1 / 37

Exploring Mars

This article discusses the surface conditions on Mars, the potential for electrostatic charging, and the relevance of these factors for future surface vehicles and astronauts. It also explores the use of robots for Mars exploration and the remaining issues to be solved regarding electrical charging on the Martian surface.

oletad
Download Presentation

Exploring Mars

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Exploring Mars Pathfinder Rover Electrostatic Charging . October 8th 2002 Joseph Kolecki

  2. Preliminary Activities • 1. What surface conditions prevail on Mars? • Cold, dry, dusty • Warm, dry, dusty • Cool, wet, crusty • All of the above • How might the surface conditions on Mars be related to ambient electrical activity? • Conducive • Not conducive • A little conducive • Conditionally Conducive

  3. Which surface element on Mars would you think most likely to develop and carry charge? • Rocks • Dust • Duracrust • Volcanic glass • What charging mechanisms do you believe are operational on Mars? • Collisional charging • Triboelectric (frictional) charging • Photoelectric effect • None of the above

  4. What are some issues associated with surface vehicle and astronaut charging? • No issues • Charge is harmless • Charge could impact operations • Charge could produce fatal conditions

  5. Northern Desert North Pole “Old” Surface - Mantle Mount Olympus Cirrus Clouds Tarsus Mariner’s Valley Mars

  6. Tarsus

  7. Mount Olympus

  8. Mariner’s Valley

  9. Martian arroyos as seen from orbit…

  10. ~100 nm Fossil Martian Nano-Bacteria?

  11. Why go to Mars??? Most earth-like planet Reachable via present day technology Possible future colonization … Simple curiosity – It’s there!!!

  12. Why Send Robots to Mars??? Robots are “more durable”/less expensive than humans. Robots can accomplish almost as much as humans. Robots can help us to learn as much as we can about the Martian environment before we send humans.

  13. Environmental Issues at Martian Surface Radiation environment Chemistry Toxicity Electrical charge Biology (?)

  14. ++++++++++ ---------- Electrical Charging in the Martian Environment

  15. Why expect charging on Mars? Cold, dry climate – good for charging things up Seasonal winds – good for stirring things up Dust storms – good for keeping things stirred up in a variety of ways

  16. What physical mechanisms might be involved? Collisional charging due to turbulent motion in dust clouds & dust storms Triboelectric charging due to vehicle or astronaut motion across the surface Photoelectric charging due to solar UV at the surface

  17. Collisional Dust-Charge Exchange Mechanism

  18. e- + -

  19. Effects of Collisional Charging in a Martian Dust Cloud

  20. Paschen’s Curve Electric Potential Difference Pressure-Distance Product

  21. Paschen Curve Minimum Electric Potential Difference 100V Pressure-Distance Product 5 X 10-5 atm-m

  22. Sojourner Rover: Triboelectric charge = Frictionally generated electric charge

  23. Rover Charging Scenario Each wheel rolls over surface dust bearing down with 1/6 of rover weight. Dust beneath wheels becomes compressed. Grains rub together liberating charge. Large grains (-) Small grains (+) Small grains cling to wheel charging rover. Large grains remain behind as charged wheel track.

  24. + + 150 V - - 150 V Dust collection in laboratory

  25. Clogged wheel Wheel track

  26. Clogged Wheels!

  27. Pathfinder: Similar to laboratory Mars: Does charging actually occur?? Theory: Predicts charging Laboratory: Confirms prediction Conclusions

  28. Because of mass constraints on rover, no instruments were carried to measure charge. Instruments will be carried on future landers and rovers to better characterize Mars’ electrical environment.

  29. Some Issues Remaining to be Solved What is the nature of Martian surface electricity? Do electrical discharges accompany dust storms? Dust devils? Can these storms be detected by radio static? Does triboelectric charging pose a hazard to future large rovers? To future astronauts?

  30. joseph.c.kolecki@grc.nasa.gov

More Related