HEY! Let's utterly screw over the ozone layer!

[thewayne]

Of the over 8,100 objects in low Earth orbit, 6,000+ are STARLINK SATELLITES. WITH AN ESTIMATED LIFE OF APPROX FIVE YEARS BEFORE THEY DEORBIT AND BURN UP IN THE ATMOSPHERE.

And what happens when they burn? Well, they're composed of lots of aluminum oxide, and aluminum oxide when it burns in the upper atmosphere, say, during reentry, causes a chemical reaction that destroys ozone.

*facepalm*

So Mister 'Colonize Mars Because We Need To Get Off The Earth' is hastening the rate at which the Earth is getting damaged! YAAAAY!

And the Muskbrat has permission to launch another 12,000 satellites with something like 41,000 planned. And Amazon has to have IT'S OWN satellite cloud.

I'm sure the greatly increased pace of rocket launches is also doing all sorts of good to the atmosphere.

https://phys.org/news/2024-06-satellite-megaconstellations-jeopardize-recovery-ozone.html

https://news.slashdot.org/story/24/06/18/2142237/satellite-megaconstellations-may-jeopardize-recovery-of-ozone-hole

Comments

[thewayne]

THAT is a very interesting concept!  What's the relative availability of titanium?  I know aluminum is relatively available.

[armiphlage]

Titanium's really energy-intensive to refine from rutile sand, so although the ore isn't that rare, the metal is about $5 per kilogram. Aluminum is a bit over $2 per kilogram.

A Falcon Heavy can launch a satellite at a cost of $1500 per kilogram.

If you use titanium rather than aluminum, you can get the same strength for about 15% less mass.

So, a 250-kilogram satellite with 30% of its mass being aluminum would have 75 kg of metal.
That'd be $150 of metal, costing $112,500 to launch.

Redesigning to use titanium would use 64 kg of metal costing $320, with $96,000 to launch. So, theoretically there'd be a net savings in switching from ozone-harming aluminum to titanium.

Of course, in real life these estimates are worthless. Nobody would use pure aluminum or titanium in a satellite, as both metals are relatively soft in pure form. Designers would use specialty alloys to get optimal properties, with vastly higher costs. It costs more to machine and weld titanium. Titanium has worse heat transfer and electrical conductivity properties, so instead of using structural elements as heatsinks and ground paths, you'd need to add separate heatsinks and grounding wires to the design. Radiation hardness calculations for electronic components assume aluminum shielding, meaning you'd have to pay more for component screening houses to custom-test your components when surrounded by titanium, to confirm cosmic rays and solar storms won't either temporarily overwrite random bits of memory (corrupting software and data), or permanently damage the silicon dies in your electronics.