[jamieplex]

I agree with Jonathan. It seems to be a very low-tech, solid steel ring gear assembled and riveted together from 4 distinct parts. Not very aero-spacey at all...

[cjbgkagh]

What other industries use rivets? Wouldn’t most non-aerospace use welds?

[mapt]

The size and shape alone says either rocketry or a piece of a jet turbine. And lacking any obvious plane crashes nearby...

M-V (Japan) Epsilon (Japan) Athena (US) Rokot (USSR) Soyuz-U (USSR) Soyuz-FG (Russia) Simorgh (Iran) ... many more

There are a comical number of options with parts that have a diameter somewhere in the 2.3-2.7m range.