Niels Bohr Institutet > Kalender - det sker på NBI > 2009 > Performance of the Rad...

Performance of the Radiometric Calibration Tagets on the NASA Phoenix Mars Lander

by Martin Patrong Haspang
The defense will be in Danish

The Improved Sweep Magnet Experiment (iSweep) on the Phoenix Mars lander was supposed to work as a radiometric calibration target for the cameras on Phoenix and to be used for studies of the dust that would settle on the iSweeps.

The thesis describes the properties of the dust accumulated on the magnetic and magnetically protected regions of the iSweeps. The dust is found to be strongly absorbing in the blue part of the spectrum with an monotonically increasing reflectance towards the red and nearinfrared, where the dust is strongly reflecting, in agreement with previous photometric measurements of Martian dust and soil. However, the dust on the Phoenix iSweeps is found to be somewhat brighter.

The magnetic component of the dust is found to be moderately forward scattering, while there are indications that the non-magnetic component is strongly forward scattering. The mean particle size is found to be about 1.2μm for the magnetic component and about 0.6μm for the non-magnetic component. The accumulation rates are found to be about 0.22μm/sol for the magnetic regions and about 2.7 • 10^-3 μm/sol for the protected and central regions. The accumulation rates are compared to results from the Mars Exploration Rovers in order to evaluate the ratio of the magnetic component of dust in the Martian atmosphere to the non-magnetic component. The non-magnetic component of the atmospheric dust is found to be 20% - 40% of the total amount of atmospheric dust.

Supervisor: Morten Bo Madsen