How Does NASA's Perseverance Rover Take Selfies On Mars?



    The historic photo of the rover next to the Mars Helicopter turned out to be one of the most difficult rover selfies ever shot. 




    The procedure is explained in detail in this video, which also includes additional audio. 





    Have you ever wondered how rovers on Mars snap selfies? 


    NASA's Perseverance rover took the historic April 6, 2021, picture of itself alongside the Ingenuity Mars Helicopter in color video. 

    The sound of the arm's motors spinning was recorded by the rover's entry, descend, and landing microphone as an added bonus. 


    Engineers may use selfies to evaluate the rover's wear and tear. They do, however, inspire a new generation of space aficionados: 


    • Many members of the rover crew may recall a favorite picture that first piqued their interest in NASA. 
    • Vandi Verma, Perseverance's lead engineer for robotic operations at NASA's Jet Propulsion Laboratory in Southern California, stated, "I got into this when I saw a photo from Sojourner, NASA's first Mars rover." 
    • Verma served as a driver for the agency's Opportunity and Curiosity rovers, and she was involved in the first selfie taken by Curiosity on Oct. 31, 2012. 
    • “We had no idea when we snapped that first selfie that these would become so iconic and routine,” she added. 
    • The rover's robotic arm twists and maneuvers to capture the 62 pictures that make up the image, as shown on video from one of Perseverance's navigation cameras. 
    • What it doesn't show is how much effort went into creating the first selfie. Let's take a deeper look. 






    Teamwork. 


    Perseverance's selfie was made possible by a core group of approximately a dozen individuals, including rover drivers, JPL engineers who conducted tests, and camera operations engineers who created the camera sequence, analyzed the pictures, and stitched them together. 


    It took approximately a week to plan out all of the necessary individual instructions. 

    • Everyone was working on “Mars time,” which meant being up in the middle of the night and catching up on sleep throughout the day (a day on Mars is 37 minutes longer than on Earth). 
    • These members of the crew would occasionally forego sleep in order to complete the selfie. JPL collaborated with Malin Space Science Systems (MSSS) in San Diego, which designed and operated the selfie camera. 




    The camera, dubbed WATSON (Wide Angle Topographic Sensor for Operations and eNgineering), is intended for close-up detail pictures of rock textures rather than wide-angle images. 


    • Engineers had to order the rover to snap hundreds of separate pictures to create the selfie since each WATSON image only captures a tiny part of a scene. 
    • Mike Ravine, MSSS's Advanced Projects Manager, stated, "The thing that required the greatest care was putting Ingenuity into the proper position in the selfie." 

    “Considering how tiny it is, I think we did fairly well.” The MSSS image processing experts got to work as soon as the pictures from Mars arrived. 


    • They begin by removing any imperfections produced by dust that has collected on the light sensors of the camera. 
    • They next use software to combine the individual picture frames into a mosaic and smooth out the seams. 
    • Finally, an engineer warps and crops the mosaic to make it seem more like a standard camera picture that the general public is familiar with. 






    Simulations on a computer. 



    Perseverance, like the Curiosity rover (seen taking a selfie in this black-and-white video from March 2020), has a spinning turret at the end of its robotic arm. 


    • The WATSON camera, which remains focused on the rover during selfies while being tilted to record a portion of the landscape, is housed in the turret among other scientific equipment. 
    • The arm serves as a selfie stick in the final result, staying just out of frame. 
    • Perseverance is considerably more difficult to get to video its selfie stick in action than Curiosity. 
    • Perseverance's turret is 30 inches (75 centimeters) wide, compared to Curiosity's 22 inches (55 centimeters). 
    • That's the equivalent of waving a road bike wheel a few millimeters in front of Perseverance's mast, the rover's "head." 
    • JPL developed software to prevent the arm from colliding with the rover. 
    • The engineering team changes the arm trajectory every time a collision is detected in simulations on Earth; the procedure is repeated hundreds of times to ensure the arm motion is safe. 
    • The last instruction sequence brings the robotic arm as near to the rover's body as possible without touching it. 

    Other simulations are performed to verify that the Ingenuity helicopter is properly positioned in the final photo, or that the microphone can catch sound from the robotic arm's motors, for example. 





    Microphone Onboard




    Perseverance has a microphone in its SuperCam instrument in addition to its entrance, descent, and landing microphones. 


    • The microphones are a first for NASA's Mars mission, and audio will be a valuable new tool for rover engineers in the coming years. 
    • It may be used to give crucial information about whether something is functioning properly, among other things. 
    • Engineers used to have to make do with listening to a test rover on Earth. 


    “It's like your car: even if you're not a technician, you may hear an issue before you know there's a problem,” Verma said. 


    The humming engines sound strangely melodic when echoing through the rover's chassis, despite the fact that they haven't heard anything alarming thus yet. 





    More Information about the Mission. 



    • Astrobiology, particularly the hunt for evidence of ancient microbial life, is a major goal for Perseverance's mission on Mars. 
    • The rover will study the planet's geology and climatic history, lay the path for human exploration of Mars, and be the first mission to gather and store Martian rock and regolith (broken rock and dust). 
    • Following NASA missions, in collaboration with the European Space Agency (ESA), spacecraft would be sent to Mars to collect these sealed samples from the surface and return them to Earth for further study. 


    The Mars 2020 Perseverance mission is part of NASA's Moon to Mars exploration strategy, which includes Artemis lunar missions to assist prepare for human exploration of Mars. 


    The Perseverance rover was constructed and is operated by JPL, which is administered for NASA by Caltech in Pasadena, California. 



    For additional information about Perseverance, go to: 

    mars.nasa.gov/mars2020/ 

    nasa.gov/perseverance


    Courtesy: NASA.gov


    ~ Jai Krishna Ponnappan

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