The morning of January 27, 1967, Gus Grissom and his Apollo 1 crew put on their flight suits. Foil-clad, with breathing masks, they looked like a mid-century vision of the future brought to you by Reynolds Wrap. The crew of three were to perform a launch test that day, to see what it would be like when they rode a metal cone to space.*

Grissom had been to space before during the Gemini program. That day’s practice wasn’t going great, not like one would hope an actual launch would go. First, the astronauts smelled something rotten in their oxygen. That delayed them by more than an hour. Then, their communications system began to fritz out. Of this, Grissom famously groused, “How are we going to get to the moon if we can't talk between two or three buildings?”

Later, though—into that same microphone and over those same lines—came a single word: “fire.”

It was true: Damaged wires had likely ignited a spark, which fed on the all-oxygen air, growing with its consumption of space-age material—nylon, foam.

The crew tried to escape the capsule. But the hatch wouldn’t open. All three astronauts suffocated inside the vessel that was supposed to carry them—and with them, us—into the future.**

The agency’s two other fatal accidents occurred during the same January week as Apollo’s: Challenger 19 years later, Columbia 17 years after that.*** And just three years ago, the private-spaceflight industry endured its first human loss, when Virgin Galactic’s SpaceShipTwo lost its copilot.****

After each fatal incident, the nation has responded with shock and grief. These explorers—our explorers, Earth’s explorers—paid for that exploration with their lives. Questions arose. Some—How did this happen?—are left to inspectors and investigators. But others—How big a cost are humans willing to bear to leave the planet?—lie in the public domain. The answers seem to have changed throughout the decades, as space travel seemed to evolve from something novel to something routine.

Today, industry and government are both upshifting gears, back into novelty, which means the public’s attitudes toward space travel and its inevitable accidents may return to what they were in NASA’s early, more adventurous days. After decades in a stable and predictable orbit, American spaceflight will return to new vehicles and, maybe, new destinations. The country is deciding which far-off world to point ships toward next, with the moon and Mars the most likely candidates. Private companies are doing the same, and preparing to take high rollers on suborbital romps. And with that leap into the unknown, Americans may become more tolerant of the loss of astronaut life. If they don’t, the government and private industry might not be able to make the leap at all.

We all know people probably will die on these new missions, especially if they become commonplace, as many hope. What no one knows is how we will all respond to those losses.

* * *

When Grissom and his compatriots signed on to the astronaut corps, times were different. They were different: cowboy test pilots—military men, mostly, with that rightest of stuff. Space, and the flight paths to and through it, was basically uncharted. Rockets blew up—a lot—listing sideways, spinning tail over teakettle, exploding heads in the ground like ostriches.

And the astronauts themselves were, for the most part, inured to their mortality. In The Right Stuff, Tom Wolfe repeatedly references the euphemism the early astronauts used to describe fatal crashes: The fliers had “screwed the pooch.” It’s gallows humor: The pilots and astronauts couldn’t completely control their survival—but they could at once face death, distance themselves from it, and use tone to strip it of power.

The public perceived these guys (and they were all guys) as all-American swaggerers, laying their lives on the line for the primacy of the country.

“It was a battle in the Cold War,” says Rand Simberg, author of Safe Is Not An Option: Overcoming the Futile Obsession With Getting Everyone Back Alive That Is Killing Our Expansion Into Space.

The nation, of course, mourned the Apollo 1 crew’s loss—especially given its gruesome nature. But the public and the government were perhaps not surprised, or philosophically disturbed, that people had to die if Americans were to get to the moon in a decade. In an article called “Space Travel: Risk, Ethics, and Governance in Commercial Human Spaceflight,” space strategist Sara Langston looks to other fields to understand attitudes and regulations about space exploration. “In the Encyclopedia of Public Health, [Daniel] Krewski defines acceptable risk as the likelihood of an event whose probability of occurrence is small, whose consequences are so slight, or whose benefits (perceived or real) are so great that individuals or groups in society are willing to take or be subjected to the risk that the event might occur,” she writes. The risk of space accidents, by inference, are subject to the same kind of cost-benefit analysis.

After Apollo, though, came the staid shuttle program. And with it, the tenor of spaceflight changed. The Cold War ended in the ’90s. The spacecraft was called a shuttle. You know, like the bus that takes you to the airport. The Americans had already conquered spaceflight—we got to the moon, which was very hard and very far away and involved orbiting other bodies and sometimes landing. Spinning ellipses around our own planet in a sturdy vehicle? Easy.

The shuttle program left Americans—and perhaps the world—with the false sense that the space-pioneer days were over.

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In technical terms, as the shuttle program developed, people began to think of its flights as operational rather than experimental. In experimental mode, engineers are still figuring the details out, fingering the edges of a craft’s envelope and seeing how hard and fast they can press before they get a cut. In operational mode, though, engineers are supposed to know most everything—the ups, downs, ins, and outs of performance given sundry contingencies.

While the shuttle mostly functioned well, that performance was never actually a given. The vehicle remained, to its last days, experimental, a status reflected in its success/failure rate. “I think people that know our industry kind of understand the edge we're on here, because these systems are tremendously complex,” says David Bearden, general manager of the NASA and civil-space division at the Aerospace Corporation. “If you look back, empirically or historically, at any launch system, about the best you're ever going to get is 1 in 200. On an airline it is a one-in-a-million chance. People who know the industry and know the way those systems operate understand that, I think.”

* * *

I was only six months old when space-shuttle mission STS-51-L sat on the launchpad on January 28, 1986. Aboard were six astronauts and Christa McAuliffe, a teacher from Concord, New Hampshire. The shuttle lifted off on the cold Florida morning. But then, nine miles above Earth’s surface, that seemingly reliable spacecraft broke apart, undone by the uncharacteristic chill at Cape Canaveral that day.

As a Miami Herald Tropic investigation later detailed, the astronauts didn’t die right away: The crew vehicle stayed intact, and continued to go up, before tipping back toward Earth, traveling 12 miles of sky before crashing into the cold ocean water—hard as the cement on the launchpad. The astronauts, the article said, were very likely alive until the very end and might have even been conscious.

Coverage from the days after the tragedy expresses, of course, sadness. “The Shuttle Explosion; Suddenly, Flash of Fear Dashes Watchers’ Hopes,” read a New York Times headline.

“What Went Wrong? Shuttle Loss in Ball of Fire Stuns Nation,” went one from the local Orlando Sentinel.

Both papers, though, declared that the show must go on: “Reflecting on Loss: Welling of Tears, a Desire to Press On,” said the Times.

“Three shuttle veterans lose peers but not faith in program,” said the Sentinel.

The losses, while tragic and (as the Rogers Commission Report would later reveal) avoidable, shouldn’t squash the program. Sacrifices, after all, must be made, for a new program whose utility the nation was still proving.

* * *

I was 17 when NASA lost the space shuttle Columbia in 2003. I’d grown up in Central Florida, not far from Kennedy Space Center. I’d seen almost every shuttle launch in person—with my classmates outside on the sidewalks of my schools, with my sisters in the backyard, and very occasionally from the far side of Cape Canaveral, with my parents. The sonic booms from landings sometimes set off the burglar alarms that hung from our door handles.

But in 2003, I had things to do that didn’t include watching out for spacecraft. I was on my way to a band (marching band, not the cool kind of band) rehearsal session when I heard about Columbia. News of the accident came slow and halting over whatever alt-rock station I was blasting from my Grand Am.

Later, investigators would reveal that a piece of foam had fallen from the shuttle’s wing during launch, leaving a hole that let gas come through when the shuttle re-entered the atmosphere. The shuttle was going Mach 18, 37 miles above the ground, when it broke apart, shaking debris across thousands of square miles.

I remember sitting in my car in a church parking lot, thinking how it couldn’t be real. I remember thinking the radio host didn’t sound like he thought it was real. We’d probably both watched shuttles launch and land safely for much of our lives. To us, the whole program seemed routine—operational. It had moved into that realm of seeming safety, and risks seemed not just less likely but also less justified. And while we always knew this could happen, we never thought it would.

The Columbia disaster represented, unlike the Challenger explosion before it, the start of the finish for the shuttle program. NASA announced its end the very next year. Two strikes, shuttle’s out.

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Sometimes, you hear the phrase “Failure is not an option” associated with NASA. But it was never a slogan at the agency; no one in mission control, that we know of, ever said it, and no manager passed it down. It was just a line in the movie Apollo 13. Failure is always an option: It has to be.

Of course, no one wants a rocket to blow up or a crew capsule to fall to Earth. But to undertake space travel, the undertakers have to acknowledge those possibilities and mitigate the risks. As NASA administrator William Gerstenmaier said in his paper “Staying Hungry: the Interminable Management of Risk in Human Spaceflight,” “We never simply accept it, but NASA, our stakeholders, and the public must acknowledge the risk as we move forward.”

The public, to some extent, also knows that’s the equation. But a 1/200 mission-failure rate means that one doesn’t happen very often, which means that every one comes as a shock.

Still, astronauts’ deaths don’t always cause communal moral outrage. “A particularly risky venture can become socially acceptable in correlation with the value placed on it,” Langston wrote in her risk paper. If people value a space-exploration program, in other words, they’re okay with others risking their lives to push it forward.

Simberg contends that wasn’t fully true with the shuttle, as compared to Apollo—an inspiring and aspiring mission with political importance. “The reason we were so upset about losing these seven astronauts was that what they were doing was kind of trivial,” he says of Columbia.

We don’t always demand, though, that people be doing something Valuable that Benefits Humanity to let them risk their lives (and there were lots of ways the shuttle and, in particular, its trips to the always-peaceful International Space Station did benefit humanity). About 1 percent of people who try to climb Mount Everest historically die in the attempt, for example. And this despite the fact that topping Everest is not exactly exploration, with its $40,000 price tag and Sherpa guides and commercial expeditions. And it’s been done before.

Shuttle astronauts, meanwhile, have a 1.5 percent chance of dying on a given trip to space. And trying to keep them at least as safe as that—or safer—means the agency can’t go as boldly as private industry can.

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The major players in the crewed-commercial space are SpaceX, which wants to eventually build a martian colony; Blue Origin, whose Jeff Bezos envisions an outer space full of industry and long-term habitation; and Virgin Galactic, which wants to democratize access to space closer to home, with a carrier plane that rides up to 50,000 feet, then travels up on its own and glides back down at the behest and guidance of its pilots.

On October 31, 2014, Virgin Galactic paid a human price for that system. During that October test flight, copilot Michael Alsbury unlocked SpaceShip’s feathering system, which changes the shape of the plane to aid reentry, early. The wind then pushed the system open, and the vehicle destabilized. While pilot Peter Siebold parachuted to safety, Alsbury remained with the ship, and died on impact.

After the accident, Virgin allowed its already-booked customers to back out, but just 3 percent did.

SpaceX, meanwhile, has had its own explosive setbacks, and yet the company and leader Elon Musk still remain the industry’s darlings. SpaceX blew up an uncrewed Falcon 9 rocket in September 2016. In June of the year before, the company lost another Falcon that was supposed to resupply the Space Station. In test launches and landings of its reusable rockets, SpaceX has also had a vessel tip over into the ocean and explode (January 2016); crash into a ship (January 2015); and land “too hard for survival” (April 2015).

Based on this, the NewSpace industry seems to exist firmly in the experimental phase. But, more than that, the public seems to know—and accept—that status. “You understand that you're in a test-pilot phase,” says Bearden. “The public can process that and say, ‘That's not me. By the time I fly, they're going to have worked it out.’”

The public permits mistakes for the private space companies—because they produce rockets and results on non-geologic timescales, and lay out visions like “you can go to space” and “you can have a house on Mars.”

The FAA, which regulates commercial space activity via the Human Spaceflight Requirements for Crew and Spaceflight Participants, is also relatively forgiving. “Congress mandated these regulations in the Commercial Space-Launch Amendments Act of 2004,” says the FAA’s description of this law. “Recognizing that this is a fledgling industry, the law required a phased approach in regulating commercial human spaceflight, with regulatory standards evolving as the industry matures,” attempting not to crush innovation with regulation. Flight providers do, though, have to get extremely informed consent from would-be astronauts.

NASA recognizes the value in this model, and in its different posture toward risk. The agency has teamed up with such space companies—letting them, among other things, shuttle cargo and crew to low Earth orbit. NASA no longer has to be all things to all people and missions, and can let those experimental upstarts do a little legwork.

The agency may also see, though, that the public perceives New Space cadets as pioneers—a lens through which they don’t see NASA like they used to—and so forgive their mistakes, tallying them as the cost of innovation, rather than a cost not worth bearing. And perhaps the agency hopes the same thing for itself, as it turned those duties over to private companies so that it can focus on its own bold goals, its own new risky, experimental phase of operations with both the costs and the benefits that come with that.

* This article originally stated that there were four crew members aboard Apollo 1.

** This article originally misstated the cause of death for the Apollo 1 crew.

*** This article originally implied that the Columbia disaster occurred 36 years after the Challenger explosion.

**** This article originally stated that the Virgin Galactic crash resulted in the death of the craft’s pilot. We regret the errors.