Fwd: Mars Missions to Pause Commanding in June, Due to Sun

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: June 5, 2015 at 11:02:54 AM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: Mars Missions to Pause Commanding in June, Due to Sun

 

 

 

June 3, 2015

Mars Missions to Pause Commanding in June, Due to Sun

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. Image Credit: NASA/JPL-Caltech
› Full image and caption

Fast Facts:

› In June 2015, Mars will pass almost directly behind the sun from Earth's perspective, a geometry called Mars solar conjunction.

› Mars solar conjunction happens about every 26 months.

› Because the sun disrupts radio transmissions between Earth and Mars during conjunction, communications are curtailed.

In June 2015, Mars will swing almost directly behind the sun from Earth's perspective, and this celestial geometry will lead to diminished communications with spacecraft at Mars.

The arrangement of the sun between Earth and Mars is called Mars solar conjunction. It occurs about every 26 months as the two planets travel in their sun-centered orbits. The sun disrupts radio communications between the planets during the conjunction period. To prevent spacecraft at Mars from receiving garbled commands that could be misinterpreted or even harmful, the operators of Mars orbiters and rovers temporarily stop sending any commands.

The teams running NASA's three active Mars orbiters and two Mars rovers will refrain from sending commands to their spacecraft from about June 7 to June 21. During that period, the sun will be within two degrees of Mars in Earth's sky. (Don't try to look, though, because looking at the sun is dangerous to the eyes.) The operators also will put restrictions on commanding -- such as using only reduced data rates or communicating only in an emergency -- during the days before and after that period.

Spacecraft will continue making some science observations during the conjunction period, though rovers will not do any driving or arm movements.

"Our overall approach is based on what we did for the solar conjunction two years ago, which worked well," said Nagin Cox, a systems engineer at NASA's Jet Propulsion Laboratory, Pasadena, California, who is leading conjunction planning for NASA's Curiosity Mars rover. "It is really helpful to have been through this before."

NASA's MAVEN spacecraft, which arrived in Mars orbit last September, will be experiencing its first solar conjunction. Its team has prepared thoroughly. MAVEN -- short for Mars Atmosphere and Volatile Evolution -- will continue monitoring the solar wind reaching Mars and making other measurements. "The data will be stored and transmitted back to us after communications are reestablished at the end of the solar conjunction period," said James Morrissey, MAVEN deputy project manager at NASA's Goddard Space Flight Center, Greenbelt, Maryland.

Transmissions from NASA's two other Mars orbiters -- Mars Odyssey and Mars Reconnaissance Orbiter -- will continue through the conjunction period, but some of those transmissions are not expected to reach Earth. Science data transmitted during conjunction will also remain stored aboard the orbiters, for reliable retransmission in late June. The active Mars rovers -- Curiosity and Opportunity -- will send limited data to orbiters throughout conjunction for relay to Earth during and after conjunction.

Mars Odyssey, which reached Mars in 2001, will be in its seventh solar conjunction. For Opportunity and Mars Reconnaissance Orbiter, the 2015 solar conjunction is the sixth and fifth, respectively.

In preparation for conjunction, orbiter and Curiosity mission teams have been clearing some science data from spacecraft memories to optimize availability of memory for storing science data during the conjunction period. Data that Opportunity collects and sends daily to orbiters will be kept on the orbiters for replay after conjunction. No conjunction-period data from Opportunity will be kept on the rover. Opportunity will operate during conjunction in a mode avoiding use of non-volatile flash memory, the type of memory that can retain data when the rover powers down overnight.

A video showing Mars solar conjunction geometry is at:

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

NASA's five current missions at Mars are preparing the way for human-crewed missions there in the 2030s and later, in NASA's Journey to Mars strategy.

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 the California Institute of Technology in Pasadena, manages the Odyssey, Reconnaissance Orbiter, Opportunity 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:

http://mars.jpl.nasa.gov

http://www.nasa.gov/mars

 

Media Contact

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster@jpl.nasa.gov

2015-190  

 

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NASA Mars Spacecraft Enter Communications Blackout Sunday

by Mike Wall, Space.com Senior Writer   |   June 05, 2015 07:50am ET

 

This diagram depicts the relative 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 the perspective of Earth. Credit: NASA/JPL-Caltech View full size image

An alignment of Mars, Earth and the sun will force NASA's fleet of Red Planet spacecraft to fend for themselves for two weeks beginning on Sunday (June 7).

From June 7 through June 21, Mars will be behind the sun from Earth's perspective. This celestial geometry, known as a Mars solar conjunction, makes radio communications between the two planets difficult — and potentially dangerous, as choppy or garbled instructions could actually harm spacecraft or hamper their missions, NASA officials said.

As a result, engineers won't send commands to NASA's three active Mars orbiters, or to the agency's two rovers, Opportunity and Curiosity, during this two-week stretch. Commanding will also be reduced on the days leading up to and following conjunction. [How NASA Deals with a Mars Solar Conjunction (Video)]

But that doesn't mean Opportunity, Curiosity, Mars Odyssey, the Mars Reconnaissance Orbiter (MRO) and the Maven spacecraft will get a two-week vacation.

"Spacecraft will continue making some science observations during the conjunction period, though rovers will not do any driving or arm movements," NASA officials wrote in a statement Wednesday (June 3).

Mars solar conjunctions occur every 26 months, so NASA has dealt with them before. In fact, this will be the seventh conjunction that Mars Odyssey has experienced, the sixth for Opportunity and the fifth for MRO. (Odyssey arrived at the Red Planet in 2001, while Opportunity and MRO got there in 2004 and 2006, respectively.)

The Curiosity rover touched down in August 2012 and is therefore a conjunction veteran as well.

"Our overall approach is based on what we did for the solar conjunction two years ago, which worked well," Nagin Cox of NASA's Jet Propulsion Laboratory in Pasadena, California, who is leading conjunction planning for Curiosity, said in the same statement. "It is really helpful to have been through this before." 

Curiosity and Opportunity will send some data up to the orbiters during the conjunction period, NASA officials said. MRO and Mars Odyssey will continue to relay information to Earth from June 7 through June 21, but they will also store the data on board for re-transmission after conjunction. Maven (whose name is short for Mars Atmosphere and Volatile Evolution) won't transmit any information back home until conjunction is over. 

Curiosity will store its own information on board as well. But Opportunity, which has been experiencing memory problems lately, will rely on the orbiters to safeguard the science data it gathers during conjunction.

 

 

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