 The SPS ignited at 69 hours , 8 minutes , and 16 seconds after launch and burned for 4 minutes and 13 seconds , placing the Apollo 8 spacecraft in orbit around the Moon . The crew described the burn as being the longest four minutes of their lives . If the burn had not lasted exactly the correct amount of time , the spacecraft could have ended up in a highly elliptical lunar orbit or even flung off into space . If it lasted too long they could have struck the Moon . After making sure the spacecraft was working , they finally had a chance to look at the Moon , which they would orbit for the next 20 hours . 
