JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Solar System
.

For Moratorium on Sending Commands to Mars, Blame the Sun

Jul 14, 2017
This diagram illustrates the positions of Mars, Earth and the sun during a period that occurs approximately every 26 months, when Mars passes almost directly behind the sun from Earth's perspective.› Full image and caption
Credit: NASA/JPL-Caltech

This month, movements of the planets will put Mars almost directly behind the sun, from Earth's perspective, causing curtailed communications between Earth and Mars.

This month, movements of the planets will put Mars almost directly behind the sun, from Earth's perspective, causing curtailed communications between Earth and Mars.

NASA will refrain from sending commands to America's three Mars orbiters and two Mars rovers during the period from July 22 to Aug. 1.

"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," said Chad Edwards, manager of the Mars Relay Network Office at NASA's Jet Propulsion Laboratory, Pasadena, California.

Data will keep coming from Mars to Earth, although loss or corruption of some bits is anticipated and the data will be retransmitted later. "We will continue to receive telemetry, so we will have information every day about the status of the vehicles," Edwards said.

As seen from Earth, Mars periodically passes near the sun about every 26 months, an arrangement called "Mars solar conjunction." During most solar conjunctions, including this year's, Mars does not go directly behind the sun.

Viewers using proper eye protection to watch the total solar eclipse on Aug. 21 will gain a visible lesson in why Mars doesn't need to be directly behind the sun for communications between Earth and Mars to be degraded. The sun's corona, which always extends far from the surface of the sun, becomes visible during total eclipses. It consists of hot, ionized gas, which can interfere with radio waves that pass through it.

To prevent the possibility of the ionized gas near the sun corrupting a command radioed to a spacecraft at Mars, NASA avoids transmitting for a period including several days before and after Mars gets closest to passing behind the sun.

Teams that operate Mars orbiters and rovers have been preparing for weeks in anticipation of the moratorium that will begin on July 22.

"The vehicles will stay active, carrying out commands sent in advance," said Mars Program Chief Engineer Hoppy Price, of JPL. "Orbiters will be making their science observations and transmitting data. The rovers won't be driving, but observations and measurements will continue."

The rover teams are determining the most useful sites for the rovers Curiosity and Opportunity to remain productive during the solar-conjunction period.

All of NASA's active Mars missions have experience from at least one previous solar conjunction. This will be the eighth solar conjunction period for the Mars Odyssey orbiter, the seventh for the Opportunity rover, the sixth for the Mars Reconnaissance Orbiter, the third for the Curiosity rover and the second for the MAVEN orbiter.

Edwards said, "All of these spacecraft are now veterans of conjunction. We know what to expect."

A video showing Mars solar conjunction geometry is at:

http://mars.nasa.gov/allaboutmars/nightsky/solar-conjunction

NASA's five current Mars missions, plus Mars missions scheduled for launches in 2018 and 2020, are part of ambitious robotic exploration to understand Mars, helping to lead the way for sending humans to Mars in the 2030s.

NASA's Goddard Space Flight Center manages the MAVEN project for the principal investigator at the University of Colorado, Boulder, and for the NASA Science Mission Directorate, Washington. JPL, a division of Caltech in Pasadena, manages the Odyssey, Opportunity, Reconnaissance Orbiter, and Curiosity projects, and NASA's Mars Exploration Program, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built all three NASA Mars orbiters. For more about NASA's Mars Exploration Program, visit:

https://mars.jpl.nasa.gov

https://www.nasa.gov/mars

http://mars.nasa.gov

News Media Contact

Guy Webster

818-354-6278

guy.webster@jpl.nasa.gov

Laurie Cantillo / Dwayne Brown

202-358-1077 / 202-358-1726

laura.l.cantillo@nasa.gov / dwayne.c.brown@nasa.gov

2017-191

Related News

Mars .

NASA to Reveal New Video, Images From Mars Perseverance Rover

Mars .

NASA's Mars Perseverance Rover Provides Front-Row Seat to Landing, First Audio Recording of Red Planet

Mars .

NASA’s Perseverance Rover Sends Sneak Peek of Mars Landing

Mars .

NASA’s Mars Helicopter Reports In

Mars .

Touchdown! NASA’s Mars Perseverance Rover Safely Lands on Red Planet

Mars .

Searching for Life in NASA’s Perseverance Mars Samples

Mars .

The Mars Relay Network Connects Us to NASA’s Martian Explorers

Mars .

NASA Invites Public to Share Thrill of Mars Perseverance Rover Landing

Mars .

InSight Is Meeting the Challenge of Winter on Dusty Mars

Mars .

Where Should Future Astronauts Land on Mars? Follow the Water

Explore More

Image .

Deep Jet Streams in Jupiter's Atmosphere

Image .

Power On: Psyche Spacecraft

Video .

What's Up - February 2021

Image .

Juno's Mission Goes On

Topic .

Solar System

Image .

Jupiter's Storm Oval BA As Viewed By An Artist

Image .

Jupiter North Pole Detail

Image .

A Hot Spot on Jupiter

Image .

A Jupiter Circumpolar Cyclone

Image .

Two Views of Jupiter Hot Spot

About JPL
Who We Are
Executive Council
Directors of JPL
JPL History
Documentary Series
Virtual Tour
Annual Reports
Missions
All
Current
Past
Future
News
All
Earth
Mars
Solar System
Universe
Technology
Galleries
Images
Videos
Audio
Podcasts
Infographics
Engage
JPL and the Community
Lecture Series
Public Tours
Events
Team Competitions
JPL Speakers Bureau
Topics
Solar System
Mars
Earth
Climate Change
Stars and Galaxies
Exoplanets
Technology
JPL Life
For Media
Contacts and Information
Press Kits
More
Asteroid Watch
Robotics at JPL
Subscribe to Newsletter
Universe Newsletter
Social Media
Get the Latest from JPL
Follow Us

JPL is a federally funded research and development center managed for NASA by Caltech.

More from JPL
Careers Education Science & Technology Acquisitions JPL Store
Careers
Education
Science & Technology
Acquisitions
JPL Store
Related NASA Sites
Basics of Spaceflight
Climate Kids
Earth / Global Climate Change
Exoplanet Exploration
Mars Exploration
Solar System Exploration
Space Place
NASA's Eyes Visualization Project
Voyager Interstellar Mission
NASA
Caltech
Privacy
Image Policy
FAQ
Feedback
Site Manager: Veronica McGregor
Site Editors: Tony Greicius, Randal Jackson, Naomi Hartono