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Ralph Lorenz

Research Scientist
Johns Hopkins University Applied Physics Lab
11100 Johns Hopkins Road
Laurel, Maryland 20723

Lorenz's research focuses on Titan (all aspects of Titan science, but especially climate, weather and landscape), Icy Satellite Geology and Geophysics, Engineering and mission design of spacecraft, instrumentation and in-situ planetary exploration vehicles (balloons, penetrators, etc.). Additional research includes planetary climate, non-equilibrium thermodynamics, and Dust Devils on Earth and Mars.

Title 1: Titan Unveiled

Abstract:

Cassini-Huygens has revealed Titan to have a strikingly Earth-like meteorology and landscape. While the chemistry and physical conditions are very different, Titan's weather has many striking parallels with Earth's, with occasional violent methane storms cutting washes and rounding icy cobbles between long droughts. Its landscape toois evocative - its vast equatorial sand seas, likely made of organic particulates, resemble the Earth's largest dunefields, and its high latitude lakes show a range of morphologies reminiscent of karst, playa lakes and flooded terrain. There
is some evidence of cryovolcanism, and the relative lack of impact craters is testament to ongoing resurfacing processes. Astrobiologically, Titan is of particular interest in that it likely has an internal water ocean, and has abundant surface deposits of complex organic molecules.
This talk reviews what we have learned about Titan as a planetary system, wherein the interior, surface, atmosphere and space environment interact in manifold ways.



Title 2: Descent into the Unknown - The Huygens Probe

Abstract:

In late 2004, the Huygens probe was released towards Titan's atmosphere by Cassini after a 7 year, billion mile voyage to the Saturnian system. The probe was Europe's first planetary mission, and presented some severe engineering challenges such as hypersonic entry into an exotic atmosphere and the operation of systems in a cryogenic environment.

As with other planetary probe missions, not everything went as expected. A design flaw in the radio system was discovered some 3 years after launch, but re-engineering of the on-board software and the mission design provided a workaround. While the heat shield and parachute systems worked well, the probe's spin behavior during descent was not as expected. Nonetheless, the probe mission was overall an outstanding success, providing ground truth for Cassini's remote observations, and blazing a trail for future in-situ exploration, perhaps by more ambitions vehicles such as balloons.

This talk reviews the design of the Huygens probe and its instrument payload, and the Cassini mission as a whole. The speaker will relate some of his experiences working on Cassini
throughout his entire career (from an engineer straight out of college working for the European Space Agency, then building part of Huygens' instrumentation as a graduate student in the
UK, through planning Cassini's radar observations in the USA).