Re:The Kessler Syndrome: Space junk in orbit
by modeless on Sunday November 21, 2021 @06:11PM
(#29300727)
These satellites are designed to fully burn up on reentry, so no solid debris reaches the ground. Meanwhile, many tons of space dust burn up in the atmosphere every day, and meteors large enough to hit the ground happen multiple times a day on average as well.
Space dust contains plenty of things that are more hazardous than anything in these satellites. According to [1] the abundances on this page multiplied by [2] 40000 tons per year, the stuff naturally hitting the atmosphere each year includes 0.3 kg uranium, 1.6 kg thorium, 3 kg radioactive isotopes of potassium, 10 kg mercury, 18 kg cadmium, 50 kg lead, 72 kg arsenic, and 120 tons of chromium, among other things. This stuff burns up in the atmosphere all day long, and has for billions of years.
As far as emissions, one Falcon 9 launch emits 300 tons of CO2 and they've been launching one or two times per month to build out the Starlink constellation. Meanwhile commercial aviation emits 2 million tons per day and is still a small fraction of the world total.
Space dust contains plenty of things that are more hazardous than anything in these satellites. According to [1] the abundances on this page multiplied by [2] 40000 tons per year, the stuff naturally hitting the atmosphere each year includes 0.3 kg uranium, 1.6 kg thorium, 3 kg radioactive isotopes of potassium, 10 kg mercury, 18 kg cadmium, 50 kg lead, 72 kg arsenic, and 120 tons of chromium, among other things. This stuff burns up in the atmosphere all day long, and has for billions of years.
As far as emissions, one Falcon 9 launch emits 300 tons of CO2 and they've been launching one or two times per month to build out the Starlink constellation. Meanwhile commercial aviation emits 2 million tons per day and is still a small fraction of the world total.
[1] https://periodictable.com/Properties/A/MeteoriteAbundance.v....
[2] https://link.springer.com/chapter/10.1007%2F978-1-4419-8694-...