Ad Astra director James Gray has said he wanted the movie about searching the galaxy for his missing father to be "the most realistic depiction of space travel that's been put in a movie."
NASA to make the science believable., already , is out on Blu-ray, 4K, and DVD on Tuesday, and in an called "Reach for the Stars," Gray talks about working with
"The exchange of ideas, and where they think things are going -- you want to get the details right," he said. "I've called them up in 2 in the morning and asked, 'Would this actually happen?'"
NASA technical consultant Robert Yowell, a former NASA engineer, also had a few things to say about the science sharing the screen with Brad Pitt.
"What Gray was looking for in terms of realism was the physics," Yowell said in the video. "For instance, 'Could you fire a gun on the moon?' The answer is yes. A bullet has its own oxidizer that comes right out of the barrel."
Another question Yowell tackled for the movie was what blood looks like in space: "Any fluid in spaces in zero gravity will tend to become a sphere."