Presentation on theme: "Mars Rover Acknowledgements: NASA website:-"— Presentation transcript:
Mars Rover Acknowledgements: NASA website:- http://mars.jpl.nasa.gov/mer/
shuvra das, University of Detroit Mercy Objectives Overall Mars science strategy to "Follow the Water." Understanding the history of water on Mars is important to meeting the four science goals of NASA's long-term Mars Exploration Program: Determine whether Life ever arose on Mars Characterize the Climate of Mars Characterize the Geology of Mars Prepare for Human Exploration
shuvra das, University of Detroit Mercy Objectives Because scientists cannot go to Mars themselves at this point in time, they will have to rely on robot geologists-- the rovers--to look for signs of past water activity on Mars for them. To do their job, the rovers will carry a number of science instruments that will analyze rocks and soils on the Martian surface and perform other important tasks and studies.
shuvra das, University of Detroit Mercy Mars-Earth Comparison
shuvra das, University of Detroit Mercy Mars Rover: A Mechatronic System These will act as robot geologists on Mars Surface Robot Parts are similar to a living creature Body, Senses, Arm Brains Nerves Health
shuvra das, University of Detroit Mercy The Body Strong outer layer that protects the computer, electronics and battery Responsible for protection and temperature control
shuvra das, University of Detroit Mercy The Body The warm electronics box is closed on the top. The Rover Equipment Deck makes the rover like a convertible car, allowing a place for the rover mast and cameras The gold-painted, insulated walls of the rover body controls temp. (Mars night temp can be -140 F)
shuvra das, University of Detroit Mercy The Neck and Head Called PanCam Mast Assembly Stands 1.4 m above base of wheel Human Geologists perspective Periscope for inside-body equp. (Mini-TES) Better point of view for Pancams and Navcams
shuvra das, University of Detroit Mercy The Neck and Head A motor turns this 360 deg. In horizontal plane A motor points camera 90 above and 90 below horizon A motor enables Mini- TES to point 30 above and 50 below horizon During cruise Pancam assembly lays horizontal on equipment deck
shuvra das, University of Detroit Mercy The rover's "eyes" and other "senses" Each rover has nine "eyes." Six engineering cameras aid in rover navigationrover navigation three cameras perform science investigations. science investigations 4 HAZCAMS 2 NAVCAMS 2 PANCAMS 1 Miro-Imager
shuvra das, University of Detroit Mercy Brains Computer inside the Rover Electronics module (REM) Onboard memory of 128MB DRAM 3MB of EEPROM Roughly equivalent to a high end laptop Special memory to tolerate extreme radiation in space Safeguard against power-off cycles
shuvra das, University of Detroit Mercy Nerves The rover carries an Inertial Measurement Unit (IMU) This provides 3-axis information on its position The rover makes precise vertical, horizontal, and side-to-side (yaw) movements. This device is used in rover navigation to support safe traverses and to estimate the degree of tilt the rover is experiencing on the surface of Mars.
shuvra das, University of Detroit Mercy The rover´s "arm" Holds and maneuvers instruments Has flexibility through shoulder, elbow and wrist joints 4 tools The Microscopic Imager The Mössbauer Spectrometer The Alpha Particle X-Ray Spectrometer The Rock Abrasion Tool (RAT)
shuvra das, University of Detroit Mercy The rover´s "arm" Forearm holds a small brush that the adrasion tool can spin against for cleaning 30% of the mass comes from tools To make the titanium arm as lightweight as possible holes are drilled in places to minimize weight
shuvra das, University of Detroit Mercy Protecting the arm Upon completion of task the arm stows itself underneath the "front porch" of rover body The elbow hooks back onto a pin, and the turret has a T- bar that slides back into a slotted ramp It can withstand shocks of 6 G´s while roving along the rocky terrain During launch and landing, the arm is restrained by a retractable pin restraint, and can withstand even higher loads of 42 G´s.
shuvra das, University of Detroit Mercy The rover´s wheels "legs" The Mars Exploration Rover has six wheels, each with its own individual motor. The two front and two rear wheels also have individual steering motors (1 each). This steering capability allows the vehicle to turn in place, a full 360 degrees. The 4-wheel steering also allows the rover to swerve and curve, making arching turns.
shuvra das, University of Detroit Mercy The rover´s wheels "legs" suspension system is a "rocker-bogie" "bogie" comes from old railroad systems. is a train undercarriage with six wheels that can swivel to curve along a track. "rocker" comes from the design of the differential, which keeps the rover body balanced, enabling it to "rock" up or down depending on the various positions of the multiple wheels.
shuvra das, University of Detroit Mercy The rover´s wheels "legs" When one side of the rover goes up, the differential or rocker in the rover makes the other side go down to even out the weight load on the six wheels. The rover is designed to withstand a tilt of 45 degrees in any direction without overturning. However, the rover is programmed through its "fault protection limits" in its hazard avoidance software to avoid exceeding tilts of 30 degrees during its traverses.
shuvra das, University of Detroit Mercy Rover Speed The rover has a top speed on flat hard ground of 5 centimeters (2 inches) per second. To ensure a safe drive, the rover is equipped with hazard avoidance software that causes the rover to stop and reassess its location every few seconds. So, over time, the vehicle achieves an average speed of 1 centimeter per second. The rover is programmed to drive for roughly 10 seconds, then stop to observe and understand the terrain it has driven into for 20 seconds, before moving safely onward for another 10 seconds.
shuvra das, University of Detroit Mercy The Rover´s Energy The main source of power for each rover comes from a multi-panel solar array. When fully illuminated, the rover solar arrays generate about 140 watts of power for up to four hours per sol (a Martian day). The rover needs about 100 watts (equivalent to a standard light bulb in a home) to drive. Includes two rechargeable batteries that provide energy for the rover when the sun is not shining, especially at night.
shuvra das, University of Detroit Mercy The Rover´s Energy Over time, the batteries will degrade. By the end of the 90-sol mission, the capability of the solar arrays to generate power will reduce to about 50 watts due to anticipated dust coverage on the solar arrays Mars will drift farther from the sun as it continues on its yearly elliptical orbit, and because of the distance, the sun will not shine as brightly onto the solar arrays. Additionally, Mars is tilted on its axis just like Earth is, giving Mars seasonal changes. Later in the mission, the seasonal changes at the landing site and the lower position of the Sun in the sky at noon than in the beginning of the mission will mean less energy on the solar panels.
shuvra das, University of Detroit Mercy Temperature controls night temperatures on Mars can drop to -96º C (-140º F) Temp variation during day could be 113C(235F) "vital organs" needs to be between -40º C to +40º C Several methods are used to control heat loss from rover Preventing heat escape through gold paint Preventing heat escape through insulation called “aerogel" Keeping the rover warm through heaters Making sure the rover is not too hot or cold through thermostats and heat switches Making sure the rover doesn't get too hot through the heat rejection system
shuvra das, University of Detroit Mercy Temperature controls The gold paint of rover minimizes radiation loss (like a thermos) A special layer of light-weight insulation called “solid- silica-aerogel” is used to block off heat loss. The rover will be heated by heat from electronics, radioisotope heater units and electricity from battery (~1W from each) Thermostats used to turn-off and-on heaters to control temp
shuvra das, University of Detroit Mercy The Rover’s Antenna (voice and ears) The rover has both a low-gain and high-gain antenna. They are located on the equipment deck (its "back"). The low-gain antenna is "omni-directional." The antenna transmits radio waves at a low rate to the Deep Space Network (DSN) antennas on Earth. The high-gain antenna can send a "beam" of information in a specific direction and it is steerable.Deep Space Network They can also communicate with other spacecraft orbiting Mars, utilizing the 2001 Mars Odyssey and Mars Global Surveyor2001 Mars OdysseyMars Global Surveyor
shuvra das, University of Detroit Mercy Test Tracks: A Race against Time An obstacle course dubbed the "rock gauntlet" challenged test wheels to scale everything from small rocks to concrete blocks. Engineers also conducted airbag interaction tests in which they drove the wheels into the deflated airbags again and again until they had enough information to proceed with wheel design changes. The mobility team and the assembly test and launch operations team gathered to conduct ramp tests with the flight rovers to make sure the rover brains were communicating effectively with its legs and wheels.
shuvra das, University of Detroit Mercy Airbags
shuvra das, University of Detroit Mercy Machinists
shuvra das, University of Detroit Mercy First Steps The rover lands on Mars in January, 2004. Once the lander petals open and the rover "wakes up," it may take up to five days for it to drive off the lander. After every command given to the rover, engineers will wait to make sure everything is working properly before they proceed. Due to the delay in sending and receiving signals from Earth to Mars and back, it takes 20 minutes to see the difference When it is confirmed that all systems are working, they will tackle the decision of which direction to go. Rocks or deflated airbags will determine the route to leave the lander. GOAL: Not to break speed records. But to do important and interesting science
shuvra das, University of Detroit Mercy What’s been happening? http://marsrovers.jpl.nasa.gov/spotlight/