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Naive eh? What "nasty things" do you think are released into "every layer of atmosphere"? Since we're specifically talking about SpaceX and Starlink, let's tal

by zizee 4y ago

Naive eh? What "nasty things" do you think are released into "every layer of atmosphere"? Since we're specifically talking about SpaceX and Starlink, let's talk about Falcon and StarShip rockets. Let's look at the "long list of very nasty things". Falcon 9 is expecting to launch a record number of flights this year, recent reports suggesting 52. Falcon 9 burns RP1 (a refined kerosene, very similar to jet fuel), a hydrocarbon that mostly produces CO2 when burnt, but also Carbon monoxide, and plain old carbon. The Falcon 9 has about 200k litres of fuel when fully loaded. It sounds like a lot, but for perspective a fully loaded Airbus A380 has a fuel capacity of 380k litres. So, they output of a record breaking year will be the equivalent of around 25 long distance flights of a large passenger aircraft. I'm not going to find out how many long distance large plan flights are happening, but many estimates are over 100k a day. So a record breaking year outputs a fraction of a percentage that airline flights do each hour. And the "nasty" stuff is mostly CO2, CO, and C. Starship will burn Methane, and will burn even cleaner than Falcon 9. It will also be fully reusable, resulting in less waste again. On the downside, methane is a potent greenhouse gas, so any unburt fuel would be not great. That said, rockets are designed to make the most efficient of fuel, and any unburt fuel is not going to be released in normal operation. > I'm no rocket engineer Colour me shocked! As for going through "every layer" of the atmosphere, I wouldn't get too worried about that. A lot of a rocket's fuel is burnt at lower altitudes (the same level at which passenger and military Jets operate) and the various zone mix readily, and are really so massive that you would have trouble measuring the impact of hundreds to thousands of flights of Starship per year. https://space.stackexchange.com/questions/13082/calculate-falcon-9-co2-emissions https://space.stackexchange.com/questions/13082/calculate-fa... https://www.sciencefocus.com/space/what-is-the-environmental-impact-of-the-spacex-falcon-heavy-launch/ https://www.sciencefocus.com/space/what-is-the-environmental... https://www.sciencefocus.com/space/what-is-the-environmental-impact-of-the-spacex-falcon-heavy-launch/ https://www.sciencefocus.com/space/what-is-the-environmental... https://space.stackexchange.com/questions/32002/what-percentage-of-overall-fuel-does-a-rocket-burn-up-to-get-to-max-q https://space.stackexchange.com/questions/32002/what-percent...

lm28469 4y ago
They specifically talk about falcon engines here: https://www.space.com/rocket-exhaust-pollution-upper-atmosphere https://www.space.com/rocket-exhaust-pollution-upper-atmosph... https://www.sciencedaily.com/releases/2022/05/220517112210.htm https://www.sciencedaily.com/releases/2022/05/220517112210.h... Anyways, "just one more car", "just one more plane", "just one more coal plant", "just want more launch", "it's not that much worse, just a tiny bit" https://sdup.esoc.esa.int/discosweb/statistics/static/PLtrafficMissionLEO.png https://sdup.esoc.esa.int/discosweb/statistics/static/PLtraf... https://www.eesi.org/images/content/World_Passenger_Traffic_Evolution_-_1945-2022_(Courtesy_ICAO).png https://www.eesi.org/images/content/World_Passenger_Traffic_...
- zizee 4y ago
  From your links: > When it comes to greenhouse gasses alone, the contribution of rocket launches is rather negligible, accounting for only 1% of aviation's carbon footprint — which in itself only amounts to 2.4% of annual global carbon emissions, according to the Environmental and Energy Study Institute Apart from the fact they overinflated the impact to 1% (there is no way it is close to 1%) there is a reason they chose the adjective "negligible" to describe the impact. > Eventually, the circulation of the atmosphere dissipates those greenhouse gases and brings the concentrations back to "standard" levels. It is, however, unknown how long the concentrations remain elevated and what their impact on the temperature of the mesosphere could be. Reality is that these scientists did a simulation, got some results that can be made to sound alarming, but just don't know if these is any inpact. I'm all for studying this more to see if there is a real issue. My gut says it's not going to be a problem until we have at least a couplr of orders of magnitude increase in launches, but it's worth looking at it further. And I'm not sure why you included the graph of objects in orbit? This looks exciting, but it really is just that companies are now launching clusters of smaller satellites. The good news is that these tend to deorbit in under ten years. Unlike practices of old, this new style of satellite will not result in long lasting space junk. Finally, what is the point of including a graph of airline flights over time? What bearing does it have on rocket launches?

by zizee 4y ago

lm28469 4y ago

They specifically talk about falcon engines here: https://www.space.com/rocket-exhaust-pollution-upper-atmosphere https://www.space.com/rocket-exhaust-pollution-upper-atmosph... https://www.sciencedaily.com/releases/2022/05/220517112210.htm https://www.sciencedaily.com/releases/2022/05/220517112210.h... Anyways, "just one more car", "just one more plane", "just one more coal plant", "just want more launch", "it's not that much worse, just a tiny bit" https://sdup.esoc.esa.int/discosweb/statistics/static/PLtrafficMissionLEO.png https://sdup.esoc.esa.int/discosweb/statistics/static/PLtraf... https://www.eesi.org/images/content/World_Passenger_Traffic_Evolution_-_1945-2022_(Courtesy_ICAO).png https://www.eesi.org/images/content/World_Passenger_Traffic_...

zizee 4y ago
From your links: > When it comes to greenhouse gasses alone, the contribution of rocket launches is rather negligible, accounting for only 1% of aviation's carbon footprint — which in itself only amounts to 2.4% of annual global carbon emissions, according to the Environmental and Energy Study Institute Apart from the fact they overinflated the impact to 1% (there is no way it is close to 1%) there is a reason they chose the adjective "negligible" to describe the impact. > Eventually, the circulation of the atmosphere dissipates those greenhouse gases and brings the concentrations back to "standard" levels. It is, however, unknown how long the concentrations remain elevated and what their impact on the temperature of the mesosphere could be. Reality is that these scientists did a simulation, got some results that can be made to sound alarming, but just don't know if these is any inpact. I'm all for studying this more to see if there is a real issue. My gut says it's not going to be a problem until we have at least a couplr of orders of magnitude increase in launches, but it's worth looking at it further. And I'm not sure why you included the graph of objects in orbit? This looks exciting, but it really is just that companies are now launching clusters of smaller satellites. The good news is that these tend to deorbit in under ten years. Unlike practices of old, this new style of satellite will not result in long lasting space junk. Finally, what is the point of including a graph of airline flights over time? What bearing does it have on rocket launches?