8 August 2019
Sols 2489-2491: A Change in the Weather (Observations)
Posted by Ryan Anderson
Over the weekend, Curiosity successfully dropped off a portion of the Glen Etive drill sample. But for some reason, the sequence was interrupted, so no images of the portion were acquired. Curiosity’s Remote Sensing Mast (RSM), on which ChemCam, both Mastcams, and all four Navcams are mounted, briefly stopped pointing as commanded on sol 2488. The RSM worked well in the tests planned on sol 2489 and downlinked ahead of today’s planning, however. So while the engineers continue to diagnose the issue, such as whether it involves recent changes to the way we heat motors connected to the RSM, we used it again cautiously in the sol 2490 plan. This meant avoiding observations that require us to look up from the surface or deck, to avoid any risk of dust piling up on lenses if the RSM became stuck there.
The net result was that most of the ENV Science Theme Group’s cloud and dust monitoring activities could not be included, as all of them involve using Mastcam or Navcam to look near the horizon or higher up. In the sol 2489 plan, we included some attempted dust devil imaging using the Rear Hazcams, but in today’s plan we focused on adding extra REMS one-hour extended blocks to measure air and ground temperature, pressure, humidity, and UV radiation. This should result in us measuring over 37 of the 48 Mars hours contained in this two-sol plan, compared to the 13 hours we’d have measured usually, including seven periods with 5 hours of continuous REMS. Long periods of continuous atmospheric data are useful for tracking weather patterns, atmospheric wave activity, and even clouds that we can detect in the REMS UV and ground temperature data after sunset. The ENV group also planned DAN active and RAD observations.
Meanwhile, the GEO Science Theme Group planned to recover yesterday’s planned observations, which were lost due to the RSM issue. Because delivery of the Glen Etive sample to the SAM inlet cover and documentation imaging did not complete, the highest priority for the sol 2490 plan was to perform the SAM drop-off and do ChemCam LIBS observations of the drill hole. Other activities were ChemCam and Mastcam observations of a single rock target ‘Argyll,’ consisting of dark bedrock with a white vein, of ‘Dornock’ and ‘Thrumster,’ both containing sulfate veins, and of ‘Tap O Noth,’ a nearby bedrock target.
Finally, further Mastcam imaging was performed to monitor any surface changes that may occur as a result of strong winds or intense atmospheric vortices that are able to move sand and/or dust particles. Targets of this imaging included the rover deck as well as images of two surface targets called ‘Dundee 1’ and ‘Dundee 2.’ These targets were chosen because they contain both sand and bedrock, which makes it easier to spot small changes between images, such as sand shifting slightly further onto the rock. These ‘change detection’ studies are repeated at roughly equal intervals over the Mars year, and help us to understand how sand motion and dust lifting varies with season, which in turn helps us to understand how dunes form, how the surface is eroded, and how dust storms occur.
Written by Claire Newman, Atmospheric Scientist, Aeolis Research