Is it just marketing or is there an actual structural difference?
In: 807
I build space mechanisms for a living.
90% are just 6061-T651 which is the same aluminum used everywhere. I recall back in the day advertising started to say 6061-T6 was “aircraft aluminum” (I recall that Mag-lite started this but who knows) and I feel like saying “space-grade” is now just a form of one-upping.
There ARE stronger aluminum alloys than 6061, like 7075 which is nearly as strong as some steels. We use that where required but the range of sizes the raw stock is available in is limited compared to 6061, so it’s rarely a starting point.
We also use uncommon aluminums like 1100 series, which I have no idea if any other industries use. 1100 is nearly “pure” aluminum so it’s terrible to machine and the strength is awful. But the thermal conductivity is excellent and it’s much lighter than copper, so it makes sense for thermal control devices on spacecraft… sometimes.
It’s worth mentioning that there IS such a thing as space-grade aluminum foil. UHV foil (ultra high vacuum) is made without the oil residue from the foil rolling process that is present on industrial and food grade foils. Oils in space vaporize and settle on sensors and instruments potentially causing problems. There is an anecdote from an old space program (Voyager maybe?) about not having enough UHV foil and being forced to use some from the grocery store… guess it worked out!
Edit: thinking on this I don’t want to send the wrong message… just because “space aluminum” is the same alloy doesnt mean that we can buy raw material from McMaster and be on our way (in fact we can’t buy from McMaster except in special cases). Aluminum for space use needs to come with a wide array of test data and certifications that confirm its acceptability. Mill cert., Material assay (composition), tensile testing cert., ultrasonic flaw inspection etc are some examples.
Latest Answers