Mars Opportunity Rover Stubbornly Silent / Hyades Frames Waning Moon

NASA’s Opportunity rover appears as a blip in the center of this square in a photo taken on Sept. 20, 2018 by NASA’s Mars Reconnaissance Orbiter. The dust storm over Perseverance Valley has substantially cleared. The square highlighting Opportunity is just over a half-mile (1 kilometer) across. NASA/JPL-Caltech

The skies are clearing over NASA’s Mars Opportunity rover but we’ve still not heard from the robotic explorer since June 10. That’s when a planet-encircling dust storm kicked into gear, saturating the thin Martian air with fine dust and choking off the sunlight the rover needed to power its solar arrays and recharge its batteries.

Areas on Mars that were once invisible under dust clouds including the shrinking south polar ice cap have returned to view in this photo taken on Sept. 29. Christopher Go

The Opportunity science team has been listening for the rover over a broad range of times using the Deep Space Network (DSN) Radio Science Receiver. They’ve also increased the number of commands sent to Opportunity in an attempt to get a response. Based on satellite observations of the rover’s location in the aptly named Perseverance Valley there’s enough sunlight right now to provide the necessary energy for the rover to send the “I’m OK” signal.

“If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover,” said John Callas, Opportunity project manager. At that point, the team will report to NASA headquarters to determine whether to continue with the strategy or adjust it. Callas added, “In the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun’s energy, we will continue passive listening efforts for several months.”

Opportunity’s panoramic camera took multiple images to create this wide scene from outside Endeavor Crater over a span of several days in June 2017. NASA/JPL-Caltech/Cornell/Arizona State Univ.

There’s always the possibility a dust devil, a common phenomenon on the Red Planet, will spin by and blow off layers of dust that may be covering the solar arrays. These “cleaning events” were first discovered by teams in 2004 when, on several occasions, battery power levels aboard both Spirit and Opportunity rovers increased by several percent during a single Martian night, when they’d otherwise be expected to decrease.

Catch the moon inside the Hyades star cluster tonight. At 10:30 p.m. (Central time) it will lie just 1¼° southwest of bright Aldebaran. The two will be closest — just under one moon-diameter — around 1 a.m. Stellarium

The solar-powered Opportunity rover has been exploring Mars for nearly 15 years. You can send good thoughts its way any clear when bright Mars shines due south at nightfall. If you’re doing that tonight, stay up a little later and make a point to catch the moon in the eastern sky around 10:30 or later. It’s in its waning gibbous phase approaching last quarter and will shine squarely from inside the V-shaped Hyades star cluster. The Hyades, a true, physical cluster, shines directly below the more familiar Pleiades (Seven Sisters) cluster.

The moon’s brightness will make it somewhat difficult to distinguish the many Hyades stars, the reason I encourage you to point your binoculars there. Should be a very pretty sight! As the moon slowly moves eastward during the night, it will get closer and closer to Aldebaran until only a moon diameter separates them around 1 a.m. Central Time.