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Comment by lolc | Hacker News Reader

I for one would like to see the satellites modified with a heat shield so they could punch through and hit a designated deorbit zone. I would even offer my backyard, but I fear it's too small.

Wouldn't that be the ultimate tourist attraction? "Witness the next deorbit round tomorrow at Crater Park Observatory!"

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they kinda already do, there's a place called the spaceship graveyard where de-orbiting craft target to avoid collisions with inhabited areas

https://en.wikipedia.org/wiki/Spacecraft_cemetery

I've often wondered if you could take out a boat there to see a particularly impressive de-orbit. Maybe when they do the ISS, which is scheduled to go there eventually.

There have been cases where craft ended up in inhabited areas. iirc one hit australia and upset some people a few years ago?

I remember watching a video of people on a boat waiting for the fireworks of a satellite overhead.

Disney corp could even pay to have regularly scheduled "shooting stars" over their parks.

I've thought about the idea of launching a whole payload full of sand and marbles in a way that produces a show like that over a wide area. But now it's getting nearly impossible with so many satellites up there.

Wouldn't that be some form of kinetic orbital bombardment. Not sure that you want to have this in your backyard.

Why not use this energy for mining? What is the terminal velocity anyhow?

I'm sure I want it. Unfortunately my house is too close to the center of my backyard.

My neighbours are too close too. Any stray parts would cut into the proceeds of ticket sales to the bunker at the center where you can watch live streams of the parcels hitting on top of you.

It wouldn't. Small objects, like satellites, decelerate to terminal velocity. The impact of one of those would be the same as if they fell from an aeroplane.

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.

> 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.

>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.

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.

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.

>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-i...

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