Continuity mistake: When Katherine is working out the math in the conference room for John Glenn's start off to the Bahamas there is no chalk or pencils on the desk, but they reappear when Al Harrison hands Katherine the chalk. (01:23:40)
Continuity mistake: When Katherine realises she can use Euler's Method to calculate how to bring John Glenn safely back to earth, she is seen wearing a wristwatch when she's at the chalkboard. The watch is not on her when she leaves to get a book about Euler's Method. It reappears when she's back at the chalkboard.
Continuity mistake: In a scene where Katherine is writing on the big chalkboard, calculating the reentry spot (or something similar) for Friendship 7, her left hand is shown with an engagement ring. Her boyfriend doesn't propose until after this scene. You only see it for a second.
Continuity mistake: In the beginning of the movie when the car is broken down you can see either a whole bunch of cows are in the field through the passenger window. When Dorothy starts the car with the screwdriver the cows are gone. (00:03:10 - 00:05:54)
Continuity mistake: When John Glenn is attempting re entry, Dorothy Vaughn is driving out to the beach/country and she stops the car near a barn where there is a dark and creamy two tone car parked. The scene cuts straight back to the city to see the other girls watching re entry and the exact same two tone car is parked on the side of the road.
Continuity mistake: When Atlas is launched, Catherine stands in the control room next to the person who has radio contact with Glen. There are three different takes from the same camera angle, and in the last one, Catherine is not standing next to the radio person. It's only a few seconds apart. (01:44:02)
Continuity mistake: In the final scene between Harrison and Katherine. Her pearl necklace starts tucked into her dress, then out while she says "You too, Mr. Harrison", and then back in. (01:56:36)
Continuity mistake: After Katherine grabs the book with Euler's Method she writes a formula on the board and puts a circle around it. The circle changes shape between shots.
Continuity mistake: In the scene in the briefing room, some of the calculations on the blackboard change writing styles between shots, such as brackets moving closer to numbers.
Continuity mistake: In the last scene in which Vivian gives Dorothy an assignment, her lanyard is at first hanging neatly from her neck. The camera goes back and forth between her and Dorothy, and when you last see Vivian, the ball chain for the lanyard is no longer hanging neatly; it is pulled to the side because it's caught on her jacket lapel.
Continuity mistake: When Katherine is putting her 3 children to bed the child to the left has the blanket down to her chest when Katherine is shot from behind. When she is shot from the front the blanket has moved to cover the girl's shoulder. This repeats at least three times in the scene.
