Aerospace aluminum isn't as easily recycled as beer cans.
If you're building a space ship you have very tight tolerances and specifics needed for the alloying of the metals you use. The aluminum in aircraft is full of strange things that need to be removed for general use aluminum and definitely need to be removed for building new aircraft.
You're right that melting and re-casting aluminum is really cheap and efficient for beer cans, it's not so much the same for aerospace aluminum.
When it comes down to spaceships, the energy used to produce them is usually a very small portion of the total cost of the mission and we don't make very many of them – recycling isn't and shouldn't be a priority.
The Falcon 9 burns 110,000 liters of kerosene every launch, if it were made of carbon fiber, maybe it wouldn't matter how the structure was disposed.
I never thought about it but I became curious as to what the differences are, here's what I was able to find:
[0] Aircraft grade aluminum alloy's composition roughly includes 5.6–6.1% zinc, 2.1–2.5% magnesium, 1.2–1.6% copper, and less than a half percent of silicon, iron, manganese, titanium, chromium, and other metals.
[1] Aluminum cans are typically 1% magnesium, 1% manganese, 0.4% iron, 0.2% silicon, and 0.15% copper.
There are a lot of metrics that determine the appropriate use of various grades of aircraft level alloys [2]. I guess from the outside some big considerations are how the metal reacts to temperature change and how well a metal cylinder can handle stress while staying light.
>how well a metal cylinder can handle stress while staying light.
Are we talking beer cans or rockets? Maybe they are the same after all :)
All spot on. There are lots of alloys used for lots of different things and economics and availability play their part too. When you're designing your airplane every slight detail matters.
If you're building a space ship you have very tight tolerances and specifics needed for the alloying of the metals you use. The aluminum in aircraft is full of strange things that need to be removed for general use aluminum and definitely need to be removed for building new aircraft.
You're right that melting and re-casting aluminum is really cheap and efficient for beer cans, it's not so much the same for aerospace aluminum.
When it comes down to spaceships, the energy used to produce them is usually a very small portion of the total cost of the mission and we don't make very many of them – recycling isn't and shouldn't be a priority.
The Falcon 9 burns 110,000 liters of kerosene every launch, if it were made of carbon fiber, maybe it wouldn't matter how the structure was disposed.