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Science in NASA’s Vision for Space Exploration 1 The Impetus to Explore In the winter of 1804-1805, a small band of Americans, two French-Canadian voyageurs, and a Shoshone woman and her baby faced the bitter cold in a camp on the upper Missouri River in what is now the state of North Dakota. They were on the way to the Pacific Ocean—sent on a journey of exploration by President Thomas Jefferson. The explorers survived the winter and pushed on to spectacular success, returning in 1806 with information that transformed the nation’s view of itself. Although settlers had drifted across the Allegheny Mountains and down the Ohio River Valley after the Revolutionary War, the Lewis and Clark expedition was the first American scientific exploration of the Far West. The bounty of geographic and biological knowledge gathered by the Lewis and Clark expedition of 200 years ago initiated American migrations westward that have shaped the United States for two centuries, a transformative process that is continuing to this day. Over the last few decades, humanity has used the vantage point of space and the power of robotics to dramatically advance the exploration of our planet, the solar system, and the universe beyond. This also has been a transformative era, because our understanding of every aspect of the cosmos has been profoundly altered. Robotic laboratories have produced evidence for water on Mars and have explored Saturn and its rings and moons in breathtaking detail. New space telescopes have revealed fluctuations in the primeval universe that show the influence of a mysterious form of dark energy; they have discovered that black holes are ubiquitous and have witnessed their birth via intense bursts of gamma rays; and they have begun to reveal the atmospheres of planets in other stellar systems. Other telescopes have revealed details about the surface and the interior of the Sun and have shown how the Sun’s magnetic field explodes as solar flares. New robotic plasma physics laboratories have produced images that trace how high-energy particles interact with our magnetosphere and hit Earth. Other remote sensing instruments in space have documented an accelerating decline in arctic sea ice, mapped the circulation of the world’s oceans, created quantitative three-dimensional data sets to improve the quality of hurricane forecasting, and created new tools to address a host of agricultural, coastal, and urban resource management problems. Despite the breadth and magnitude of these revolutionary advances, many fundamental questions remain just beyond our grasp. For the first time in human history, we may be nearing a time when the answers to fundamental questions about life—such as, Are we alone? Where did we come from? What is our destiny?—may be within our reach. So also may be the answers to such equally fundamental cosmological questions as, Where did the universe come from? What is its destiny? Is there only one universe? ELEMENTS IN A VIBRANT APPROACH TO EXPLORATION What approach to exploration will now serve the nation well? The issue of how to proceed in space exploration following the Columbia accident was the subject of an NRC workshop on national space policy held in November 2003.1 In contrast to the dramatic strides in understanding made in recent decades as a result of the robotic science program, progress in human space exploration has been limited, with astronauts confined to low Earth orbit, circling Earth without a clear long-range direction for further exploration. The principal theme of the workshop was that the human spaceflight program needed clearly 1 National Research Council, Issues and Opportunities Regarding the U.S. Space Program: A Summary Report of a Workshop on National Space Policy, National Academies Press, Washington, D.C., 2004.
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Science in NASA’s Vision for Space Exploration articulated long-range goals for human exploration and a step-by-step program to meet such goals. It emphasized that it was essential to recognize the importance of humans in exploration and to break the bounds of low-Earth orbit and once again have humans venture forth into the solar system. In agreement with views expressed at the workshop, the committee believes that aspects of the robotic science program’ s planning and execution are applicable to the human spaceflight program, and the committee recommends that successful aspects of the robotic science program—especially its emphasis on having a clear strategic plan that is executed so as to build on incremental successes to sustain momentum, use resources efficiently, enforce priorities, and enable future breakthroughs—should be applied in the human spaceflight program. Workshop participants also argued that human space exploration conducted synergistically with robotic exploration would produce the best possible overall space program. There also was recognition that success in this new type of venture would require a cultural change in the organization and management of NASA itself. In discussing the rationale for sending humans into space, the NRC workshop participants noted that the old issues tied to Cold War competition with the Soviet Union have been superseded by more complex dimensions of global technological competition, and today the reasons emerge from an innate human desire to know—to learn, to extend our grasp with technology, to move civilization forward. We do so by exploring, and we choose the means that are most appropriate. In some cases, we can achieve our exploration goals through robotic missions that conduct in situ sampling or telescopic observations. In other cases, the human presence and human expertise and experience are necessary. On January 14, 2004, NASA received specific instructions from President George W. Bush to undertake a space exploration program with a clear set of goals, including “[implementation of] a sustained and affordable human and robotic program to explore the solar system and beyond” and “[extension of] the human presence across the solar system, starting with a human return to the Moon in preparation for human exploration of Mars and other destinations.”2 Thus the president’s new vision for space exploration shares many of the characteristics defined independently in the November 2003 NRC space policy workshop. A statement in the president’s speech accompanying his announcement particularly resonates with the views of workshop participants: “This is a journey, not a race.” That principle recognizes that reorienting the human spaceflight program toward exploration goals is a pivotal step in the inevitable march of humankind into space.3 It also emphasizes the risk and inefficiency of artificial deadlines, and it supports the “go as you pay” principle enunciated in the 2003 workshop. EXPLORATION AND SCIENCE In considering the various opportunities available in the context of a reinvigorated human exploration program, the committee concluded that expansion of the frontiers of human spaceflight and the robotic study of the broader universe can be complementary approaches to a larger goal. The robotic exploration of space has led to and will continue to provide paradigm-altering discoveries: Understanding the dark energy that powers the universe as well as the Sun’s role in influencing Earth’s climate, for 2 A Renewed Spirit of Discovery, the President’s Vision for U.S. Space Exploration, The White House, January 2004. 3 Analyzing roles for humans in space exploration was not part of the committee’s charge, but the value of human exploration is a premise that the committee accepts. That subject has been addressed in the NRC report Scientific Opportunities in the Human Exploration of Space (National Academy Press, Washington, D.C., 1994). Specific examples of past benefits from astronauts’ flexibility and capacity to evaluate complex situations and adapt to unexpected situations are documented in Where No Man Has Gone Before, A History of the Apollo Lunar Exploration Missions (by William David Compton, The NASA History Series, NASA SP-4214, NASA, Washington, D.C., 1989) and in Assessment of Options for Extending the Lifetime of the Hubble Space Telescope (National Academies Press, Washington, D.C., 2004).
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Science in NASA’s Vision for Space Exploration example, will expand the horizons of our knowledge in profound ways. Human spaceflight also presents a clear opportunity to change our sense of our place in the universe. It surely will be a transformative event to place humans on Mars. The science conducted through the robotic exploration of space and human spaceflight to the Moon and Mars are synergistic enterprises. Both are worthy of inclusion in a robust space program that serves the aspirations of our civilization, and both enhance U.S. leadership in science and technology. Indeed, human exploration and science are united in their purpose to understand the universe in which we live as well as to improve life here on Earth. The committee also recognized that major advances in understanding will be required to send humans forth on long-duration spaceflight beyond Earth. For example, we do not know with confidence today how to sustain humans in microgravity and how to protect them from the effects of space radiation for long periods. Nor do we know how sound the scientific basis is for the systems needed to support long-duration human spaceflight and remote operations to reliably put humans into space. The behavior of fluids in microgravity will require special attention; the reliability and predictability of materials exposed for long periods to the conditions of space must be investigated; both the medical and the psychological issues related to humans engaging in long-duration spaceflight need to be better understood; and countermeasures for the effects of exposure to radiation and reduced gravity will have to be developed. These essential tasks pose new engineering and science challenges that require fundamental discoveries through basic research across multiple traditional disciplines. The appropriate science in a vibrant space program is, therefore, nothing less than that science that will transform our understanding of the universe around us, and will in time transform us into a space-faring civilization that extends the human presence across the solar system. This viewpoint is captured well in NASA’s mission statement as articulated in its 2003 strategic plan:4 “To understand and protect our home planet, To explore the universe and search for life, To inspire the next generation of explorers, … as only NASA can.” NASA’s mission has its foundation in the Space Act that created NASA, and in other more recent national policy directives. The committee believes that this is a bold and appropriate agenda. The opportunities for discovery are vast. They encompass the Earth on which we dwell, the Moon and Mars and other places in the solar system where humans might be able to visit, the broader solar system including the Sun that we probe with robotic spacecraft missions, and the vast universe beyond that is reachable only via telescopes. Indeed, there is an extraordinary richness to the opportunities, although not all can be actively pursued given the resources available. The issue then is not what to pursue ultimately, but rather what to pursue first, and then how to prioritize what follows. The standard for deciding what science to select can be set by recalling the motivation for pursuing space exploration. We do so to ensure that we will continue to advance our intellectual understanding of the cosmos, including our place in it, and will continue our development as a civilization for which human spaceflight becomes routine and inevitable. The array of choices can include plans for missions and enabling science that will not be achieved for decades or longer, but it also needs to include programs from which major achievements can be expected in the nearer term. What is selected must include the essential enabling science that not only will make long-duration human space exploration possible but also will provide the basis and rationale for future space exploration. The results 4 NASA, National Aeronautics and Space Administration 2003 Strategic Plan, NP-2003-01-298-HQ, NASA, Washington, D.C., 2003.
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Science in NASA’s Vision for Space Exploration of such enabling science must be available and current so as to support timely engineering and programmatic decisions that will allow humans to go into space with the greatest assurance of success at the minimum possible risk.
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