https://cdnph.upi.com/ph/st/th/8051786591871/2026/upi/41fa9feeb32d1d8610f777ee919da642/v1.5/After-30-years-of-service-NASA-astronaut-Mike-Fincke-retires.jpg" /> Astronaut Mike Fincke announced he was retiring Wednesday following 30 years of service and 549 days in space, the fourth most among NASA astronauts.