presented at the ISPRS Working Group IV/8 Planetary Mapping and Spatial Data Bases Berlin, September 24/25, 2015

Transcription

1 NEW SPIN AXIS, SPIN RATE AND PRIME MERIDIAN EXPRESSIONS FOR PRECISION MARS CARTOGRAPHY by T. Duxbury, George Mason University, Fairfax, VA, USA W. Folkner and T. Parker, Jet Propulsion Laboratory, Pasadena, CA, USA R. Kirk and B. Archinal, US Geological Survey, Flagstaff, AZ, USA J. Oberst, German Space Center DLR and Technical University Berlin, Berlin, Germany presented at the ISPRS Working Group IV/8 Planetary Mapping and Spatial Data Bases Berlin, September 24/25, 2015 Oral Session 4 (24 September 16:00-17:30) Chairperson: Randy Kirk Mars 9/24/15 Mars Inertial Orientation 1

2 HISTORY THE CURRENT EXPRESSIONS FOR THE MARS INERTIAL ORIENTATION ARE BASED UPON REGISTERING AIRY 0 TO MOLA (Duxbury, Caplinger, Neumann, 1999) AND THE SPIN POLE / SPIN RATE DETERMINED FROM RADIOMETRIC TRACKING OF THE VIKING AND MPF LANDERS (Konopliv, et al., 1999). Airy 0 MOLA DIM and VO-1 Imaging Duxbury GMU MOLA ground track and a MOC Image THESE EXPRESSIONS ARE DOCUMENTED IN THE MGCWG REPORT BY Duxbury, et al., 2002 FOR MORE HISTORY SEE Archinal and Caplinger, /24/15 Mars Inertial Orientation 2 Caplinger MSSS Neumann GSFC Folkner JPL

3 AN UPDATE TO THE MARS INERTIAL ORIENTATION IS NEEDED THE MARS SPIN POLE AND SPIN RATE HAVE VARIATIONS DUE TO THE SEASONAL MASS MOVEMENT BETWEEN THE POLES (Konopliv, et al., 2011) THE ABSOLUTE LOCATION OF AIRY 0 RELATIVE TO THE MOLA GLOBAL DTM IS UNCERTAIN AT THE 50 m 1-σ LEVEL (Duxbury, et al., 2014) Airy 0 > Airy 0 FULL STEREO PHOTOGRAMMTRIC REDUCTION OF THEMIS IR TIED TO MOLA MOC IMAGE WITH MOLA GROUND TRCK Duxbury et al GMU Folkner JPL 9/24/15 Mars Inertial Orientation 3

4 AN UPDATE TO THE MARS INERTIAL ORIENTATION IS NEEDED (CONT.) THE ABSOLUTE LOCATIONS OF VL-1, VL-2, MPF, MER-A, MER-B AND MSL RELATIVE TO THE MOLA GLOBAL DTM HAVE UNCERTAINIES AT THE 50 m 1-σ LEVEL Kirk USGS 9/24/15 Mars Inertial Orientation 4

5 AN UPDATE TO THE MARS INERTIAL ORIENTATION IS NEEDED (CONT.) THE ABSOLUTE LOCATIONS OF VL-1, VL-2, MPF, MER-A, MER-B AND MSL RELATIVE TO THE MOLA GLOBAL DTM HAVE UNCERTAINIES AT THE 50 m 1-σ LEVEL (CONT.) HiRISE image PSP_001719_2025 VL-1 LANDING SITE 9/24/15 Mars Inertial Orientation 5 Parker JPL

6 THE POSITION ADOPTED BY THE MGCWG THE ORIENTATION OF THE MARS SURFACE IN INERTIAL SPACE IS TIED TO THE LOCATION OF CRATER AIRY 0. THE MOLA GROUND TRACKS HAVE ALTIMETRY EVERY 300 m IN LATITUDE BUT HAVE GAPS OF 2 3 km IN LONGITUDE AT THE EQUATOR (Smith, et al., 2001 and Neumann, et al., 2001). THEREFORE THE ABSOLUTE LOCATION OF AIRY-0 IN INERTIAL SPACE / RELATIVE TO THE MOLA GLOBAL DTM CAN ONLY BE DETERMINED TO AN ACCURACY OF 10 S OF METERS USING ANY IMAGING DATASET TIED TO MOLA. THE LANDER LOCATIONS CAN BE DETERMINED TO THE METER LEVEL OF ACCURACY FROM THE EARTH-BASED RADIOMETRIC TRACKING. THE LANDERS ARE VISIBLE IN ORBITER IMAGES. THEREFORE DETERMINE THE MOST ACCURATE MARS-FIXED LOCATION OF VL-1 IN IMAGES TIED TO THE MOLA GLOBAL DTM / CURRENT BEST GUESS AS TO THE AIRY 0 LOCATION THIS IS KNOWN TO HAVE AN UNCERTAINTY OF 50 m 1-σ HOLD CONSTANT THIS MARS-FIXED LOCATION OF VL-1 AND REDUCE ALL RADIOMETRIC TRACKING DATA OF ALL LANDERS TO DETERMINE THE LOCATION OF ALL OTHER LANDERS RELATIVE TO VL-1 WHEN SOLVING FOR THE SPIN AXIS DIRECTION AND SPIN RATE. THE PRIME MERIDIAN EPOCH VALUE IS NOW FIXED AND TIED TO THE LOCATION OF VL-1 ANY FUTURE CHANGES TO THE PRIME MERIDIAN EPHEMERIS POSITION AT J CAN BE TIED TO CHANGES IN LANDER LOCATIONS, EXPECTED TO BE AT THE METER LEVEL, AND NOT TO ANY NEW OBSERVED LOCATION OF AIRY 0 THAT IS EXPECTED TO BE ACCURATE TO ONLY 50 m 1-σ. 9/24/15 Mars Inertial Orientation 6

7 THE UPDATED MARS INERTIAL ORIENTATION EXPRESSIONS (Kuchynka, et al., 2014) Mars Spin Axis Right Ascension in J Mars Spin Axis Declination in J Mars Prime Meridian in J NOTE: The current expressions only have epoch value and secular rate terms (1 st two terms) 9/24/15 Mars Inertial Orientation 7

8 THE CHANGE TO THE COMPUTED MARS INERTIAL ORIENTATION 1 X 10-3 deg = 60 meters 9/24/15 Mars Inertial Orientation 8

9 THE STATUS OF THE UPDATED MARS INERTIAL ORIENTATION EXPRESSIONS THE NEW EXPRESSIONS WERE REVIEWED AND APPROVED BY THE NASA MARS EXPLORATION PROGRAM OFFICE GEODESY AND CARTOGRAPHY WORKING GROUP (MGCWG). AN ALPHA TEST NAIF SPICE PLANETARY CONSTANTS KERNEL (PCK) IS AVAILABLE THE MGCWG RECOMMENDED THE NEW STANDARD TO THE IAU WORKING GROUP FOR CARTOGRAPHIC COORDINATES AND ROTATIONAL ELEMENTS (WGCCRE) FOR ADOPTION. THE IAU WGCCRE (B. Archinal Chairman) IS INCLUDING THE NEW STANDARD IN ITS PUBLICATION TO BE RELEASED IN Giovanni Schiaparelli 9/24/15 Mars Inertial Orientation 9

10 REFERENCES Archinal, B. A., and M. Caplinger (2002), Mars, the meridian, and Mert: The quest for Martian longitude, Eos Trans. AGU, 83(47), Fall Meet. Suppl., Abstract P22D-06. [Available at abstracts/p22d-06.html.] Christensen, P. R., et al. (2004), The Thermal Emission Imaging System (THEMIS) for the Mars 2001 Odyssey mission, Space Sci. Rev., 110, Duxbury, T. C., R. L. Kirk, B. A. Archinal, and G. A. Neumann (2002). Mars Geodesy/Cartography Working Group Recommendations on Mars Cartographic Constants and Coordinate Systems, ISPRS, v. 34, part 4, Geospatial Theory, Processing and Applications, Ottawa. See Also available at Kuchynka, P., W. M. Folkner, A. S. Konopliv, T. Parker, S. Ryan, S. Park, S. Le Maistre, and V. Dehant (2014), New constraints on Mars rotation determined from radiometric tracking of the Opportunity Mars Exploration Rover, Icarus, 229, ,doi: /j.icarus Konopliv, A. S., S. W. Asmar, W. M. Folkner, O. Karatekin, D. C. Nunes, S. E. Smrekar, C. F. Yoder, and M. T. Zuber (2011), Mars high resolution gravity fields from MRO, Mars seasonal gravity, and other dynamical parameters, Icarus, 211, Malin, M. C., G. E. Danielson, A. P. Ingersoll, H. Masursky, J. Veverka, M. A. Ravine, and T. A. Soulanille (1992), The Mars observer camera, J. Geophys. Res., 97(E5), , doi: /92je Neumann, G., F. Lemoine, D. Rowlands, D. E. Smith, and M. T. Zuber (2001), Crossover analysis in MOLA data processing, J. Geophys. Res.,106(E10), 23,753 23,768. Smith, D. E., et al. (2001), Mars Orbiter Laser Altimeter: Experiment summary after the first year of global mapping of Mars, J. Geophys. Res., 106(El0), 23,689 23,722 NASA MGS MOC IMAGES, M. MALIN PI, MSSS NASA ODY THEMIS IR IMAGES, P. CHRISTENSEN PI, ASU NASA MRO HiRISE IMAGE, A. McEWEN PI, U of AZ NASA MGS MOLA DTM, D. SMITH PI, MIT 9/24/15 Mars Inertial Orientation 10