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back to article NASA to launch microwave SPACE LASSO to probe Earth's wet spots

At the end of the month, NASA will launch one of its most unusual satellites yet: a radar hurling a 19-foot-long (6-metre) mesh antenna around its head every four seconds. "We call it the spinning lasso," said Wendy Edelstein, instrument manager for the Soil Moisture Active Passive (SMAP) sensor built by NASA's Jet Propulsion …

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  1. Anonymous Coward
    Anonymous Coward

    Other heavenly bodies.

    This thing is almost certainly going to work better for other planetary bodies like Mars, Luna, and the Gallilean moons in orbit around Jupiter, than it will on Earth. Did NASA deploy it for Earth simply to get funding?

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    1. Mark 85
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      Re: Other heavenly bodies.

      Maybe it's not about funding. A mile wide swath with penetration of only a few inches. That just tells you where it's rained recently if it passes over that area. If I read the link correctly, it makes no mention of how much terrain will be covered in one orbit. Will it take multiple orbits to cover the whole planet? But there's the last sentence in the article about gathering data on the carbon cycles of Earth's vegetation that caught my attention. I don't think that instrumentation would be aboard for a flight somewhere else at this point. I do wonder what else it can "see" with that sensitivity or is it doing something in studying climate change?

      The article and link raise more questions than the answers they give. No tin foil hat here, just curious.

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      1. DropBear
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        Boffin

        Re: Other heavenly bodies.

        Actually, the article contains that information - you have to go a tenth of the way to the Moon to be able to stay put relative to the Earth, anything closer orbits *much* faster (try to catch the ISS with a non-motorised telescope - yeah, good luck...). Coupled with the mentioned interval of three days, it becomes clear that has to mean the amount of time it takes for the satellite to get back over the same spot, over quite a number of orbits it has to do in the mean time...

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        1. This post has been deleted by its author

  2. Alister

    I'm intrigued to know how they test something which must unfurl with micrometric precision in a space environment, and yet be tested on earth. One would think the forces acting on the mesh would be very different.

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    1. JDX Gold badge
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      Not VERY different. Basically just gravity; one expects they do their tests in vacuum. Maybe they even test it in controlled free-fall?

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      1. Wzrd1 Silver badge
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        Just gravity and a massive thermal difference between in sun and in shade of a few hundred degrees.

        As for unfurling testing conducted in free fall, the Vomit Comet has quite a short period of free fall, lest the free fall be rudely interrupted by an unintentional air-ground incursion.

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    2. DropBear
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      Well, "a few millimetres" is not exactly micrometric precision, to be fair... I suppose it just means "mostly deployed" and "pointed in the general direction of the Sun" that would probably suffice with a regular solar array won't do here - this thing has to deploy exactly as designed, nothing may snag even a little bit.

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    3. Terry Cloth
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      I want to watch...

      I was disappointed that the fine Youtube animation skipped right past deployment of the big reflector. Does anyone know where such a thing is to be had, showing some of the fine points of what's going on?

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  3. Hugh Pumphrey

    Three days?

    "SMAP will orbit the planet every three days." No, it won't: SMAP is at an altitude of 685km, so it will orbit the planet about once every 90 minutes. A given point on the Earth's surface gets observed once every two or three days (depending on latitude).

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  4. Faux Science Slayer

    Water vapor 'absorbs' in +50,000 spectral bands

    Ozone, Oxygen and Carbon Dioxide 'absorb' in a few spectral bands, although 'absorb' is immediately followed by an emission of a longer wavelength, lower energy photon, making the actual process a 'filtering' or buffering of energy transfer [1]. The 'absorbed' EMR energy is then Kinetic Energy and is immediately transferred to adjoining air molecules, creating an upward convective current [2]. There is NO phantom back radiation 'warming' force. This satellite will have difficulty sorting the atmospheric and top soil MW signals. The planet is bathed in MW signals from constant sunlight on one or another ocean and reflections of those emissions horizontally in the atmosphere [3].

    [1] "Greenhouse Gas Ptolemaic Model" at FauxScienceSlayer

    [2] "Science Goes Over/Under, Inside/Out" at FSS

    [3] "Water Is A Polymer" by Stephen Crothers, youtube.com/watch?v=nXF098w48fo

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