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Calculating Environmental Damage From Space Tourism Rockets

Posted by Soulskill on from the i-can-see-the-smog-around-my-house-from-here dept.

MithrandirAgain writes "A new study from several scientists at the Aerospace Corporation claims spaceships that rely on rubber-based fuel could help cause climate change. The fuel apparently expels a black carbon soot into the stratosphere when burned with nitrous oxide, which could be contributing to global climate changes, like shrinking the icecaps. However, the authors are careful about their work being an end-all study and are 'inviting others to take a look.' Virgin Galactic, whose SpaceShipTwo just made its first solo flight (and uses the type of fuel discussed in the study), is listening to the scientists' concerns. CEO George Whitesides said, 'I think we and others in the industry welcome the opportunity to talk about all of these issues.' SpaceShipTwo does use a hybrid engine 'because of its significantly lower environmental impact than other designs,' and Whitesides stresses, 'I think as we look at this more, we'll find the impact will be far smaller than that set out in the paper. In any case, I welcome the conversation.'"

20 of 83 comments (clear)

  1. I'm impressed ... by ScrewMaster · · Score: 2, Interesting

    However, the authors are careful about their work being an end-all study and are 'inviting others to take a look.'

    A refreshing attitude ... that's how science is supposed to work. There have been far too many bombastic claims made about global warming.

    --
    The higher the technology, the sharper that two-edged sword.
    1. Re:I'm impressed ... by Arthur+Grumbine · · Score: 2, Insightful

      However, the authors are careful about their work being an end-all study and are 'inviting others to take a look.'

      A refreshing attitude ... that's how science is supposed to work.

      While I agree that researchers should encourage others to perform independent studies, I find the approach of this group to be disingenuous at best. I find this comment (in the comments to the Wired article) to be particularly insightful:

      This is close to corporate blackmail, and is symptomatic of the way climate science is abused to generate alarmist headlines. They take three flights every day for 40 years, and no doubt the assumptions about the amount of soot particles is similarly “generous,” plug in absolute worst-case numbers until they get an alarming result, and PROFIT$$$.

      The profit for them is to generate alarming headlines. You can’t afford to not pour more money into my field or the WORLD WILL END!! (please be sure to spell my name right when you mention my research) And if you are Richard Branson, we will give your company a sooty black eye unless you fund more of our research. C’mon, rich man, pay up!

      There is certainly room for sober investigation, and as environmentally conscious as Branson is, he probably would have okayed a chase plane sampling the exhaust trail. Certainly all the atmospheric science models could use vastly more data to move beyond the wild guess stage. The constant claims of impending disaster from overstated claims, though, will backfire.

      --
      Now that I think about it, I'm pretty sure everything I just said is completely wrong.
    2. Re:I'm impressed ... by Anonymous Coward · · Score: 2, Interesting

      To be honest I think this study is environmental FUD. They are saying that 40,000 launches over 40 years can cause significant environmental change including 1.8 degree temperature shift (positive) at the poles.

      The obvious question that comes to my mind is why do think that any significant amount of soot from the 1000 rockets launched this year would still be in the atmosphere in 40 years? Do they have any reason to suspect that it stays around that long? The thing that comes to mind for me with high level soot is volcanic eruptions and their effects are no where near that long lived (from what I can find on wikipedia, they usually only effect the weather for about 1 year).

      Finally, again comparing to volcano's, the best data I can find for a volcanic eruption that changed the climate (1991 Pinatubo) suggests that it dumped 17 million tons of CO2. I know this is talking about rubber particulates and not CO2, but there's a big difference in magnitude between 17 million tons in a few days and 1.3 million tons over 40 years.

    3. Re:I'm impressed ... by damburger · · Score: 3, Insightful

      This offends your worldview so you dismiss it.

      For a better analysis, lets review the story so far:

      1. A group of highly qualified academics publish research showing that hybrid rocket engines *may* have a polluting effect far out of proportion to the emissions they have on paper. The researchers are careful to stress the word *may*

      2. They find another expert in the field who says "This is interesting, but not a definitive conclusion" i.e. agrees with the assessment of the original team.

      3. Spokespeople for corporations who want to make profits from the use of hybrid rockets say its all bullshit, despite these spokespeople having no real qualifications.

      Then you come along with some volcano analogy, despite the fact the entire study is based on the *high altitude* generation of soot particles and I haven't seen any flying volcanos recently.

      When science says things you don't like, and you decide to dismiss the academic structures on which science is based just because you don't like the new (possible) reality, that is a bit of a dick move.

      Here is the real bitch though; nobody is going anywhere significant in N20/rubber hybrid rockets. They are good for quick-and-easy sub-orbital rides because they are safe and simple to build, but to get into orbit you need more powerful fuels which likely do not have the soot problem - so if space tourism does take off and get some non-pathetic technology, they will have moved on from producing soot-rich exhausts anyhow.

      --
      If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?
    4. Re:I'm impressed ... by ScrewMaster · · Score: 4, Insightful

      Then you come along with some volcano analogy, despite the fact the entire study is based on the *high altitude* generation of soot particles and I haven't seen any flying volcanos recently.

      The GP is absolutely correct though. The article was talking about stratospheric effects. As it happens, vulcanism is perfectly capable of ejecting all sorts of substances that can have profound effects on weather into the stratosphere. How do you think eruptions like Krakatoa and Pinatubo had globe-spanning effects?

      --
      The higher the technology, the sharper that two-edged sword.
    5. Re:I'm impressed ... by Teancum · · Score: 2, Insightful

      How is the stuff from volcanoes any different? Volcanoes contain traces of just about every naturally occurring element including Uranium, extreme heat in its plume, and these compounds produced from a volcanic explosion certainly do make it to the stratosphere and sometimes even higher.

      All at once (relatively speaking), in a plume from one point. Whereas the rocket exhaust originates over a much larger area

      In this regard the rocket is much, much more focused to a very small area compared to a volcano, and a vast majority of this "soot" remains by definition in the troposphere where it rains down as... rain. It doesn't stay long in the sky. In other words, the impact of a particular rocket launch is minor compared to that of a volcano, so much so that it can be completely dismissed as having any significant impact on the global climate at all. It would take many more than 40k launches to make a difference.

      As for "high altitude nuclear weapons tests" are concerned, define "high altitude" before you come to any conclusions. The problem with the high altitude tests that ended up creating the "Nuclear Test Ban Treaty" is that they were detonated at an altitude about where the Space Shuttle flies, and the fallout persisted for some time at that altitude in the form of charged particles trapped in the Van Allen Belts, causing persistent and long term ionizing radiation problems for folks and spacecraft that had to travel into space. That is not even a legitimate or remotely fair comparison to some ash that is left over at a much lower altitude.

      The comparisons to major volcanic eruptions is very much spot on analysis as it is comparing the same things, and in some cases even the same compounds where the volcanic eruptions are going to be even more extreme in terms of heating conditions that produce those compounds.

  2. Why warming and not cooling? by ScrewMaster · · Score: 4, Interesting

    What I find interesting is that they're claiming that injecting soot into the stratosphere would cause global warming (at least according to the summary, didn't RTFA.) When blasts of particulate matter from other sources have reached those heights (for example, when Krakatoa went postal) it resulted in global cooling instead. I'm assuming there's a different mechanism involved.

    --
    The higher the technology, the sharper that two-edged sword.
    1. Re:Why warming and not cooling? by ScrewMaster · · Score: 2

      What I find interesting is that they're claiming that injecting soot into the stratosphere would cause global warming (at least according to the summary, didn't RTFA.) When blasts of particulate matter from other sources have reached those heights (for example, when Krakatoa went postal) it resulted in global cooling instead. I'm assuming there's a different mechanism involved.

      What I think is fascinating is that you couldn't combine the above and this into one post. It's almost as though you wanted twice the karma...

      A. I don't need the karma and ...

      B. the second thought occurred to me after I clicked Submit.

      If you have nothing to contribute to this discussion (because, frankly, you've contributed nothing so far) just lurk, don't post.

      --
      The higher the technology, the sharper that two-edged sword.
    2. Re:Why warming and not cooling? by KibibyteBrain · · Score: 2, Informative

      It all depends on if the particulate, after settling, causes a net reflection or absorption of radiation. This would depend on the precise chemical makeup of the particulate, the altitude dispersed, and the process that dispersed it(temp, pressure, velocity, etc).

    3. Re:Why warming and not cooling? by goodmanj · · Score: 4, Informative

      To oversimplify:

      Volcanoes generally release sulfate aerosols -- tiny clear droplets of sulfuric acid -- and pale grey ash particles. These are lighter in color than the ground below them, so adding them to the atmosphere makes the planet as a whole lighter in color, so it reflects more sunlight, causing cooling.

      Black soot is black: adding it to the atmosphere *darkens* the planet overall, causing it to heat up.

  3. Dudes have their drugs mixed up ... by PolygamousRanchKid+ · · Score: 2, Funny

    The fuel apparently expels a black carbon soot into the stratosphere when burned with nitrous oxide

    You don't burn nitrous oxide, you just inhale it.

    Is, like, our druggie-head culture going to Hell in a hand basket?

    Oh, what a sorry state of the nation, when teenagers don't know how to do whippets anymore . . .

    --
    Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
    1. Re:Dudes have their drugs mixed up ... by Anonymous Coward · · Score: 3, Funny

      Seriously! We can use the N2O to send six people into space, or use the same amount to make, like, a million people think they're in outer space - for about thirty seconds anyway.

    2. Re:Dudes have their drugs mixed up ... by nacturation · · Score: 2, Funny

      The fuel apparently expels a black carbon soot into the stratosphere when burned with nitrous oxide

      You don't burn nitrous oxide, you just inhale it.

      I thought that's exactly what's happening. The rocket engine inhales the nitrous oxide which is what makes it get so high.

      --
      Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
  4. Nice attitude, but the real reaon for the motor... by arikol · · Score: 4, Informative

    The reason they went with this motor design was simplicity of construction, low chance of explosions and other nasty failure modes, reliability and price. Yet another is that this motor type can be shut off before the burn is complete (unlike the SpaceShuttle side boosters which use a thermite-like mixture (with a rubber-like binder) which provides its own oxidizer.
    The Rutan design uses nitrous oxide as an oxidizer to be able to better control the burn.

    I don't recall environmental factors being discussed when Rutan and co. were publicizing the motor design.
    The engineering reasons are perfectly good, though, and research into figuring out a blend which spews out less soot would probably be good from all standpoints (possibly even upping the specific energy content of the motor/fuel)

  5. The reporting bugs me by khallow · · Score: 3, Informative

    While the Wired story doesn't show blatant bias unlike the Nature story, "Space tourism to accelerate climate change", it still remains that no mechanism for the claimed climate changes has been described. It's just, "These guys ran their computer model and this is what they got." That's extremely unhelpful.

    1. Re:The reporting bugs me by goodmanj · · Score: 3, Interesting

      it still remains that no mechanism for the claimed climate changes has been described. It's just, "These guys ran their computer model and this is what they got." That's extremely unhelpful.

      If you have access to AGU journals, you should read the original article. It's quite detailed about the mechanisms involved.

      Even without the original article, the mechanism here really isn't rocket science. Black stuff in the atmosphere makes the planet absorb more sunlight and therefore heat up. Really simple. To go beyond mechanism to get a numerical estimate of climate change, you unavoidably need a model. And take it from me, the one they're using is a good one.

      You're using a lot of breath to cast doubt on the results here, with far less justification for your conclusions than the Nature and Wired authors you're attacking.

  6. Re:Leave it to the Environmental Wackos .... by Vectormatic · · Score: 2

    how is both this and my sibling a troll? insightfull is more like it

    i guess there are some hippies with mod point around (and i dont care, i have karma to burn, this is when all that insightfullness finally pays off)

    --
    People, what a bunch of bastards
  7. Found the actual article... by goodmanj · · Score: 4, Interesting

    Careful now: FUD as we typically use it on Slashdot is doubt raised by pure rhetoric, in the absence of facts. These guys have actual *data*. You can question their assumptions, but they're not just using scary words.

    The obvious question that comes to my mind is why do think that any significant amount of soot from the 1000 rockets launched this year would still be in the atmosphere in 40 years? Do they have any reason to suspect that it stays around that long?

    I've found the original Geophysical Research Letter article (it's behind a paywall unless you're at an institution that subscribes to GRL, which I am).

    They do *not* assume that the soot sticks around for 40 years: they include a settling time for the soot particles of a couple of years (details more complicated). But they run the model for 40 years to give the ocean and cryosphere time to adjust.

    They use a detailed model of the interaction of sunlight with soot particles: this model was developed for studying nuclear holocaust scenarios. They make some assumptions here about the size and properties of rocket soot particles, but I don't see any red flags.

    Finally, again comparing to volcano's, the best data I can find for a volcanic eruption that changed the climate (1991 Pinatubo) suggests that it dumped 17 million tons of CO2. I know this is talking about rubber particulates and not CO2, but there's a big difference in magnitude between 17 million tons in a few days and 1.3 million tons over 40 years.

    Soot particles have a *very* different climate effect than CO2, it's apples and oranges.

    Based on what I read in their article and on my personal experience as a climate modeling scientist, I can tell you that they're using the right computer model for the job, and their assumptions about soot input seem reasonable, and they're including all the relevant physics.

    It should also be mentioned that the climate change effects they're predicting (1 polar temperature rise, 5-15% northern polar sea ice loss) are observable, but *much* smaller than the predicted changes from anthropogenic greenhouse gas emissions (up to 8C polar temperature rise, possible total loss of summer sea ice). But still, no joke.

  8. Re:How about the impact of plain tourism first? by goodmanj · · Score: 3, Informative

    A very important distinction: planes, ships, and buses are designed to run clean, with little or no soot output. They also operate in the troposphere, where rainfall "washes" the atmosphere and cleans out the soot and other particles regularly. This is a very different thing than NO+rubber rockets (which are literally as clean-burning as a burning tire) in the stratosphere, where small particles tend to linger for years.

  9. Re:How about the impact of plain tourism first? by goodmanj · · Score: 2

    Oh, and also: the authors aren't claiming that these rockets are a bigger deal than traditional tourism: the point is that the environmental impact of space tourism may be very large *relative* to the size of the industry.