Rocketeers are Geoengineers
March 30, 2020 6:50 PM   Subscribe

In 2018, the 225 tons of black carbon emissions from rocket launches equaled that of the entire aviation industry. Injected into the stratosphere, these particles accumulate and could cause regional temperature shifts. With space launches growing at 8% a year, the launch industry may be conducting a planetary-scale geoengineering experiment far outstripping the impact of their CO2 emissions.
posted by head full of air (27 comments total) 18 users marked this as a favorite
 
Ooooh, another good argument for space elevators!
posted by kaibutsu at 6:58 PM on March 30 [9 favorites]


I wish that the FAA and NASA had tight over-sight and enforcement on this kind of exhaust. I also wish that we were not having secretive private corporations working to make the most powerful rockets instead of, to affirm kaibutsu's sentiment, making a space elevator.
posted by Ignorantsavage at 7:17 PM on March 30 [3 favorites]


Ooooh, another good argument for space elevators!

Alternately, an argument for development of better, more economical, safer ways to use liquid hydrogen/liquid oxygen based propulsion so that we can use less kerosene, and less solid fuels.
posted by tclark at 8:12 PM on March 30 [9 favorites]


"For this reason, Toohey urges that Musk spread out his plans to send a million people to Mars. "My first impression would be to do it slowly, not in the same year."

L.O.L.
An accountant and raw materials specialist walk into a bar.

"proliferated low-Earth-orbit constellations."
had to look that up and cool but let's get the CleanSpace One out there.
I like space elevators in theory but again I like rollercoasters but wont ride them, why an elevator? to ferry things and people in Earth's orbit to go where? experiment tether? one would think a station is the destination, tether up, space Uber from elevator to station. Then what.
I don't want space factory(s) in Earth's orbit.

that's what the moon is for.
posted by clavdivs at 8:13 PM on March 30 [3 favorites]


NASA's technical conservatism can lead to fairly polluting choices. I was disappointed the SLS will use solid boosters and continue dumping dioxins into the everglades like the space shuttle did.
posted by head full of air at 8:20 PM on March 30 [1 favorite]


that's what the moon is for.

Indeed! The elevator saves most of the cost of getting to the moon; just bring some gas with you for the second leg of the journey. Getting out of the dumb atmosphere and this bottomless pit of a gravity well is a hell of a lot of work...

Looking at Wikipedia, it's normally about 14 km/s to get to geo sync orbit, and another 5 to the moon.
posted by kaibutsu at 9:53 PM on March 30


The single best argument for space elevators that I’ve yet heard is that it will substantially reduce the cost of putting a horse into cislunar space.
posted by aramaic at 10:09 PM on March 30 [12 favorites]


I will now predict that a space elevator will present unexpected and deeply troubling consequences of it's own.
posted by bonobothegreat at 10:18 PM on March 30 [5 favorites]


Well, you don’t want to be anywhere near one when it fails.
posted by ricochet biscuit at 11:03 PM on March 30 [8 favorites]


Well, you don’t want to be anywhere near one when it fails.

So would it fall more or less down, or across? Like one big pile of rubble, or a long line of destruction?
posted by Literaryhero at 11:17 PM on March 30 [1 favorite]


"I don't want space factory(s) in Earth's orbit.

that's what the moon is for."


No, that makes little sense unless you can cheaply manufacture fuel on the Moon. The energy expenditure to climb back out of the Moon's gravity well is significant and not worth it unless you're getting your reaction mass from the Moon. As far as a factory is concerned, there's no way you'd get all the materials and fabricated components you need from only the Moon, so lifting stuff from Earth and sending it down to the Moon for assembly makes no sense at all if you can place your factory in orbit.

This is why Trump's Moon base idea is dumb. Manned spaceflight is very hard to justify in any case, and building a manned base on the Moon an extreme version of this.

I mean, I grew up on SF and was a member of the Planetary Society for many years, so I get it. I understand the sentiment. But the last two decades have proven just how much genuine science is possible when you focus on, you know, the science part.

"I will now predict that a space elevator will present unexpected and deeply troubling consequences of it's own."

It's not an environmental free lunch. It's not even the energetic free lunch that so many people think it is. No matter how you do it, you have to accelerate to escape velocity and ascending a space elevator means accruing a large amount of angular momentum, which is conserved. This will cause the anchor to lose the angular momentum the elevator gained and that has implications. Sufficient tensile strength and structural integrity and flexibility could allow it to (over time) be conserved via exchange with the Earth. You could try to conserve the angular momentum and keep the anchor stable by always sending an equal mass down the elevator as you bring some up, but I think there would be wave and resonance issues that would also make keeping structural integrity of the elevator challenging. And, anyway, at present and for the foreseeable future we cannot construct anything with the required tensile strength to weight ratio needed at that scale. Placing an anchoring mass well beyond geostationary orbit would make the conservation of angular momentum problem easier to manage, but at the cost of requiring an even greater tensilw strength than we already cannot achieve.

A lot of this has implications for just how environmentally "clean" this system would be. But, in addition, you have to account for the environmental consequences of a structural failure.

If feasible, a space elevator makes a lot of sense. But that's a big "if".

Finally, going back to the basic physics of it, you can't avoid the fact that you're doing a lot of work to put something into orbit. No matter how you do it, the more you do it, the more waste heart you create. Not that that is meaningful compared to the environment impacts this link is discussing, but large-scale industrialization of space travel is going to have a big environmental impact no matter how you manage it. Some ways are much better than others, but none are free of any adverse environmental impact.

On preview:

"So would it fall more or less down, or across? Like one big pile of rubble, or a long line of destruction?"

A line, pretty much however the collapse happens. But not necessarily a neat or easily predictable one. (If you have to worry about structural failure in the first place, you have to worry about it being an unpredictable cascade. On the other hand, you might be able to engineer a controlled, planned self-destruct as soon as the initial failure is detected. That might work.)
posted by Ivan Fyodorovich at 11:35 PM on March 30 [6 favorites]


September, 13, 1999...your right Ivan, it doesn't make cents for a change.

so let's put the Space X walmart-motors in the moons orbit.

feasabily putting a 100 people on Mars is like a down the road man but a million people. love the dude but get real.
posted by clavdivs at 12:16 AM on March 31 [1 favorite]


"The magnitude of present-day cooling from rocket particles is about the same as the magnitude of warming from aviation carbon dioxide. In other words, rocket launches cool Earth’s surface by about the same amount that aviation warms it."

"...questions are not being asked about rocket emissions."

Yes they are. This exact article is asking that question.
posted by happyinmotion at 12:44 AM on March 31 [1 favorite]


Sounds like a job for the Diamoni.
posted by y2karl at 1:36 AM on March 31 [1 favorite]


"For this reason, Toohey urges that Musk spread out his plans to send a million people to Mars. "My first impression would be to do it slowly, not in the same year."

That is an old article, from 2008, the current plan for their 'Starship' uses methane/oxygen instead of kerosene/oxygen. I know that methane leads to less engine coking, wouldn't surprise me if it led to substantially less black carbon as well.
posted by atrazine at 1:49 AM on March 31 [2 favorites]


NASA's technical conservatism can lead to fairly polluting choices. I was disappointed the SLS will use solid boosters and continue dumping dioxins into the everglades like the space shuttle did.

Well, that, but mostly politics. Solid rocket boosters are made by Northrop (nee ATK, nee Thiokol) in Utah with staff in Alabama and a number of design choices around SLS have been about keeping as many delegations and appropriations committees happy. This happened on Constellation as well; Ares I was horrific- no one thought putting astronauts on top of a solid rocket was a good idea.
posted by theclaw at 6:54 AM on March 31 [2 favorites]


The "what happens when your space elevator fails" section of the Robinson Mars books is extremely memorable. They seem like a really cool idea but anything that huge is just going to require so much energy to make and run, and so much devastation if it fails, that the costs seem really high.
posted by emjaybee at 7:16 AM on March 31 [10 favorites]


An argument against space elevators is that they are presently a fantasy.
posted by Ansible at 7:17 AM on March 31 [12 favorites]


Alternately, an argument for development of better, more economical, safer ways to use liquid hydrogen/liquid oxygen based propulsion so that we can use less kerosene, and less solid fuels.
I guess DIVH is an (expensive) existence proof that it can be done, and New Shepard shows they can be landed and reused... Hydrogen's pretty much still a fossil fuel right now though, so not much cleaner than the methane that much of the industry seems to be pivoting towards.

So would it fall more or less down, or across? Like one big pile of rubble, or a long line of destruction?
Depends which variety of unobtainium you make it out of, and where the break happens, but if it's built out of carbon nanotubes the bits that don't fall outwards would mostly burn in the atmosphere. The lower parts would fall but, with their incredibly low mass per unit area (CNT elevator designs are mostly ribbon-like), probably not destructively. Space Elevators are easier to build on the Moon or Mars, but a collapse would be more destructive there (thin/no atmo and you'd build it out of dyneema which is denser). Of course, a space elevator can't actually hurt anyone because, as Ansible points out, they are presently a fantasy.

I know that methane leads to less engine coking, wouldn't surprise me if it led to substantially less black carbon as well.
Musk's also talking his usual big game about making low/zero carbon Sabatier methane to fly SS/SH on. Orbex, one of the many many small launch startups, are supposedly already doing that for their propane, though they haven't launched anything as yet.

design choices around SLS have been about keeping as many delegations and appropriations committees happy
It's also handy for an ICBM-armed country to be able to amortize solid rocket costs over something that launches a lot.
posted by rhamphorhynchus at 7:58 AM on March 31 [1 favorite]


My concern is that the existence of lower-emissions technologies doesn't signal an emissions transition for the industry. In the 60's and 70's an increasing number of small cars and trucks (Saab, Subaru, etc.) were oil-spewing 2-strokes, even as clean burning fuel injected 4-stroke engines were hitting the market.

If regulation isn't put in place, emissions will be locked into national development programs, like with the SLS and its solid boosters, or all the kerosene Roscosmos rockets and hydrazine CASC and ISRO rockets.
posted by head full of air at 10:07 AM on March 31 [1 favorite]


that's what the moon is for.
posted by clavdivs


Eponhysterical!
posted by doctornemo at 11:51 AM on March 31 [2 favorites]


So would it fall more or less down, or across?

Pretty much, yeah.
posted by ricochet biscuit at 12:27 PM on March 31 [1 favorite]


An argument against space elevators is that they are presently a fantasy.

Well, for a long time Space Force was too. But here we are.
posted by ricochet biscuit at 12:28 PM on March 31 [1 favorite]


well, it has a patch and mandate. if you had a robotic sub orbital space craft wouldn't a laser or EMP pellet gun be added? the Russians had one on thier 20th century spy station and admittedly, defensive.
posted by clavdivs at 2:03 PM on March 31


Regarding space elevators, I cannot see how they can possibly work in light of the very lightly damped longitudinal, lateral, and gyroscopic vibrations modes that would inevitably plague these systems. The amplitudes of these modes will be many kilometers, and I suspect that the ends of these systems would behave like whips.
posted by haiku warrior at 2:50 PM on March 31 [1 favorite]


This is why I want a space escalator.
posted by romanb at 11:41 PM on March 31


This is why I want a space escalator

Space escalator temporarily stairs. Sorry for the convenience.
posted by Literaryhero at 12:30 AM on April 1 [1 favorite]


« Older Crossing Africa and the Sahara by Truck in 1959/60   |   "I don't know, they seem pretty determined to... Newer »


This thread has been archived and is closed to new comments