Why We Explore

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Exploration, Discovery and Science
Why We Explore

Editor's Note: This is the 11th in a series of essays on exploration by NASA's Chief Historian, Steven J. Dick.

The terms "exploration" and "discovery" have been headlined since President George W. Bush announced new goals for NASA and the nation in January 2004.

The new space exploration policy laid out that day to go to the Moon, Mars and beyond was entitled "A Renewed Spirit of Discovery." It was followed in February by a more detailed "Vision for Space Exploration," pointing out the importance of exploration and discovery to the American experience, in the tradition of Lewis and Clark. By June a nine-member Presidential Commission on Implementation of United States Space Exploration Policy had produced a report on "A Journey to Inspire, Innovate, and Discover." In February 2005 NASA’s strategic objectives were released in a report called "The New Age of Exploration."

Image from Mars rover Spirit Image above: One of the first images of Mars returned by the Spirit rover in January 2004. Photo credit: NASA/JPL/Cornell.

The renewed emphasis on exploration at NASA raises the question of the relation between exploration, discovery and science – and not just for academic reasons. One formulation holds that exploration and science are one and the same, and that when it comes to spaceflight, exploration equals science. A recent National Research Council study, Science in NASA’s Vision for Space Exploration, asserted that "Exploration is a key step in the search for fundamental and systematic understanding of the universe around us. Exploration done properly is a form of science."

Yet, while it is clear that there is a synergy between exploration and science, as historian Roger Launius argued at a recent meeting on "Critical Issues in the History of Spaceflight," I would argue they are not one and the same. After all Magellan was an explorer, not a scientist or a natural philosopher.

Many scientists undertake routine science that can hardly be called exploration. Adding another decimal point to the positional precision of a star or planet is hardly exploration, even if it can occasionally illuminate anomalies (such as the 43 seconds of arc discrepancy in the advance of the perihelion of Mercury, later explained by Einstein’s theory of relativity.)

Thus, even routine science can lead to discovery, but often it does not. Exploration can also lead to discovery, but not necessarily. In either case, exploration and science are not the same.

Another approach to understanding this relationship is that exploration is undertaken, sometimes leading to discoveries, which then are explained by science and in turn add to our body of scientific knowledge. This seems to me a more robust formulation, leaving open the idea that exploration and science are not coextensive. MIT physicist Philip Morrison, a pioneer in the Search for Extraterrestrial Intelligence (SETI) who died last month at the age of 89, answered critics who said that such a search was not science by explaining that "unlike science, this topic extends beyond the test of a well-framed hypothesis … that has a proud name in the history of thought as well; it is called exploration." Exploration can be more open-ended than science, holding the possibility of discoveries totally unexpected - or no discoveries at all.

Even though science may be a motivation for exploration and a product of it, human exploration is more than the sum of all science ... it is individually a primordial human urge, and in a larger sense the mark of a creative society.
These distinctions become an issue of public policy when decisions must be made about the balance between human and robotic exploration. Critics of human space exploration, including space science pioneers like James van Allen, point out that robotic spacecraft are generally much cheaper and generate more science. This controversy has a long history in the space program, and in NASA in particular. The Apollo program, generally considered NASA’s greatest triumph, was nevertheless criticized for generating little science relative to its high cost. The only scientist among the 12 astronauts who walked on the Moon was geologist Harrison Schmitt on Apollo 17, the program's last flight in 1972. Yet, Apollo represented something beyond science, and will forever be remembered as one of humanity's greatest triumphs, precisely because it was in the long tradition of human exploration.

To be sure, in the past human spaceflight has been deeply bound up with national prestige. And it remains so today, with the Chinese entering the arena. Yet, those ventures were, and still are, couched in the language of exploration, a significant motivator in itself. Many space scientists have come to this realization.

At a recent NASA meeting on Risk and Exploration, Steve Squyres, the science principal investigator for the Mars Exploration Rovers, allowed how he loved his machines, which are still active after 16 months. But, he added, "when I hear people point to Spirit and Opportunity and say that these are examples of why we don't need to send humans to Mars, I get very upset. Because that's not even the right discussion to be having. We must send humans to Mars. We can't do it soon enough for me."

Squyres reflects a deep truth: even though science may be a motivation for exploration and a product of it, human exploration is more than the sum of all science. As I have argued in past essays, it is individually a primordial human urge, and in a larger sense the mark of a creative society.

The New Age of Exploration speaks of a human and robotic partnership for exploration - robotic reconnaissance, followed by human voyages that satisfy that desire to explore in person and up close. In the end the National Research Council study also concluded that "the expansion of the frontiers of human spaceflight and the robotic study of the broader universe can be complementary approaches to a larger goal." To achieve that balanced partnership with the limited resources at hand, in the midst of turbulent events on Earth, is the challenge now before NASA.

Further Reading: Dick, Steven J. and Keith Cowing (eds.), Risk and Exploration: Earth, Sea and the Stars (NASA SP 2005-4710) (forthcoming August 2005)

Dick, Steven J. and Roger Launius (eds). Critical Issues in the History of Spaceflight (in press).

NASA, The New Age of Exploration: NASA's Direction for 2005 and Beyond (NP-2005-01-397-HQ; online at http://www.nasa.gov/pdf/107490main_FY06_Direction.pdf.

National Research Council, Science in NASA's Vision for Space Exploration (2005); online at http://www.house.gov/science/hot/Hubble/NASVisionSpace.pdf .

Steven J. Dick
NASA Chief Historian