Back when NASA released Curiosity’s first self-portrait from the surface of Mars, there was a surprisingly large number of people who doubted the veracity of the image. Most of these doubts revolved around the 7-foot robotic arm that captured the photo, but which isn’t actually visible. As with the Moon landing photos, there were conspiracy theorists who claimed that the self-portrait was actually shot here on Earth. “It’s impossible to shoot a photo and not have your arm visible,” the tinfoil-hat-wearing fruitcakes decried. “A third party must’ve taken the photo… or it’s CGI!”

NASA, which is rightfully rather proud of its ability to land a one-ton rover on another planet after a 352-million-mile journey, seemingly took these attacks to heart and has now published information about how the self-portrait was taken.

As we originally reported, the self-portrait is a mosaic of 55 images captured by the Mars Hand Lens Imager (MAHLI), which sits on the end of Curiosity’s 7-foot robotic arm. These 55 images were taken in such a way that the arm was mostly out of shot — and where that wasn’t possible, data from other images (other angles) was used to fill in the gaps.

As you can see in the animation above, the moves that MAHLI makes as it traverses Curiosity are very exact. According to National Geographic, these movements were planned out last year by none other than James Cameron, and Michael Malin and Michael Ravine of MSSS, the company that manufactured Curiosity’s cameras. “Actually, there weren’t that many images with the arm in them because of how we positioned the arm,” Ravine explains. “It’s like if you hold a camera out in front of you with your elbow crooked and shoot—what you’ll probably get is your face and top of your body including your shoulder, but most of your arm is out of the frame.”

The exact movements to shoot all 55 images were then programmed into NASA’s Rover Sequencing and Visualization Program (RSVP), and then tested on the Curiosity’s stunt double — the Vehicle System Test Bed at the Jet Propulsion Lab in Pasadena (pictured above). Before trying out new maneuvers, just as an extra precaution, NASA generally tests them on the VSTB first. Finally, to take the actual self-portrait on Mars, NASA simply presses “play” in RSVP, transmitting the commands to NASA’s Deep Space Network antennae, which squirts them across 200 million miles of deep space to the rover.

In other news, Curiosity has now reached the region of Glenelg, and is powering along to Yellowknife Bay, where the rover will hopefully try out its percussive hammer for the first time (by drilling into an interesting rock). The photo below was taken at Shaler, where Curiosity briefly stopped to take some photos and other scientific measurements. Curiosity will likely spend a few weeks/months in the Glenelg region before turning south to Mount Sharp — the final destination of the rover’s primary mission.