2
NASA’s Airborne Research Capabilities

2.1
INTRODUCTION

The Airborne Science Program (ASP) of NASA’s Science Mission Directorate (SMD) is responsible for providing aircraft systems (platforms, associated core sensors and data systems, and operational infrastructure) that enable unique measurements of Earth—its atmosphere, oceans, land surface, and cryosphere. These measurements can be obtained with very high spatial and temporal resolution, thereby providing a unique complement to synoptic-scale measurements from satellites.


Finding: Airborne science is an integral and essential component of NASA’s observational research strategy. In addition to this vital research role, the ASP together with the other suborbital programs is critical for the achievement of NASA’s goals in education, employee development, and planning and implementing future spacecraft missions.


Management of the ASP resides within the Earth Science Division (ESD) of SMD since, with rare exceptions, the airborne scientific user community is chiefly concerned with the six Earth science research focus areas (atmospheric composition, carbon cycle and ecosystems, climate variability and change, Earth surface and interior, water and energy cycle, and weather). Scientific priorities within each of these focus areas drive the capabilities requirements of the ASP. While science priorities differ among the focus areas, all airborne science missions have in common the following broad objectives:

  • Process-scale studies (i.e., high-spatial- and high-temporal-resolution studies of various processes that take place within the atmosphere, ocean, land, and so on) of Earth system science,

  • The calibration and validation of satellite sensors and associated retrieval algorithms (computer processing to extract information from the data), and

  • The development and testing of new instruments, either for new satellite concepts or for use in satellite calibration/validation or in process studies.

The science priorities of airborne science programs and the campaigns to implement their objectives are developed through collaborations among the ESD research and analysis (R&A) programs, satellite mission science teams, and technology development programs (such as the Earth Science Technology Office).



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2 NASA’s Airborne Research Capabilities 2.1 INTRODuCTION The Airborne Science Program (ASP) of NASA’s Science Mission Directorate (SMD) is responsible for providing aircraft systems (platforms, associated core sensors and data systems, and operational infrastructure) that enable unique measurements of Earthits atmosphere, oceans, land surface, and cryosphere. These measure - ments can be obtained with very high spatial and temporal resolution, thereby providing a unique complement to synoptic-scale measurements from satellites. Finding: Airborne science is an integral and essential component of NASA’s observational research strategy. In addition to this vital research role, the ASP together with the other suborbital programs is critical for the achieve - ment of NASA’s goals in education, employee development, and planning and implementing future spacecraft missions. Management of the ASP resides within the Earth Science Division (ESD) of SMD since, with rare excep - tions, the airborne scientific user community is chiefly concerned with the six Earth science research focus areas (atmospheric composition, carbon cycle and ecosystems, climate variability and change, Earth surface and interior, water and energy cycle, and weather). Scientific priorities within each of these focus areas drive the capabilities requirements of the ASP. While science priorities differ among the focus areas, all airborne science missions have in common the following broad objectives: • Process-scale studies (i.e., high-spatial- and high-temporal-resolution studies of various processes that take place within the atmosphere, ocean, land, and so on) of Earth system science, • The calibration and validation of satellite sensors and associated retrieval algorithms (computer processing to extract information from the data), and • The development and testing of new instruments, either for new satellite concepts or for use in satellite calibration/validation or in process studies. The science priorities of airborne science programs and the campaigns to implement their objectives are developed through collaborations among the ESD research and analysis (R&A) programs, satellite mission science teams, and technology development programs (such as the Earth Science Technology Office). 

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 NASA’S AIRBORNE RESEARCH CAPABILITIES The ASP has a long history of staging field operations at remote locations around the world. Over the past two decades, ASP’s various aircraft have successfully deployed and operated at latitudes ranging from the Arctic to the Antarctic for campaign durations as short as a few days (with several hours of total flight time) to as long as several weeks (with nearly 300 hours of total flight time). During this period, approximately 30 airborne science field campaigns have been conducted to research ESD priorities in the following areas: 1 • The atmospheric transport of trace gases and particles between the troposphere and stratosphere (STEP, TOTE/VOTE, STRAT, CRAVE), • The chemistry of stratospheric ozone with particular emphasis on the effects of naturally occurring and anthropogenic trace gases (AAOE, AASE, AASE II, ASHOE/MAESA, POLARIS, SOLVE, SOLVE II, PAVE), • The atmosphere’s oxidation potential, to better quantify its ability to cleanse itself of gases and material emitted from Earth’s surface or from airborne sources (SPADE, SUCCESS), • The interactions between Arctic atmospheric composition and climate (POLARIS, ARCTAS), • Convective processes in the tropics, including the investigation of the physical properties and formation processes of tropical cirrus clouds (CRYSTAL-FACE, TC4), • The dynamics and thermodynamics of precipitating cloud systems and tropical cyclones (TCSP, NAMMA, CAMEX series, TEFLUN), • The transport and transformation of gases and aerosols on transcontinental/intercontinental scales to assess the impacts on air quality and climate (INTEX-NA, INTEX-B), • The impact of subsonic and supersonic aircraft emissions on atmospheric composition and climate (SPADE, ASHOE/MAESA, SUCCESS, SONEX), • The distribution and cycling of carbon among the land, ocean, and atmospheric reservoirs and ecosystems (BOREAS, LBA, SAFARI 2000). Many of these airborne-science research areas illustrate the unique and critical role that advanced measure - ment capabilities on aircraft have played in environmental assessment. For example, the study of stratospheric ozone chemistry is a NASA mandate from Congress that stems from international concern about halogen-catalyzed destruction of ozone raised in the 1970s. In June 1975, Congress passed legislation directing NASA “to conduct a comprehensive program of research, technology and monitoring of the phenomena of the upper atmosphere.” This language, in NASA’s fiscal year (FY) 1976 authorization bill, gave the agency a clear mandate to perform research concerned with depletion of the ozone layer, and NASA’s Upper Atmosphere Research Program (an active program within the ESD atmospheric composition focus area) was born. NASA suborbital research programs have played a lead role in studies to understand stratospheric ozone depletion processes. The NASA aircraft program allows measurements of important data in studies of cloud physics, provides platforms for testing of future satellite instrumentation, and is invaluable in a host of other atmospheric science research missions. —Greg Forbes, Severe Weather Expert, The Weather Channel, Atlanta, Georgia Airborne measurements associated with the chemistry of stratospheric ozone have been critical to determin - ing the cause of the Antarctic Ozone Hole and to understanding the sensitivity of the Arctic stratosphere to ozone changes due to industrial chemicals. These measurements have been cited extensively for more than two decades in the international Scientific Assessments of Ozone Depletion conducted under the auspices of the United Nations Environmental Programme and the World Meteorological Organization as required by the Parties to the United Nations Montreal Protocol under the Vienna Convention for the Protection of the Ozone Layer. The 1995 Nobel 1 Mission acronyms are defined in Appendix E.

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0 REVITALIZING NASA’S SUBORBITAL PROGRAM Prize in Chemistry was awarded to Mario Molina, Paul Crutzen, and F. Sherwood Rowland for their pioneering work in calling attention to the threat that industrial halocarbons pose to Earth’s stratospheric ozone layer. The fact that the NASA ASP has played an instrumental role in understanding the associated chemical processes was acknowledged in their acceptance addresses. Many of these campaigns reflect the evolving emphasis of Earth system science on climate studies. Thus, measurements of the atmospheric abundances and distributions of radiatively active trace gases and measurements of the radiative properties of clouds and aerosols have been made in many of the campaigns listed above. These data have played, and continue to play, prominent roles in the climate assessments conducted by the Intergovern - mental Panel on Climate Change. The ASP has also contributed significantly to developing the quality assurance of space-based observations and the achievement of mission success. A large number of past and present satellite instruments for Earth system science have a heritage in airborne or balloon science, either through the actual instrument development or through the development of algorithms for the analysis of the measurements. The links between several satellite instruments and the associated airborne/balloon instruments are shown in Table 2.1. The discovery of the Antarctic Ozone Hole by the British Antarctic Survey set in motion the Airborne Ant- arctic Ozone Experiment (AAOE) using the NASA ER-2 deployed from Punta Arenas, Chile. Equipped with in situ instruments, the ER-2 was used to determine the cause of the observed ozone loss that reoccurred each austral spring confined within the polar vortex. We had been engaged in the mission—to be deployed in August 1987—in November 1986 to build instruments for the detection of Cl, ClO, and BrO from the ER-2. The required instruments were designed based directly on the instruments developed in the course of stratospheric balloon flights, including the optics, electronics, data systems, gas addition systems, etc. A new double-ducted architecture was developed to confine and control the flow from the high velocity of the aircraft at altitude. In the period between August 1987 and late September 1987, simultaneous measurements of ClO, BrO, and O3 revealed the dramatic on-set of ozone loss within the Antarctic vortex wherein ClO and O3 were anti-correlated. Further, ozone was lost within the vortex at a rate correspond- ing to the sum of the rate-limiting steps of the chorine and bromine radical catalyzed conversion of ozone to molecular oxygen. This provided irrefutable scientific evidence that chlorine and bromine from CFCs, halons, and methyl bromide were responsible for the dramatic loss of ozone within the Antarctic vortex. This was the foundation upon which the scientific case behind the Montreal Protocol and the subsequent London and Copenhagen amendments was built, and the NASA airborne program was directly respon- sible. Subsequently, the cause for dramatic ozone loss in the Arctic was also established to be chlorine and bromine radicals in the AASE, AASE II, and SOLVE missions using the NASA ER-2 aircraft that set in place long-term U.S. policy on CFC regulation. —James G. Anderson, Phillip S. Weld Professor of Atmospheric Chemistry, Harvard University The use of the NASA research aircraft fleet in the last three decades has created substantial scien- tific wealth related to understanding the budgets of gases and aerosols in the troposphere and lower stratosphere and their associated transformation processes, as well as insights into the fundamentals of atmospheric dynamics and air parcel transport. The aircraft fleet and its research payloads coupled with carefully considered deployment locations and flight profiles have facilitated many important discoveries about the atmosphere—discoveries that exceeded the expectations of the principal investigators. Scientific understanding leaps forward with discoveries; hence, maintaining routine airborne access to the tropo- sphere and lower stratosphere to deploy in situ and remote observing instruments will continue to have high regard among atmospheric scientists. —David W. Fahey, Program Leader in Atmospheric Composition and Chemical Processes, NOAA Earth Systems Research Laboratory

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 NASA’S AIRBORNE RESEARCH CAPABILITIES TABLE 2.1 Satellite Instruments Associated with Airborne or Balloon Instruments Satellite Instrument Associated Airborne or Balloon Instrument Moderate Resolution Imaging Spectroradiometer (MODIS) MODIS Airborne Simulator (MAS) on the Terra and Aqua satellites Moderate Resolution Imaging Spectroradiometer (MODIS) MODIS/ASTER Airborne Simulator (MASTER) on the Terra and Aqua satellites Measurements of Pollution in the Troposphere (MOPITT) MOPITT Test Radiometer on the Terra satellite Multiangle Imaging SpectroRadiometer (MISR) on the Airborne MISR instrument (AirMISR) Terra satellite Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Cloud Physics Lidar (CPL) Observation (CALIPSO) on the CALIPSO/CloudSat satellite CloudSat Radar on the CALIPSO/CloudSat satellite Airborne Cloud Radar Sensor (CRS) Tropospheric Emission Spectrometer (TES) on the Aura Airborne TES satellite National Polar-orbiting Operational Environmental NPOESS Aircraft Sounder Testbed-Microwave (NAST-M) Satellite System (NPOESS) Microwave Sounder National Polar-orbiting Operational Environmental NPOESS Aircraft Sounder Testbed-Interferometer (NAST-I) Satellite System (NPOESS) Cross-track Infrared Sounder (CrIS) Atmospheric Chemistry Experiment (ACE) on the Airborne and balloon infrared, UV, and visible wavelength Canadian SCISAT-1 spectrometers Microwave Limb Sounder (MLS) on the Upper Airborne Heterodyne System for Stratospheric OH Measurements Atmosphere Research Satellite (UARS) and the Aura and Balloon-borne Far-Infrared Limb Observing Spectrometer satellite (FILOS) Microwave Limb Sounder (MLS) on the Upper Balloon-borne Submillimeter wave Limb Sounder (SLS) Atmosphere Research Satellite (UARS) and the Aura satellite Climate Absolute Radiance and Refractivity Observatory Far-Infrared Spectroscopy of the Troposphere (FIRST) balloon- (CLARREO) missionin development borne instrument For more than a decade, all major Earth science airborne campaigns have been required to have explicit satellite validation and complementary science objectives. Some examples of this are the SOLVE campaigns that were designed for validating the SAGE-III satellite mission, and the CAMEX series of missions associated with validating tropical rainfall measurements. More recently, a multi-year series of airborne measurement campaigns (the Aura Validation Experiment, AVE) using NASA’s WB-57F weather research aircraft were designed and imple - mented to provide validation and complementary science for the entire Aura satellite mission. With the growing attention to environmental issues that are global in scope, inter-agency and international cooperation has become essential for the successful implementation of the various field measurement campaigns. The ASP management has done an excellent job in securing the necessary agreements and partnerships with domestic and foreign institutions and agencies to enable operations from the variety of locations required for the achievement of mission objectives. Recent campaigns have benefitted from the simultaneous staging and coordi - nated flying of multiple aircraft, even from deployment sites with operations that have been extremely challenging due to limited host infrastructure and severe weather conditions. While NASA personnel and platform resources have recently been stretched to their limits in addressing these difficulties, the ASP has successfully supported process studies in several Earth-science focus areas, enabled detailed characterization of environmentally sensitive areas, provided critical data for satellite validation, and fostered the development of new measurement technolo - gies. However, the science could have been significantly furthered by more comprehensive, more frequent, and simply more missions.

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 REVITALIZING NASA’S SUBORBITAL PROGRAM Finding: The lack of sufficient resource contingency for reacting to various operational issues that can arise during a campaign deployment has created situations that can require the unanticipated curtailment, realignment, and/or reprioritization of mission objectives in the field. 2.2 STATuS NASA’s ASP provides a unique inventory of highly specialized aircraft suitable for scientific research purposes that is not duplicated by any international institution or agency. As such, it has helped to establish U.S. leadership in this area. The heaviest utilization occurs for the vehicles within ASP’s Core Airborne Systems. These are con - ventionally piloted vehicles, each of which have their own unique operational capabilities and can accommodate in situ and remote sensing instruments as described below. • The DC-8 is a one-of-a-kind reconfigurable heavy-lift flying laboratory that accommodates a large group of principal investigators and their instruments for operations at altitudes up to approximately 40,000 ft (see Figure 2.1). This aircraft is the largest long-range, upper-tropospheric asset available to the research community. FIGURE 2.1 DC-8. SOURCE: Courtesy of NASA.

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 NASA’S AIRBORNE RESEARCH CAPABILITIES FIGURE 2.2 Left: WB-57F. Right: ER-2. SOURCE: Courtesy of NASA. • The heavy-lift high-altitude ER-2 and WB-57F each accommodate large payloads of autonomously operated instruments at altitudes from 50,000 to 70,000 ft (see Figure 2.2). These aircraft make the ASP the only govern - ment program with its own high-altitude flight capability. • The heavy-lift low-altitude P-3B can accommodate both instruments and scientists for operations up to 28,000 ft. • The Gulfstream G-III modified business jet serves as a test bed for a variety of flight research experiments at altitudes approaching 45,000 ft. Joining these core, conventionally piloted vehicles are unmanned New Technology Airborne Systems. Among these unmanned aircraft systems (UASs), the recently acquired Global Hawk (see Figure 2.3) is receiving the high - FIGURE 2.3 Global Hawk. SOURCE: Courtesy of NASA.

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 REVITALIZING NASA’S SUBORBITAL PROGRAM est attention from the Earth science research community due to its combined long flight duration (>24 hours) and range (>10,000 nautical miles), large payload accommodation (>1,100 lb), and high-altitude capability (65,000 ft). While broad utilization of UASs for scientific campaigns is in its infancy, as FAA confidence develops with respect to their reliability and control in civilian airspace these new aircraft are expected to play an increasing role in NASA’s airborne science strategy in the years to come. In particular, their exceptional flight range and duration together with their ability to access potentially hazardous environments without danger to human operators make UASs an extremely exciting complement to NASA’s manned aircraft fleet. The NASA ASP is the sole program with access to a heavy-lift autonomous UASs. Finding: The ability of the ASP to conduct comprehensive field campaigns utilizing the unique operational capa - bilities of its multiple aircraft (as described above) has established the program as an international asset that cannot presently be replicated by any institution. Finding: The combined use of manned and unmanned aircraft is vital to addressing ESD science and mission objectives for the foreseeable future. However, as described below, such advanced utilization cannot be achieved without considerable additional hardware investments. Capabilities under the Core and the New Technology Airborne Systems have been established in consultation with NASA’s research community and are considered essential to addressing Earth science research priorities. ASP subsidizes costs for the utilization of these platforms by NASA customers. These unique ASP capabilities have been recognized as a national asset and are often utilized by other NASA directorates, other U.S. government agencies, and state agencies. ASP aircraft have provided measurements critical for response to natural disasters (such as the California wildfires and Hurricane Katrina). Historically, approximately one-third of the operating costs under these categories have been reimbursable to NASA. Finding: Presently, the reliance on partners and reimbursable flights has reached a critical level where the ASP could not survive without them. While non-NASA utilization of these assets is important nationally, basing the ASP’s operational survival on activities that are often in response to emergency situations is not a sustainable situation. In addition to the Core and the New Technology Airborne Systems, the ASP provides a catalog of vehicles that can be chartered for use by NASA and non-NASA customers. These vehicles are available from various service suppliers, either within NASA or from other agencies or commercial suppliers. These catalog aircraft include the King Air B-200, de Havilland Twin Otter, Cessna Caravan, S-3B Viking, Beechcraft T-34C, Learjet 23 and 25, Gulfstream G-I, and the remotely piloted aerosonde. These vehicles have often been used in NASA experiments. However, in such cases their use has not been mission critical for the accomplishment of specific Earth science goals. Hence, given their broad availability for chartering by NASA, they are not currently subsidized under the ASP, and their future direct subsidy as components of the core fleet of vehicles cannot be justified. ASP capabilities are now contributing to satellite mission studies discussed in the National Research Council (NRC) decadal survey in Earth scienceEarth Science and Applications from Space: National Imperatives for the Next Decade and Beyond (NRC, 2007). These contributions include new technology demonstration, measurement strategies, and measurement gap filling. Particular examples include: • Analysis of TC4 and ARCTAS data for refining the requirements of the Aerosol-Cloud-Ecosystems (ACE), Geostationary Coastal and Air Pollution Events (GeoCAPE), and Global Atmospheric Composition (GACM) missions; • Studies of the scales of atmospheric variability to better constrain the requirements for the GEO-CAPE mission; • Flights of the Airborne Compact Atmospheric Mapper (ACAM) in support of the GEO-CAPE mission;

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 NASA’S AIRBORNE RESEARCH CAPABILITIES • Flights of new instrument technologies developed under NASA’s Earth Science Technology Office to gain an understanding of measurement capabilities and measurement retrieval errors in support of the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission; • Flights of the Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) in support of the Deforma - tion, Ecosystem Structure, and Dynamics of Ice (DESDynI) mission; and • Implementation of the Polarimeter Definition Experiment (PODEX) to test various polarimeter designs as part of the pre-Phase A study for the ACE mission. The NASA suborbital program has been an integral part of my entire research career. My association with the suborbital program began as a graduate student at Johns Hopkins University with rocket measure- ments of astrophysical objects. This association continued for the next 10 years as a postdoctoral fellow and research associate at Harvard University with laboratory studies of chemical kinetics and measure- ments from stratospheric balloons and the high-altitude ER-2 aircraft. For the last 20 years, as a profes- sor at the Pennsylvania State University, my research has involved measurements from stratospheric balloons and the ER-2 and DC-8 aircraft. From all of these studies, we have derived new understanding of extraterrestrial objects, stratospheric composition and transport, and tropospheric oxidation chemistry. Several specific examples of achievements made possible by the NASA suborbital program during my career can be cited. Stratospheric Ozone Loss and the Antarctic Ozone HoleI am proud to have played a role in determining the cause of the Antarctic ozone hole and of Arctic stratospheric ozone loss. When the Antarctic ozone hole was first reported in 1985, it stunned the atmospheric sciences community. The first evidence that reactive chlorine was involved came in 1986 from the deployment of ground-based remote sensing instru- ments to Antarctica, an effort led by Dr. Susan Solomon. However, the NASA suborbital program had a high-altitude aircraft, the ER-2, and many of the instruments needed to make measurements directly in the ozone loss region. What was missing was an ER-2 instrument that could measure the reactive chlorine. At that time I was a member of Professor James Anderson’s research group at Harvard University and was using stratospheric balloon instruments to measure reactive chlorine in the stratosphere above the United States. With NASA support we quickly developed an ER-2 instrument with similar measurement capabilities. The ER-2 was then deployed to southern Chile for measurements in the Antarctic ozone hole in 1987. A plot of data from this mission, which shows ozone going down and reactive chlorine going up as the ER-2 penetrated the Antarctic ozone hole, has often been called the “smoking gun” in establishing chlorine’s role in stratospheric ozone loss. We used the same ER-2 instrument in subsequent NASA mis- sions to show that the Arctic wintertime polar stratosphere was also primed for ozone loss. Because of the investments by NASA’s Research and Analysis and Airborne Science programs, in only a few years, the evidence for the role of chlorine and bromine in the stratospheric ozone loss was overwhelming, leading to the Montreal Protocol and its amendments to ban many halocarbons. Stratospheric Transport of AirHigh-spatial-resolution measurements of atmospheric constituents that trace the motion of air were not possible in the critical altitude region between 20 and 30 km except with instruments on large helium-filled balloons. Hence, I was asked by NASA program management to lead a team of scientists from four different institutions in putting together a balloon payload that could measure the appropriate atmospheric constituents, such as carbon dioxide, water vapor, ozone, nitrous oxide, and the chlorofluorocarbons. As a result of NASA’s support and these collaborations, we launched nine suc- cessful flights over 5 years from sites in New Mexico, Brazil, Alaska, and Sweden. The measurements from these flights have shed light on the transport of air into, out of, and through the stratosphere and have provided important data that are being used to understand changes in atmospheric composition and its relationship to climate change. Atmosphere’s Oxidation PotentialThe atmosphere’s ability to cleanse itself of gases emitted from Earth’s surface or from airborne sources is associated with the hydroxyl radical (OH), formed mainly from ultravio- let sunlight, ozone, and water vapor. However, because OH reacts so fast with other atmospheric gases, its abundance is quite small and difficult to measure. Others were just beginning to measure atmospheric OH when I joined the faculty of the Penn State Department of Meteorology in 1988. I proposed to measure OH

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 REVITALIZING NASA’S SUBORBITAL PROGRAM and the hydroperoxyl radical (HO2) with a technique developed at Portland State University and was soon funded jointly by NSF and NASA. After a few years of development and ground-based field campaigns, we received NASA support to build an instrument for the NASA DC-8. Within a year, we had developed and then deployed it during the 1996 SUCCESS airborne study over the central United States. The analysis of these early measurements confirmed a recent result that OH production was much greater than models had suggested in the upper troposphere and later extended this result over more of the troposphere. Over the last dozen years, we have measured OH and HO2 as part of seven more DC-8 aircraft missions. These missions examined a wide range of atmospheric chemistry issues, from the atmospheric effects of aircraft to the chemistry of the remote atmosphere to the global influence of atmospheric pollution to the regional effects of urban pollution and biomass burning. Our instrument and others have demonstrated that, by add - ing measurements of other OH source gases to the model, the measured and modeled OH and HO2 now generally agree over wide swaths of Earth’s lower atmosphere. However, significant differences remain in the outflow of convection, in urban and regional pollution plumes, and above forests. The NASA airborne science program will play a major role in resolving these discrepancies. The NASA suborbital program has provided an environment that has stimulated me, along with hundreds of others, to push the envelope of discovery in atmospheric science. It is also responsible for creating the next generation of scientists, some of whom are my research associates and graduate students. Consider- ing all of the science and scientists that have emerged from the NASA suborbital program, it is clear that a healthy suborbital program remains essential for NASA to fulfill its science mission. —William H. Brune, Distinguished Professor and Head of Meteorology, Pennsylvania State University 2.3 TRAINING OPPORTuNITIES Through its various scientific deployments, the ASP has provided hands-on involvement for numerous gradu - ate students and postdoctoral associates as well as for young professionals recently employed in the scientific and engineering fields. Over the past 20+ years, the ESD has conducted approximately 30 airborne science field campaigns. Each one of these has included instrument teams from various universities and these teams typically include at least one graduate student or postdoctoral associate. While many of the teams have participated on multiple deployments, one can conservatively estimate that these individuals number well in excess of 100 over this period. Some of these individuals have gone on to establish research teams at NASA centers and universities such as Harvard University, California Institute of Technology, Pennsylvania State University, and so on. Finding: The ASP has exercised a strong responsibility in the development of the next generation of scientists and engineers via cradle-to-grave mission experience. In addition to the inherent training that is accomplished in every field experiment, ASP conducts activities whose primary focus is student training. One particular example is the NASA Student Airborne Research Program (SARP) in Earth system science, organized by the National Suborbital Education and Research Center at the Uni - versity of North Dakota.2 The SARP’s objectives were to strengthen NASA’s and the nation’s workforce in Earth system science and related fields by: • Introducing students to NASA airborne science and its role in Earth system research, • Providing students with hands-on experience of end-to-end aspects of a scientific mission, and • Addressing future workforce needs in the aerospace and airborne science community. 2 See NASA DFRC News Release 09-42 and http://www.nserc.und.edu/learning/SARP.html.

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 NASA’S AIRBORNE RESEARCH CAPABILITIES Finding: Programs such as the “2009 Student Airborne Research Mission,” which utilized the DC-8 aircraft, are very effective. The future planning and conduct of such programs would benefit from a “lessons learned” docu - ment based on the SARP experience. Airborne Element of Recommendation 3: The committee strongly endorses programs such as the “2009 Student Airborne Research Mission.” The ASP should draft an SARP “lessons learned” document to guide its formulation of a plan for further activities. 2.4 PLANNED IMPROvEMENTS Most of the improvements that would benefit the ASP were presented to this committee by NASA manage - ment as future needs. Under the current ASP budget, resources do not appear to be available to implement the maintenance, modifications, and operating needs (which are listed in more detail in Section 2.5). For example, the ongoing modification to the WB-57F aircraft for increased payload capacity (i.e., superpod installation) is only one, albeit an important, step in enhancing the usefulness of this platform (see engine discussion in Section 2.5). The committee acknowledges the completion and opening of the new Dryden Aircraft Operations Facility in Palmdale, California. The shared use of this facility by the DC-8, two ER-2s, the G-III, and the SOFIA platform will significantly enhance pre-mission preparations for these aircraft by flight personnel, scientists, and engineers. However, even this achievement comes with serious concerns about adequate staffing for simultaneous operations by the various aircraft (see Section 2.5). 2.5 NEEDS The vitality of the ASP is critical to addressing many of the recommendations expressed in the NRC decadal survey in Earth science (NRC, 2007). In particular, the survey recommended that “airborne programs, which have suffered substantial diminution, should be restored, and unmanned aerial vehicle technology should be increasingly factored into the nation’s strategic plan for Earth science” (p. 14). The ASP is striving to maintain its key role in Earth observations, including the utilization of UASs. Meanwhile, this committee heard from the SMD chief scientist that the current suborbital budget is reasonably sized with respect to the current science budget within SMD. Furthermore, the committee was told that an increase in suborbital resources would only occur subsequent to augmentation of those for science, and that significant increases in the latter were unlikely to occur in the current flat budget scenario. Thus, the R&A and ASP programs find themselves in a no-win situation in which (1) resource reductions in the R&A program justify the lack of planned growth and advancement in the ASP program, while (2) limitations in capabilities within the ASP program can be cited to argue against increased mission resources in the R&A program. Finding: Given that science drives the suborbital program, increased resources in both the science and platform areas are essential. Airborne Element of Recommendation 1: The committee strongly supports the recommendations of the NRC decadal survey in Earth science that the ASP be restored to its former peak capabilities and that uASs be combined with manned aerial vehicles to address ESD science and mission objectives. Finding: NASA’s current view of the suborbital program as a “capability” balanced to current funding limitations has resulted in a lack of managerial ownership and stewardship of this vital national capability. This has in turn led to a steady and serious erosion of capabilities, because no one is charged with or accountable for viewing the suborbital capabilities as a whole and developing appropriate and necessary strategic plans. The fragmented management has led to a situation in which all three suborbital program elements are man - aged in what can be described as a reactionary mode. The program elements are not managed with an outlook for

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 REVITALIZING NASA’S SUBORBITAL PROGRAM developing the capabilities needed to address the science priorities of today, tomorrow, and the longer term. The fragmented management of the program elements prevents the ASP and other suborbital programs from continuing as unique and essential national assets. Airborne Element of Recommendation 2: To avoid fragmented management, the three suborbital program elements should be coordinated by a program lead on the staff of the associate administrator for the Science Mission Directorate for the suborbital program as a whole. This lead would be responsible for the develop - ment of short- and long-term strategic plans for maintaining, renewing, and extending suborbital facilities and capabilities, would monitor progress toward goals in the plans, and would be an advocate for enhanced suborbital activities and integration of suborbital activities and workforce development within NASA. This approach would ensure the long-term recognition of the combined value of the three suborbital program elements to the directorate, to NASA, and to the nation. Finding: There is presently very good informational exchange between the R&A programs and ASP regarding near-term and future operational requirements. However, the lack of funding does not permit appropriate program management from ASP to implement a long-term development strategy in line with the research needs. The implementation of Venture-class3 missions flown on suitable suborbital platforms to address focused sets of scientific questions was also recommended by the NRC decadal survey in Earth science (NRC, 2007). However, these can only occur if: • Suborbital programs like the ASP are restored to their peak capabilities and given sufficient resources to infuse new technology, and • Increased resources are provided to the science programs to enable full utilization of ASP capabilities. It appears that NASA SMD has engaged in a feedback loop in recent fiscal years in which declining utiliza - tion of ASP assets due to diminished R&A budgets serves as justification for not increasing the budgets of the ASP itself. Finding: As recommended by the NRC decadal survey in Earth science, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond (NRC, 2007), resource increases in both R&A and suborbital operational areas are required, as well as the design of future satellite mission packages that include essential ground-based and suborbital studies throughout the planned mission lifetimes. Presently, calibration and validation aspects of satellite missions are budgeted for only a portion of the antici - pated mission lifetime. Experience has taught that mission science objectives are often refined and become far more challenging as early results are interpreted. In an era of full cost accounting, the calibration and validation of space mission data using the suborbital program are clearly important and should be funded by the larger-bud - geted space missions. Airborne Element of Recommendation 1: The refinement of scientific objectives as missions progress argues for an adequately funded operational partnership with the suborbital program throughout the life of all future satellite missions. In addition to generic budget issues, several specific concerns can be cited based on formal presentations to the committee that are associated with several vehicles in the Core and New Technology Airborne Systems and constitute recommendations from this committee. 3Low-cost research and application; see http://eospso.gsfc.nasa.gov/eos_homepage/mission_profiles/index.php, last accessed October 2, 2009.

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 NASA’S AIRBORNE RESEARCH CAPABILITIES Airborne Element of Recommendation 4: NASA should conduct a comprehensive study of the moderniza - tion requirements for its ASP fleet. Examples of identified needs include the following: • The Real Time Mission Management (RTMM) system has recently become an essential component of ASP field deployments, allowing for the advanced utilization of multiple aircraft for scientific studies via real-time coordination of flight trajectories. The RTMM needs to be supported as a core component of the ASP to ensure its continued utilization on all aircraft and its continued development to address future measurement and mission planning needs. • DC-8 maintenance has grown increasingly more difficult due to the age of the aircraft; this model of aircraft is no longer in commercial passenger flight or military use. If NASA is to maintain a unique obser- vational platform with capabilities at least equivalent to that of the current DC-8, plans must be developed to replace this vehicle with one of more recent vintage and improved operational capabilities. • The ER-2 is heavily dependent on the uSAF’s continued use of its u-2 program. When the uSAF u-2 program is retired, NASA will lose this support and will need to adjust to the lack of availability of Jet Propellant Thermally Stable jet fuel (a high-thermal-stability, high-altitude fuel especially prepared for the u-2). Plans should be established to address this eventuality. • upgrades to the WB-57F necessary to support science mission requirements have progressed quite slowly. Addressing the compelling need for increased payload capacity of the WB-57F appears to be on track with the addition of superpods to the wings in the near future. However, replacement of the current engines (which are no longer being used in other aircraft) with newer models would enhance vehicle performance and lessen the impact of increased payload weight on operational capability. Plans for this replacement should be made. Replacement of the autopilot is also needed to comply with reduced vertical separation minimum (RvSM) requirements at certain flight levels and should be undertaken. • Replacement of the P-3B autopilot should be initiated, as should other upgrades that will improve maintainability. • Significant hardware purchases are recommended for the Global Hawk in order to advance its uti - lization as a full-fledged scientific platform. These include a deployable operating station to expand to East Coast operations and associated spare parts. Utilization of the new WB-57F superpods will require substantial modifications of existing instruments that have flown in other configurations and even instruments that have flown on ER-2 superpods. Many investigator teams do not have in-house engineering capabilities to facilitate instrument modifications required for integration into specific aircraft payload areas. Airborne Element of Recommendation 3: The establishment of a core ASP engineering capability should be a priority since it could reduce individual investigator and science program costs, especially with respect to instrument integration. Assigning engineering support out of central pools to get these new measurement technologies onto these platforms will not only reduce costs but will also expand the range of new technolo - gies for new measurements that can be used in the suborbital program. The current limited resource contingency within the ASP has made it difficult to optimize and stabilize the subsidization of user costs within the ESD. This, in turn, has had a negative effect on the level of utilization of airborne platforms by the Earth science research communities. Airborne Element of Recommendation 4: A cost plan having multi-year stability for NASA program users needs to be established. Standardizing instrument-aircraft interfaces among the various aircraft could also increase scientific utilization. This engineering task should be undertaken and would have the added benefit of assisting in instrument portability among platforms.

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0 REVITALIZING NASA’S SUBORBITAL PROGRAM While the committee is pleased to note the slight upturn in science flight hours that occurred in FY 2008 in contrast to the rather steady decline seen from FY 1999 to FY 2007, it does not appear that this is a presage for the future. Finding: The diminishment of R&A resources has led to a much lower frequency of large airborne science mis - sions, with gaps of up to 5 years. While the effects of these gaps can be lessened somewhat by the occurrence of small, short-duration, single-aircraft campaigns, significant long-term damage can occur in the training of new scientists and engineers, in addressing of critical questions associated with climate change, and in the very vitality of the ASP itself. The ASP, if properly funded, could support a significantly greater number of science flight hours than have occurred in recent years. Finding: Lifecycle training opportunities for principal investigators, program managers, and system engineers are on the verge of becoming severely limited. This will increase the risk profile for future major NASA missions requiring a proven and experienced workforce. Finally, there is concern about how the future full utilization of the Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft (see Chapter 5) will impact ASP workforce capabilities. Airborne Element of Recommendation 4: A workforce study should be implemented to ascertain whether current staffing is sufficient to enable both SOFIA and the ASP aircraft at the new Palmdale, California, facility to conduct simultaneous pre-deployment and flight activities. Based on the results of such a study, appropriate staff realignment or augmentation should be pursued.