Curiosity Exceeds Creator Expectations

    The United States is currently hosting the 44th Lunar and Planetary Science Conference, at which the new results of Mars studies by MSL Curiosity are unveiled. Scientists from the USA said that they were pleasantly surprised by the capabilities of their MastCam cameras, who were able to see what was not supposed to, and scientists from Russia - that they were surprised by the surface of Mars, which was saturated with water as no models promised .
    (I warn you right away: there are a lot of science and graphics inside).

    MastCams are two color two-megapixel cameras that are located on the mast of the rover. They have a fixed focal length: right 100 mm and left 34 mm. Due to this, the right “eye” is used for detailed shooting, and the left - for the survey. When Curiosity was just being designed, a 3D movie fan directed by James Cameron put in a lot of effort to fly two identical cameras with variable focal lengths. They were made, but did not have time to pass the tests, so Curiosity is farsighted in one eye and shortsighted in the other. (A detailed technical description of these cameras and some other Curiosity devices can be found: here )

    However, this does not interfere with creating high-quality stereo panoramas. (Available on VKontakte for the tag #MarsAnaglyph ).

    The cameras have a Kodak KAI-2020 1600x1200 CCD matrix with a standard Bayer filter , which means they take color photos without the processing that was necessary for his Martian predecessors. In addition to the non-removable filter, each camera is equipped with a set of additional ones that allow only waves of a certain length to pass through. They are located on the wheel between the lens and the sensor.

    The combination of Bayer filters and optional filters provides up to 12 different spectral ranges in which Curiosity can shoot. Moreover, only half of the filters captures the visible range, the rest allow analysis in the infrared range inaccessible to vision.

    All this allows us to investigate the surface in more detail, as far as even the experienced eyes of a human geologist would not have provided. Scientists compared the survey with MastCam cameras and compared them with spectral data obtained by other instruments. Thanks to this, it was possible to find out that multispectral photography is able to identify hydrated materials, that is, those in the formation of which water was involved and contained in them.

    The graph on the left shows the degree of reflection of light of different wavelengths of the Knorr section, recorded by mast cameras through different filters, on the right - the degree of reflection characteristic of various materials. Failure in infrared light for hydrated materials is characteristic. Clay, in which light veins are visible, although formed under the influence of water, does not include it at the molecular level, so the difference is determined when shooting MastCam.

    NASA uses color coding that reflects a “hydration signal” of varying strengths: a

    Tintina pebble that was broken off by a wheel showed a white kink:

    And its hydration signal turned out to be very strong:

    But the comparison of four surface areas at the John Klein site did not show hydrated materials, although the difference in soil characteristics is visible:

    They also spoke at the conference about the difference between “raw”, “natural” and “balanced” (white balanced) the color of the pictures. As much as anyone would like, the real Mars is “redder” than even what the cameras of the rover show. And colors close to our vision are obtained by additional processing “as if we saw on Earth”.

    Such data was obtained by NASA through the use of color markers placed on the Curiosity sundial:

    To identify finer color details, false colors are processed, and their falsity will appear if you look at the sundial in the same mode:

    The dull orange-brown color of Mars is due to its dustiness, while fresh fractures reveal unexpected colors like this white-blue Sutton_Inlier stone.

    From news from California, let's move on to news from Moscow.

    At the same Lunar and Planetary Conference, Russian representatives shared the results of the DAN device.
    Let me remind you - this is a device that detects with what energy neutrons fly out of the surface of Mars. This happens when it is bombarded by cosmic charged particles, or from a DAN neutron source. Depending on whether the device catches cosmic neutrons or produces them, the operating modes of it are called passive or active.

    Hydrogen in the soil inhibits neutrons, so you can determine how much of it is under the device by estimating the percentage of “fast” and “inhibited” particles. In the bulk, hydrogen means either water or hydroxyl (OH). A detector to a depth of 60 cm determines confidently, but is able to pick up signals up to 1 m.

    Even when Curiosity overcame the first hundred meters, scientists noted that the data from the DAN generally met expectations: the soil turned out to be very dry and only at the maximum achievable depth the water reached 5% , and above did not exceed 1%. This was quite predictable, because at the Martian equator in summer the temperature can rise above 30 degrees Celsius, and low pressure leads to the fact that the water immediately evaporates. Such conditions leave no chance to find ice within a half meter-meter from the surface.

    When Curiosity went down to Yellowknifle Bay, which is considered the bottom of an ancient lake, the data from the device began to surprise. He began to show that, in places, the top layer of the surface is wet - up to 3%, and under it begins the “desert” with 1% water content. That is, the DAN revealed the “layering” of Mars even at shallow depths, and these data will allow scientists to more fully present the picture of changes on the planet that have led to the situation that is being observed now.

    The difference in testimony was determined not only on significant segments of the run:

    But also in a few "steps" of the rover:

    Scientists are in no hurry to interpret the information received and will continue to work further. Although no rover movement is expected in the coming weeks, so we will not see updates from DAN soon. It is hoped that the revenge will be when Curiosity sets off on a long journey to the mountain.

    At the conference, Canadians also shared their results.
    They work with the Alpha-Proton X-Ray Spectrometer (APXS), which is located on the manipulator:

    It allows you to determine the chemical content of the surface that is being examined. In order to improve the quality of analysis, Curiosity is equipped with a brush that removes dust:

    APXS has already performed many analyzes, but published the results of one, from the Portage site. The graph in a schematic form shows the content of various elements in three types of surfaces: uncleaned from dust, peeled, peeled and rich in white veins. The latter is distinguished by a high content of sulfur and calcium, which generally corresponds to gypsum.

    The conference is still ongoing, and the results will be replenished in the next couple of days. At least ChemCam laser materials are expected.

    This weekend, the Curiosity computer again returned an error, but this time the problem was quickly identified and eliminated - the culprit turned out to be an erroneous file that was deleted. The rover should return to work in the coming days, but on April 4, communication with it will be interrupted for 4 weeks, while the Sun will pass between Mars and the Earth. I think at this time I will tell you what interesting things were told there at today's conference.

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