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NASA prepares its Martian explorers for solar conjunction radio silence

solar conjunction

With the Sun sitting between Earth and Mars, called a solar conjunction, NASA will suspend communications with its explorers at the Red Planet for nearly two weeks. Image Credit: NASA / JPL

For more than twenty years, NASA has had explorers surveying the Red Planet. Dutifully, the stalwart robotic travelers have followed commands beamed from their Earth-bound handlers and returned gigabytes of information of their Martian observations.

However, for a few days every 26 months, communication from Earth to Mars takes a Sun-induced break. Beginning July 22, 2017, and lasting through August 1, 2017, NASA will avoid sending commands to its Mars-based craft.

solar conjunction

Animation of a Mars Solar Conjunction. Animation Credit: NASA / JPL

The Sun giveth, the Sun taketh away

While the Sun provides life-supporting energy to Earth and supplies power to solar panels on spacecraft, its highly ionized corona holds a significant potential to disrupt data transmission when it sits between the two planets. Although the two planets won’t be directly obscured by the Sun, the far-reaching effects of its outer layer can still induce data loss.

“Out of caution, we won’t talk to our Mars assets during that period because we expect significant degradation in the communication link, and we don’t want to take a chance that one of our spacecraft would act on a corrupted command,” stated Chad Edwards, manager of the Mars Relay Network Office at NASA’s Jet Propulsion Laboratory (JPL), in a release issued by the agency.

Though commands won’t be sent to Mars during the conjunction window, telemetry will still be sent to Earth. Should data loss occur, the robotic craft can be instructed to repeat its transmission once clear of solar interference.

This command black-out period extends for two days both before and after a solar conjunction event.

Able to work independently

Even though no commands will be sent to Mars during the conjunction, NASA’s rovers and orbiting spacecraft will still have work to do. In fact, engineers have been preparing the explorers far ahead to ensure observations run unabated.

“The vehicles will stay active, carrying out commands sent in advance,” stated JPL’s Mars Program Chief Engineer, Hoppy Price.

While the agency’s two active rovers – Curiosity and Opportunity – will be conducting pre-programmed investigations, they will remain stationary during the blackout.

Although the lack of communications may sound worrisome, all of the orbiters/rovers have already endured at least one Mars Solar Conjunction. Indeed, the Mars Odyssey orbiter will be undergoing its eighth conjunction, while Opportunity holds the surface record at just one less than its orbiting cousin.

“All of these spacecraft are now veterans of conjunction. We know what to expect,” concluded Edwards.

NASA's Mars Science Laboratory rover 'Curiosity' at the Namib Dune in Gale Crater.

Curiosity will remain stationary during the blackout period, but will still conduct investigations. Image Credit: NASA / JPL / MSSS



Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

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