Today the Earth and Mars have moved into an arrangement called a “Solar Conjunction”. This is similar to an eclipse: The Sun is positioned between the Earth and Mars.
The arrangement of the inner planets as of Sept 9
The Earth is the blue circle, and Mars is in red.
The solar conjunction means that the Mars Rovers need to operate without human assistance for two to three weeks. Radio transmissions can’t be sent through the Sun. The rovers will be parked taking spectrograph readings of rocks and dust, and observing how the winds affect a depression in the soil.