• NASA's Perseverance rover will land on Mars this week

    From alexander koryagin@2:5075/128.130 to All on Mon Feb 15 15:07:02 2021
    Hi, All!

    -----Beginning of the citation-----
    NASA's Perseverance rover will land on Mars this week.

    By Ashley Strickland, CNN

    (CNN)Perseverance, NASA's most sophisticated rover to date, is expected
    to land on the surface of Mars on Thursday, February 18, around 3:55
    p.m. ET.

    The rover has been traveling through space since launching from Cape Canaveral, Florida, at the end of July. When it reaches Mars,
    Perseverance will have traveled 292.5 million miles on its journey from

    Perseverance is NASA's first mission that will search for signs of
    ancient life on another planet to help answer the big question: Was life
    ever present on Mars? The rover will explore Jezero Crater, the site of
    an ancient lake that existed 3.9 billion years ago, and search for microfossils in the rocks and soil there.

    Along for the ride with Perseverance is an experiment to fly a
    helicopter, called Ingenuity, on another planet for the first time.
    Here's what to expect this week.

    How to watch

    NASA is inviting the world to tune in to its countdown and landing
    commentary, which will stream live beginning on Thursday at 2:15 p.m.
    ET. Tune in via NASA's public TV channel, website, app, YouTube,
    Twitter, Facebook, LinkedIn, Twitch, Daily Motion or THETA.TV. In a
    first, the agency will also offer a Spanish language show for the landing.

    During the landing coverage, NASA's mission control team will be able to confirm if the rover safely landed on the surface of Mars.

    Naturally, the rover has its own Twitter and Facebook accounts, where
    you can expect updates from the mission team from the perspective of the rover. And you can bet the Curiosity rover and InSight lander will be welcoming Perseverance to their home, the red planet.

    The agency has fun ways to participate in the countdown excitement, like
    photo booths and activities for kids and students. You can also follow
    every step of the rover's landing through a NASA interactive.

    "If there's one thing we know, it's that landing on Mars is never easy,"
    said Marc Etkind, NASA associate administrator for communications, in a statement. "But as NASA's fifth Mars rover, Perseverance has an
    extraordinary engineering pedigree and mission team."

    Just weeks after the landing, if all goes according to plan, cameras and microphones on the spacecraft will show the rover's perspective for the
    first time.

    Landing on Mars: '7 minutes of terror'

    If successful, Perseverance will be NASA's ninth landing on Mars. First,
    it has to go through the infamous "seven minutes of terror."

    The one-way time it takes for radio signals to travel from Earth to Mars
    is about 10.5 minutes, which means the seven minutes it takes for the spacecraft to land on Mars will occur without any help or intervention
    from NASA teams on Earth.

    The ground teams tell the spacecraft when to begin EDL (entry, descent
    and landing) and the spacecraft takes over from there -- and mission
    control begins an agonizing wait.

    This rover is the heaviest NASA has ever attempted to land, weighing in
    at over a metric ton.

    The spacecraft hits the top of the Martian atmosphere moving at 12,000
    miles per hour and has to slow down to zero miles per hour seven minutes
    later when the rover softly lands on the surface.

    The spacecraft's heat shield will endure peak heating of 2,370 degrees Fahrenheit, 75 seconds after entering the atmosphere.

    Perseverance is targeting a 28-mile-wide ancient lake bed and river
    delta, the most challenging site yet for a NASA spacecraft landing on
    Mars. Rather than being flat and smooth, the small landing site is
    littered with sand dunes, steep cliffs, boulders and small craters. The spacecraft has two upgrades -- called Range Trigger and Terrain-Relative Navigation -- to navigate this difficult and hazardous site.

    Range Trigger will tell the 70.5-foot-wide parachute when to deploy
    based on the spacecraft's position 240 seconds after entering the
    atmosphere. After the parachute deploys, the heat shield will detach.

    The rover's Terrain-Relative Navigation acts like a second brain, using cameras to take pictures of the ground as it rapidly approaches and
    determines the safest spot to land. It can shift the landing spot by up
    to 2,000 feet, according to NASA.

    The back shell and parachute separate after the heat shield is discarded
    -- that will happen when the spacecraft is 1.3 miles above the Martian surface. The Mars landing engines, which include eight retrorockets,
    will fire to slow the descent from 190 miles per hour to about 1.7 miles
    per hour.

    Then, the famed sky crane maneuver that landed the Curiosity rover will
    occur. Nylon cords will lower the rover 25 feet below the descent stage.
    After the rover touches down on the Martian surface, the cords will
    detach and the descent stage will fly away and land at a safe distance.

    The mission: What the rover will do

    Once the rover has landed, Perseverance's two-year mission will begin.
    First, it will go through a "checkout" period to make sure it's ready.

    Perseverance will search for evidence of ancient life and study Mars'
    climate and geology and collect samples that will eventually be returned
    to Earth by the 2030s.

    For that reason, Perseverance is also the cleanest machine ever sent to
    Mars, designed so it doesn't contaminate the Martian samples with any
    microbes from Earth that could provide a false reading.

    Jezero Crater was chosen as Perseverance's home because billions of
    years ago, the basin was the site of a lake and river delta. Rocks and
    dirt from this basin could provide fossilized evidence of past microbial
    life, as well as more information about what ancient Mars was like.

    "Perseverance's sophisticated science instruments will not only help in
    the hunt for fossilized microbial life, but also expand our knowledge of Martian geology and its past, present, and future," said Ken Farley,
    project scientist for Mars 2020, in a statement.

    The path Perseverance will traverse is about 15 miles long, an "epic
    journey" that will take years, Farley said. What scientists could
    discover about Mars, though, is worth the journey. To accomplish its
    goals, Perseverance will drive a little less than 0.1-miles per hour,
    three times faster than previous rovers.

    Perseverance also carries instruments that could help further
    exploration on Mars in the future, like MOXIE, the Mars Oxygen In-Situ Resource Utilization Experiment. This experiment, about the size of a
    car battery, will attempt to convert Martian carbon dioxide into oxygen.

    Not only could this help NASA scientists learn how to produce rocket
    fuel on Mars, but also oxygen that could be used during future human exploration of the red planet.

    Ingenuity, the first helicopter on another planet

    Perseverance isn't traveling to Mars by itself. Along for the ride is Ingenuity, which will be the first helicopter to fly on another planet.

    After landing, the rover will also find a nice, flat surface to drop the Ingenuity helicopter so it has a place to use as a helipad for its
    potential five test flights during a 30-day period. This will occur
    within the first 50 to 90 sols, or Martian days, of the mission.

    Once Ingenuity is settled on the surface, Perseverance will drive to a
    safe spot at a distance and use its cameras to watch Ingenuity's flight.

    Ingenuity weighs only 4 pounds and features four carbon-fiber blades,
    solar cells and batteries.

    Mars has an incredibly thin atmosphere, so the design for Ingenuity had
    to be lightweight, while including larger and faster rotors than those
    of typical helicopters on Earth to get it up in the air.

    If Ingenuity is successful, it could pave the way for more advanced
    robotic aircraft to be used on future missions to Mars, both robotic and human, according to NASA.

    ----- The end of the citation -----

    Bye, All!
    Alexander Koryagin

    --- Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0
    * Origin: Usenet Network (2:5075/128.130)