Mars has always been held as more Earth-like than any other planet in the known Solar System. Since "canals" were first seen in the red planet (now known not to be canals), humans have held that life may exist on Mars. That is why it is fast becoming one of the most extensively studied planets in the Solar System. In fact, you can even find the current weather of Mars, as well as its position relative to Earth at the Mars Today home page.

Past Exploration:


Courtesy of http://pds.jpl.nasa.gov (see Bibliography)

The Viking 1 craft was launched from Florida's Cape Canaveral on August 20, 1975 on board a Titan 3E-Centaur D1 rocket. Its main mission was to study the air, surface, and to search for micro-organisms in Mars's soil. The lander, also containing two robot explorers, set down on the western slopes of Chryse Planitia on July 20, 1976. It did not find the evidence needed to support life on Mars, but its findings are still being debated today. Viking 1 also sent back color panoramas of Mars, and showed that the sky was pinkish due to all of the red dust (rust) in the air, and that there was red soil and red boulders as far as it could see. Also sent back were pictures of canyon systems, and what looked like dry river beds. The last data was collected on November 11, 1982. After six and a half unsuccessful months, the mission was put to an end on May 21, 1983.

Viking 2 was launched on September 9, 1975, and landed on Mars on September 3, 1976 in Utopia Planitia. It carried out the same mission as the Viking 1, but it also had a working seismometer, which recorded one Marsquake, possibly hinting at active plate tectonics (the forces that make mountains, valleys, and the continents move on the Earth).

Twenty-one years later, on July 4, 1997, after seven months of traveling through space, the Pathfinder probe landed on Mars in the Ares Villis valley. When it was between 3.6-6 miles above ground zero, it let out a parachute which abruptly slowed its descent. As it was about to reach the ground, it inflated air bags to help soften the landing; it still bounced approximately sixteen times.

It was three hours before the Martian sunrise when it landed. The probe quickly deflated the air bags, then opened up like a flower, each "petal" being a solar panel to help generate power. Four hours later, it broadcasted a signal to Earth.

Then, at 1:38:55 A.M. on July 6, a small rover, less than three feet long, rolled out and onto the Martian surface, becoming the first rover on Mars. The rover's name, Sojourner, was given by thirteen-year-old Valerie Ambroise of Bridgeport, Connecticut, in early 1996.

Courtesy of http://www.nasa.gov/projects.html (see Bibliography).

Sojourner contained an on-board camera, with which it could relay signals back to the base and then have them relayed to Earth. If scientists wanted Sojourner to explore a part of the region, then they signaled it through the base. There was a time delay of seven to twenty-two minutes because the distance between Mars and Earth is so large.

Sojourner used Laser beams much like an insect uses feelers, and if confronted with an obstacle, it would just keep bumping into it until it got across.

Sojourner's main purpose was to detect the chemical composition of Martian rocks, looking for carbonous compounds which could indicate life. It accomplished this by sending a beam of helium nuclei into the rock. Radiation emitted was recorded and unscrambled by Sojourner's spectrograph, which could then display a set of "chemical fingerprints" which indicated the rock's composition.

One discovery that the Pathfinder made, combined with data from the Viking crafts, shows that Mars has a crust, mantle, and core, with the heavier elements nearer to the center. Such a structure had been guessed at, but now scientists have direct evidence of such layering.

A discovery that Sojourner made (early August 1997) was finding evidence that winds up to 125 mph (200 kph) used to blow across the region where they landed. Evidence was found when examining rocks, and finding that they had been sandblasted in several places. Such sand blasting could have only been formed by fast winds whipping sand around.

Pathfinder's last transmission to Earth was on September 27, 1997. Ground receivers haven't heard routine signals since October 6, 1997. After a month of attempted contact, NASA stopped on November 4, 1997. NASA now believes that its batteries have died, two months after its thirty-day expected life. Without batteries to keep it warm, the craft probably stopped functioning. Sojourner, programmed to return to Pathfinder if no signal has been received for five days, probably returned to it. NASA, still attempting to contact Pathfinder a few times every month, believes that in one Martian year, the summer warmth may help to rejuvenate the lander.

Current Exploration:

Launched on November 7, 1996, the Mars Global Surveyor (MGS) is currently orbiting Mars. With sophisticated equipment, it is starting to map Mars, rotating the planet about once every two hours. The MGS uses lasers to map Mars. It bounces a beam of laser light off Mars at a rate of ten per second, and then it records how long it takes the light to return to the craft. It works like sonar that ships use to map the ocean floor.

Unfortunately, the main Mars mapping mission was postponed until March of 1999, due to a damaged solar panel. When the MGS arrived at Mars in September of 1997, it was supposed to continually dip down into the Martian atmosphere until the resistance of the atmosphere slowed the craft down and brought it into a circular orbit nominal for mapping. However, in early October 1997, the craft encountered dense air which caused a solar panel to flip back and forth. NASA suspended aerobraking for three weeks, after which NASA adopted a plan which brought the craft less deep into Mars's atmosphere on November 7, 1997. This prevented the solar panel from breaking off or being damaged.

One discovery (early October 1997) is that Mars has over eight "magnetic patches" that might be the remnants of an ancient magnetic field. The patches' axes though, are pointing in all different directions. The strongest field is only about 1.3 per cent that of Earth's magnetic field. The field fragments could have been formed when iron-rich rocks rose at different times, and then became trapped in the surrounding rocks. This model shows that each field fragment is a picture of what Mars's magnetic field looked like at various times.

Another discovery (taken October 1997, analyzed early March 1998) is that above fifty degrees latitude (about the upper half of the northern hemisphere), Mars is practically flat, with no hills or valleys. This is leading scientists to theorize that oceans may have flattened it, for the only areas on Earth that are this flat are at the bottoms of deep oceans. If this is true, further mapping may reveal a shoreline. After the MGS's major mapping mission is completed, it will be used as a relay station for about three years by other spacecraft in orbit and on Mars.

The Russian Space Agency is sending an orbiting station as well as two landers. The landers will record for weather conditions, soil conditions, quakes, and will take panoramic views. Two more Russian craft will look like giant golf tees, and will travel through the atmosphere with no type of braking system. They will crash through the soil and their instrument laden "spears" will record soil temperature. Meanwhile, the orbiter will relay the information to Earth.

Future Exploration:

1999

Japan's spinning Planet B probe will arrive in 1999 to survey the upper atmosphere. This is an important step for Japan, for it is the first planetary probe they have ever launched.

Russian craft Marsokhod will arrive next. The craft is about 1.5 meters long. It will maneuver on six cone-shaped wheels.

Also in 1999, NASA's Mars Surveyor mission will include one lander and one orbiter. The Mars Surveyor '98 Orbiter is supposed to be launched on December 10, 1998, and the Lander is set for launch on January 3, 1999. The orbiter should arrive on September 23, 1999, and the lander should land near the South Pole on December 3, 1999. The lander includes the Mars Volatile and Climate Surveyor (MVACS), which is integrated into the lander payload, the Mars Descent Imager (MARDI), and an atmospheric radar experiment, which was provided by the Russian Space Agency Institute for Space Science. The integrated lander payload also includes a surface stereo imager with Mars Pathfinder heritage, a meteorology package, an instrumented robotic arm for soil samples, soil manipulation, and close-up imaging of the surface and subsurface, and the thermal and evolved gas analysis experiment for determining the nature and abundance of volatile material in the Martian soil. The lander will also look for life in the frozen water and carbon dioxide that make up the poles. It will also analyze the layers of ice and rock in an attempt to learn about Mars' past. The Mars Surveyor '98 Orbiter will create global weather maps.