Sun., April 14, 2013 6:00pm (EDT)

Mars Rovers Go Quiet, As Sun Blocks Transmissions
By Bill Chappell
Updated: 1 year ago

The rover Curiosity and other NASA spacecraft at Mars are now in a radio blackout, as the sun is interfering with transmissions. Curiosity took this self-portrait by combining 66 exposures in February.
The rover Curiosity and other NASA spacecraft at Mars are now in a radio blackout, as the sun is interfering with transmissions. Curiosity took this self-portrait by combining 66 exposures in February.
Communications between the Earth and Mars are on hiatus for several weeks, thanks to interference from the sun. That means NASA's orbiters and rovers that study Mars will be left to their own devices until radio signals can once again travel between the two planets.

Known as "solar conjunction," the problem arises when the orbit of planets places the sun directly between them.

"It's like being on either side of a huge bonfire," NASA explains, in a video on its website. "We can't see Mars, and our landers, orbiters and rovers can't see us."

The sun obstructs Earth's radio contact with Mars about once every 26 months. How long the outage lasts depends on Mars' placement "behind" the sun, and on the sun's solar flare activity. In this case, the blackout is expected to peak on April 17.

"Transmissions from Earth to the orbiters will be suspended while Mars and the sun are two degrees or less apart in the sky, from April 9 to 26," NASA says.

But that doesn't necessarily mean the spacecraft will go on spring break.

In a report for our Newscast desk, NPR's Joe Palca says that the two rovers, Opportunity and Curiosity, "will continue to operate but will have to record any data they collect and forward that to Earth... when communications are restored."

The same goes for the two orbiters, Mars Odyssey and Mars Reconnaissance, although NASA says Odyssey, in a sort of older-sibling role that befits its longer tenure at the red planet, will stay in touch with Earth and transmit its data again later, to be sure nothing is lost. The biggest risk, NASA says, would be to send a command from Earth to the spacecraft that becomes garbled.


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