In the Book
In the Movie
There were several problems with Glenn's flight, but this was not one of them. When Glenn was launched into orbit he was scheduled for 4 orbits, but extended to 7 due to the favorable launch. Problem with the attitude control system and a faulty heat shield indication led to the decision to fire the retro rockets after the third orbit; the retro rocket package would be left in place to hold the heat shield on in case it was actually loose.
There is a problem with Glenn's orbit as the computer numbers don't match Katherine's anymore. She does some calculations to verify which set of numbers is correct.
Dorothy Vaughan was not involved in the programming for Mercury, but did assist with programming on Mercury-Scout in 1961.
Mercury-Scout is not shown in the movie.
Glenn's landing was off by 40 miles due to an incorrect capsule re-entry weight data entry.
Katherine claimed Glenn would land within 20 miles of the desired spot in the ocean and he did do so.
Of the black employees working in research at Langley, only 5 were engineers and 16 titled as mathematicians. Floyd Thompson wrote to James Webb lamenting that “very few Negroes” were applying for science and engineering positions at Langley due to the segregated nature of the surrounding community.
Not addressed in the movie.
Joh Glen is around 40 at take-off
John Glen is around 25 at take-off