200 1 how did the female astronaut take a picture with a floating pen in her hand during the space roaming?

Stanley kubrick, the director, used the "front projection special effects technology" for the first time in this film, that is, when shooting, an independent projector was used, and a single mirror was placed 45 degrees in front of the camera, and the projector with a 90-degree angle with the camera projected the background picture onto the single mirror, so that when the actors performed in front of the camera, the camera would capture all the actors and background pictures in the camera, further enhancing the realism of the picture. This technology has continued to this day, and it was not gradually replaced until the green screen technology was popularized. Not only that, but the modeling technique in the film is also the peak. It is necessary that the spaceships that travel in space are hand-made models by special effects artists.