The term “rocket science” evokes visions of human innovation at its finest—ultraprecise technologies that launch satellites into orbit, and buoy astronauts beyond the boundaries of our own world.
But not all rocket technology gets to have its day in the sun. Hard as we might try, there are just some things that are probably better off not attached to a rocket engine. Here are three that didn’t quite make it off the ground. At least, not yet.
1. The lost art of rocket mail
The postal service is far from perfect. Mail travels slowly by today’s digital standards; it’s often misplaced; and delivery methods are far from tamper-proof. But take comfort in the fact that things could have been way worse: Once upon a time, the world tried to deliver its mail by missile.
The idea is believed to have started with a German writer in 1810. Although rocketry in its infancy in the 19th century, early projectiles’ speed and power were already inspiring romantic visions of everyday use. In the days of plodding ground travel, when commercial telegraphy was still emerging, having rockets deliver messages probably seemed like… well, the whole package.
But the first true launch probably didn’t happen until decades later. Close to turn of the 20th century, a group of intrepid sailors hoping to bridge communication gaps between the Tonga islands decided to attach mail canisters to short-range Congreve rockets and fire them at the isolated outcrop of Niuafoʻou. The overwhelming majority of these attempts were disastrous.
Nevertheless, the dream persisted, and around the 1930s, a smattering of successful launches was celebrated in Austria, Scotland, and India. Rocket mail then gathered steam for a final hurrah in 1959, evolving from eccentric hobby to state-sponsored enterprise under the wing of what would become the United States Postal Service. That summer, a Regulus I cruise missile successfully traversed the 100 miles between the deck of a Navy submarine and a naval station in Mayport, Florida in just 22 minutes, hauling a cache of 3,000 letters.
Upon the triumphant landing, then-Postmaster Arthur E. Summerfield boasted, “Before man reaches the moon, mail will be delivered within hours from New York to California, to Britain, to India or Australia by guided missiles. We stand on the threshold of rocket mail.”
Yeah, not so much. Flashy though it was, the concept of projectile-powered parcels was probably always dead on arrival. The 1959 demo was both the first and last missile-based trial conducted by USPS—and while it may have been prompted by a postwar bump in letter traffic, there’s a pretty good chance it was more a publicity stunt by the Department of Defense, hoping to flaunt its firepower in the face of our rivals in the Soviet Union.
Besides, by this time, single-day transatlantic flights were already commonplace—and with the advent of airmail, these planes sure did deliver. Rockets might have trimmed transit time by a few hours, but they simply weren’t worth the risk and cost.
Just like any other rockets, letter-laden vessels were dangerous, complicated, and expensive, says Tom Lassman, a curator and space historian at the Smithsonian’s National Air and Space Museum. “The public had a fascination with rockets as a driver of technological progress… so they wanted to find all these applications,” he says.
But unlike automobiles or airplanes, rockets’ ultimate impracticality barred them from any sort of “routine” use, Lassman says. Thus, mail-ferrying rockets went the way of the carrier pigeon.
2. Yes, there’s a reason we don’t all have jetpacks.
Let’s be clear: Jetpacks are real. In fact, they’ve been around since 1960, when personal propulsion was optioned for military use. So why are so many of us still enduring freeway gridlock on the way to work?
It all boils down to one thing: We’re big, dense sacks of aerodynamically-challenged flesh—and it’s no easy task to fly us from point A to point B.
For a jetpack to work, one must grapple with the Sisyphean task of overcoming gravity. That requires a lot of fuel—which itself tends to pack on the pounds. To this day, a jetpack that keeps its user aloft for more than a few minutes is a pretty impressive feat. (Except, notably, hydro “jetpacks,” which, depending on who you ask, don’t really count: They get around that pesky fuel thing by essentially tethering you to a substantial body of water that can supply a continuous source of hydraulic power.)
“You’re fighting the atmosphere and gravity—you need a lot of energy to get any kind of payload off the ground,” says spaceflight historian Amy Shira Teitel. To put this in perspective, consider the fact that some hydro jetpacks have to pump through up to 1,000 gallons of water per minute to keep the user aloft. Water isn’t the same as rocket fuel, but even a pretty skewed exchange rate would make flight over land energetically costly.
Besides, Teitel has a pretty compelling case against traditional propellants, most of which rely on combustion: “The last thing I want is hot, raging fire going down my back,” she says. “That’s a personal choice, though.”
And achieving liftoff is just the beginning. Once you’re in the air, Teitel says, good luck maintaining control. Humans have enough trouble with fine motor control on ground; imagine trying to maneuver midair with a jet engine strapped to your back.
“Rocket technology is still pretty dangerous and inefficient,” says Elizabeth Garbee, Program Associate for the Community Engagement Fellowship Program at the American Association for the Advancement of Science who specializes on the intersection of science and society. “It’s frankly astonishing to think about what we have been able to do with it so far.”
At the end of the day, though, the jetpack dream has yet to reach its denouement. “It’s a childhood fascination that’s never died,” Teitel says. “I don’t know that people will ever stop pursuing the jetpack, even if it’s unfeasible for the time being.”
3. Final frontier, or final resting place?
Technically, space burials may be a “trend” still on the rise. In the past couple decades, hundreds of people have paid companies like Celestis and Elysium Space to shoot the cremated remains of their loved ones (and pets) into outer space. (NASA has also sponsored the sojourns of certain individuals, like astronomer Clyde Tombaugh; a portion of his ashes is currently aboard the New Horizons spacecraft, now some 4 billion miles from Earth.)
“There’s something romantic about it,” Teitel says. “Humans aren’t good with death. There’s kind of an appeal to knowing my remains could spend eternity just drifting through the solar system.”
But before you get too caught up in visions of urns careening past Uranus, there are a few things to keep in mind.
One is the price tag. Depending on the exact trajectory you want your ashes to take, the cost can get, well, astronomical. If you’re okay with your remains making only a glancing blow with outer space before U-turning back into Earth’s atmosphere, some options are probably on par with rites done at sea level (funerals aren’t exactly cheap). But for Celestis to escort your remains into deep space, you’ll need to pay at least $12,500—and that’s for just one gram of ash (for perspective, cremation typically yields between three and 10 pounds of material).
Even if prices come down, there are other issues. For one, future funereal spacecrafts intended for orbit may have to contend with the serious traffic jam of space junk—the increasingly congested halo of human-made debris that enshrouds our planet. “We already have a totally cluttered lower orbit, full of satellites and trash,” Garbee says. “It’s basically a cloud that goes around the entire planet.”
Celestis and Elysium Space are aware of this problem; none of their associated spacecrafts are intended for permanent orbit, and either burn up upon re-entry into the atmosphere, or end up elsewhere in the galaxy. Still, however fleeting their flights, these vessels could contribute to the clutter. It’s getting harder and harder to navigate through the haze—and launches of any kind run the risk of collision.
The crowding issue may even apply for those pondering interplanetary internment. Space is, in no uncertain terms, vast. But, locally, at least, it has its limits. “Eventually, we could have junk strewn all over the solar system, just because we decided to put stuff there,” Teitel says.
At the end of the day, space burials may never go mainstream—especially when one considers non-Western cultures. “Many societies have already figured out their own rituals to feel integrated with the universe when they look up at the sky,” Garbee says.
Does that mean curtains for space burials? That remains to be seen. After all, even missile-borne parcels and solo flight gear could still make a comeback. For now, it’s all up in the air.