So you'll often build two or three test versions of the sat that you subject to serious, and sometimes destructive, testing to simuluate launch stresses, etc. S

So you'll often build two or three test versions of the sat that you subject to serious, and sometimes destructive, testing to simuluate launch stresses, etc. So if a given satellite blows up on the pad, they can use these test articles as a backup. So they don't really start from scratch..