Master's Thesis Master's Thesis
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2010:056 CIV 2010:056 CIV MASTEMASTER’SR’S THESIS THESIS2010:056 CIV MASTER’S THESIS The Seasonal Behaviour of Ice and 2010:056 CIV Features in Craters at the The SeasonalMASTE BehaviourR’S THESIS of Ice and NorthernFeatures Polar in Craters Region at of the Mars Northern Polar Region of Mars The Seasonal Behaviour of Ice and Features in Craters at the Northern Polar Region of Mars Mitra Hajigholi Mitra Hajigholi MASTER OF SCIENCE PROGRAMME SpaceMitra Engineering Hajigholi MASTERLuleå OF University SCIENCE of Technology PROGRAMME Department of AppliedSpace Physics Engineering and Mechanical Engineering MASTER DivisionOF SCIENCE of Physics PROGRAMME Luleå UniversitySpace Engineering of Technology Universitetstryckeriet, Luleå Department#)6s)33. s)32.,45 %8 3% of Applied Physics and Mechanical Engineering Luleå University of Technology Division of Physics Department of Applied Physics and Mechanical Engineering Universitetstryckeriet, Luleå Division of Physics #)6s)33. s)32.,45 %8 3% Universitetstryckeriet, Luleå #)6s)33. s)32.,45 %8 3% Preface This report is the diploma thesis for a Master of Science in the Space Engineering Pro- gramme at Luleå University of Technology. It is the result of an internship at NASA Ames Research Center in California between October and January 2009/2010. It was possible due to a collaboration initiated by Luleå University of Technology. This thesis project was directed under Dr. Chris P. McKay (scientist at NASA Ames Research Center) and supervised by Dr. Adrian Brown (post-doc at SETI), who presented the idea upon which this project is based. I and my fellow student, Angelique Bertilsson, from Luleå University of Technology have worked side by side on this project. The resulting two thesis works are both about the geological characteristics of craters, on the Martian Northern Polar Region (NPR), related to seasonal ice coverage and features. I would like to begin by thanking Dr. Chris P. McKay for his time with us. He has supported the project with invaluable inputs, ideas and inspiration. He welcomed us with great hospitality to California and to NASA Ames Research Center. I would like to show my gratitude to Dr. Adrian Brown for his time, knowledge and encouraging enthusiasm for this project. He provided us with essential knowledge about craters and the NPR of Mars. Further, I would like to thank my examiner Prof. Sverker Fredriksson, for reading the report and giving constructive suggestions on it, and for giving me the opportunity to start with this thesis in collaboration with the NASA Ames Research Center. I would like to thank Angelique Bertilsson for helpful discussions and creative ideas, and for our unforgettable memories together in California. I also would like to thank Mi- kaela Appel, Robin Ramstad and everybody who made the stay at NASA Ames an unfor- gettable time. Last but not least I would like to send my huge gratitude to my family and beloved friends for supporting, inspiring and being there for me. Mitra Hajigholi April 9, 2010 i ii Abstract This Master Thesis work in Space Engineering was conducted at NASA Ames Research Center. It is a pre-study to understand how the Martian weather conditions affect water and carbon dioxide ice annually in craters, located in the Northern Polar Region (NPR) of Mars. Different (known and unknown) features have been investigated when observing the 87 craters included in this work and located poleward of 60° in latitude. These craters are studied with images from CTX and HiRISE mainly, but also from CRISM. There are many images taken by both CTX and HiRISE of the craters over seasons, acquired from 2006 to 2008. Over 500 possible crater images were examined. To make a good scientific observation and a satisfactory description of the ice amount and features covering the crater, a sort out of some insignificant data was needed. Only images where the crater is visible and easily identifiable have been used i.e., not obscured by any clouds, dust storms or even glaring from the Sun to the camera. The 87 craters chosen to be investigated on the NPR have been carefully selected. Only craters larger than 10 km in were monitored, unless they have a given name. Since large craters are created by high energy impacts and cause a more complex crater, they are more interesting for this study. All craters were localized on a virtual spherical map over Mars and pinned to be saved in a folder, so that the observed place/surface/image is easily found again. To organize the entire collection of image data from varying solar longitude, of every 87 craters, a database called Information on Craters in the Martian Northern Polar Region was created by the writer and Angelique Bertilsson. The database is in addition to organize all the collected data, also designed to better, faster and easier use the information collected. For future scientific study of this work, Information on Craters in the Martian NPR will probably in the future be a public tool on a website easily accessible for scientist and stu- dents to use. Through this work both expected and unexpected seasonal variations have been ob- served. Theories of why the ice behaves, as it does, and how the features change seasonally are explained and discussed in this work. iii iv Nomenclature DDS Dark Dune Spot GRS/NS Gamma Ray Spectrometer/Neutron Spectrometer LS Solar longitude MEP Mars Exploration Program MGS-TES Mars Global Surveyor -Thermal Emission Spectrometer MRO Mars Reconnaissance Orbiter NPLD North Polar Layered Deposit NPR Northern Polar Region NPRC Northern Polar Residual Cap PLD Polar Layered Deposit SPC Southern Polar Cap v vi List of Contents 1 Introduction .............................................................................. 1 1.1 NASA Ames Research Center ...................................................... 1 1.2 SETI ............................................................................................ 2 2 Mars.......................................................................................... 3 2.1 Mars orbit and seasons ................................................................. 3 2.2 Crater formation .......................................................................... 5 2.3 Climate and atmosphere ............................................................... 5 2.4 The polar regions ......................................................................... 7 3 Tools used to study the Martian craters .................................. 13 3.1 Cameras on MRO ...................................................................... 13 3.2 IAS viewer ................................................................................ 16 3.3 Google Earth ............................................................................. 17 3.4 Database .................................................................................... 19 3.5 Criteria used for image selection ................................................ 19 4 The features that craters can contain in the Martian Northern Polar Region............................................................ 21 4.1 Dunes ........................................................................................ 21 4.2 Dust Devils ................................................................................ 22 4.3 Defrosting features ..................................................................... 24 4.4 Dark dune spots ......................................................................... 26 4.5 Polygons .................................................................................... 27 5 Crater characteristics, on Martian Northern Polar Region, related to seasonal ice coverage and other features .................. 31 6 Results .................................................................................... 67 6.1 Ice amount in all craters ............................................................. 67 vii 6.2 Dunes ........................................................................................75 6.3 Dust Devils ................................................................................76 6.4 Defrosting ..................................................................................78 6.5 Dark dune spots .........................................................................79 7 Discussion ............................................................................... 81 7.1 Ice amount in all craters .............................................................81 7.2 Dunes ........................................................................................82 7.3 Dust Devils ................................................................................84 7.4 Defrosting ..................................................................................85 7.5 Dark Dune Spots ........................................................................86 8 Future work ............................................................................ 89 References ................................................................................... 91 Appendix A ................................................................................. 95 Appendix B ................................................................................102 Appendix C ................................................................................103 Attachment ................................................................................104 viii 1 Introduction As early as the eighteenth century the