Traffic Jams At Mars? Say It Ain’t So

This graphic depicts the relative shapes and distances from Mars for five active orbiter missions plus the planet's two natural satellites. It illustrates the potential for intersections of the spacecraft orbits. Credit: NASA/JPL-Caltech
This graphic depicts the relative shapes and distances from Mars for five active orbiter missions plus the planet’s two natural satellites. It illustrates the potential for intersections of the spacecraft orbits. Credit: NASA/JPL-Caltech

Looking for a job as a celestial traffic cop? Consider giving NASA a call. With the arrival last summer of two additional orbiters at Mars, there are now five active satellites with their eyes on the Red Planet. NASA tracks those and the approximate location of its Mars Global Surveyor, a 1997 orbiter that’s not longer working, to make sure they don’t thump together like bumper cars anytime soon.

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) and India’s Mars Orbiter Mission joined the 2003 Mars Express from ESA (the European Space Agency) and two from NASA — the 2001 Mars Odyssey and the 2006 Mars Reconnaissance Orbiter (MRO) to form the quintet.

Looking like some kind of nature painting, you're seeing the effects of dust devils. Each track is where a dust devil swept away bright dust to reveal the darker surface beneath. It was taken on March 2, 2015 by NASA's Mars Odyssey orbiter. Credit: NASA
Looking like pencil on parchment, this photo, taken by NASA’s Mars Odyssey orbiter on March 2, shows hundreds of dark streaks near a small crater on Mars. Each streak was made by a dust devil  that swept away bright dust to reveal the darker surface beneath. Credit: NASA

While the total number of spacecraft is important, consider that each conducts its own science mission from a different orbit, which can be lowered or raised depending on the needs of the mission. MAVEN studies the upper atmosphere and loops around Mars in an elongated orbit that climbs higher than any other probe but also dips below them on the opposite side of its orbit, crossing the altitudes of their orbits.

To be on the safe side, NASA not only monitors its own but also the Indian and European satellites with the aim of avoiding potential collisions:

Dark, seasonal flows emanate from bedrock exposures at Palikir Crater on Mars in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. These flows, now documented at several places on Mars, form and grow during warm seasons when surface temperature is warm enough for salty ice to melt, and then fade or completely disappear in the colder season. Credit: NASA
Dark, seasonal flows emanate from bedrock exposures at Palikir Crater on Mars in this image taken by NASA’s Mars Reconnaissance Orbiter. These flows, now documented at several places on Mars, form and grow during warm seasons when surface temperature is warm enough for salty ice to melt, and then fade or completely disappear in the colder season. Credit: NASA

“MAVEN’s highly elliptical orbit, crossing the altitudes of other orbits, changes the probability that someone will need to do a collision-avoidance maneuver. We track all the orbiters much more closely now. There’s still a low probability of needing a maneuver, but it’s something we need to manage,” said Robert Shotwell, Mars Program chief engineer at the Jet Propulsion Lab (JPL) in California.

Despite the increased focus on safety at Mars, there’s far less concern there than closer to home, where more than 1,000 active orbiters plus lots of inactive hardware add to trackers’ headaches. Still, more missions to the Red Planet are in the planning stages including NASA’s InSight, slated to launch in 2016, and the Mars 2020 rover. And that’s just what the U.S. has in its back pocket. China and the European Space Agency are working on their own Mars missions as you read this.

All five active Mars orbiters use the communication and tracking services of NASA’s Deep Space Network, which is managed at JPL. The amount of uncertainty in the predicted location of a Mars orbiter a few days ahead is more than a mile (~2 km). Calculating projections for weeks ahead multiplies the uncertainty to dozens of miles, or kilometers.

“When two spacecraft are predicted to come too close to one another, we give people a heads-up in advance so the project teams can start coordinating about whether any maneuvers are needed,” said Joseph Guinn, manager of JPL’s Mission Design and Navigation Section.

An artist concept image of where seven carefully-selected instruments will be located on NASA’s Mars 2020 rover. The instruments will conduct unprecedented science and exploration technology investigations on the Red Planet as never before. Credits: NASA
More on the way! An artist concept image of where seven carefully-selected instruments will be located on NASA’s Mars 2020 rover. The instruments will conduct  science and exploration technology investigations on the Red Planet as never before. Credit: NASA

On Jan. 3 this year, automated monitoring determined that two weeks down the road, MAVEN and MRO could come within about two miles (3 km) of each other. Before an avoidance maneuver was planned, uncertainties in the calculations shrank to within safe parameters and nothing untoward happened.

Although two spacecraft approaching within a few hundred yards of each other would be a bad thing, it could also serve as a tool to simultaneously observe the same features with complementary instruments at the same time. A brilliant idea!

4 Responses

  1. caralex

    Nice new layout for your blog, Bob! One thing – the topics in ‘Popular Searches” are almost impossible to read – the background and the font are too close in colour. Can you change one or the other, or both?

    1. astrobob

      Hi Carol,
      I agree. This is what admin bequeathed to us. I’m trying to get it changed.

  2. Hi Bob,

    With all these assets being sent to Mars, it looks like NASA is serious about eventually sending humans to Mars.

    From all that Ive heard, it doesnt sound like space is a very healthy place for humans…they must be advancing our ability to survive in space though. Looks like the next 10 years could be a very exciting time for humans in space!

    The International Space Station is interesting enough, but to see humans actually head farther out and really start safely exploring is what I want to see.

    1. astrobob

      David,
      I think as long as the different governments, supported by us taxpayers, are willing to make these investments, manned space exploration to other worlds could begin again.

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