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Nifty idea. But don’t satellites have toxic components? While most of it will be burnt up some bits get to the ground. Satellites are made from material, and

Nifty idea. But don’t satellites have toxic components? While most of it will be burnt up some bits get to the ground. Satellites are made from material, and can’t be safely disassembled. Rentry is uncontrolled incineration, depending on a large part of the pollutants being diluted across the sky, and the ground and water on which they fall. Background levels would rise.

mlindner 3y ago
> But don’t satellites have toxic components? That depends on how you define "toxic". If you mean toxic fuels, most do not. However the idea is just terribly impracticable. Heat shields are heavy and more than that you would need to design your satellite around the heat shield. It would need to be able to fold up like origami into the heat shield. You also need to add extra fuel to perform the targed re-entry. This whole idea is bad.
- colechristensen 3y ago
  >If you mean toxic fuels, most do not. Hydrazine is quite common and quite toxic, of the "seek medical attention immediately" variety. 1 ppm is a threshold for exposure for a few hours, satellites can launch with hundreds of pounds of the stuff. A crashed satellite would not be safe to be around, you might get liver failure if you go poking around one and get a good ammonia-like whiff of hydrazine.
  - mlindner 3y ago
    Hydrazine is certainly on some satellites, but by numbers of satellites launched and by mass of satellites launched hydrazine is not on a minority of them. Most satellites being launched by mass and number are now Starlink satellites which don't have hydrazine. Even then, the second largest category of satellites is smallsats and cubesats which often have no propulsion at all or use cold gas.
Zigurd 3y ago
The semiconductors in satellites do have some toxic elements that would be released from otherwise inert conditions on burning up on reentry. but that's orders of magnitude less than what's put into the atmosphere from burning coal and gas. Coal contains lots of stuff other than carbon.
MPSimmons 3y ago
>While most of it will be burnt up some bits get to the ground Starlink satellites are designed to be fully demised, which means that _nothing_ gets to the ground. https://spectrum.ieee.org/spacex-claims-to-have-redesigned-its-starlink-satellites-to-eliminate-casualty-risks https://spectrum.ieee.org/spacex-claims-to-have-redesigned-i...

mlindner 3y ago

> But don’t satellites have toxic components? That depends on how you define "toxic". If you mean toxic fuels, most do not. However the idea is just terribly impracticable. Heat shields are heavy and more than that you would need to design your satellite around the heat shield. It would need to be able to fold up like origami into the heat shield. You also need to add extra fuel to perform the targed re-entry. This whole idea is bad.

colechristensen 3y ago
>If you mean toxic fuels, most do not. Hydrazine is quite common and quite toxic, of the "seek medical attention immediately" variety. 1 ppm is a threshold for exposure for a few hours, satellites can launch with hundreds of pounds of the stuff. A crashed satellite would not be safe to be around, you might get liver failure if you go poking around one and get a good ammonia-like whiff of hydrazine.
- mlindner 3y ago
  Hydrazine is certainly on some satellites, but by numbers of satellites launched and by mass of satellites launched hydrazine is not on a minority of them. Most satellites being launched by mass and number are now Starlink satellites which don't have hydrazine. Even then, the second largest category of satellites is smallsats and cubesats which often have no propulsion at all or use cold gas.

Zigurd 3y ago

The semiconductors in satellites do have some toxic elements that would be released from otherwise inert conditions on burning up on reentry. but that's orders of magnitude less than what's put into the atmosphere from burning coal and gas. Coal contains lots of stuff other than carbon.

MPSimmons 3y ago

>While most of it will be burnt up some bits get to the ground Starlink satellites are designed to be fully demised, which means that _nothing_ gets to the ground. https://spectrum.ieee.org/spacex-claims-to-have-redesigned-its-starlink-satellites-to-eliminate-casualty-risks https://spectrum.ieee.org/spacex-claims-to-have-redesigned-i...