NASA reports first high-altitude clouds of autumn season spotted at Gale Crater

NASA said the Curiosity rover marked the start of Mars year 39 at the beginning of the northern hemisphere spring on the Red Planet. The new year began at a solar longitude of 0 degrees at the end of September on Earth. Autumn has now arrived in Gale Crater, just south of the equator.

The space agency said the rover conducted a drill campaign at Basque Lakes. The SAM team decided on an additional Gas Chromatograph Mass Spectrometry experiment. Four whole sols were available in Monday's plan for remote-sensing activities from Mastcam and ChemCam and contact science of the drill tailings.

According to the report, the rover observed its first high-altitude clouds of the season during late afternoon cloud movies on Wednesday. Twilight clouds were bright enough to be seen in raw Navcam images. Most clouds at Gale Crater are too thin to be seen with human eyes or the rover's cameras.

NASA said the weekend plan included a couple more sols to wrap up drill activities at Basque Lakes before driving back toward the Chiu Chiu region. The region contains neat crystal forms that the team wants to explore.

Alex Innanen, an atmospheric scientist at York University, wrote that twilight cloud activity will pick up as the autumn progresses. The low sun angle at sunset illuminates the high-altitude twilight clouds beautifully.