- On November 11, NASA stopped sending commands to Martian spacecraft, and this communication blackout will continue until November 25.
- The reason for this two-week hiatus is because Mars is currently in solar conjunction, meaning the Sun currently lies directly between Earth and Mars, and radio commands could be disrupted by the Sun's charged particles.
- Although receiving no new commands, the Martian rovers, satellites, and one tiny helicopter will have a pre-planned list of scientific objectives and will continue to send health checks during the two-week break.
For more than a week, NASA has been incommunicado with all its robotic missions on and in orbit of Mars—but don’t worry, that’s by design.
Roughly every two years, Earth and Mars experience a brief period known as solar conjunction when the two planets are on opposite sides of the Sun. According to the stargazing website In the sky, both the Sun and Mars will be in the constellation Libra and that means Mars will be lost in the glare of the Sun for weeks and communication with our robotic friends on the fourth rock will be sketchy at best.
On average, Mars is usually about 140 million miles away, but that balloons during solar conjunction. That distance stretches to about 235 million miles—roughly 2.5 astronomical units (AU) from Earth. This is essentially the cosmic opposite of Mars opposition, which is when Earth is instead sandwiched between Mars and the Sun (and the God of War planet looks particularly bloodthirsty in the night sky.)
So why do we have to bid adieu to our mechanical brethren for two weeks? Well, the problem is the Sun, which is essentially a giant orb of interference. When rovers, orbiters, and one impressive helicopter try to send data back to Earth, the information can be disrupted by the charged particles of the Sun, which could leave behind gaps in data. But the reverse is a more disastrous scenario because confused commands sent by NASA could lead to a mission’s doom. NASA will suspend commands from November 11 to November 25.
As NASA explains, that doesn’t mean these robots will be taking an extended holiday. The immobile Curiosity of Perseverance rovers will continue monitoring the Martian surface, the Mars Reconnaissance and Odyssey orbiters will continue on as usual (though without phoning home, of course), the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft will still study the atmosphere, and even NASA’s pint-sized helicopter Ingenuity will monitor the movement of Martian sand while grounded.
“Our mission teams have spent months preparing to-do lists for all our Mars spacecraft,” Roy Gladden, manager of the Mars Relay Network at NASA’s Jet Propulsion Laboratory in Southern California, said in a press statement. “We’ll still be able to hear from them and check their states of health over the next few weeks.”
However, even those health checks will go dark for a 48-hour period while Mars is directly behind the disk of the Sun. While the various mission controls collectively hold their breath, hopefully after two days the familiar signs of mechanical life will whirr back into existence, and humanity’s Martian companions will be eager to share the things they’ve learned while we were away.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.