Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

Today we’re answering a question from listener Molly Magid:

Molly Magid: So I thought of this question because last year, there was a lot of buzz about the flights of SpaceX and Virgin Galactic, bringing people who are not astronauts into space and sort of sparking this discussion of what commercial space travel might look like. So I’m wondering, what are the environmental impacts of space travel and how does it compare to say, taking a plane flight

We had Charlie Adams and Ashley Junger from our Possibly Team look into this.

Megan Hall: Welcome Charlie and Ashley!

Charlie Adams: Hi, Megan!

Ashley Junger: Hey, Megan!

Megan Hall: The thought of traveling to space for ordinary (non-billionaire) people like me seems like something that’s pretty far into the future. Do I really need to worry about this? 

Charlie Adams: Yeah, not many of us can afford the $500,000 it costs to travel to space, but it does look like the industry is growing. Experts estimate that the commercial space travel industry could generate as much as a billion dollars in revenue by 2040.

Ashley Junger: So, it’s possible that more and more people will start going to space. 

Megan Hall: Got it. So what are the environmental impacts of space travel?

Charlie Adams: Rockets burn kerosene or natural gas, which means they emit carbon dioxide when they blast into space. 

Megan Hall: But how do rocket flights compare to plane rides when it comes to carbon emissions?

Ashley Junger: It depends on the aircraft, but a single SpaceX flight emits about as much carbon dioxide as two round trips flights between New York and South Africa.  

Megan Hall: Really? That’s actually not as bad as I thought it would be. 

Charlie Adams: Well, there’s more to this question.

Ashley Junger: It’s not just about what these space crafts are emitting, it’s about where those emissions happen.

Charlie Adams: When you fly into space, you’re going higher than most planes, into what’s known as the stratosphere. 

Ashley Junger: And the particles and gasses that come out of a rocket behave differently up there than in the lower parts of the atmosphere. 

Megan Hall: Differently good or differently bad? 

Charlie Adams: Well, it’s complicated. 

Ashley Junger: The truth is, we are only just learning about how those elements act when they’re more than six miles above the planet.

Charlie Adams: Some, like soot, or black carbon, are thousands of times more effective than CO2 at heating the upper atmosphere.

Ashely: And black carbon released in the stratosphere can linger for up to ten years, so it can have a long-lasting impact.  

Charlie Adams: But other substances come out of rocket boosters too, like aluminum which reacts with the atmosphere to form particles that reflect sunlight. This can actually cool the atmosphere.

Megan Hall: Wait, the stuff that comes out of rockets might cool the planet? 

Ashley Junger: Well, anything that blocks sunlight would likely cool things down, just like things that absorb sunlight will warm things up. But the exact effects are hard to predict.

Charlie Adams: So while we don’t know all the effects of space tourism on the atmosphere, it does seem pretty frivolous to burn all that fuel for a billionaire joy ride. On the other hand, those same people fly around in private 747s, which isn’t helping much either

Thanks, Charlie and Ashley!

That’s it for today. For more information, or to ask a question about the way your choices affect our planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts. 

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Possibly is a co-production of the Institute at Brown for Environment and Society, Brown’s Climate Solutions Initiative, and The Public’s Radio.

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