How Did Perseverance Rover Take a Selfie on Mars? NASA Explains Process

NASA's Perseverance rover recently captured a historic photo with the Ingenuity helicopter on Mars. Perseverance's out-of-this-world selfie has now been revealed in part by the Jet Propulsion Laboratory at the California Institute of Technology.

Taking a selfie is as simple as holding a camera out at arm's length, pointing, and pressing the button. That selfie, on the other hand, is a multi-step process for a robot on another planet.

The Perseverance selfie is made up of 62 individual photographs shot by the rover's WATSON camera one at a time. JPL said, per Phys.org, the camera is mainly designed for taking close-up detail photographs of rock textures, not wide-angle images.

A robotic arm twisted and manipulated the WATSON camera around to gain a comprehensive view of the rover, the Ingenuity chopper, and their Martian environs - all based on commands supplied by NASA scientists - to combine the tiny photos into one larger image.

JPL said the robotic arm on which the WATSON camera is mounted that acts as a selfie stick. Because so many shots are combined to form one final result, the arm ends up "just out of frame."

According to JPL, a core team of "approximately a dozen people" was responsible for planning, testing, and implementing the process. Engineers conducting testing at JPL, rover drivers, and camera operations engineers "designed the camera sequence, processed the photos, and stitched them together" were among the crew members.

Team Took Time to Plot Commands for Rover

JPL said plotting the various commands involved took about a week.

That week was also on "Mars time," which corresponded to a planet with a day 37 minutes longer than Earth's. To get the Perseverance selfie together, the team would frequently stay up late at night and sleep in the middle of the day, resulting in interplanetary jetlag.

Mike Ravine, Advanced Projects Manager at Malin Space Science Systems in San Diego, said per CNET, the team exerted most time and effort in placing Ingenuity into the right spot in the selfie.

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MSSS image processing engineers stitched the photographs together after each individual image returned to Earth after being broadcast from Mars. The engineers "assemble the individual image frames into a mosaic and smooth out their seams using software," so they all look like one larger photo, after wiping away "blemishes created by dust that gathered on the camera's light detector."

While Perseverance's photo is significant in its own right, it is not the first selfie taken by a rover from another planet. The Curiosity rover achieved this feat on Oct. 31, 2012, when it shot a black-and-white image of itself from the surface of Mars.

"When we took that first selfie, we didn't realize these would become so iconic and routine," said Vandi Verma, Perseverance's chief engineer for robotic operations at JPL, in a statement from the lab.

In addition to her more recent work on the Perseverance selfie, Verma assisted in creating the first Curiosity selfie as a driver for the Opportunity and Curiosity rovers.

Perseverance Rover Had to Develop Algorithm that Avoids Collision

According to JPL, the Perseverance shot was more challenging to take since the "selfie stick" turret on Perseverance is 30 inches long, significantly longer than Curiosity's 22-inch turret. During the selfie process, JPL had to develop specific algorithms to avoid collisions between the robotic arm and the rover itself, which are only "centimeters" apart.

The software's instruction sequence takes the arm "as close as we could go to the rover's body without touching it," according to Verma.

Because the Perseverance rover is the first ship to send microphones to Mars, the selfie is also accompanied by sound.

An entry, descent, and landing microphone, as well as a microphone linked to the rover's SuperCam sensor, are all carried by the rover. Part of their mission is to assist scientists in identifying any issues that may have arisen on Mars.

However, a robotic buzzing noise that accompanies Perseverance's selfie is a side effect of the microphones, which Verma described as "musical, like a flute" when the pitch fluctuates.

The end result is a stunning image of two spacecraft on their way to investigate another planet's geology and previous climate.

"When we took that first selfie, we didn't realize these would become so iconic and routine," said Verma per NDTV.