restaurants for you guys? F: It feels unfair. I know you don't really want us to have phones at dinner table. Why do you think that is? F: Because it's rude and you want to have a conversation with us. But it ends up with you checking your phone. I get really mad. Will you remind me when I'm checking my phone too much and tell me if it makes you sad or mad? C: Yeah. Can we hear the recording now? The recording that I'm making on my phone right now? F: As we speak!
Dieter Nagl—AFP / Getty Images

Irwin’s camera is now being auctioned off by an Italian collector of historical artifacts at the Westlicht Gallery in Vienna, which expects it to go for $200,000 to $270,000. That may be a lot to pay for a camera that will never take another picture, but it’s nothing at all considering the history this particular Hasselblad captured—and made. The lunar Hasselblad had only a few key differences from Earthly models. Its knobs had to be especially well-sealed against moon dust, which is finer than confectioner’s sugar and has a nasty habit of jamming unprotected gears.

An ultra-thin film had to be invented for the missions, allowing 240 exposures to fit into a single magazine, which minimized the number of times the astronauts would have to change canisters. The cameras had the same F-stop, focus and depth controls any other camera does, but in this case, a small post poked from each knob, making it easier for astronauts wearing bulky lunar gloves to turn them with a one-finger-push instead of a five-finger twist.

“The only major issue we had to deal with was the sun,” Apollo 15 commander Dave Scott told TIME in a recent conversation. On the airless moon, sunlight simply doesn’t behave the way it does on a world in which the atmosphere creates all manner of colors, shades and other effects. “You were either pointing up-sun, down-sun or cross-sun and we had to adjust the shot to accommodate that. Otherwise, there was little we did that was different from what you’d do on Earth.”

But if the point-focus-and-shoot process was familiar, the things the astronauts’ photographed were radically different.The moon pictures that have stuck in the popular imagination are typically the glamour shots—the glittering lunar module, the spindly moon car, the saluting astronauts, the rising Earth. But the ones the scientists were interested in were all about geology. Every single one of the 843 lbs. (342 kg) of rocks that the six Apollo landing missions returned had to be identified in terms of exactly where it was found, the better to distinguish the properties of samples collected on foothills or mountains from those on plains or crater rims. And that meant a lot of scene-setting pictures. “Every time I stopped the lunar rover, I’d do a switch-off and a clean-up and Jim would get out and do a 360-degree pan,” says Scott. “He just nailed it every time. I did OK, but Jim left us a real legacy.”

The very ordinariness of some of Irwin’s pictures is what makes them feel especially real. It’s not just the shots in which the rover is badly framed or a piece of Scott intrudes from a corner—pictures that never made it into NASA’s carefully curated press releases. It’s the ones of the soil that also include crumpled bits of film packaging left on the ground—lunar litter indistinguishable from the Earthly variety nearly every tourist has been guilty of dropping at some point. “When you’re onsite and doing things, you don’t think about photographing for the ages,” Scott says. “We just took pictures of everything we could.”

All of Scott’s and Irwin’s pictures—as well as those from Apollos 11 through 17—survive on NASA’s Apollo Lunar Surface Journal, a searchable site that also includes air-to-ground transcripts and extensive captions explaining the images. The descriptions are technical—even arid, sometimes—befitting the exercise in physics and engineering that all of the moon missions, regardless of their drama, really were. The humanity lies elsewhere—in the very improbability of the pictures, taken at a time when Americans went to the moon simply because they decided to do such an outrageous thing.It lives too in the memories of the surviving men who made the journeys and in what they can pass on. Scott currently lectures at Brown University, teaching Millennial students something about the last millennium’s culture,when explorers worked with engineers who worked with politicians who worked with the public to collaborate on achieving something fleeting but wonderful.

“We got involved in this thing and it goes so fast and then it’s over,” Scott says. “Back in test pilot school, we had automatic cameras in the cockpit to photograph everything, so that when we got back we could remember what happened.” The hand-operated cameras Scott and Irwin and the others used serve the same function, but in this case it’s not just the pilots who get to remember, it’s all of us.

The 70mm Hasselblad used on the Apollo 15 mission in 1971 will be auctioned at Vienna’s Westlicht Gallery on March 21, 2014.

Jeffrey Kluger is an editor-at-large at TIME, overseeing the magazine’s science, health and technology reporting.

Write to Jeffrey Kluger at