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Calculating Environmental Damage From Space Tourism Rockets
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.'"
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.
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.
For 1,000's of years mankind has dreamed of going into space and now that someone is setting up a business to take us there, the environmental wackos want to take it away.
Seriously, just about anything seriously fun is now illegal or politically incorrect.
I'd like to know how much pollution is generated by the unthinking environmentalists (as opposed to the thinking ones) and how far the environment can be saved if they simply didn't propagate.
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!
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)
I don't recall environmental factors being discussed when Rutan and co. were publicizing the motor design.
Well, they aren't using hydrazine and fuming red nitric acid. Toxicity of the fuel did play a part in their choices.
They didn't use people as motorfuel, so they must be alright.
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.
A quick google query and you can figure this out for yourself.
Volcanoes create a cooling effect due to the sulfur they spew into the high atmosphere.
Direct sulfur injection is actually a proposed geo-engineering solution to global warming.
http://www.livescience.com/environment/060727_inject_sulfur.html
Give me a break.
Just guessing here, but I'd bet good money that granola crunching campers "cause" more global warming burning their frigging campfires.
When the shuttle was being developed, it was thought it would be much more environmentally destructive that it turned out to be. OTOH, if we were to have shuttle launches every day, we would probably see an unacceptable level of environmental destruction due to acid fallout.
That is my concern. When we have entrenched interests like coal mining, or auto manufacturers, or factory farming, that are clearly destructive, we can't get rid of them. Coal mining is fine until we blow up mountains and poison rivers. Autos are the most responsive, they got rid of lead, are safer, less fuel wasteful, but still resis some basic changes. Factory farming was never a good idea, but makes cheap meat so no one wants to give that up.
The point is that we need to let technology develop, and then have the wil to fix the problems, or scrap the technology, if it is destructive. We can do. Almost no one uses CRT monitors anymore, at a savings of 50% of the power. My computer runs on less than 100 watts. Of couse most of the time we let FUD keep up from solutions, as we see with windmills. Not ideal, but really fairer to everyone.
"She's a scientist and a lesbian. She's not going to let it slide." Orphan Black
is obviously a Saturn V Prius...
I take my children to see Madonna(..), but I never for once ever thought I was in the same business.Chris Rea.
Take up bottled CO2 up with each launch and jettison it towards the sun.
The ultimate form of carbon credits.
The greenhouse gas emissions of all the space bound rockets in the world would be insignificant compared to say the fireworks and rockets used on 4th July, or even those used on 5th November (for UK and NZ readers).
And what about the environmental impact of next weeks midterm elections, all that advertising that goes straight into the garbage (its glossy so won't recycle) or even the gas used by people driving to the polling booth.
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.
Give me a break. The environmental damage contributed by plain tourism itself (e.g. flights/cruise ships/train/buses, not to mention hotels, theme parks, etc) would be orders of magnitude more than anything *space* tourism can do for the foreseeable decade or two.
Let me guess, a more "environmental friendly" engine is available from those scientists' company/sponsor?
Oliver.
Please see: http://www.amazon.com/Aftermath-LeVar-Burton/dp/0446519936
Radyo dinle
radyo dinle
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.
When the Asteroid hits in the year 2157 and wipes out 95% of land dwelling life on earth it will be worth it because the asteroid impacted upon a earth that shunned space travel and the pristine wilderness destroyed by the asteroid strike was a far better thing for all those now extinct species than having space tourism and colonization and the infrastructure that it requires to divert the asteroid. Oh well....
Hopefully in another 65 million years evolution will evolve another intelligent species that can think more long term than we did....
Tsukasa: All I really want, is to be left alone...
They didn't use people as motorfuel, so they must be alright.
How would you feel about being launched into orbit on a Soylent Green booster?
The higher the technology, the sharper that two-edged sword.
Scaled Composites & Richard Branson came out with a statement that they are fully aware of some of these issues and that they are working on alternative fuels to perhaps mitigate this problem too. As you point out, there were many reasons why they went with this particular solution, where vehicle safety is one of the things that was of primary importance where they don't necessarily want to be on the bleeding edge of technical performance. The goal is to have an airline quality of performance for roughly how often this vehicle is going to be going into space, and to be able to "refuel" this spacecraft quickly.
The Yellowstone eruption is more likely to cause harm to earth even in its unlikeliness to erupt than a few pollutant space ships in the next 100-years. I'm sure that if 10 volcanoes erupted in the next 100-years, it would be a lot more devastating for the environment than what humans would have been able to do with space travel. Go on vegetarians, kill the cows you love so much to "protect" the earth. Global warming is a damn cult.
Like the type dumped into the atmosphere by the Space Shuttle since 1981? Lets not worry....but now that the shuttle is nearly is nearly at an end and non-US space flights are ready to start, let the complaints begin! Sour grapes anyone?
My web domain.
Note that while Shuttle SRB's cannot be shut off, this was a design decision made by NASA - not a universal property of solid fuel motors. Shutting off solids in flight has been pretty much routinely done since the late 1950's.
Meh. They just need to switch over to a salami rocket instead. Problem solved.
No, you are wrong on this. A true (simple) solid rocket CANNOT be shut down once lit. Shut-off requires removing the oxidizer, which in case of a true solid rocket is embedded within the material.
Mixed designs (hybrid rockets) have been available, but are generally of a lower specific energy, and require a pressurized oxidizer of some sorts (liquid or gas) meaning that the oxidizer has to be kept separate and in a heavy pressurized bottle with all the plumbing required.
A simple solid rocket is, well, simple, powerful and cheap, which is why NASA selected that method for the SRBs for the Space Shuttle. They can release those from the main fuel tank early if required (SRB separation).
When you say "Shutting off solids in flight has been pretty much routinely done since the late 1950's." are you sure you're not mixing it up with liquid fueled rockets such as the X-1 and X-15 used? Or referring to hybrid rockets?
No, *you* are wrong. Worse yet, when told you're wrong, you just parrot what you've heard before and make nonsensical claims and erect strawmen to 'prove' yourself correct.
The fact is that unconfined, all modern solid fuel does is essentially smolder - they require high pressure to actually burn. Vent the casing, and thrust drops rapidly to nearly zero. Thats is all that's needed.
SUBROC, ASROC, Polaris A-1, Polaris A-2, Poseidon, Minuteman I, Minuteman II, Minuteman III, Peacekeeper... I imagine you've heard of at least some of these. If not, a few moments with Google will enlighten you.
NASA selected solids because they seemed to be simple, powerful, and cheap. But in reality, they could only get one of those - and they chose powerful. SRB's aren't simple (mostly because of the need to be re-usable, but there is some significant complexity due to the need to segment them) and they aren't cheap (ditto). Nor can the be separated prior to burnout, once lit - that's all she wrote. NASA considered using thrust termination on the SRB's, but rejected it for various reasons.
Seriously?
Ok.
Venting generally does not shut down the burn, but does get thrust to zero, leaving you with a dangerous hunk of smoldering explosives. Not much room for error.
Venting has ONLY been used on unmanned systems, and relatively small ones at that, because venting a LARGE solid rocket generally involves blasting the casing apart longitudinally. Venting the casing really is not as simple as you make it out to be, because the burn chamber needs to be vented, and that's inside the cast motor bit. THAT'S where you need to drop the pressure. And you need to drop it fast. This is complex, and in case of failure you are likely to have an explosion due to regional overpressure on your hands, which is not cool for a manned vehicle.
Venting does not equal shutdown in any meaning of the word that I am familiar with. Even if you put your car in neutral you don't claim to have shut it off, do you? Especially if that "shutdown" leaves you with the thing in a more dangerous state than it was before.
Price/power/simplicity can be debated, and depends on which part of the cost you look at, what you compare the specific power to and what you compare it to on complexity.
Some of the other claims I will buy. SRB separation can only happen after burnout, my error there.
But the proper inflight shutoff, possible in a reliable and safe manner is the domain of liquid fueled rockets and hybrids. In the case of the hybrids it involves shutting the valve for the oxidizer. No explosive (or otherwise complex and dangerous) venting and the oxidizer flow rate is a reliable indicator of whether it's on or not.