back to article Don't mean to alarm you – but NASA is about to pummel the planet with huge frikkin' space laser

An orbital Earth sciences laser, NASA's ICEsat-2, is in the final stages of preparation ahead of next month's launch. With the bird about to fly, the space agency is touting the elevation accuracy Earth observation will get from the satellite's laser, the Advanced Topographic Laser Altimeter System (ATLAS). Firing 10,000 …

  1. }{amis}{ Silver badge
    Joke

    Management Headaches! even at NASA

    You know, I have one simple request. And that is to have sharks with frickin' laser beams attached to their heads! Now evidently my cycloptic colleague informs me that that cannot be done. Ah, would you remind me what I pay you people for, honestly? Throw me a bone here! What do we have?

    1. Korev Silver badge
      Pint

      Re: Management Headaches! even at NASA

      You beat me by a couple of seconds to post this

      Have one on me-->

  2. Korev Silver badge
    Joke

    I'm not worried...

    ...until the frickin' lasers are attached to sharks' heads...

    Mutant sea bass are a bit more scary though

    1. Hans Neeson-Bumpsadese Silver badge

      Re: I'm not worried...

      What about laser breams?

      1. W4YBO
        Pint

        Re: I'm not worried...

        "laser breams"

        Brilliant! Thanks for a good laugh.

    2. Adam Foxton

      Re: I'm not worried...

      Are they ill-tempered?

      1. Inventor of the Marmite Laser Silver badge

        @ Adam Foxton

        Only if you keep carping on about it

      2. Korev Silver badge
        Coat

        Re: I'm not worried...

        They are in this plaice

    3. Michael H.F. Wilkinson Silver badge
      Coat

      Re: I'm not worried...

      Mutant sea bass? wouldn't that be a bit of a fluke?

      Sorry, I'll get me coat. The one with "Get Thee to a Punnery" in the pocket please

      1. JMcL

        Re: I'm not worried...

        Would ye all stop, you're only codding me

  3. Ken 16 Silver badge
    Boffin

    This is the voice of the Mysterons.

    We know you can hear us, Earthmen.

  4. 0laf Silver badge
    Mushroom

    Ah now we know who's melting the ice!

  5. 89724102172714182892114I7551670349743096734346773478647892349863592355648544996312855148587659264921

    Disquieting, the prospect of Uranus being pummelled by a huge frikkin' space laser.

  6. King Jack
    Coat

    Now we know

    NASA were strapped for cash but suddenly they can do this? They told the Orange one that they had lasers in space and could shoot terrorists from orbit. Then SPACE FORCE was born.

  7. Aladdin Sane Silver badge

    That's no moon

    It's ICESat-2

  8. Chris G Silver badge

    Safe?

    Aaaaarrgh!! I can't see, my eyes! My eyes!

    Maybe not but your eyes are exactly 167cm above ground level.

    1. John Brown (no body) Silver badge

      Re: Safe?

      Actually, I was just wondering if there was some decently accurate data on when it might be scanning my house so I could pop out, look up and save a fortune on having my eyes fixed :-)

  9. imanidiot Silver badge

    Que alarmist news articles, 1 year after launch

    New data shows ice caps at an all time low!

    (Maybe, maybe not, it's the first time we'll have data this accurate. Measuring small features might tell us we've been overestimating ice mass to begin with)

    1. Rich 11 Silver badge

      Re: Que alarmist news articles, 1 year after launch

      ¿Qué?

      Aptly named.

      1. imanidiot Silver badge

        Re: Que alarmist news articles, 1 year after launch

        Cue, queue, whatever.

  10. Atomic Duetto
    Pint

    Err

    Fantastic, triple green lasers firing 10K a second providing a mapping range as small as 70cm..... just the one question, just how accurate is this touted elevation accuracy, +- 1mm or 10Km.. unless I missed it (I’m in an liquorice and Heineken enhanced haze here), there’s perhaps absolutely no mention??

    1. Yet Another Anonymous coward Silver badge

      Re: Err

      Raw return accuracy is 15cm for ice, about 1m on ground and 10m on steep ground.

      One of the problems/features is that the measuring spot is quite big on the ground (100m) so you average out small scale variations but end up with low overall elevation accuracy compared to terrestrial LIDAR

    2. Alistair Silver badge
      Windows

      Re: Err

      @Atomic:

      The red stuff or the black stuff?

      And if the Heineken was red, I don't want to know the rest of the story yet. (There's a quart of stout upstairs somewhere I'll need to grab)

  11. Martin Gregorie Silver badge

    Missing information

    So, now we know that the horizontal resolution is an impressive 70cm, but not so much about the vertical resolution.

    Resolving round trip time to a billionth of a second gives a theoretical accuracy of 0.1mm, but when other factors such as the accuracy with which the orbital altitude is known, atmospheric interference, etc are included, the measurement accuracy will almost certainly not be +/- 0.1mm. Its disappointing that the expected error bars on this measurement weren't quoted.

    1. Nial

      Re: Missing information

      "Resolving round trip time to a billionth of a second gives a theoretical accuracy of 0.1mm"

      You sure?

      Speed of light in air = 3.10^9 m/s

      Divide by 1.10^9 = 3.1m

      That's a round trip so can resolve to half that, so ~1.5m.

      Having said that resolving to 1nS isn't much to boast about, is that correct?

      1. Anonymous Coward
        Anonymous Coward

        Re: Missing information

        You sure?

        Speed of light in air = 3.10^9 m/s

        You sure? Wikipedia says 299,792,458 metres per second, which would be approx 3 x 10^8 m/s.

        Hence 1ns = 15cm round-trip.

        1. JeffyPoooh Silver badge
          Pint

          Re: Missing information

          "You sure?" etc.

          "Hence 1ns = 15cm round-trip."

          Exactly.

          Historical giant and computer-pioneer Grace Hopper was famous for her...

          1 foot = 1 nanosecond

          ...memory aid.

      2. terrythetech
        Boffin

        Re: Missing information

        Speed of light in air is 299,700 km/s (~3*10^8 m/s) very close to the speed of light in a vacuum so not sure where you get the 3.10^9 from (which according to my calculator is 26439.6)

        Rule of thumb - light goes at about 1ft per nanosecond or more accurately 30cm/ns. Resolving to 1ns isn't too bad but better is easily achievable.

        1. Yet Another Anonymous coward Silver badge

          Re: Missing information

          Measuring time interval to 0.1ps is easy, measuring a laser return isn't.

          You are assuming you send out a perfect square wave and get back a perfect return. At this range you send out a pulse that is a few of micro-seconds wide and get back a tiny fraction of that energy smeared over the pulse width - you have no idea where (in time) in the outgoing pulse the peak return is. It is further complicated because the same outgoing pulse will reflect off different layers in the target and give multiple return pulses.

          1. JeffyPoooh Silver badge
            Pint

            Re: Missing information

            YAAC suggested, "...send out a perfect square wave..."

            Hopefully they make use of a more-clever modulation technique than just square waves. And of course they'll employ repetition and signal processing techniques.

            Now, excuse me... I've got to start gathering some large first-surface mirrors so that I can assemble my mediumly-huge corner reflector. Give them something to talk about...

    2. Anonymous Coward
      Anonymous Coward

      Re: vertical resolution

      I've always had a concern how far up it goes

  12. Jason Bloomberg Silver badge
    Alien

    Keep Calm and Carry On

    Me; I'm finally buying a tinfoil hat.

    1. I ain't Spartacus Gold badge

      Re: Keep Calm and Carry On

      My tea cosy is far superior. It protects my head from frost, mind control rays and physical damage, due to being padded.

      Plus I can use it to keep my tea warm.

      Oh and it's the same shape as the Pope's hat, so I can blend in if I'm ever required to hide in the Vatican City.

      1. Robert Helpmann?? Silver badge
        Big Brother

        Re: Keep Calm and Carry On

        My tea cosy is far superior. It protects my head from frost, Check! mind control rays Noted!* and physical damage, due to being padded. Good! Plus I can use it to keep my tea warm. All at the same time? Impressive!

        * Someone will be there to chat shortly.

        1. Anonymous Coward
          Anonymous Coward

          Re: Keep Calm and Carry On

          "All at the same time?"

          Yep plenty of room in a Pope's hat for a decent sized teapot on top of the head.

          1. Hans Neeson-Bumpsadese Silver badge

            Re: Keep Calm and Carry On

            Yep plenty of room in a Pope's hat for a decent sized teapot on top of the head.

            I should say so - the thing is a mitre high

            1. Alistair Silver badge
              Windows

              Re: Keep Calm and Carry On

              --- so -- thats where the grey smoke comes from.......

            2. Clarecats
              Go

              Re: Keep Calm and Carry On

              "Yep plenty of room in a Pope's hat for a decent sized teapot on top of the head.

              I should say so - the thing is a mitre high"

              His Holiness is currently visiting Ireland so I don't imagine he needed to bring his own teapot.

              Cup of tea, Father? Ah go on.

  13. Pink Duck

    Height measurement precision

    From https://www.nasa.gov/sites/default/files/thumbnails/image/icesat-2-infographic.jpg, it's equivalent to 3 cm resolution in the vertical.

    1. Martin Gregorie Silver badge

      Re: Height measurement precision

      I see the satellite's orbit is being measured by star-tracker and GPS. Thats fine for Lat/lon determination to about a metre, but vertical GPS resolution is a lot worse, somewhere in the 3-5m range, so either there's another scheme thats not being talked about for measuring the orbital altitude, correcting for gravitational variation etc., or the +/- 3cm height resolution calculated from photon flight time and mentioned in the referenced graphic is somewhat irrelevant.

      1. Anonymous Coward
        Anonymous Coward

        Re: Height measurement precision

        I always thought that the GPS height accuracy had more to do with the geoid model (which one you chose and how accurate it is for your local position) than absolute 3D positioning. Also, if you're using GPS to measure something on earth, you have the effects of the atmosphere to consider.

        The other part to consider is that the absolute height of the satellite might not be critical, as long as the error is slow and predictable. If your measurements show that the ice cap dropped by 11cm and you also orbit over New York's Central Park and show that dropped by 11 cm, you can probably determine that your altitude has changed (I'm sure the orbital dynamics are more complicated, but you get the idea).

        1. Yet Another Anonymous coward Silver badge

          Re: Height measurement precision

          The height problem in GPS is because the satellites are much more similar in height than they are in distance to you.

          Measuring the height of this satellite doesn't depend on GPS - it just depends on measuring the orbit time (easy and accurate) and knowing where the planet is and how much it weighs (trickier but we do this)

          I'm guessing you can nail this to higher accuracy than the LIDAR system, so they will likely use passes over known flat fixed earth targets to calibrate the laser ranger assuming a known orbit - rather than use the LIDAR to measure the satellites' height.

  14. JeffyPoooh Silver badge
    Pint

    FAKE NEWS !!!! <---- ;-)!!

    22 August 2018: Europeans launch the British-built Aeolus weather satellite that will "...get its data by firing a powerful laser down into the atmosphere to trace the movement of air particles." [BBC]

    23 August 2018: El Reg, a British-based Tech News / Comedy website seeks to distract from their own European/British frickin' laser-wielding planet-frying death-dealing "weather" Aeolus satellite by publishing something about a future ICEsat-2 satellite: "NASA is about to pummel the planet with huge frikkin' space laser..."

    It's an amusing juxtaposition of reality versus the headline. One day in the gap!!!! GEESH! :-)

  15. Anonymous Coward
    Anonymous Coward

    Re. gap

    I hear its photons all the way down.

    (RIP Terry Pratchett)

  16. Gene Cash Silver badge

    ESA’s Aeolus gets there first

    You mention NASA, but you leave out ESA’s Aeolus with it's own big wind-measuring IR laser?

    It's the same bus design as Mars Express, too.

    It's designed to measure winds, but the launch was delayed by a day because of uncertain winds. Nice.

    1. John Brown (no body) Silver badge

      Re: ESA’s Aeolus gets there first

      "It's the same bus design as Mars Express, too."

      Bloody typical. You wait ages for a bus then two come along at once!!

  17. Wedge2
    Joke

    Re: I'm not worried...

    "the satellite's only instrument."

    Canteen Worker: What's the Death Star?

    Darth Vader: This is the Death Star! You're in the Death Star! I run this star!

    Canteen Worker: This is a star?

    1. allthecoolshortnamesweretaken

      Re: I'm not worried...

      "I can kill catering with a thought!"

  18. David 164 Bronze badge

    Let hope this climate monitoring satellite make it to orbit. Climate monitoring satellites seem to have a suspiciously high failure rate in the US.

  19. Version 1.0 Silver badge

    Turn the planet into a CD?

    It's big, it's round, it spins ... we're just a big CD now. I think this explains the Nazca Lines - they are just a lead-in track for an ancient aliens CD ...

  20. Stevie Silver badge

    Bah!

    Oh great! Like the globe wasn't warm enough already without melting stuff with giant space lasers!

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