Rockets and the Ozone Layer

[Spaced Out]

Just curious. Do aerospace companies think about the impact their rockets will have on the environment? Rocket exhaust plumes can destroy up to 40 percent of the ozone it hits. Is this ever a concern? As of right now rockets are only one percent of the man-made things destroying the ozone layer, but what will happen if the launch cadence rises?

[sevenperforce]

2 minutes ago, Spaced Out said:

Just curious. Do aerospace companies think about the impact their rockets will have on the environment? Rocket exhaust plumes can destroy up to 40 percent of the ozone it hits. Is this ever a concern? As of right now rockets are only one percent of the man-made things destroying the ozone layer, but what will happen if the launch cadence rises?

Launch cadence would have to rise astronomically high (no pun intended) before it would make much of a difference, and rocket plumes only hit the ozone layer briefly.

I'd like to see a space startup that uses biofuels, though.

Edited September 9, 2017 by sevenperforce

[mikegarrison]

10 minutes ago, Spaced Out said:

Just curious. Do aerospace companies think about the impact their rockets will have on the environment? Rocket exhaust plumes can destroy up to 40 percent of the ozone it hits. Is this ever a concern? As of right now rockets are only one percent of the man-made things destroying the ozone layer, but what will happen if the launch cadence rises?

It's a known issue. Not necessarily a big problem for the more mundane fuels like kerolox. Some of the solid fuels and hypergolics can have some pretty bad environmental effects. Generally speaking, however, I think it is mostly ignored because of the low total amount of emissions compared to other sources.

But it's worth noting that rockets are pretty much the only things that actually emit up at altitudes above where planes fly. All other emissions have to get up there by circulation, which is difficult due to the stratosphere not having much vertical transport (thus the name stratosphere). Only rockets can inject their emissions directly up into the high upper atmosphere.

[Spaced Out]

19 minutes ago, mikegarrison said:

It's a known issue. Not necessarily a big problem for the more mundane fuels like kerolox. 

Isn't exhaust from kerosene carbon dioxide and soot though?

[mikegarrison]

25 minutes ago, Spaced Out said:

Isn't exhaust from kerosene carbon dioxide and soot though?

Yes (plus water). And that's not nearly as chemically reactive as some of the stuff that comes out of solids and hypergolics.

Here's a random paper on rocket exhaust. https://www.eucass-proceedings.eu/articles/eucass/pdf/2013/01/eucass4p657.pdf Note that what especially concerns them are the chlorine and aluminum from the solid rockets.

Water is also more of a concern than you might think, because usually there is very little of it in the upper atmosphere. So a big cloud of water opens up new possible chemistry.

Edited September 9, 2017 by mikegarrison

[Spaced Out]

11 hours ago, mikegarrison said:

Water is also more of a concern than you might think, because usually there is very little of it in the upper atmosphere. So a big cloud of water opens up new possible chemistry.

So what are the effects of this?

[mikegarrison]

17 minutes ago, Spaced Out said:

So what are the effects of this?

I'm not a chemist, but I work with one and have talked with him about this sort of thing before.

Chemistry always has something controlling the rate it happens at. That might be the concentrations (too diffuse and the molecules just never bump into each other). Or it might be the lack of some part of the reaction. If there are reactions up there that destroy ozone and need water, then they are mostly stopped by the fact that there is no water. Which means that if you inject a lot of water into the air, these reactions can take place.

Also, there are a number of gases that will react with water to turn into acid droplets, which can then help facilitate more and different chemistry. Hypergolics, for instance, pretty much always seem to use some kind of witch's brew of nitric compounds, and if they form N2O in the exhaust then that is just looking for some water in order to turn into nitric acid.

[Spaced Out]

@mikegarrisonHas the water up there been know to affect anything like global warming yet?

[mikegarrison]

Just now, Spaced Out said:

@mikegarrisonHas the water up there been know to affect anything like global warming yet?

There is a lot of attention paid to water from jet airplane exhaust possibly increasing cirrus formation and thus increasing radiative forcing. There are a lot more airplanes than rockets, however.

You would have to search the literature to find out if anybody has studied the specific global warming/cooling effects of rocket-deposited water in the mesosphere and above.

[Spaced Out]

@mikegarrison positive or negative radiative forcing?

[mikegarrison]

3 minutes ago, Spaced Out said:

@mikegarrison positive or negative radiative forcing?

Cirrus? Both, depending on whether it is day or night. But overall, positive (ie. bad).

[Spaced Out]

@mikegarrison do rocket parts falling in the ocean pollute?

[mikegarrison]

2 minutes ago, Spaced Out said:

@mikegarrison do rocket parts falling in the ocean pollute?

Not my area of expertise.

[Nightfury]

3 minutes ago, Spaced Out said:

do rocket parts falling in the ocean pollute?

 would say not, because there should be nothing except some metall

 

[Spaced Out]

@mikegarrison Well thanks for the other answers though. 

[sevenperforce]

34 minutes ago, Spaced Out said:

@mikegarrison do rocket parts falling in the ocean pollute?

No, not in any meaningful sense. Almost everything sinks, and what doesn't is so sparse compared to the ginormous diluting capacities of the whole friggin' ocean.

[Spaced Out]

2 minutes ago, sevenperforce said:

No, not in any meaningful sense. Almost everything sinks, and what doesn't is so sparse compared to the ginormous diluting capacities of the whole friggin' ocean.

But do rockets parts have chemicals that are bad for the nearby sealife?

[Steel]

37 minutes ago, Spaced Out said:

But do rockets parts have chemicals that are bad for the nearby sealife?

Probably, in the same way that sunken ships do.

[Shpaget]

While I certainly wouldn't say that nothing should be done about rocket stages splashing down into oceans to sink and be forgotten, there are more pressing environmental issues that are both much more serious in terms of damage done and are easier to deal with. After all, perspective is very important.

When it comes to ocean pollution, rockets are not really significant factor when compared to literal mountains of trash that are dumped without control every day.

Just take a look at this image and keep in mind that this is just physical debris that floats. There is much more of it that sinks, and still more chemicals in liquid form dumped from various manufacturing and processing plants.

Our environmental efforts should be prioritizing this sort of thing, and once we bring this source of trash under control, rocket stages can be our next goal.

 

[FleshJeb]

On 9/9/2017 at 8:11 AM, mikegarrison said:

There is a lot of attention paid to water from jet airplane exhaust possibly increasing cirrus formation and thus increasing radiative forcing. There are a lot more airplanes than rockets, however.

You would have to search the literature to find out if anybody has studied the specific global warming/cooling effects of rocket-deposited water in the mesosphere and above.

There was some study done to look at the effects of having all commercial jets grounded for three days after 9/11/01.

http://news.psu.edu/story/361041/2015/06/18/research/jet-contrails-affect-surface-temperatures

http://globalnews.ca/news/2934513/empty-skies-after-911-set-the-stage-for-an-unlikely-climate-change-experiment/

Edited September 12, 2017 by FleshJeb
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