Mars: The Cheatsheet

Name: From the Roman God of War

Distance from the Sun: 144 mil mi, or 249 mil Km max, 206 mil Km.

Distance from the Earth: 399mil Km max, 56 mil km minimum.

Daily rotation (day): 24.6 hrs

Diameter: 4212mi , or 6786 km

Tilt of axis: 25.2deg

Gravity: .38 that of Earth

Atmosphere: mostly CO2 (95%), Nitrogen (2.7%), Argon (1.6%), and traces of water, carbon monoxide and other gasses.

Air pressure: 8mb (Earth is 1000mb) it can change up to 30% due to the melting of the polar caps.

Moons: Phobos (fear) 21km dia, Deimos (panic) 12km dia

Rings: none

Magnetic field: weak

Valles Marinaris: Deepest canyon in the solar system. 4000km long and 7km deep.

Olympus Mons: Tallest volcano/mountain in the solar syst. It is a shield volcano that's 624km wide, and 25km high.

South Pole: Ice cap is mostly water and carbon dioxide

Temperatures: During Pathfinder's lifespan, it recorded temperatures ranging from 1deg f at the hottest to -178 deg. F at the coldest (-17.2 -143deg c). The warmest temperature occurs during the Martian summer and was 81 deg f at the equator, according to the Viking spacecraft (1976).

Winds: Winds range from 0mph, to up to 60mph.

Dust storms: Due to seasons of drastic pressure changes, strong winds cause major dust storms. These storms occur usually during the summer and they can last anywhere from weeks to months. These storms block the view of mars.

Sol: Sol is the term used to refer to a Martian day (24.6hrs).

Seasons: Mars has 4 seasons, that are drastically different due to the tilt of the planet. During the summer, the poles melt and shrink, and during the winter they grow, sometimes reaching 45deg latitude.

Southern Hemisphere: is covered mostly with craters and experiencing a great deal of erosion.

Northern Hemisphere: is covered with fewer craters, leading scientists to believe that there have been recent lava flows covering the surface. The north is covered with large plateaus, and the Tharsis Bulge, that holds Olympus Mons, the tallest volcano in the solar system. Olympus Mons is a basaltic volcano.

Faults: There are faults everywhere on Mars, but no folding caused by plates. This leads scientists to believe that Mars is lacking in major plate techtonics.

Core: Mars is lacking in a metal core, proof is found in the low density of the planet. Mars is also lacking in any measurable amout of magnetism, due to a lack of liquid metals under the surface.

Mars Pathfinder Information

(Taken from Time Magazine, and Sky and Telescope Magazine)

Pathfinder: left Earth Dec. 4, 1996 On a Delta -7925 Rocket. Pathfinder landed on Mars on July 4, 1997.

Earth is at its closest to Mars every 26 months.

To land on Mars, Pathfinder first used a Parachute, then retro rockets The air bags that allowed it to bounce 15 times on the surface, up to 15m high. The lander hit the surface at 18gs.

Landing site: Ares Vallis Basalt floodplain, a target 60 miles wide.

On landing, the low gain antenna gives a short signal to JPL letting JPL know that it got to Ares Vallis safely. On landing, one of the airbags blocked the rover from leaving the lander, the bag had to be retracted out of the way. Signals from Earth to Pathfinder take 11min, so controlling Pathfinder is difficult. The Ares Vallis was chosen because it is the largest known flood plain in the solar system. What this means is that the waters brought rocks of various sorts into this flood plain, providing a perfect mix of rocks to explore. The Sourjourner is designed to explore for a month before its batteries give out, and the Pathfinder lander (called the Carl Sagan Memorial Station) is designed to keep sending messages back to Earth for up to a year.

Cost of Pathfinder: 170 million for Pathfinder, 25million for Sourjourner, 250 million total cost, compared to the Viking missions that cost 3billion.

Solar panels: used for electricity

Camera: to monitor Sourjourner, as well as to photograph the surface. This is important for deciding where to send Sourjourner to examine rocks.

High-gain antenna: Primary antenna used for communication required the most electricity.

Low-gain antenna: more of a back up antenna, uses less electricity, not as strong as the high gain.

Weather mast/windsock: used to find wind speed and wind direction.

Radio modem: used to communicate with Earth: works at 9600 baud.

Solar panel: used for powering sourjourner. It also uses 9 lithium batteries.

Cameras: There are 2 black and white cameras on the front, used for stereo 3D images. This becomes important for navigation. There is one camera on the back of Sourjourner used for taking color photos.

Laser navigation: There are 5 lasers used to lay down a path and look for rocks that might be in the way.

Wheels: 6 metal wheels that adapt to the terrain and can climb rocks as high as 10 inches.

Motors: mini electric motors in each wheel that move Sourjourner 2 ft per minute. (120 ft. per hr)

Processor: Intel 80C85 which is a low cost processor.

Alpha proton X-ray Spectrometer: Will analyze rocks for chemical makeup.

What is the IMP?: Imager for Mars Pathfinder. This includes all of the instruments mentioned above including the ASI/MET atmosphereic structure investigation/meteorology package.

Name of Rocks Viewed From Pathfinder: Chimp, Sandworm, Snoopy, Wedge, Tigger, Geordi, Ginger Janewaay, Darth Vader, Shark, Ren, Bam Bam, Half Dome, Moe, Stimpy, Flat Top, Pumpkin, Broken Wall, Frog, Little Flat Top, Mouse, Pancake, Twin Peaks, T.Rex, Hippo, Lone Star, Woodie, Lunchbox, Grommit, Wallace, Pyramid, Pinnochio, Jiminy Cricket, Dragon, Dilbert's Boss, Anthill, Raatbert, Bullwinkle, Rocky, Barnacle Bill, Duck, Potato, Scout, Froggy, Couch, Valentine, Jazzy, Cradle, Turtle, Platypus, Flipper, TheDice, Yogi, Boo Boo, Picnic, Basket, Hero Hedgehog, Kitten, Baarsoom, Lamb, Hardstop, Iguana, Piper, Shaggy, Boo, Casper, Scooby Doo, Lumpy, Mesa, Baker's Bench, Desert Princess, Rye Bread, Marvin the Martian, Snowy, Calvin, Hobbes, Mint Julep, Mini Matterhorn, Spock, Spud, Pooh Bear, Piglet, Hamster, Squash, Pyramid, Otter, Mermaid, Bosco, Sausage, Squid, Hassock, Lozenge

Other Important Tidbits:

Pathfinder Landed on America's 221^st Bday. It registerd 40million hits on its web site.

Pathfinder was the first spacecraft to enter the Martian atmosphere without first orbiting it. When it landed, it landed on its base so that it would not have to do a maneuver to fix itself.

On Sol 1, After Pathfinder landed, it sent back to Earth a brief message at 11:34am PDT on its low gain antenna, saying that it made it safely to Mars.

On Sol 2, Sojorner rolled down its rear ramp and used its stereo cameras to take pictures of the surface.

Sol 3: first test drive of Sourjourner. It rolled over a rock without a problem. It went up to Barnacle Bill with its APXS and tested its chemical composition.

Sol 4 Sourjourner started testing the chemical composition of the rocks, using its xray spectrometer.

What was learned from Sourjourner?

Water flowed freely on mars at one time. Ares Vallis was chosen because it was once an ancient flood plain, a site where rocks were left after the water evaporated. This is evident by what looks likes layering of rocks, first the big rocks, then smaller sands, soils, and silt. Twin Peaks provides evidence that there was once gullies on Mars. It also showed how water cut through the land shaping it, very similar to the earth. The layering in some rocks tells us that they are sedimentary rocks. In Ares Vallis, There is evidence of both Igneous (volcanic rocks), and sedimentary rocks. Before Pathfinder, knowledge of rocks was based only on Martian metorites. In addition, the presence of valley networks tells us that Mars was once warmer and wetter with a thicker atmosphere, and liquid water that was stable.

Barnacle Bill is mostly Quartz, a rock called Anedesite. This is different from the Basalt igneous rocks (Basalt is the rock that makes up most of our ocean floor). This finding tells us that Mars must have had many episodes of lava flow to melt the rock and separate out the quartz.

Yogi is a much different rock. Yogi is a two toned rock; one side is blue and the other side is red. The red is a result of the basalt and it's minerals, silicon and iron oxide.

The atmosphere had more dust than expected, and this dust resulted in temperatures being 20-60 deg. C than was orginally predicted. Mars is warm because the dust creates sort of a Greenhouse Effect. Mars has a year of 22.5 months. This is because Mars is tilted 24deg. And because its orbit is more ellipical than the Earth's, it has a dramatic effect on the seasons. In the southern summer solstice (when Mars is closest to the Sun), there are many dust storms, and the dust storms can cause the temperature to fluctuate more than 40 deg. C. (note: summer-warm and dusty, winter-clear and cold!). According to Sourjourner's Xray Spectrometer, most of Mars is made of Mars is made of Magnesium, Silicon, and Iron Oxide. Some of its rocks are Terrestrial ultramafic rocks found, similar to rocks found in our own core. Rocks such as Yogi are Terrestrial Basalts, which are similar to the ocean crust, or the black sand beaches found on the big Island of Hawaii. The area was formed by two major floods, The Ares and Tiu floods. These two floods may have led to the formation of Twin Peaks. There is evidence of wind erosion around rocks, and large rocks are the result of depositing by the Ares and Tiu floods.

Rocks with high silica content formed in the mantle and were deposited by volcanoes. Rocks that are high in sulfer were formed on the surface, with evidince being the high erosion rate.

Sourjourner also found conglomerate rocks suggesting the presence of running water to deposit the pebbles and sediments and minerals to cement the pebbles together.

Temperatures fluctuated with time of day and altitude. This suggests that cold morning air is warmed by the surface, and is convected (rises up) until it cools.

In the first month of surface operations, the mission returned 1.2 gigs of data, with 9669 Pathfinder images, and 384 Sourjourner images. In addition, 4 million temperature, pressure, and wind instruments. The rover traveled over 52m in 114 commanded movements, performed 10 chemical analyses of rocks and soil, carried out soil mechanics, technology experiments, and explored over 100m squared of Martian surface.

This page researched by L.A.S.A Martian Research Station; Ares Vallis, Martian Northern Hemisphere

Copyright © 1998 LASA Aerospace. Revised Aril 11, 1999