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Space Studies Board Annual Report 2005 6 Congressional Testimony Members of SSB committees may be invited to testify before committees of the U.S. House of Representatives or the U.S. Senate about the findings and recommendations of their reports. In February 2005, the chair of the ad hoc Committee on an Assessment of Options for Extending the Life of the Hubble Space Telescope, and one of the co-chairs of the decadal survey released in 2000 by the standing Committee on Astronomy and Astrophysics, testified to the House Science Committee about issues concerning the future of the Hubble Space Telescope in the wake of the 2003 space shuttle Columbia tragedy. In April 2005, one of the co-chairs of the ad hoc Committee on Earth Science and Applications from Space (ESAS) testified to the House Science Committee about the ESAS interim report. The texts of their prepared statements to the House Science Committee follow. The House Science Committee archives the Web casts of its hearings on its Web site; they can be viewed at http://www.house.gov/science.
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Space Studies Board Annual Report 2005 6.1 Options for Hubble Science Statement of Louis J. Lanzerotti, chair of the NRC Committee on the Assessment of Options for Extending the Life of the Hubble Space Telescope and Distinguished Professor of Physics, New Jersey Institute of Technology, and Consultant, Bell Laboratories, Lucent Technologies, before the Committee on Science, U.S. House of Representatives, February 2, 2005. Mr. Chairman, Ranking Minority Member, and members of the committee: thank you for inviting me here to testify today. My name is Louis Lanzerotti and I am a professor of physics at the New Jersey Institute of Technology and a consultant for Bell Laboratories, Lucent Technologies. I appear today in my capacity as chair of the National Research Council (NRC)’s Committee on the Assessment of Options for Extending the Life of the Hubble Space Telescope. As you know, the NRC is the unit of the National Academies that is responsible for organizing independent advisory studies for the federal government on science and technology. In early 2004 the NRC was asked by Congress and NASA to examine the issues surrounding the cancellation of the final servicing mission (SM-4) for the Hubble Space Telescope and to consider both the value of preserving Hubble and the potential methods for doing so. Specifically called out in the tasking was a requirement to survey the potentials of both on-orbit and robotic intervention. The National Research Council formed a committee under the auspices of the Space Studies Board and the Aeronautics and Space Engineering Board to respond to this request. After detailed examination of the astronomical evidence that was presented to it, the committee concluded that NASA should commit to a Hubble servicing mission that accomplishes the objectives of the originally planned SM-4 mission. This includes the emplacement of two new instruments, the Cosmic Origins Spectrograph (COS) and the Wide Field Camera-3 (WFC3), as well as refurbishments of those spacecraft subsystems that are required to preserve the health and safety of the telescope, for science as well as for eventual safe deorbiting. The committee’s principal conclusions related to the mission risk of servicing Hubble were as follows: The need for timely servicing of Hubble, due to lifetime limits on various engineering subsystems, imposes difficult requirements on the development of a robotic servicing mission. The very aggressive schedule, the complexity of the overall mission system design (which is in a rudimentary state), the current low level of technology maturity (other than the yet-to-be flown International Space Station (ISS) Special Purpose Dexterous Manipulator System (SPDM) and Grapple Arm (GA; essentially the shuttle Remote Manipulator System (RMS)), and the inability of a robotics mission to respond to unforeseen failures that may well occur on Hubble between now and a robotic servicing mission make it highly unlikely that the science life of HST will be extended through robotic servicing. A shuttle servicing mission is the best option for extending the life of Hubble and preparing the observatory for eventual robotic deorbit; such a mission is highly likely to succeed. The committee believes that this servicing mission could occur as early as the seventh shuttle mission following return to flight, at which point critical shuttle missions required for maintaining the ISS will have been accomplished. It is obvious that a robotic servicing mission to Hubble would involve no risk to astronauts. However, the committee was informed that the nation is committed to 25 to 30 human shuttle flights to the International Space Station. In reviewing all of the data presented to it, and in making use of the expertise of the committee’s members who have deep experience in human spaceflight as well as in managing the nation’s human spaceflight program, The committee concluded that the difference between the risk faced by the crew of a single shuttle mission to the ISS—already accepted by NASA and the nation—and the risk faced by the crew of a shuttle mission to HST is very small. Given the intrinsic value of a serviced Hubble, and the high likelihood of success for a shuttle servicing mission, the committee judges that such a mission is worth the risk. As I noted, these conclusions were reached after a considerable, in-depth examination of technical data and documents, presentations by expert witnesses, extensive exchanges and consultations with NASA, industry and academic colleagues, and multiple site visits to the Goddard Space Flight Center and the Johnson Space Flight Center. The committee members have outstanding, world-recognized credentials not only in the diverse fields
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Space Studies Board Annual Report 2005 relevant to this study (ranging from risk assessment to astronomy) but also in their decades of direct, practical experience with the NASA spacecraft systems and programs that were being evaluated. Two of my committee members, General Charles Bolden, a veteran former astronaut whose shuttle missions include the deployment of the Hubble Space Telescope, and Mr. Joseph Rothenberg, former associate administrator of spaceflight at NASA and former director of the Goddard Space Flight Center, are present with me today and are available to answer questions. Before I continue I would like to note, and indeed stress, that when this study was initiated, I found a broad diversity of opinion among the committee members on the question of whether Hubble should be preserved, and if so, which method of doing so was preferable. After all, from my personal experience and the experience of some members of the committee, almost no space researcher is ever in favor of turning off an operating spacecraft that is continuing to return excellent data. Hence, some members of the committee questioned at the outset of our study the very premise of keeping Hubble alive. It was only after a vigorous and painstaking exploration of the information presented to us, and considerable questioning analysis, that the committee reached the conclusions that are found in our report. Those conclusions were reached unanimously, and without reservation, by our entire membership. Of the many issues considered by the committee, I have been asked to focus today on (1) Hubble’s contribution to science and what its loss or performance interruption would mean, and (2) the comparative strengths and weaknesses of a shuttle servicing mission, a robotic servicing mission, and a rehosting mission. I will therefore devote the remainder of my testimony to these issues. The Past and Future Contributions of Hubble Over its lifetime, the HST has been an enormous scientific success, having earned extraordinary scientific and public recognition for its contributions to all areas of astronomy. Hubble is the most powerful space astronomical facility ever built, and it provides wavelength coverage and capabilities that are unmatched by any other optical telescope currently operating or planned. Much of Hubble’s extraordinary impact was foreseen when the telescope was being planned. It was predicted, for example, that the space telescope would reveal massive black holes at the centers of nearby galaxies, measure the size and age of the observable universe, probe far enough back in time to capture galaxies soon after their formation, and provide crucial keys to the evolution of chemical elements within stars. All of these predicted advances have been realized, but the list of unforeseen Hubble accomplishments may prove even greater. Hubble did discover “adolescent” galaxies, but it also saw much farther back in time to capture galaxies on the very threshold of formation. Einstein’s theory of general relativity was bolstered by the detection and measurement of myriad gravitational lenses, each one probing the mysterious dark matter that pervades galaxies and clusters of galaxies. Gamma-ray bursts had puzzled astronomers for more than 20 years; in concert with ground and X-ray telescopes, Hubble placed them near the edge of the visible universe and established them as the universe’s brightest beacons, outshining whole galaxies for brief moments. Perhaps most spectacularly, Hubble confirmed and strengthened preliminary evidence from other telescopes for the existence of “dark energy,” a new constituent of the universe that generates a repulsive gravity whose effect is to drive galaxies apart faster over time. The resulting acceleration of universal expansion is a new development in physics, possibly as important as the landmark discoveries of quantum mechanics and general relativity near the beginning of the 20th century. Closer to home, Hubble has zeroed in on our own cosmic past by uncovering virtual carbon copies of how the Sun and solar system formed. Dozens of protoplanetary disks have been found encircling young stars in nearby star-forming regions of the Milky Way. The sizes and densities of these disks show how surplus dust and gas collect near infant stars to form the raw material of planets. Dozens of large, Jupiter-like planets have been discovered, initially by other telescopes but recently by Hubble using a new and more precise method. Measuring the tiny drop in light as a planet transits the disk of its parent star, the new technique could lead to a method for discovering Earth-like planets—a discovery with tremendous long-term implications for the human race. I would like to stress that results from Hubble—its pictures and the new concepts that have flowed from these images—have captured the imagination of the general public, not only in our country but also around the world. Hubble has been one of the most important outreach instruments in terms of its contributions to public awareness of science and of the universe in which we live. Fascinating as they are, the scientific returns (and the public interest and excitement) from Hubble are far from their natural end. With its present instruments the telescope could continue probing star formation and evolution,
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Space Studies Board Annual Report 2005 gathering more data on other planetary systems, revealing phenomena of the planets and comets in our own solar system, and exploring the nature of the universe at much earlier times. Two new instruments, already built for NASA’s previously planned servicing mission (SM-4), would amplify the telescope’s capabilities by allowing qualitatively new observations in two underexploited spectral regions. Such rejuvenation via new instruments has occurred after every Hubble servicing mission, and the next one promises to be no different. Wide Field Camera-3 (WFC3) would increase Hubble’s discovery efficiency for ultraviolet and near-infrared (IR) imaging by factors of 10 to 30. The ultraviolet (UV) channel coupled with the camera’s wide field of view will image the final assembly of galaxies still taking place in the universe. The near-infrared channel of WFC3 favors discovery of the very youngest galaxies, whose light is maximally red-shifted. The available UV, visible, and near-IR channels will combine to give a sweeping, panchromatic view of objects as diverse as star clusters, interstellar gas clouds, galaxies, and planets in our own solar system. The second new instrument, the Cosmic Origins Spectrograph (COS), will increase Hubble’s observing speed for typical medium-resolution ultraviolet spectroscopy by at least a factor of 10 to 30, and in some cases by nearly two orders of magnitude. Ultraviolet spectra carry vital clues to the nature of both the oldest and the youngest stars, yet UV rays are totally invisible to ground-based telescopes. COS will fill important gaps in our understanding of the birth and death of stars in nearby galaxies. Even more impressive, COS will use the light of distant quasars to spotlight previously undetectable clouds of dispersed gas between nearby galaxies, thereby mapping in unprecedented detail the properties of the so-called “cosmic web.” The future accomplishments I have described, and the many unforeseen discoveries that are impossible to predict but certain to occur, are what would be lost if Hubble was not serviced or replaced. It might be argued, of course, that the universe will be here into the future for other space missions to explore further. However, a number of NASA space astronomy missions presently in flight as well as planned, including the X-ray satellite Chandra and the infrared satellite Spitzer, would not be as productive as they can be if synergistic data from Hubble were not to be available for analyses. The most recent decadal survey of astronomy has predicated its recommendations for the future of the research field, and for the future facilities that would be needed for future advances, on the existence of Hubble data and its use in conjunction with other NASA space astronomy missions. My colleague Professor Joseph Taylor, a co-chair of this decadal survey, is here today and can address this aspect of Hubble much better than I can. It is important to recognize that a central issue in the discussions that entered into our committee’s conclusions is that the Hubble has a limited life; it was designed from the outset to be serviced periodically. A lengthy delay in servicing (the technical details are described in detail in our report) could result in a permanent loss of the telescope and even in a telescope orientation that would prevent ultimate safe deorbit. As shown in our report, it is most likely that an interruption of science operations will occur due to gyroscope failure some time in mid-2007 unless servicing occurs. The ultimate, irreversible, failure of the telescope in the next several years is dependent on battery lifetime. Our committee spent a great deal of time investigating the conditions of the batteries (with a subgroup of the committee speaking to NASA and other engineers, including the battery manufacturer, and studying data from battery life tests in a laboratory) and concluded that the window for battery failure that would end science operations opens in about May 2007. The window for potential vehicle failure opens in 2009. While there are many considerations in coming to these dates, there are few options beyond servicing for improving the outcome. The batteries themselves are not greatly affected by lighter loading that might be possible by early termination of science operations since operations will already be terminated at an early date due to loss of gyros. Comparison of Robotic Servicing, Shuttle Servicing, and Rehosting Let us leave aside for the moment the issue of placing the Hubble instruments on some other spacecraft and begin with the realization that, given the predicted failure of the on-board gyros, HST most likely will need to terminate science operations by mid-2007. Based on this engineering determination which we believe to be correct, any servicing mission, shuttle or robotic, must be accomplished by the end of 2007 at the latest to prevent an interruption in science. A delay past 2007 not only results in increasing odds that the repair mission will meet an impaired Hubble when it launches. In the case of a robotic mission, it also means a growing reduction in the remaining lifespan of the serviced Hubble because, unlike a human servicing mission, a robotics mission will be incapable of correcting most types of avionics system failures. A 2009 robotic mission would occur at a time when the telescope is already at the 50 percent risk point.
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Space Studies Board Annual Report 2005 Even NASA’s most optimistic projection places the robotic mission in December 2007, and this estimate was made when the NASA project hoped to receive full funding for development in both 2005 and 2006, something that has not occurred. Because the impact of reduced funding is always schedule delay, and often increased risk, there is a low probability of being able to undertake a successful robotic mission in time to save HST, even if much of the hardware has already been assembled and all of the systems testing had been successfully accomplished. Now, let us compare a robotic servicing mission with a shuttle servicing one. Some of the important strengths of a shuttle servicing mission are that (1) it has been done successfully before—four times in fact—so there is no new development required; (2) all of the instruments and replacement equipment have been built or can be made ready, so there is low schedule risk; (3) numerous life extension upgrades that are not feasible on a robotics mission could be carried out; (4) the shuttle has a proven capability for repairing Hubble with 100 percent success history from four missions; and (5) a human mission has the unique ability to respond to last-minute requirements, usually driven by unforeseen failure (such as the need for new magnetometer covers that occurred on SM-1). In addition, and very importantly, the SM-4 mission could reduce the risk and cost of the eventual deorbit mission for Hubble by prepositioning a docking mechanism and associated fiducials on the aft end of the telescope so that the rendezvous and docking of the deorbit module would be greatly facilitated over the uncooperative target that the telescope currently offers to any robot approaching it. The main weaknesses in a shuttle servicing mission are that the schedule depends on successful shuttle return to flight (RTF), and there is a small crew safety risk by flying one shuttle mission in addition to the 25 to 30 that are estimated by NASA as required for completion of the ISS. The additional shuttle mission would also delay ISS assembly by 3 to 5 months, thereby increasing slightly shuttle program costs (in comparison to total shuttle program costs) at the end of the shuttle life, currently projected for 2010. The strengths of a robotic mission are that (1) it avoids the risks to astronauts of one additional shuttle flight; (2) it is exciting technology; and (3) some of the technology may have applications to other space activities. The weaknesses are primarily those associated with successfully achieving an extremely ambitious mission on an aggressive schedule, and the risk to HST (not only to HST science but also to eventual successful deorbit) of using it as a target vehicle for the demonstration of unproven technology. It also has very large costs, both near- and far-term costs; an estimate of $2.2 billion (or more including launch costs) was provided to NASA by the Aerospace Corporation. Those members of the committee who are familiar with such costs believe that this number is plausible. From the risk mitigation viewpoint, the committee stated in our report that the planned use for the robotic servicing mission of the mature ISS robotic arm and robotic operational ground system helps reduce both the schedule risk and the development risk for this mission. However, the committee found many other serious challenges to the development of a successful robotic mission. Some of these challenges are due to the simple fact that Hubble was not designed to be serviced robotically, and thus has hardware features that are designed for human, not robot, interactions. Challenging issues for a successful robotic mission include: Technologies required for close-proximity operations and autonomous rendezvous and capture of the telescope have not been demonstrated in a space environment. The control algorithms and software for several proposed systems such as the laser ranging instrument (lidar) and the camera-based control of the Grapple Arm are mission-critical technologies that have not been flight-tested. Technologies needed for autonomous manipulation, disassembly, and assembly and for control of manipulators based on vision and force feedback have not been demonstrated in space. The Goddard HST project has a long history of Hubble shuttle servicing experience but little experience with autonomous rendezvous and docking or robotic technology development, or with the operations required for the proposed HST robotic servicing mission. The committee found that the Goddard HST project had made advances since January 2004. However, the committee also found that there remain significant technology challenges and—very significantly—major systems engineering and development challenges to successfully extend the lifetime of HST through robotic servicing. The proposed Hubble robotic servicing mission involves a level of complexity that is inconsistent with the current 39-month development schedule and would require an unprecedented improvement in development performance compared with that of space missions of similar complexity. The committee concluded that the likelihood of successful development of the HST robotic servicing mission within the baseline 39-month schedule is remote.
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Space Studies Board Annual Report 2005 Rehosting Rehosting of the two new instruments, COS and WFC3, was the final option I was asked to discuss in my testimony today. In theory, the flight of these existing instruments on a new astronomy mission would be a possible means of obtaining some of the science that would otherwise be lost if Hubble were not repaired through a shuttle servicing mission. The information that was provided by NASA to the committee on possible rehosting options was very sketchy, certainly not as defined and as detailed as much of the technical information available for servicing Hubble. One clear advantage of any rehosting mission is that it would use a spacecraft that employed current-era technologies. Possible rehosting missions could be flown to either a low Earth orbit (LEO), such as the one that Hubble is currently flying in, or to some other orbit, such as geosynchronous orbit or a Lagrangian point. It was unclear to the committee which, if any, of these orbits was under any serious consideration by NASA. Thus, I have to speculate somewhat as to what might be being proposed today, some 4 months after the committee’s last meeting. A rehosting mission to geosynchronous orbit or to a Lagrangian point would require the employment of launch vehicles that would permit the mission to arrive and to survive at the selected location. A spacecraft to a Lagrangian point location would likely involve a thermal design that was simpler than that used on Hubble since no eclipses would occur in that orbit. At geosynchronous orbit, eclipses occur twice a year, such as geosynchronous communications spacecraft experience. The relative absence of eclipses at geosynchronous orbit or at a Lagrangian point would also allow a higher duty cycle for the acquisition of science data. Any new telescope located at either location would not be practical to service. Servicability is a feature that has allowed the HST to be continually upgraded since launch. Independent of the lack of solid technical (to say nothing of lack of schedule) information on rehost options, the committee had a number of important concerns with respect to the practical aspects of rehosting. In order to obtain science returns from the COS and the WFC3 comparable to the return from the instruments if they were flown on Hubble, the new satellite would have to carry a 2.4-meter-diameter mirror, with diffraction-limited performance down to the ultraviolet (such a mirror diameter is especially necessary for the science enabled by the WFC3 instrument), together with a very accurate pointing and guiding system that would be consistent with HST’s capabilities. The two instruments would also have to be modified from their present states in order to be able to effectively use the new unaberrated mirror that would likely be designed and built for the new spacecraft. (It seems inconceivable to me that an aberrated mirror would be purposefully designed for a brand new spacecraft just to match the Hubble’s aberrated mirror.) In essence then, NASA would need to commit to, and to build and fly, a new Hubble telescope with an unaberrated mirror. The original Hubble development and testing program involved a lengthy and costly process. For mission success, this new rehost development program would require a commitment of very significant resources as well as political support over an interval of several years. The committee questioned whether such a commitment is likely to be given, let alone sustained in the face of numerous competing, high-priority, peer-reviewed astronomy programs that are already planned. Even if the new Hubble program were adequately supported, such a program would come with the added risks that technical problems could halt or seriously delay development. In addition, as already noted in the Aerospace Corporation report, it was not clear to the committee that there would be significant cost savings over the options for a shuttle SM-4 repair mission, particularly given the uncertainties of developing an entirely new satellite that performs like the original Hubble. Finally, unlike a Hubble repair, a satellite with rehosted instruments would represent a significant new astronomy program that never was carefully evaluated for cost and schedule in the deliberative, detailed planning process that was carried out for astronomy research in the most recent decadal survey—a process that involved a great many resource and schedule trade-offs. The SM-4 Hubble servicing mission has been in NASA plans and budgeting profiles for years. In contrast, it would appear that any consideration of any rehosting option would need to obtain and to critically evaluate accurate data on the costs for a satellite development mission of a complexity almost identical to that for the original Hubble. In addition, the review of a rehosting mission by the astronomy community would have to establish its relative priority for funding and scheduling in terms of planned and ongoing programs. For these reasons, I personally would have strong reservations regarding a plan to rehost the COS and the WFC3 Hubble instruments on another satellite, particularly when compared to a shuttle repair mission. If a shuttle repair mission were not possible—if for instance NASA was not successful in returning the shuttle to flight—then I would argue that the trade-offs of performing a rehosting mission should be reviewed by the astronomy community in the context of its overall planning for space astronomy in the next decade.
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Space Studies Board Annual Report 2005 In conclusion, I would like to reiterate the committee’s conclusions that Hubble is a scientific asset of extraordinary value to the nation, and that shuttle servicing is the best option for extending the life of Hubble. Thank you for the opportunity to appear before you today. I am prepared to answer any questions that you may have. Statement of Joseph H. Taylor, Jr., co-chair of the NRC Astronomy and Astrophysics Survey Committee and James S. McDonnell Distinguished University Professor of Physics, Princeton University, before the Committee on Science, the U.S. House of Representatives, February 2, 2005. Mr. Chairman, Ranking Minority Member, and members of the committee: thank you for inviting me here to testify today. My name is Joseph Taylor and I am the James S. McDonnell Distinguished University Professor of Physics and former Dean of the Faculty at Princeton University. I appear today in my capacity as co-chair of the Astronomy and Astrophysics Survey Committee. As you know, the astronomy community has a long history of creating, through the National Research Council (NRC), broad surveys of the field at 10-year intervals. These surveys lay out the community’s research goals for the next decade, identify key questions that need to be answered, and propose new facilities with which to conduct this fundamental research. The most recent decadal survey, entitled Astronomy and Astrophysics in the New Millennium, was released in the year 2000.1 I have been asked to answer the following questions from my perspective as the co-chair of the committee that produced that report: To what extent, and in what ways, was the decadal survey premised on the Hubble Space Telescope having additional instruments that were to be added by a servicing mission? Would the loss of the Hubble cause you to entirely rethink your priorities? Would that change if the Hubble Origins Probe or a similar rehost mission is launched? How important are the contributions that would be expected from extending the life of the Hubble Space Telescope when compared to advancements expected from other astronomical programs at NASA to be launched in the next decade, such as the James Webb Space Telescope? Should either a Hubble servicing mission (whether by robot or by shuttle) or a new telescope such as the Hubble Origins Probe be a higher priority for funding than other astronomical programs at NASA? In the balance of my testimony I shall address all three questions. Until recently, the NRC decadal survey was an activity unique to the discipline of astronomy and astrophysics. The most recent survey involved the direct participation of 124 astronomers; moreover, the direct participants received input from many hundreds more of their colleagues. Altogether, a substantial fraction of the nation’s astronomers were in some way involved in the creation of the report. By gathering such broad community input, the survey process creates a document that reflects the consensus opinion of the researchers in the field. The value of this activity to NASA and the NSF has been demonstrated in many ways, and most recently by NASA’s request for the NRC to conduct similar surveys for planetary science,2 solar and space physics,3 and Earth science.4 The feature of the decadal astronomy survey that distinguishes it from summaries of other fields of science is the prioritized list of missions and facilities that are recommended for construction. This list is put together very carefully; many worthy projects do not make the list, while others are deferred to the next decade. I can assure you that the decision-making process is very thorough and sometimes leaves some “blood on the floor,” metaphorically speaking. One of the factors that make the process possible is the remarkable success of the surveys. The National Science Foundation and NASA have used the survey reports as the basis of their planning processes, and the vast majority of recommended projects from previous surveys have been completed—even if they have sometimes stretched over the boundaries from decade to decade. The completed projects have much to do with the leadership position of our national enterprise in the astrophysical sciences. 1 Astronomy and Astrophysics in the New Millennium, NRC, 2001. 2 New Frontiers in the Solar System, NRC, 2003. 3 The Sun to the Earth—and Beyond, NRC, 2003. 4 Study underway; see http://qp.nas.edu/decadalsurvey.
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Space Studies Board Annual Report 2005 The process of priority setting is based on a set of assumptions. For the purposes of this hearing, the most important of these is that priorities from previous decades should be completed. For example, the year 2000 survey reaffirmed the importance of completing the Atacama Large Millimeter Array that had been recommended in the 1991 survey.5 Along the same lines, the most recent survey was based on the expectation that a Shuttle Servicing Mission would install in the Hubble Space Telescope new instruments called the Cosmic Origins Spectrograph and Wide Field Camera-3, and would refurbish the satellite in other ways so that Hubble would continue to operate until 2010—about the time that the infrared James Webb Space Telescope (JWST) is planned to become available.6 We were told that this mission, now referred to as SM-4, would cost $350 million, and it was one of the considerations that led to the final shape of the priority list. There are a number of strong arguments for keeping the Hubble telescope operational until JWST is ready. The new instruments will expand Hubble’s reach farther into the near-infrared region of the spectrum. This capability will enable the selection of potentially interesting targets that will form much of the basis of the initial JWST research program. The Hubble Space Telescope is still in the prime of its scientific life. Even with some temporarily reduced capacity, astronomers are using it to observe objects that were thought to be beyond any telescope’s capability. Hubble is also important to the nation for reasons beyond its immediate scientific contributions. According to a recent NRC study, nearly one-third of all federal support for astronomy research is tied to the Hubble telescope and its affiliated research programs.7 NASA, in consultation with the community, plans to transfer these programs to the James Webb Space Telescope when it becomes operational; but the premature loss of Hubble would threaten the continuity and vitality of this research enterprise, and this source of highly trained technical personnel for the nation. We all love Hubble. It is truly a remarkable instrument. That said, the object of my committee’s decadal survey was to look ahead and identify the tools that would be needed to continue answering deep questions about the universe and the most fundamental laws of Nature. In the survey committee’s judgment, in the present decade answers to these questions are more likely to be found in regions of the spectrum outside the Hubble telescope’s capabilities. Top survey priorities such as JWST and the Constellation X-Ray (Con-X) observatory will open large spectral windows on the universe that are simply not available to instruments on the ground. While we can never be sure where the next scientific breakthrough will arise, the future with these missions seems very bright. JWST will be able to observe and examine the very first galaxies that formed in our universe, and to study the era when the first stars ignited. Con-X will be able to observe how matter and energy behave near black holes—an extreme environment in which the laws of physics have not yet been well tested. The survey does not neglect the optical region of the spectrum. Two of the survey’s top three recommendations for ground-based facilities are for new optical telescopes that will observe the universe in new and different ways.8 While Hubble can do some things that are unmatched by telescopes on the ground, the choice to move space astrophysics into the infrared and X-ray regions of the spectrum was one of the difficult decisions that the committee made. In this context, it is difficult to say that the premature loss of the Hubble telescope would significantly alter the survey’s priority list. It is possible that the committee would have given a stronger priority to the Space Ultraviolet Observatory (SUVO), which was omitted from the final priority list; but I do not believe that the rest of our list would have been very different. Mr. Chairman, the scientific promise of JWST and other survey priorities lies in the future, while your committee is grappling with decisions that need to be made very soon. Accounting methods and other changes that have taken place at NASA since the completion of the survey now make it seem very unlikely that a shuttle servicing mission would cost the Science Mission Directorate as little as $350 million. However the Hubble telescope is serviced, present cost estimates seem to run to at least $1 billion—roughly equivalent to that of a second JWST. Such a cost, if borne by the science program, will likely delay a number of other missions that are under development, including those ranked highly in NRC decadal surveys across all of space science. 5A Decade of Discovery in Astronomy and Astrophysics, NRC, 1991. 6The James Webb Space Telescope (then referred to as the Next Generation Space Telescope) was the highest-priority recommendation of Astronomy and Astrophysics in the New Millennium. 7Federal Funding of Astronomical Research, NRC, 2000, p. 54. 8The Giant Segmented Mirror Telescope and the Large Survey Telescope.
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Space Studies Board Annual Report 2005 One option that I have not yet mentioned is to host the Hubble replacement instruments COS and WFC3 on a new satellite like the proposed Hubble Origins Probe (HOP). According to the team proposing HOP, the cost for such a mission would also be roughly $1 billion, and the telescope would be ready by 2010. The proposal also calls for an additional wide-field imaging camera. Such a satellite offers significant promise; however, to start work on it would in essence insert a new priority into the mission queue, without benefit of the kind of comparative review undertaken in the survey. From the point of view of the survey committee, I believe that neither a $1 billion servicing mission nor a $1 billion rehosting satellite should be a higher funding priority than the astronomical science priorities recommended by the survey committee. Our nation’s science enterprise has been well served by having open, broadly based mechanisms for setting priorities in astronomy, and by closely following the wise decisions made in that way. A project similar to the Hubble Origins Probe could easily be included in the next astronomy survey, and would likely be a strong contender then. As you know, I am also a member of the Committee on the Assessment of Options for Extending the Life of the Hubble Space Telescope. I heartily endorse that committee’s recommendation that NASA should pursue a shuttle servicing mission to Hubble so as to accomplish the objectives of the planned SM-4 mission. However, I do not favor such a plan, much less the launch of a new satellite to host Hubble’s replacement instruments, if it would require major delays or reordering of the survey committee’s science priorities. With such a course of action, I believe that NASA would squander the excellent reputation for scientific judgment and leadership that it has so rightly earned over the years. I should stress that these opinions are my own, informed by my work on the survey and other advisory committees and by conversations with many colleagues. Thank you for your attention, and I would be pleased to answer questions.
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Space Studies Board Annual Report 2005 6.2 NASA’s Earth Science Program Statement of Berrien Moore III, co-chair of the NRC Committee on Earth Science and Applications from Space and professor and director of the Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, before the Committee on Science, U.S. House of Representatives, April 25, 2005. Mr. Chairman, Ranking Minority Member, and members of the committee: thank you for inviting me here to testify today. My name is Berrien Moore, and I am a professor of systems research at the University of New Hampshire. I appear today in my capacity as co-chair of the National Research Council’s (NRC’s) Committee on Earth Science and Applications from Space: A Community Assessment and Strategy for the Future. As you know the National Research Council is the unit of the National Academies that is responsible for organizing independent advisory studies for the federal government on science and technology. In response to requests from NASA, NOAA, and the USGS, the NRC has begun a “decadal survey” of Earth science and applications from space which is due to be completed in 2006. The guiding principle for the study, which was developed in consultation with members of the Earth science community, is to set an agenda for Earth science and applications from space, including everything from short-term needs for information, such as weather warnings for protection of life and property, to longer-term scientific understanding that is essential for understanding our planet and how it supports and sustains life, and that underpins future societal applications. The NRC has been conducting decadal strategy surveys in astronomy for four decades. But it has only started to do them in other areas fairly recently. This is the first decadal survey in Earth science and applications from space. Among the key tasks in the charge to the decadal survey committee is the request to: Develop a consensus of the top-level scientific questions that should provide the focus for Earth and environmental observations in the period 2005-2020; and Develop a prioritized list of recommended space programs, missions, and supporting activities to address these questions. The NRC survey committee has prepared a brief interim report, which I am pleased to be able to summarize today. This report provides an early examination of urgent issues that require attention prior to publication of the committee’s final report in the second half of 2006. A copy of the interim report has also been provided for your use. The report was requested by the sponsors of the study and by staff members of the Science Committee. The report also responds, in part, to direction in the FY 2005 appropriations bill that calls for “the National Academy’s Space Studies Board to conduct a thorough review of the science that NASA is proposing to undertake under the space exploration initiative and to develop a strategy by which all of NASA’s science disciplines … can make adequate progress towards their established goals, as well as providing balanced scientific research in addition to support of the new initiative.” The current U.S. civilian Earth observing system centers on the environmental satellites operated by NOAA; the atmosphere-, ocean-, ice-, and land-observation satellites of NASA’s Earth Observing System (EOS); and the Landsat satellites, which are operated through a cooperative arrangement between NASA, NOAA, and the USGS. Over the past 30 years, NASA and NOAA have contributed to fundamental advances in understanding the Earth system and in providing a variety of societal benefits through their international leadership in Earth observing systems from space. Today, this process of building understanding through increasingly powerful observations and thereby expanding the basis for needed applications is at risk of collapse. Although NOAA has plans to modernize and refresh its weather satellites, NASA has no plan to replace its EOS platforms after their nominal 6-year lifetimes end (beginning with the end of the Terra satellite mission in 2005), and it has canceled, scaled back, or delayed at least six planned missions, including a Landsat continuity mission. These decisions at NASA appear to be driven by a major shift in priorities as the agency moves to implement a new vision for space exploration. We believe this change in priorities jeopardizes NASA’s ability to fulfill its obligations in other important presidential initiatives, such as the Climate Change Research Initiative and the subsequent Climate Change Science Program. It also calls into question future U.S. leadership in the Global Earth Observing System of Systems, an international effort initiated by this administration. Indeed, the nation’s ability to
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Space Studies Board Annual Report 2005 pursue a visionary space exploration agenda depends critically on our success in applying knowledge of the Earth to maintain economic growth and security on our home planet. Moreover, a substantial reduction in NASA’s Earth observation programs today will result in a loss of U.S. scientific and technical capacity, which will decrease the competitiveness of the United States internationally for years to come. U.S. leadership in science, technology development, and societal applications depends on sustaining competence across a broad range of scientific and engineering disciplines that include the Earth sciences. The NRC’s interim report identifies a number of issues for NASA and NOAA that require immediate attention in the FY 2006 and FY 2007 programs. They include the following: The impact of canceling or delaying NASA missions; The need to evaluate plans for transferring capabilities from some canceled or scaled-back NASA missions to the NOAA-DOD NPOESS satellites; The adequacy of the technological base for future missions; The state of NASA Research and Analysis programs, which are necessary to maximize scientific return on NASA investments in Earth science and to retain the intellectual base for future missions; The need to reinvigorate the Explorer missions program; and Near-term steps that are required to develop a sustained and robust observing system from space that provides essential baseline climate observations and to create a climate data and information system to meet the challenge of production, distribution, and stewardship of climate records from NPOESS and other relevant observational platforms. With regard to these issues, the committee recommends the following actions: The NASA Global Precipitation Measurement mission should be launched without further delays. This mission is an international effort to improve climate, weather, and hydrological predictions through more accurate and frequent precipitation measurements. NASA and NOAA should complete the fabrication, testing, and space qualification of the GIFTS (Geosynchronous Imaging Fourier Transform Spectrometer) instrument and should support the international effort to launch this instrument by 2008. GIFTS will make highly detailed measurements from geostationary orbit of temperature and water vapor and will improve the prediction of severe weather conditions as well as the range of global weather forecasts. NASA and NOAA should commission three independent reviews, to be completed by October 2005, regarding three missions or instruments: (a) the Landsat Data Continuity Mission, which has been endorsed by the White House Office of Science and Technology Policy and was planned by NASA to continue the vital record of Earth land imaging after Landsat-7, which is currently failing, (b) the Glory mission to measure and characterize atmospheric aerosols and solar irradiance, which is now canceled, but which NASA had previously proposed to accelerate in response to the President’s Climate Change Science Program, and (c) the suitability of the instrumentation planned for NPOESS to measure ocean winds and direction. The guidelines for these reviews are set forth in the interim report. Mr. Chairman, we also recommend that NASA significantly expand existing technology development programs to ensure that new enabling technologies for critical observational capabilities are available to support mission starts over the coming decade. One of the problems with having nothing in the mission queue after the Global Precipitation Measurement mission, other than smaller, principal-investigator-led Explorer-class missions, is that focused technology development is no longer supported. Amongst the areas requiring increased technology investments are: Space-based interferometric synthetic aperture radar, whose numerous applications include monitoring of Earth’s crustal movements caused by volcanic or seismic activity; Wide-swath ocean altimetry, which will provide the first synoptic observations of global ocean eddies, coastal currents and tides, and internal tides; and Wind lidar, which will facilitate long-sought measurements of global wind profiles, particularly over the oceans where three-dimensional measurements are sparse and where most weather phenomena originate.
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Space Studies Board Annual Report 2005 We also recommend that NASA: Increase the frequency of Earth Explorer selection opportunities and accelerate the frequency of launch opportunities by providing sufficient funding for at least one launch per year (that is, a return to the schedule the program originally envisioned and followed prior to recent delays), and Release the next announcement of opportunity for this program in FY 2005. NASA developed its Earth System Science Pathfinder (ESSP) program as “an innovative approach for addressing Global Change Research by providing periodic ‘Windows of Opportunity’ to accommodate new scientific priorities and infuse new scientific participation into the Earth Science Enterprise … [using] … relatively low to moderate cost, small to medium sized missions that are capable of being built, tested and launched in a short time interval.” But some of the missions now being planned may not be launched until nearly 10 years after they were selected. Last, we recommend that NOAA, working with the Climate Change Science Program and the international Group on Earth Observations create a robust and sustained observing system from space that includes at a minimum a set of essential baseline climate observations. In addition NOAA should create a climate data and information system to meet the challenge of the production, distribution, and stewardship of high-accuracy climate records from NPOESS and other relevant observational platforms. These functions are within NOAA’s mandate to understand climate variability and change, but cannot be accomplished through the current NPOESS program or its data system architecture. Finally, Mr. Chairman, our committee is also concerned about diminished resources for the research and analysis (R&A) programs that sustain the interpretation of Earth science data. Because the R&A programs are carried out largely through the nation’s research universities, there will be an immediate and deleterious impact on graduate student, postdoctoral, and faculty research support. The long-term consequence will be a diminished ability to attract and retain students interested in using and developing Earth observations. Taken together, these developments jeopardize U.S. leadership in both Earth science and Earth observations, and they undermine the vitality of the government-university-private sector partnership that has made so many contributions to society. Thank you for the opportunity to appear before you today. I am prepared to answer any questions that you may have.
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Representative terms from entire chapter: