Huygens probe entry and descent trajectory analysis and reconstruction techniques

Abstract Cassini/Huygens is a joint National Aeronautics and Space Administration (NASA)/European Space Agency (ESA)/Agenzia Spaziale Italiana (ASI) mission on its way to explore the Saturnian system. The ESA Huygens Probe is scheduled to be released from the Orbiter on 25 December 2004 and enter the atmosphere of Titan on 14 January 2005. Probe delivery to Titan, arbitrarily defined to occur at a reference altitude of 1270 km above the surface of Titan, is the responsibility of the NASA Jet Propulsion Laboratory (JPL). ESA is then responsible for safely delivering the probe from the reference altitude to the surface. The task of reconstructing the probe trajectory and attitude from the entry point to the surface has been assigned to the Huygens Descent Trajectory Working Group (DTWG), a subgroup of the Huygens Science Working Team. The DTWG will use data provided by the Huygens Probe engineering subsystems and selected data sets acquired by the scientific payload. To correctly interpret and correlate results from the probe science experiments and to provide a reference set of data for possible “ground-truthing” Orbiter remote sensing measurements, it is essential that the trajectory reconstruction be performed as early as possible in the post-flight data analysis phase. The reconstruction of the Huygens entry and descent trajectory will be based primarily on the probe entry state vector provided by the Cassini Navigation Team, and measurements of acceleration, pressure, and temperature made by the Huygens Atmospheric Structure Instrument (HASI). Other data sets contributing to the entry and descent trajectory reconstruction include the mean molecular weight of the atmosphere measured by the probe Gas Chromatograph/Mass Spectrometer (GCMS) in the upper atmosphere and the Surface Science Package (SSP) speed of sound measurement in the lower atmosphere, accelerations measured by the Central and Radial Accelerometer Sensor Units (CASU/RASU), and the probe altitude by the two probe radar altimeters during the latter stages of the descent. In the last several hundred meters, the altitude determination will be constrained by measurements from the SSP acoustic sounder. Other instruments contributing data to the entry and descent trajectory and attitude determination include measurements of the zonal wind drift by the Doppler Wind Experiment (DWE), and probe zonal and meridional drift and probe attitude by the Descent Imager and Spectral Radiometer (DISR). In this paper, the need for and the methods by which the Huygens Probe entry and descent trajectory will be reconstructed are reviewed.

[1]  Jean-Pierre Lebreton,et al.  A SIMULATED DATA SET OF THE HUYGENS MISSION , 2004 .

[2]  Dennis L. Matson,et al.  The Huygens Probe: Science, Payload and Mission Overview , 1997 .

[3]  E. Lellouch,et al.  The Yelle Titan Atmosphere Engineering Models , 1997 .

[4]  Robert D. Braun,et al.  Influence of sonic-line location on Mars Pathfinder Probe aerothermodynamics , 1996 .

[5]  Jean-Pierre Lebreton,et al.  Simulation and analysis of the revised Huygens probe entry and descent trajectory and radio link modelling , 2004 .

[6]  V. Gaborit.  Procedure development for the trajectory reconstruction of a probe descending in a planetary atmosphere: application to Galileo and HASI balloon tests , 2004 .

[7]  J. Schofield,et al.  Results of the Mars Pathfinder atmospheric structure investigation , 1999 .

[8]  P. Falkner,et al.  The Characterisation of Titan's Atmospheric Physical Properties by the Huygens Atmospheric Structure Instrument (Hasi) , 2002 .

[9]  B. Rizk,et al.  The Descent Imager/Spectral Radiometer (DISR) Experiment on the Huygens Entry Probe of Titan , 2002 .

[10]  L. Sabau,et al.  The Comas sola mission to test the HUYGENS/HASI instrument on board a stratospheric balloon , 2002 .

[11]  Xun Zhu,et al.  Titan's upper atmosphere - Structure and ultraviolet emissions , 1992 .

[12]  J. Zarnecki,et al.  Analysis of entry accelerometer data: A case study of Mars Pathfinder , 2003 .

[13]  Richard Arquilla,et al.  Trapped-Electron Fluxes Measured by International Ultraviolet Explorer and AE-8 Model Predictions , 1996 .

[14]  Bobby Kazeminejad.  Methodology Development for the Reconstruction of the ESA Huygens Probe Entry and Descent Trajectory , 2005 .

[15]  S. Bauer,et al.  Molecular and eddy diffusion in the atmosphere of Titan. , 1990 .

[16]  D. H. Atkinson,et al.  THE ESA HUYGENS PROBE ENTRY AND DESCENT TRAJECTORY RECONSTRUCTION , 2003 .

[17]  J. Dymond,et al.  The Virial Coefficients of Pure Gases and Mixtures: A Critical Compilation , 1979 .

[18]  David Coscia,et al.  Huygens Probe Aerosol Collector Pyrolyser Experiment , 2002 .

[19]  Paul R. Mahaffy,et al.  Noble gas abundance and isotope ratios in the atmosphere of Jupiter from the Galileo Probe Mass Spectrometer , 2000 .

[20]  Alvin Seiff,et al.  The Galileo Probe Atmosphere Structure Instrument , 1992 .

[21]  Robert D. Braun,et al.  Mars Pathfinder rarefied aerodynamics - Computations and measurements , 1998 .

[22]  Carlo Bettanini,et al.  Huygens Atmospheric Structure Instrument (HASI) test by a stratospheric balloon experiment , 2002 .

[23]  P. Kallemeyn,et al.  Mars Pathfinder Entry, Descent, and Landing Reconstruction , 1999 .

[24]  K. Clausen,et al.  The Huygens Probe System Design , 2002 .

[25]  J. E. Richards,et al.  The Gas Chromatograph Mass Spectrometer for the Huygens Probe , 2002 .

[26]  D. Plettemeier,et al.  The Huygens Doppler Wind Experiment ' Titan Winds Derived from Probe Radio Frequency Measurements , 2002 .

[27]  Mark Leese,et al.  Huygens' Surface Science Package , 2002 .