In-situ measurements of ice on Mars
The 25th of May, the Phoenix Mars Lander landed successfully in the Martian arctic. Following NASA's guideline "follow the water", Phoenix will conduct measurements of the atmosphere, soil and ground ice to investigate the Martian water cycle. Furthermore, it will search for organic material in subsurface layers and thereby gain knowledge about the habitability of the northern plains of Mars.
Along with people from the Mars group at University of Copenhagen and Århus, Mads Dam Ellehøj is representing Center for Ice and Climate as a collaborator in the Danish team on the Phoenix mission.
By Mads Dam Ellehøj
The first mission to the Martian arctic region
After 7 nerve-breaking minutes during the entry, descent and landing procedures, the Phoenix Mars Mission landed safely on the northern plains of Mars and has sent back lots of pictures and meteorological measurements since then. Being the first mission to the Martian arctic region, Phoenix will investigate the ground ice, the Martian water cycle and habitability of the landing site. The site was chosen because of the high amount of water ice in the subsurface, revealed by gamma ray and neutron spectrometer measurements from orbit (Mars Odyssey) and supported by the characteristic surface polygonal patterns that occur during freeze-thaw cycles and when water vapor is exchanged between the permafrost and the atmosphere. These polygons can be seen on the picture below.
hoenix will access the ground ice with a robotic arm and will take pictures with a stereo camera and a robotic arm camera. It will monitor the Martian arctic climate with a meteorological station and perform measurement on the collected samples with following science instruments: A wet chemistry laboratory, a robotic arm camera (sort of a geologists magnifying glass), in some cases with a spectroscopic stereoscopic camera, optical and atomic force microscopes, a differential scanning calorimeter, and a mass spectrometer.
The mission -so far
Being on Sol 10 (1 Sol = One Mars day = 24 hour and 39 minutes) since landing, Phoenix is still in the characterization phase where the different instruments run tests to prepare for sample handling. During this part of the mission, the surroundings are examined to prepare for digging and therefore most of the data sent back are pictures. However, even though Phoenix has not released its full potential yet by analyzing samples in the science instruments, it seems to have found ice in the subsurface without digging. The picture below shows a bright, hard surface underneath the lander which was exposed by the landing thrusters.
This feature is a good candidate for the ground ice table. Some of the bright stuff was also visible in the test dig that was made (can be seen on the picture below) as a preparation for the real sample collection. -From this, it seems like the ice is right underneath the surface, just as expected!
Why am I a part of this mission?
When the spacecraft comes out of the characterization phase, an important part of the science goals are in-situ measurements of the atmosphere, ground ice and soil samples with the mass spectrometer. These measurements will reveal the composition of the atmosphere and ground ice and hence the water isotope ratios. This knowledge is important for the understanding of the processes in the Martian water cycle and my plan is to use this data along with the meteorological data in some modeling of the water isotopes in the ground ice - atmosphere system.
So for me, the next couple of days with sample aquisition will be very exciting!
The Mars group at University of Copenhagen built the radiometric calibration targets for the Surface Stereo Imager (SSI). The same combination of instruments (i.e. the SSI, the calibration targets and some additional Danish supplied targets on the lander) also serves as a scientific instrument to investigate the magnetic properties of the airborne dust. The Mars group at University of Århus built the Telltale wind monitor that has already provided lots of good science and engineering data for the Phoenix mission.
Webpages from the Danish team on the Phoenix mission can be found here:
https://www.nbi.ku.dk/english/research/astrophysics/mars/
Information about the telltale and the science it provides can be found here: