Sherwood Clark Spring (born September 3, 1944) is a retired United States Army colonel and former NASA astronaut. Spring is married with two children. He is the father of United States Olympian Justin Spring. Sherwood Spring has logged 165 hours in space, 12 of which were spent conducting spacewalks. Spring has also accumulated 3,500 hours in 25 different military and civilian aircraft; over 1,500 of those hours were spent in jet aircraft.