Why does it take so long for spacecraft to become fully operational nowadays?

[JakeWIlls92]

This video is from 2014!



And it took until 2020 to make it's first crewed flight!

Why does it take so long to develop spacecraft nowadays?

 

[MarathonMike]

Testing requirements for space qualified hardware and software is insane.

 

[occupied]

I remember someone on some documentary explaining that rocket parts have to be machined and polished to such a degree that they will work without lubrication across hundreds of degrees of temperature variation. It seems grease does not not work in the vacuum of space. That has to take a long time.

 

[fncceo]

It's not about time ... it's about ...