NASA astronauts churn out perfectly framed time-lapses, beautifully sharp photographs and stunning videos daily. Scrolling through the Instagram pictures, tweets and Facebook posts coming out of the International Space Station, you get the impression that the floating research station is staffed with professional photographers. And it kind of is.

“Apart from everything else an astronaut does on orbit, photography is actually part of our job,” NASA astronaut Don Pettit revealed to Smug Mug Films. Or, as Petit put it, “I’m Don Petit. I’m a photographer — and an astronaut.”

Photography has been part of NASA since the early space missions of the 1960s, when astronauts first started snapping photos from miles above Earth’s atmosphere. The iconic “Blue Marble”  — the first full view of Earth from space — ushered in a new appreciation for space photography in 1972, and space explorers since have been honing their artistic eye in between rigorous physical training, flight readiness tests, scientific study and dozens of other tasks.

For the teaching process once the Space Shuttle Program began in the early 1980s, NASA used a 1984 manual from Hasselblad, a camera manufacturer. Its 36 pages are stuffed with diagrams and instructions that start with basics like how to change batteries and minimize camera shaking, and escalate to describe when to use various lenses and how to frame different subjects. The guidebook promises that “it not only describes the operation of the Hasselblad 500 EL/M cameras used on the U. S. Space Shuttle but is also a concise manual on photography to assist astronauts in creating the best possible space photographs.”

Since the arrival of digital photography, NASA brought in photo/TV trainers who are now responsible for choosing camera hardware, providing ground support for orbiting missions and teaching space-bound NASA crew members.

The ISS and the spacecraft that get astronauts there are equipped with state-of-the-art photo equipment. They can livestream and capture 4K ultra high-definition video. But for astronauts with required degrees in engineering, biological science, mathematics or physical science, words like “f-stop,” “shutter speed” and “atmospheric air glow images,” can seem like a whole other language. And they already have to learn an actual foreign language — to graduate from NASA’s Astronaut Candidate Program, astronauts must complete Russian language training.

“Astronaut imagery of Earth is an example of learning what you need to take pictures of and how to take the pictures,” said Pettit, who became a prolific photographer during his two long-duration stays aboard the ISS.

And how to take those pictures in space is incredibly complex. Certain camera components, like the flash, have to be modified to work in a vacuum. The cameras need to be steadied extremely carefully to avoid motion blur. And there are certain times when astronauts are wearing bulky spacesuit gloves while taking pictures.

“Things don’t work the way they do down here on Earth. You are moving at eight kilometers a second,” Pettit explained. “And so you have to be able to slew the camera at the same rate of orbital motion while you’re taking pictures to actually get the sharpest imagery.”

Certain astronauts develop more of an affinity for photography than others. NASA astronaut and current ISS resident Jeff Williams has been described as a “photo nut.” He took about 100,000 pictures during his 6-month stay on the orbiting lab in 2006, and looks like he’s aiming to top that during his ongoing mission. Now-retired NASA astronaut Scott Kelly became Twitter-famous with his sweeping views of Earth during his nearly year in space.

Astronaut Scott Kelly spent 340 days aboard the International Space Station, longer than any American astronaut. Here's a look at the year he spent in space. (Victoria Walker/The Washington Post)

By 2010, NASA astronauts had taken roughly 900,000 images from space. And they’re not only Instagram-worthy — they create a scientific dataset over time, and also provide important feedback to ground crews working to keep astronauts safe. And perhaps most crucially, they create a connection between all of us back on the “Blue Marble” and the astronauts floating above it.

“When you explore a frontier, the people who explore bring back images and bring back stories about what these frontiers are like,” Pettit said. “I feel an obligation to share this experience so that everybody else can at least participate through the eyes of the people who do go into the frontiers.”