Mars Phoenix Lander, 10 Years Later

Dr. Tanya Harrison
6 min readMay 29, 2018
In this artist’s concept illustration, NASA’s Phoenix Lander begins to shut down operations as martian winter sets in. Credit: NASA/JPL-Caltech/University of Arizona

Ten years ago this past week, a robot named Phoenix landed in the northern plains of Mars. The mission lasted a little over five months before the lander succumbed to the frigid martian winter, about two months longer than planned. Unlike Spirit and Opportunity, its roving older siblings near the equator, Phoenix was a stationary lander positioned at 68°N latitude—above the Arctic Circle on Earth (for any fellow Canadians out there, it’s about the same latitude as Inuvik). The goal of Phoenix was “to study the history of water and habitability potential in the martian arctic’s ice-rich soil.” And riches indeed it found there! Let’s take a look back at five big contributions to science made by the Phoenix mission in its brief time on Mars:

1. Ice, ice, baby!

Phoenix’s Robotic Arm Camera captured this view beneath the lander on sol 5 of its mission. The white patches near the centre were thought to be ice exposed by the lander’s descent thrusters (visible at the top of the image) during landing. Credit: NASA/JPL-Caltech/University of Arizona/Max Planck Institute

Multiple observations from orbit had hinted at buried ice in the high latitudes of Mars. To investigate this, the Phoenix lander was equipped with a robotic arm capable of digging into the soil. However, before the lander even got a chance to use this arm, its landing thrusters did some of the work for it—blasting away a few inches of loose soil—and exposed what appeared to be ice.

These colour images of the trench informally dubbed “Dodo-Goldilocks” were acquired by Phoenix’s Surface Stereo Imager on sols 20 and 24 (15 and 19 June 2008), showing the disappearance of ice dug up by the lander. Credit: NASA/JPL-Caltech/University of Arizona

This led to even more anticipation for trench digging. Of the dozen trenches Phoenix dug during its mission, two exposed hard, white material that disappeared in less than 4 sols (martian days). Scientists interpreted this to be ice that, once exposed to the temperature and pressure conditions at the martian surface, sublimated away. Sublimation is a process where ice goes directly from solid to vapour without going through the liquid phase. Liquid water is generally not stable on the surface of Mars due to its low temperature and atmospheric pressure, but…

2. Liquid water…

Blobs of possible brine (*really* salty water) imaged on one of Phoenix’s landing struts shortly after arriving on Mars. Credit: NASA/JPL-Caltech/University of Arizona/Max Planck Institute

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Dr. Tanya Harrison

Professional Martian who's worked on rocks and robots on the Red Planet on multiple NASA Mars missions