M ars played an important role in the discovery of the elliptical orbits of the planets. When viewed from Earth, Mars seems to loop through the sky which puzzled scientists for many years. Johannes Kepler refuted Ptolemy's theory about the circular orbit of planets in 1609 when he concluded that the disparity in the orbit of Mars was caused by an elliptical orbit. Galileo made the first telescopic observations of the planet and recorded its phases the very next year.

I n the subsequent years of the 1600's and 1700's astronomers discovered that it had polar ice caps and seasonal changes. Also, it was concluded that the dark areas observed on the surface of Mars were seas. William Herschel noted bright, changing patches that he thought were clouds, suggesting that the planet had an atmosphere. It was so thought that with vast oceans and an atmosphere that life must thrive on Mars.The Martian satellites were discovered by Asaph Hall in 1877.

K nowledge of the planet has greatly increased through spacecraft missions, beginning with Mariner 4 in 1965 and the Mariner 6 and 7 flybys in 1969. The highly successful Mariner 9 mission in 1971-72, and Viking 1 & 2 launched in 1976 together imaged the entire Martian surface and revealed the geologic diversity of the planet. The Viking landers made long-term observations of the surface and atmosphere and performed experiments to determine the composition of surface materials. They performed biological tests which returned negative results. This and the new knowledge of the Martian surface forced scientists that life could not exist on Mars.

S pacecraft missions like the Mars Pathfinder will continue to occur helping us to better understand the red planet. A manned mission to Mars has even been rumored throughout NASA.