On 15 July 1965, the Mariner 4 spacecraft sent the first close-up images of the Red Planet to  Earth. These blurry images  revealed the cratered, rust-colored surface of  the planet and discouraged those who believed that there might be life on Mars. A  New York Times editorial said that “Mars is probably a dead planet” and most of the scientific community agreed, at that time, with this account.

Mariner 4 image, the first close-up image ever taken of Mars. This shows an area about 330 km across by 1200 km from limb to bottom of frame, centered at 37 N, 187 W. The area is near the boundary of Elysium Planitia to the west and Arcadia Planitia to the east. The hazy area barely visible above the limb on the left side of the image may be clouds

Mariner 4 image, the first close-up image ever taken of Mars. This shows an area about 330 km across by 1200 km from limb to bottom of frame, centered at 37 N, 187 W. The area is near the boundary of Elysium Planitia to the west and Arcadia Planitia to the east. The hazy area barely visible above the limb on the left side of the image may be clouds. Credit: NASA

Nevertheless, NASA continued its exploration of Mars. Mariner 9 (1971)  revealed a planet of varied environments and changed scientists’s perceptions about the Red Planet and led to Viking mission. Viking 1 and 2 landers were the first spacecrafts to touch successfully the surface of Mars in 1976.

A few months before the launch of Viking 1, in  1976,  NASA invited a team of specialists to discuss extensively all aspects of the Mars in a three-week meeting. Concluding the meeting Michael Mc Elroy of Harvard University, said something he had been discussing with a few other earth scientists for some time: “You know, we’ve never done anything like this for earth.”

The need for a multidisciplinary programme to study global change was the subject of the discussion for some time within the scientific community. A few Earth scientists were pondering a multidisciplinary geosphere-biosphere research programme in the context of IGY, but the political, economical and ideological circumstances that could endorse such a venture, did not exist at the time.

The arrival of Reagan administration in 1981 brought a change in NASA’s leadership. The new administrator James Beggs, and Burton Edelson, head of the Office of Space Science and Applications (OSSA), had taken a keen interest in using satellites’ technology for Earth observation but their enthusiasm was not shared by NASA’s associate administrator Hans Mark. Mark, a strong supporter of the space station – NASA’s major project that period – believed that an earthly science programme could damage NASA’s priorities in space and it could provoke an escalated antagonism with other agencies, NOAA for example.

Richard Goody

Nevertheless, Hans Mark asked the guidance of Richard Goody, a geophysics of Harvard University, with whom Mark had worked with when he was Director of the Ames Research Centre. Richard Goody recalls that Mark took him aside (in an used Xerox room) and explained him NASA’s idea about an ambitious global climate programme. It included a large space mission to observe the earth system and explore the links and the interactions between the major system components of the earth, how they have evolved, function, and how they may be expected to evolve on all time scales.

The idea of the Earth as one interacting system had a certain appeal for Richard Goody. He suggested that such a programme could bring a focus to NASA’s observation programme which, at the time, did not seem to have a sense of direction. It could also protect the agency from Reagan administration budget cuts. He agreed to participate in the project.

But, there was a problem. NASA’s Earth observation program had been in NASA’s applications division, which purpose was the development of practical commercialising technology and its  budget was far too small to support the development of new knowledge.  After much discussion,  the agency made a tempting offer that both scientists and bureaucrats found hard to turn down.  NASA proposed a satellite remote sensing system which was dubbed “System Z” and called for the Space Shuttle to lift the polar-orbiting Earth-observing platforms into space.  By carrying the cost of the satellite platforms, NASA’s  hoped that the money for System Z would have come from Space Station Freedom (the NASA project that led eventually to the International Space Station).

This artist’s concept depicts the Space Station Freedom as it would look orbiting the Earth, illustrated by Marshall Space Flight Center artist, Tom Buzbee. (1991) Source: Wikipedia

The basic concept behind System Z was integrated Earth observations. More specific to gather satellite data on world ecology and natural resources and predict the Earth’s habitability over the next 50 or so years.

The feedback received by scientists was positive and optimistic. Thomas Donahue, former chair of the NRC Space Science Board, referred to System Z, as “a gift” that “was merged with the developing ideas about putting a lot of Earth observing remote sensing instruments on a single platform”. System Z would allow them to conduct simultaneous measurements of many environmental and climate variables such as air and surface temperatures, vegetation, cloud reflectivity, and ice cover, observe the multiple factors that affect earth’s ability to support life and better understand the past and future but most importantly predict the trends of future climates.

An early sketch of “System Z.” Credit: Mark Abbott; Originally published by the Earth Observer. Source: NASA

President Reagan refused to launch the Space Station Freedom initiative in 1982 and then again in 1983.  Since System Z was tied to Space Station program it had been forces to wait until the President’s approval. He finally announced – overruling most of his advisers – his approval during his January 25, 1984 State of the Union address. “A space station will permit quantum leaps in our research in science, communications, in metals, and in lifesaving medicines which could be manufactured only in space,” he said and invited the allies of the United States to participate in the space station program.

While System Z was not approved as part of the Space Station Programme at this point, NASA decided to move forward with the development of the system, now renamed Earth Observing System (EOS).


  1. The Search For Martian Life Begins: 1959-1965,  On Mars: Exploration of the Red Planet. 1958-1978, https://www.hq.nasa.gov/pao/History/SP-4212/ch3.html
  2. Edward Edelson, “Laying the Foundation”, Mosaic 19,3/4 (Winter/Fall 1988),6
  3. Kennedy, The U.S. Government and Global Environmental Change Research, 4
  4. Richard Goody, “Observing and thinking about the Atmosphere”, Annual Review of Energy and the Environment, 27 (2002), 15
  5. M. M. Waldrop, “An inquiry into the state of the Earth”, Science, Vol. 226, No 4670 (October 5, 1984), 34
  6. G. Taubes, “Earth Scientists Look NASA’s Gift Horse in the Mouth” ,Science, Vol 259, No 5097, (12 February,1993), 912
  7. William K. Stevens, ‘Huge space platforms seen as distorting studies of earth’ New York Times 19 June 1990, Section C, page 1.
  8. Ten Presidents and NASA, https://www.nasa.gov/50th/50th_magazine/10presidents.html