I implemented various pieces of flight software for the Cargo Dragon space capsule, and to a lesser extent the Falcon 9 rocket. I got to be on a mission control shift for the C2 mission that first berthed with the International Space Station. Some of the software framework I wrote back then ended up getting used in Starlink despite having never worked on it directly, so I can say I have code orbiting the Earth on several thousand satellites.

I've spent the last 6-7 years making autonomous aircraft that deliver medical supplies in various African countries. Probably a hundred thousand deliveries or so have been for emergency blood transfusions, typically for women that hemorrhaged during labor. So that's got to be quite a few lives/families saved!