The combined CalTarget and iSweep experiment – Københavns Universitet

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The combined CalTarget and iSweep experiment


The improved sensitivity sweep magnet experiment (iSweep) is an improved version of the sweep magnet experiment previously flown on the Mars Exploration Rovers. The iSweep experiment has enhanced sensitivity to detect non-magnetic dust particles in the Martian atmosphere.

Left: Sweep magnet on MER. Image credit: NASA/JPL/Cornell/NBI-UCPH.
Right: iSweep experiment from Phoenix. Image Credit: LPL-University of Arizona/NASA-JPL/NBI-UCPH/Texas A&M University.

The sweep magnet on the Mars Exploration Rovers (MER) was designed to allow only non-magnetic particles to settle in the center and (essentially) no particles have been detected there for the entire mission. 

The Phoenix lander carried three identical iSweep experiments placed on different locations on the lander deck and each consisting of six identical sweep magnets covered with silicone chips of different colors.
The different contrasts provided by the various background colors enhanced the ability to detect any non-magnetic particles that might have settled in the center of these magnets, and this time non-magnetic (or at least very weakly magnetic) particles were found. More on that under Phoenix results .

CalTarget/iSweep. Image credit: NBI-University of Copenhagen.


In addition the three iSweeps served as calibration targets for the cameras on Phoenix (the Surface Stereo Imager and the Robotic Arm Camera).

The iSweep magnets were designed to keep their colored centers clean of magnetic dust and thereby provide virtually constant color references for the cameras during the entire mission.

Fiducial point. Image credit: NBI-University of Copenhagen.

Fiducial points

There are three fiducial points on the lander deck covered with the same colored material as the iSweeps. The primary function of the fiducial points was to serve as orientation markers for the Surface Stereo Imager and thus assist in the operation of the Robotic Arm. 

But since the fiducial points are far away from the influence of any magnets and are covered in the same colored material as the iSweeps, they also served as references for the iSweep experiment providing results concerning dust sedimentation in zero magnetic field.

We also provided the MECA magnets on Phoenix.