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Mars NASA

NASA Will Listen for Thumps From Its Rover's Arrival on Mars (nytimes.com) 40

Posted by msmash from the moving-forward dept.
When the Perseverance rover sets down on Mars on Thursday, another NASA spacecraft already there will be listening for the thump-thump that will result when the newcomer arrives. From a report: The hope is that these thumps will create enough shaking to be detected by InSight, a stationary NASA probe that arrived in 2018 to listen for marsquakes with an exquisitely sensitive seismometer. The InSight lander sits more than 2,000 miles to the east of where Perseverance is to land. "We have a reasonable chance of seeing it," said Benjamin Fernando, a graduate student at the University of Oxford in England and a member of the InSight science team. Perseverance will land on Mars at 3:55 p.m. Eastern time on Thursday. NASA Television will provide coverage of the event beginning at 2:15 p.m.

Unless something goes catastrophically wrong, the seismic signals that InSight might hear will not emanate from the rover itself. Perseverance is to be lowered to the surface from a hovering crane, bumping to the ground gently at slower than 2 miles per hour. Rather, scientists will be sifting through InSight's seismic data for signs of the impacts of two 170-pound blocks of tungsten metal that helped keep Perseverance in a stable, balanced spin during its 300-million-mile trip from Earth. At an altitude of 900 miles above Mars, they will be jettisoned as junk, and without parachutes or retrorockets to slow them down, they will then slam into the surface at some 9,000 m.p.h. "This enormous speed means that they'll make quite a substantial crater," Mr. Fernando said. In 2012, similar tungsten blocks from the Curiosity rover, which is almost the same design as Perseverance, left scars visible from orbit.
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NASA Will Listen for Thumps From Its Rover's Arrival on Mars More

NASA Will Listen for Thumps From Its Rover's Arrival on Mars

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  • "Here it comes in 3...2...1..."

    * Crash * Boom * Clink * Clunk*

    "Aaaah shit!!"

  • UTC? Mars Standard time?

    I still find it unbelievable that people put time up on the internet without telling what timezone they are in. May as well not put anything up at all.

  • I thought this was a legit headline: "NASA Will Listen for Thump From Its Rover's Arrival on Mars."

    Given that former President Donald J. Trump has been banned from all media communication outlets, NASA uses a high-precision antenna on its Mars rover to help keep the world aware of Trump's next machinations.

    • Re: (Score:2)

      by antdude ( 79039 )

      Me too. I miread that as Trump. I was like huh? DJT sure messed with our brains!

    • Right? I laughed when I reread it correctly. Son and I even had a short conversation of "Trump on Mars" or whatever. Good, clean fun.

  • Sandworms? (Score:4, Interesting)

    by awwshit ( 6214476 ) on Wednesday February 17, 2021 @10:48PM (#61074370)

    With enough Spice in you, you can ride those things.

  • A 170lbs tungsten slug hitting the ground at 9000mph... I call that a railgun

  • firing two 170 pound tungsten bullets into the Martian homeland at 9000 miles per hour is gonna get them raging.

    Next we will be being told the Martians started it.

  • Does anyone else miss the posts from the user who'd write about the martians and the probes/rovers/etc.? K'breel and gelsacs?

    • Every time there is a story about Mars, I hope to see some response from K'breel and the invasion from Earth.

  • It's amazing so much weight was allocated to this! (Score:4, Insightful)

    by psperl ( 1704658 ) on Wednesday February 17, 2021 @11:49PM (#61074474) Homepage
    Wikipedia says perseverance's launch mass is 1,025 kg. 2 * 170 pounds = 154 kg, so these tungsten blocks are about 15% of the total launch mass.

    The Planetary society says NASA paid $243 million [planetary.org] for the Atlas V launch. That's 237k per kilogram to Mars. It cost $36.5 million to launch those tungsten blocks into space.

    Now I don't know anything about interplanetary navigation, guidance, and control, but I am blown away at how much cost and weight they allocated to these tungsten bricks given the insane cost of sending anything to Mars. Whatever problem these blocks solve must be really serious.

    • Re: (Score:3)

      by cusco ( 717999 )

      Stability, so yeah, it's important. The spacecraft is spin stabilized during its journey, and you can't have the antenna wandering away from Earth.

      • Re: (Score:3)

        by pacinpm ( 631330 )

        Why can't they put some science apparatus with the same mass instead?

        • Re: (Score:2)

          by cusco ( 717999 )

          I like the idea but I'm not sure how much science could be conducted while tearing through the atmosphere at 9,000 miles an hour and mostly vaporizing on impact.

          Impactors have been designed that would aerobrake to a more reasonable speed and upon impact with the surface shove a probe as much as two meters underground, but Congress has consistently refused to fund them. I think they were supposed to be a separate science package, but I wonder if they could have been integrated somehow with the ballast, beco

        • Hey, each of the tungsten bricks weighs the same as I do, hmm...

        • Because science instruments need cabling for power and data, thus vastly increase the complexity... And they're much less dense than tungsten, thus vastly increasing the volume.

    • Wikipedia says perseverance's launch mass is 1,025 kg. 2 * 170 pounds = 154 kg, so these tungsten blocks are about 15% of the total launch mass.

      That's the launch mass of the rover. The launch mass of the spacecraft (of which the rover is only one part) appears to be somewhere around 3,500kg [wikipedia.org]. (Assuming I did my sums right, it's late and I'm tired.)

      The Planetary society says NASA paid $243 million for the Atlas V launch. That's 237k per kilogram to Mars. It cost $36.5 million to launch those tungst

    • Re:It's amazing so much weight was allocated to th (Score:5, Informative)

      by Bomazi ( 1875554 ) on Thursday February 18, 2021 @04:25AM (#61075096)
      The capsule's centre of gravity is deliberatley off-axis. These are counterweights that put it back on the vertical axis. This is needed from launch all the way to separation of the cruise stage, after which they are jettisoned. Thus the capsule enters at an angle, and generates lift. It is therefore aimed a bit short. If you look at the EDL animation you'll see nitrogen thrusters on the back shell that adjust the orientation of the capsule during entry. If the trajectory is short, the capsule pitches up thus increasing lift. If it is long, it pitches down thus decreasing lift. Cross-range errors can also be corrected to some extent. All this significantly reduces the size of the landing ellipse, and allows the rover to drive to its target in a reasonable amount of time.

      • And more to the point, this is nothing new. Curiosity used exactly the same mechanism. Just, when Curiosity landed, there were either no assets (at all, or close enough) to monitor its ejected balance mass(es) impact with the surface.

        The below video (and separate slide deck available for download) go into some detail on this:

        https://nescacademy.nasa.gov/v... [nasa.gov]

        This backs up my rememberance that Curiosity was the first to use lifting guided EDL. Viking apparently used lift, but it was unguided. Pathfinder and M

    • Re: (Score:2)

      by tlhIngan ( 30335 )

      Now I don't know anything about interplanetary navigation, guidance, and control, but I am blown away at how much cost and weight they allocated to these tungsten bricks given the insane cost of sending anything to Mars. Whatever problem these blocks solve must be really serious.

      I see it more as insurance that the odds of the spacecraft making it to Mars increases significantly.

      Mars missions have about a 50% success rate on making it to the planet.

      Considering the whole program probably cost $billions, spend

  • Gonna watch it live, well 11 minutes and 14 seconds late due to distance between Earth and Mars.

  • 2 thumps good. 3 thumps bad.

    • Knock three times on the ceiling if you want me; Twice on the pipe, if the answer is no.

    • The Protector heard thumps coming from the outside of the habitat. He softened the hull at the point of the thumps and found a staff or rod poking through, and realized that the native Martians were investigating. Aware that Martians had massacred the first human expedition to Mars, he did what a Protector has to do.

      He set the water tank near the thumps, hooked up a hose, softened the hull, and placed the hose through it. He turned the valve. As the water flowed, the thumping became violent and occurred alo

  • I sure hope any Martians in the strike zone of these kinetic orbital weapons will not see this as an act of interplanetary war.

  • Is it just because of it's density and strength?

    • Is it just because of it's density and strength?

      We're hoping that instead of considering the tungstenfall a strategic strike, Martian observers will instead get a "light bulb" moment.

      Sorry. I'll see myself out.

    • Lead and Gold have too low of a melting point.

      Deleted Uranium is frowned upon, for some reason.

      • "At an altitude of 900 miles above Mars, they will be jettisoned as junk"

        Since it's getting rid of these prior to entry into the Martian atmosphere, where does heat resistance come into play?

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