This week was a sobering reminder about the inherent dangers of space flight.

On Tuesday, an unmanned Antares rocket containing 5,000 pounds of supplies and experiments bound for the International Space Station malfunctioned, prompting its operator, Orbital Sciences, to trigger its self-destruct system.

And then today, during a manned test flight, Virgin Galactic and Scaled Composites’ space plane SpaceShipTwo suffered an “anomaly” — code for something seriously wrong — and crashed. As I’m writing this, the status of the pilots is unknown, but it appears that one was killed and the other suffered serious injuries.

We don’t know all the details of these two incidents — it may take months to complete full investigations — so I’m not going to speculate. But I think I can say that this week will set the private space industry back by years.

That’s unfortunate, but it is probably necessary.

Our admiration for the work astronauts do has always been tempered by our knowledge of how dangerous it is.

I grew up reading books and poring over photos of the Apollo program, which was a terrific triumph (we put men on the moon, and did it in less than a decade) punctuated by the disasters of the Apollo 1 launchpad fire and Apollo 13.

Later, like many aspiring nerds, I obsessed about the Space Shuttle program. There, too, years of success were marred by two high-profile disasters. When the Challenger exploded 72 seconds into its flight in 1986, killing everyone aboard, I was in high school. I can still remember how the principal came on the P.A. to let us know what had happened, and to ask for a moment of silence and prayer. The images of that explosion’s fragmenting smoke trails still make my heart clench. Then, many years later, in 2003, the Columbia broke apart upon reentry, killing its crew. After that happened I felt like the Shuttle program might never recover. And in some ways it didn’t: While NASA continued to fly Shuttle missions, they happened less frequently and at far higher cost than the designers of the Shuttle had ever anticipated, partly because of the complexities involved in making sure they were safe.

But for the past five years, it has seemed that we’d moved into a new era of space flight. Instead of the old, expensive, nationalistic bureaucracy of NASA, we have a nimble, international movement powered largely by private corporations.

As these corporations began to play a larger role, the variety of space travel increased, encompassing high-budget and low-budget projects and everything in between.

That’s been a fantastic thing to watch for space enthusiasts like me, and I think it’s on balance been good for humanity, too. National governments could cooperate to build and supply the International Space Station. Ordinary schoolkids could design experiments and actually send them into space. The super-rich, like Richard Garriott (aka Lord British) or Anousheh Ansari, could spend tens of millions of dollars to play space tourists aboard the ISS. A NASA astronaut could record a music video for YouTube or publish Instagram photos from orbit, engaging millions in the adventure of space travel.

And those who were wealthy enough to afford a $250,000 ticket could dream of going on a short but exhilarating suborbital flight aboard Virgin Galactic, which made remarkably fast progress toward FAA approval and actual paid space flights, which were scheduled to begin in 2015.

All of that seems sadly naive now.

Yes, there is a lot of vibrant innovation happening in space travel now. And that innovation is both exhilarating and, I think, necessary. But after this week, it seems clear we need to take a strong, sober look at the risks, as well as the rewards, of space flight.

Bloomberg estimates that, if U.S. air travel were as risky as space travel is, we’d have 272 airplane crashes a day. Clearly there is more work to be done in making rockets safer, and maybe that’s what the space industry needs to focus on next.

Those risks, great as they are, should not ever stop us from going into space. But we should be looking at them with open eyes.

And while we ponder those risks, let’s stop for a moment to silently reflect on the bravery of those who are leading the way, and who — like today — sometimes pay the ultimate price.

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