September 9, 1997
The Zagami meteorite started off as a volcanic rock that cooled on the Martian surface about a billion years ago. The rock was flung into space after a comet or an asteroid slammed into Mars about 2.5 million years ago.
Following a long journey through the inner solar system, the meteorite fell to Earth in Zagami, Nigeria, in 1962. The return trip began Nov. 7 of last year with Surveyor's launch from Cape Canaveral, Fla. The Mars Global Surveyor will begin orbiting Mars on September 11.
ASU geology Professor Philip Christensen used his own funds to buy a small piece of the meteorite from a private collector to conduct tests for his thermal emission spectrometer. TES, which will map the surface minerals of Mars, is one of Mars Global Surveyor's seven instruments.
Christensen chipped a sand grain from the greenish-white meteorite and attached it to a plaque on the instrument last summer. His motivation: to commemorate the accomplishments of space scientists and engineers.
"This tiny fragment of Mars represents the culmination of science and engineering capability never before seen on this planet," he said.
The grain was encapsulated in a resin bubble attached to the TES signature plaque. The resin containing the sand grain was molded into a specially designed niche on the plaque to ensure it could not break loose during the flight to Mars.
For hundreds of years, geologists and atmospheric scientists have worked to understand the composition of rocks and gases on Earth. The work has enabled researchers to develop powerful theories explaining Earth's origin and history. In the past 25 years, planetary scientists also have studied similar data from spacecraft sent to Mars to learn how it differs from Earth in composition and origin.
"As a result of these achievements, we now, for the first time in our history, know enough about our planet and the solar system we live in to be able to recognize rocks that did not originate on the Earth," Christensen said. "We are now able to identify a class of meteorites that came from Mars. The engineering capability of the human race has also reached a spectacular level -- to the point where we can send multiple, complementary spacecraft from our planet to explore Mars."
During its 2-year mission, Mars Global Surveyor will create a global portrait of Mars, setting the stage for the success of all future landers. Through the Zagami meteorite attached to TES, Christensen also sees it as a reminder of the past.
"This sand grain is a symbol of the achievements of all the scientists and engineers who have worked to develop the understanding, insight, and technical capability to make this first ever interplanetary 'sample return mission' a reality," Christensen said.