NASA Spacecraft Prepare to Study Comet Flying by Mars


By Robert Marshall, Educator, Carnegie Science Center

After the discovery of comet C/2013 A1 by the 20” telescope of the Sliding Spring Observatory earlier this January, scientists are predicting its close encounter with the red planet on October 19, 2014. Each observation since its discovery has led to better orbital trajectories, helping to determine the time, velocity and distance at which it will pass.

Red Planet Safe from Impact

Original mathematical calculations gave Mars a 1 in 2,000 chance of impact. Those odds were high. Though such an impact would only exhibit one-third the amount of energy as the theorized dinosaur extinction event on Earth 65 million years ago, such an event would change Mars, a planet with merely one-tenth the mass of Earth. Scientists would then have a chance to study a global climate-changing event, in real-time, right here in our own solar system. But today, odds of impact have been reduced to 1 in 120,000.

Martian Encounter

Regardless, the comet is expected to pass within approximately 186,000 miles of Mars, making this event unprecedented for the network of Martian spacecraft, giving scientists a look at another world from another world. Odyssey and MRO (Mars Reconnaissance Orbiter) currently orbit the planet, taking images of the rusty oxidized surface. Adjusting their pitch so that their instrumentation can be directed out toward space could provide a solution. But engineers are not even sure if this is possible. Additionally, C/2013 A1 will be buzzing by quickly at 125,000 mph, presenting an additional challenge for capturing images.

However, these satellites don’t offer the only chance for close observation. From the surface, Opportunity or MSL (Mars Science Laboratory) could look up and photograph the comet’s nighttime glow. These wheeling spacecraft are almost on opposite sides of the planet from one another, meaning the rotation of Mars during the comet’s pass will determine which rovers — maybe both — get a peak.

Classroom Discussion

  • Where do comets originate?
  • What other retired spacecraft missions have been sent to Mars? What about planned future spacecraft