Mars Climate Sounder Collects 20 Millionth Sounding

Last week Mars Climate Sounder collected its 20 millionth sounding at Mars. Mars Climate Sounder is scanning without problems, collecting science observations of the atmosphere of Mars. Mars Climate Sounder has now been observing Mars for over 17 months (three quarters of a Mars year and also approximately three quarters of the Mars Reconnaissance Orbiter primary science mission).

The problems with Mars Climate Sounder's elevation actuator have been solved by scanning the instrument within a limited range of 122 degrees in elevation. This allows us to fully calibrate the instrument, track the limb around the orbit, and view the planet slightly below the limb. This restores the full atmospheric science observations and may allow for a bit of the surface science to be recovered. Mars Climate Sounder started this improved scanning in mid-June 2007 and has added capability since then.

Limb tracking and space views were the first addition. At the end of June we added black body calibrations. In late September we added solar calibration target views. In early October we stepped below the limb position to recover a surface view. The first step, 10 degrees below the limb worked fine with no errors. A second step, to 20 degrees below the limb, generated position errors so we immediately stopped that scanning and returned to only going 10 degrees below the limb (the current setting).

Each sounding takes two seconds to collect, and Mars Climate Sounder produces a continuous stream of soundings, even when the other instruments are taking data. Most of the soundings provide information on the atmosphere when the instrument is pointed at the limb. Some are observations of the surface of Mars to provide information on the surface and atmosphere near the surface. Some of the soundings are used to look at calibration targets and others are taken while the instrument is moving, but the science team tries to minimize these two categories as much as possible.

The Mars Climate Sounder team is currently working toward two major goals at the end of May. The first is to help the Phoenix mission land successfully near the north pole. Mars Climate Sounder will soon start to provide near-real-time measurements of the martian weather so that Phoenix can take it into account when planning where to land. Also, in early June, Mars Climate Sounder will be releasing to the public the first atmospheric profiles of temperature, dust, and water ice. The data will be made available through the Atmospheres Node of NASA's Planetary Data System.