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PHYSICS & SPACE

Flying the Right Mission

Neglecting Space-Based Science Is a Mistake of Cosmic Proportions

Pie chart of dark matter and dark energy in the universe SOURCE: n/a Space-based research could greatly improve our understanding of "dark energy," which accounts for fully 70 to 75 percent of the total mass-energy content of the universe.

Fifty years ago, the Soviets launched Sputnik and started something truly significant in the human story: the “Space Age.” Fifty years later, the rest of the world is starting to catch up. Commercial enterprises are getting into the space act, and many other nations have the technological means to launch satellites. But even so, the one thing that NASA and the United States have over all other worldwide efforts is the ability to use their resources to contribute to science: from Earth science to robotic exploration of the planets to cosmology. The 2006 Nobel Prize in Physics, awarded to John Mather and George Smoot for their work on cosmic microwave background radiation, attests to the importance of having a scientific presence in space, and recognizes the effort of individuals who work in highly collaborative environments such as NASA.

The Bush Administration’s policies are out of balance, focused on using NASA to support political goals while crippling its ability to do important and fundamental science.

But as far as science is concerned, things could be better at NASA. Both internal NASA policies and external Bush administration policies currently contribute to a steady loss of scientific opportunities and risk the nation’s leadership in science, especially in the physical sciences. If the United States loses this leadership, it loses it for good, and as the American Competitiveness Initiative clearly spells out, the U.S. economy will pay dearly.

The problems are easy to state. First, the Bush administration’s policies are out of balance, focused on using NASA to support political goals while crippling its ability to do important and fundamental science. Second, NASA’s internal policy is designed for a “mission oriented” agency, suitable for much of what NASA does, but old-fashioned and inefficient for playing a role in supporting basic science. The scientific opportunities that NASA is missing are at the core of the important discussion about how to maintain the nation’s economic competitiveness into the future, as that competitiveness directly relates to our leadership in the physical sciences.

The innocent beeping of Sputnik catapulted humans into the Space Age, and the response of the U.S. government to that tiny silver orb paved the way for one of the most significant scientific and technological achievements of the 20th century: human exploration of the moon. NASA, and many important technologies, grew from this original mission, but NASA has abandoned the capabilities that set it apart from other agencies, chiefly among them the ability to use its resources to advance scientific research in a wide variety of fields including Earth science, interplanetary robotic exploration, and cosmology. Without re-orientation of the agency’s priorities, NASA will be unable to provide scientists with the resources that allow them to better understand our fragile planet and our place within the universe. And this loss would be another example of our benign neglect costing the United States its lead in science.

There are no burning scientific questions that scientists around the world are clamoring to know about that can only be answered by sending humans to the moon or Mars.

The solution to the first problem of unbalanced priorities is easy: The administration should stop saddling NASA with its misguided over-emphasis on a return trip to the moon and exploration of Mars. Such an emphasis has no significant basis in science. That is, there are no burning scientific questions that scientists around the world are clamoring to know that can only be answered by sending humans to the moon or Mars. These efforts might support our aerospace industry, and that is arguably a very important role that NASA plays, but that’s not all NASA should be doing. Politics and political gain are colliding with scientific research and opportunity. NASA should stop throwing away precious resources on shuttle launches that have no useful purpose other than political pageantry and public relations.

There are claims that manned exploration of the solar system is an inevitable human destiny, but there are stronger arguments that exploration should not come at the expense of real scientific advancement, especially at a time with so many critical problems in space-based science and so many opportunities to make progress on our understanding of those problems. Our destiny can wait. The administration should make it possible for the agency to support basic science: from fundamental research in astrophysics to the strategic research such as space-based measurements of the Earth and sun—extremely important areas of study in this age of global climate change and the environmental considerations that will accompany the looming energy crisis.

The second problem, NASA’s narrow “mission-focused” operations, involves a fundamental difference between how NASA and other important players in science funding—like the National Science Foundation, the Department of Energy, and the National Institutes of Standards and Technology—support science. To illustrate the problem here, consider the juxtaposition between the phenomenal recent discovery by U.S. scientists of the accelerating universe and “dark energy,” and how little progress has been made in capitalizing on this discovery with a space-based mission.

The discovery relied upon observations of particular kinds of stellar explosions called supernovae. The physics of these explosions is so well understood that they can serve as “standard candles”—they have a known intrinsic brightness. By measuring the amount of their light that reaches Earth, we can calculate the supernova’s distance, and hence how far back in time the explosion occurred. By measuring the change in the spectral colors from elements ejected by the supernova, we can measure the relative velocity of the distant star. Using both measurements together tells us the velocity of these exploding stars at different times in the 14 billion-year-old expansion of the universe, mapping out the history of the expansion.

There is no question in the scientific community at this point about whether “dark energy” is worth investigating.

Until the late 1990s, observations, coupled with our understanding of the theory of gravity, painted a definite picture of how this expansion changes over billions of years as the gravitational force from the collective mass of the cosmos retarded the expansion. Beginning in the late 1980s, a project led by a team of scientists from the Lawrence Berkeley National Laboratory made it possible to actually measure this expansion directly. In the mid-1990s, a simultaneous effort led by a team of scientists at the Mount Stromlo Observatory in Australia mounted a similar effort. Both teams of talented scientists were attempting to measure the expansion rate directly, hoping to verify expectations.

In early 1998, both teams announced their results, and what they found has turned out to be one of the most significant scientific discoveries of all time: The expansion of the universe is actually accelerating, driven by an unexpected and completely unknown opposing force. While it is still true that gravity is acting to impede expansion, as the universe gets bigger the gravitational force of attraction gets smaller, and this new force—christened “dark energy,” since it cannot be detected directly like other mass-energy forms—is beginning to have a larger and larger cosmological effect. Eventually, the “dark energy” will dominate over gravitational attraction, ultimately leading to a universe devoid of stars and empty of energy in any usable form.

Moreover, the new supernova observations—when combined with other cosmological efforts such as properties of the radiation left by the echo of the Big Bang, and as measured by Mather and Smoot in the Nobel Prize-winning work —tell us that this “dark energy” accounts for fully 70 to 75 percent of the total mass-energy content of the universe. And we have no understanding of the nature of this dark energy. We don’t even know whether it has properties that change or are constant in time and space. It’s one of the best scientific mysteries of all time.

Tycho SupernovaThe Tycho Supernova pictured here was first observed in the 16th century. Observations of Type 1A supernova, a variant of all supernovae, led to the discovery of the mysterious “dark energy” driving galaxies apart.

This discovery has not only shocked the scientific community—it has energized it. Significant scientific interest has been focused on the discovery, and what to do next in trying to understand the nature of this expansion, anti-gravity, etc. For the past nine years, a collaboration of scientists headed by a group from the Berkeley Lab has been working diligently to prepare a space-based experiment on a satellite in high orbit—that is, outside the lunar orbit—called SNAP, for SuperNova Acceleration Probe. Such an orbit would put the satellite far outside the Earth’s atmosphere, which limits the ability to measure those “standard-candle” supernovae that are the furthest away from Earth. Moreover, an orbit outside the Earth’s shadow would avoid the large temperature swings that accompany going in and out of sunlight, an effect that bedeviled the Hubble Space Telescope. A satellite experiment would generate an extremely precise measurement of the universe’s acceleration, and tell us a great deal about the “dark energy.”

Graph of future possibilities for the universe under the influence of dark energyEventually, the “dark energy” will dominate over gravitational attraction, ultimately leading to a universe devoid of stars and empty of energy in any usable form. Gross characteristics of the fate of the universe depend heavily on properties of the dark energy. In one such scenario, referred to as the “Big Rip,” the acceleration overwhelms all known forces of nature and rips everything apart. Without space-based research, we cannot hope to fully understand this phenomenon.

The Berkeley Lab has put considerable internal resources into supporting a SNAP proposal to both the DOE—which has given support for this effort as a development project—and NASA. Other teams at other universities and national labs are also interested in this kind of science, although “interested” is an understatement. Students are ecstatic about doing research in this area, and funding agencies such as DOE and NSF recognize the significance. There is no question in the scientific community at this point about whether “dark energy” is worth investigating. In fact, the discovery of dark-energy effects is one of the most exciting events in the history of human investigation of nature. Everybody has a stake in the outcome because the future of civilization depends directly on our ability to comprehend and exploit physical principles.

This exciting research is a part of a larger field that includes the NASA-funded Cosmic Background Explorer and Wilkinson Microwave Anisotropy Probe missions, NSF’s Laser Interferometer Gravitational-Wave Observatory, and both the NSF and DOE investment in high-energy physics efforts at Fermilab, SLAC, and CERN, just to name a few. We have a tremendous prior investment in these fields. People want to work on this research. It’s a great place to train future scientists, and the discovery potential is huge. How can we lose?

The answer is distressingly simple. We can lose by continually delaying the opportunity to take advantage of unique and important scientific discoveries such as dark energy. And that is precisely what we are doing.

While there are some proposals for ground-based efforts to learn about the dark energy, the space-based SNAP, or a mission like it, would enable significant strides toward a definitive understanding of this phenomenon. And as the nation’s steward of space-based science, NASA must drive and support that research. But NASA is “mission oriented,” and as such has a very different approach to science from that of “program oriented” non-defense funding agencies such as NIH, NSF, NIST, and the DOE. The difference is extremely important and worth understanding.

These other agencies use variations on a merit-review system. They are always prepared to consider proposals from scientists—both young and old, both individually and as part of collaborations—as part of a program of research established in the agency, usually in close collaboration with the scientific community. For instance, the NSF is funding a neutrino telescope dubbed “IceCube” at the South Pole, and the LIGO gravity wave observatory, two extremely large projects consisting of a diverse group of international scientists from many different institutions working together in collaboration. Scientists working in collaboration make the proposals, and the funding agencies assemble objective reviewers to assess each proposal’s relative merit, consider the scientific objectives, and whether the proposal can or should be funded. And these agencies try to be flexible in how they define the program so that it can evolve coherently with the scientific progress.

NASA, on the other hand, works in a way more suited to an agency that in the 1960s was singular in its ability to support space research, and very concerned with missions—and NASA has not changed. A proposal to NASA for a specific piece of research, in an area that NASA might not already be involved in, will trigger consideration of whether or not NASA should have such a mission, and this takes considerable time.

Such is the nature of science: you have to run fast to keep from standing still, and that is precisely what we are not doing with respect to a dark energy space-based mission.

If NASA decides to fund the mission, it will request mission proposals from competing teams, and this process takes years to come to completion before NASA can decide on whether it wants to support such a mission. During that time, the scientists who could otherwise be collaborating are pitted against each other, an unhealthy situation in the scientific community. If NASA doesn’t feel it has enough competition, it will pull teams apart or perhaps invent new teams in an attempt to create more competition. The agency wants to control not only the mission, but the team involved, and ultimately own the entire effort. The agency sees the scientists as vendors—NASA decides all aspects of the mission and builds the scientific team to get the science done. This takes a great deal of time, is inefficient, and goes against the grain of how researchers do science. This structure was arguably well suited to an earlier era, before satellite technology became a commodity now ubiquitous in both government and private industry, and when the main purpose of NASA as an organization was to help develop advanced aeronautics. But times have changed, and basic science, along with satellite and rocket technology, has advanced far beyond where it was at NASA’s founding. The scientific program relevant to NASA has incredible breadth and complexity. Research proposals are now extremely complex in their details and scientific goals, and experiments move faster than they did previously. Acknowledging the complexity and speed of space-based research is especially important given that the European and Asian scientific communities are not only not standing still but are arguably gaining on us in expertise and resources.

For the past nine years, NASA’s mission orientation has made it difficult to work with the DOE and the scientific community to find a way to move forward on a space-based dark energy mission in any reasonably timely fashion, and this is out of place in the modern era. The very slow and clumsy effort to date is ineffective, an example of a lack of flexibility. And because of this, we are running the risk of losing our leadership. Enough time has gone by that now the Europeans, via the European Space Agency, are beginning their own studies of dark energy, and they may very well pick up this ball and run with it if we continually fail to do so. Such is the nature of science: You have to run fast to keep from standing still, and that is precisely what we are not doing with respect to a dark energy space-based mission.

NASA is a marvelous organization, with a collection of resources and expertise that we should be proud of. But NASA in the 21st century has the wrong balance: It should be a tool for promoting and executing scientific research like the NIH, NSF, NIST, and DOE, working in concert within the larger scientific program. The agency should not be a tool for promoting administration claims of having had an impact on science. And NASA should shift its focus precisely because of the importance to our nation and the world of space-based science. If we let NASA do what it does best—push the boundaries of aeronautics technology and use its resources to learn as much about our universe, from both under and above our thin atmosphere, as it possibly can—we will strengthen our industrial economy and our world leadership in the physical sciences.

Drew Baden is a professor of physics and chair of the physics department at the University of Maryland, where his research focuses on high-energy physics.

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