For more than a week, the daily chatter between Earth and Mars will go silent.
On the surface of Mars are NASA’s Curiosity rover and InSight lander. Above Mars are several orbiters, including India’s Mars Orbiter Spacecraft (Mangalyaan), which has completed its official mission life but remains in orbit. Antennas on Earth and those on active spacecraft on or around Mars regularly exchange data.
Now this will pause because of a phenomenon called Mars solar conjunction. For NASA’s spacecraft, this will happen between August 28 and September 7.
During Mars solar conjunction, Mars and Earth will be on opposite sides of the Sun. The Sun expels hot, ionised gas from its corona, which extends far into space. During solar conjunction, this gas can interfere with radio signals when engineers try to communicate with spacecraft at Mars, corrupting commands and resulting in unexpected behaviour from those space explorers, NASA said in a statement. When Mars disappears far enough behind the Sun’s corona that there is increased risk of radio interference, engineers hold off on sending commands. Solar conjunction occurs every two years.
This time, the hold on issuing commands — called a “command moratorium” — will run from August 28 to September 7, NASA said. In 2015, the conjunction period for Mangalyaan had lasted for more than a month — from May 27 to July 1.
Besides Curiosity and Insight on the Mars surface, NASA has the Odyssey orbiter, the Mars Reconnaissance Orbiter and the MAVEN orbiter. Some instruments aboard spacecraft will be inactive, especially cameras that generate large amounts of data. However, NASA said, all of its Mars spacecraft “will continue their science; they’ll just have much simpler ‘to-do’ lists than they normally would carry out”.
On the surface, Curiosity will stop driving and InSight will not move its robotic arm. Above, Odyssey and the Mars Reconnaissance Orbiter will continue collecting data from Curiosity and InSight, but only Odyssey will attempt to relay that data to Earth before conjunction ends. MAVEN will continue to collect its own science data but won’t support any relay operations during this time.
All of this means that there will be a temporary pause in the stream of raw images available. Once conjunction is over, the spacecraft will beam the data they have collected. If any of the collected science data are corrupted, they can usually have that data retransmitted, NASA said.