Space Exploration: DOE Could Improve Planning and Communication Related to Plutonium-238 and Radioisotope Power Systems Production Challenges
Published: 2017-09-08T00:00:00

Fast Facts:
Radioisotope power systems enable NASA to conduct space exploration missions where solar or other power sources are not feasible (such as in deep space). These systems convert heat generated by the natural decay of plutonium 238 (Pu-238), a scarce resource, into electricity.
In 2015, the Department of Energy produced new Pu-238 for the first time since 1988. However, this process is highly technical and the department faces challenges meeting NASA's expected need for Pu-238.
We recommended that the department improve its planning and communication about the challenges it faces in producing Pu-238.

Highlights:
section_title: Why GAO Did This Study
paragraphs: NASA uses RPS to generate electrical power in missions in which solar panels or batteries would be ineffective. RPS convert heat generated by the radioactive decay of Pu-238 into electricity. DOE maintains a capability to produce RPS for NASA missions, as well as a limited and aging supply of Pu-238 that will be depleted in the 2020s, according to NASA and DOE officials and documentation. With NASA funding, DOE initiated the Pu-238 Supply Project in 2011, with a goal of producing 1.5 kg of new Pu-238 per year by 2026. Without new Pu-238, future NASA missions requiring RPS are at risk.
GAO was asked to review planned RPS and Pu-238 production to support future NASA missions. This report (1) describes how NASA selects RPS for missions and what factors affect RPS and Pu-238 demand; and (2) evaluates DOE's progress and challenges in meeting NASA's RPS and Pu-238 demand. GAO reviewed NASA mission planning and DOE program documents, visited two DOE national laboratories involved in making new Pu-238 or RPS work, and interviewed agency officials.
section_title: What GAO Found
paragraphs: The National Aeronautics and Space Administration (NASA) selects radioisotope power systems (RPS) for missions primarily based on the agency's scientific objectives and mission destinations. Prior to the establishment of the Department of Energy's (DOE) Supply Project in fiscal year 2011 to produce new plutonium-238 (Pu-238), NASA officials said that Pu-238 supply was a limiting factor in selecting RPS-powered missions. After the initiation of the Supply Project, however, NASA officials GAO interviewed said that missions are selected independently of decisions on how to power them. Once a mission is selected, NASA considers power sources early in its mission review process. Multiple factors could affect NASA's demand for RPS and Pu-238. For example, high costs associated with RPS and missions can affect the demand for RPS because, according to officials, NASA's budget can only support one RPS mission about every 4 years. Expected technological advances in RPS efficiency could reduce NASA's demand for RPS and Pu-238.
DOE has made progress in reestablishing Pu-238 production to meet NASA's future demand to fuel RPS and has identified challenges to meeting its production goals. Specifically, since the start of the Supply Project, DOE has produced 100 grams of Pu-238 and expects to finalize production processes and produce interim quantities by 2019. However, DOE has also identified several challenges to meeting the Supply Project goal of producing 1.5 kilograms (kg) of new Pu-238 per year by 2026. DOE officials GAO interviewed said that DOE has not perfected the chemical processing required to extract new Pu-238 from irradiated targets to meet production goals. These officials also said that achieving the Pu-238 production goal is contingent on the use of two reactors, but only one reactor is currently qualified for Pu-238 production while the second reactor awaits scheduled maintenance. Moreover, while DOE has adopted a new approach for managing the Supply Project and RPS production—based on a constant production approach—the agency has not developed an implementation plan that identifies milestones and interim steps that can be used to demonstrate progress in meeting production goals and addressing previously identified challenges. GAO's prior work shows that plans that include milestones and interim steps help an agency to set priorities, use resources efficiently, and monitor progress in achieving agency goals. By developing a plan with milestones and interim steps for DOE's approach to managing Pu-238 and RPS production, DOE can show progress in implementing its approach and make adjustments when necessary. Lastly, DOE's new approach to managing the Supply Project does not improve its ability to assess the potential long-term effects of challenges DOE identified, such as chemical processing and reactor availability, or to communicate these effects to NASA. For example, DOE officials did not explain how the new approach would help assess the long-term effects of challenges, such as those related to chemical processing. Under Standards for Internal Control in the Federal Government , agencies should use quality information to achieve objectives and to communicate externally, so that external parties can help achieve agency objectives. Without the ability to assess the long-term effects of known challenges and communicate those effects to NASA, DOE may be jeopardizing NASA's ability to use RPS as a power source for future missions.
section_title: What GAO Recommends
paragraphs: GAO is making three recommendations, including that DOE develop a plan with milestones and interim steps for its Pu-238 and RPS production approach, and that DOE assess the long-term effects of known production challenges and communicate these effects to NASA. DOE concurred with GAO's recommendations.

section_title: Letter
paragraphs: The National Aeronautics and Space Administration (NASA) has long  used radioisotope power systems (RPS) to generate reliable electrical  power and heat energy for long-duration space missions. RPS produce  power by converting heat from the natural radioactive decay of plutonium- 238 (Pu-238) into electricity and can operate where solar panels or  batteries would be ineffective or impossible to use, such as in deep space  or in shadowed craters. RPS also have the advantage of being able to  operate continuously and provide power for more than a decade.  Currently, a single RPS unit is being used to power the Mars Science  Laboratory, also known as Curiosity, NASA’s unmanned robotic surface  rover that has been exploring the planet Mars since 2012.
The Department of Energy (DOE) and its predecessor agencies have  been providing Pu-238 and fabricating RPS for NASA and other federal  agencies for more than 5 decades. Historically, Pu-238 was produced  domestically or was purchased from Russia. Domestic Pu-238 production  ended in 1988, and DOE has not purchased material from Russia since  2009. As a result, supplies of available Pu-238 to support new missions  have diminished. Because of a limited availability of Pu-238, the National  Academy of Sciences expressed concern about future missions in the  Vision and Voyages for Planetary Science in the Decade 2013-2022  survey report, which identifies the science community’s highest priority  space exploration interests, because many of the highest priority  missions identified in the report can only be enabled by RPS.
According to DOE documents and agency officials, DOE currently  maintains about 35 kilograms (kg) of Pu-238 isotope designated for  NASA missions, about half of which meets power specifications for  spaceflight. This supply, however, could be exhausted within the next  decade based on NASA’s solar system exploration plans. Specifically,  NASA plans to use about 3.5 kg of Pu-238 isotope for one RPS for the  Mars 2020 mission. NASA could use an additional 10.5 kg of Pu-238  isotope for the New Frontiers #4 mission if it were to use three RPS, a  decision that NASA officials said the agency expects to make in July 2019  to support a 2025 launch window. If DOE’s existing Pu-238 supply is used  for these two missions, according to DOE documentation, NASA will be  forced to eliminate RPS as a power source for future missions, delaying  future missions that require RPS until DOE produces or acquires more  Pu-238. New Pu-238 can be blended with existing Pu-238 that does not  meet power specifications so that the blended Pu-238 can be used for  future NASA missions.
Under the authority of the Atomic Energy Act of 1954, DOE maintains the  nation’s capability to support the development, production, and safety of  RPS used in NASA’s space exploration missions. Three DOE national  laboratories—Idaho National Laboratory (INL), Oak Ridge National  Laboratory (ORNL), and Los Alamos National Laboratory (LANL)—are  currently involved in RPS production. In 2011, with funding provided by  NASA, DOE initiated the Pu-238 Supply Project (Supply Project) in order  to reestablish the capability to domestically produce Pu-238. Since 2011,  DOE has produced approximately 100 grams of Pu-238 isotope under the  Supply Project. DOE identified an interim goal of producing 300 to 500  grams of new Pu-238 per year by 2019, and in 2010, it established a goal  of producing 1.5 kg of new Pu-238 per year—considered full production— by 2023, at the earliest.
In 2009, the National Academy of Sciences reported that NASA has  been making mission-limiting decisions for some time because of a  limited supply of Pu-238 and that NASA has been eliminating RPS as an  option for some missions and delaying other missions that require RPS  until DOE can reestablish production of Pu-238. In the National  Aeronautics and Space Administration Transition Authorization Act of  2017, Congress required NASA and the Office of Science and  Technology Policy to conduct an analysis of, among other things, the  risks associated with NASA’s ability to carry out planned, high-priority  robotic missions in the solar system and other surface exploration  activities beyond low-Earth orbit, resulting from a lack of adequate  radioisotope power system material or Pu-238.
You asked us to examine NASA’s process for considering and selecting  power sources for missions, in particular the use of RPS, and to review  DOE’s ability to maintain the necessary infrastructure and workforce for  RPS and Pu-238 production. This report (1) describes how NASA selects  RPS for missions and what factors affect RPS and Pu-238 demand; and  (2) evaluates DOE’s progress in meeting NASA’s RPS and Pu-238  demand and what challenges, if any, DOE faces in meeting the demand.
To describe how NASA selects RPS for missions and what factors affect  RPS and Pu-238 demand, we reviewed documentation related to how  NASA’s mission procedural requirements were considered during  planning for recent missions that considered or used RPS as a power  source. We also interviewed officials from the Planetary Science  Division (PSD) of NASA’s Science Mission Directorate and from the  Human Exploration and Operations Mission Directorate (HEO).
To evaluate DOE’s progress in meeting NASA’s RPS and Pu-238  demand, and what challenges, if any, DOE faces in meeting the demand,  we reviewed documentation related to DOE’s efforts to develop the  Supply Project and to DOE’s RPS production process. We also  interviewed officials from DOE’s Office of Nuclear Energy and DOE’s  national laboratories involved in RPS work—INL, LANL, and ORNL—and  conducted site visits to ORNL, the laboratory responsible for the Supply  Project, and INL, the laboratory primarily responsible for overseeing RPS  production. Finally, we compared DOE’s efforts to collect and assess  quality information about challenges associated with RPS and Pu-238  production and to communicate these challenges against criteria outlined  in federal internal control standards. We also evaluated DOE’s  management approach for RPS and Pu-238 production against key  management practices established in prior GAO work. For more  detailed information on our methodology, see appendix I.
We conducted this performance audit from March 2016 to September  2017 in accordance with generally accepted government auditing  standards. Those standards require that we plan and perform the audit to  obtain sufficient, appropriate evidence to provide a reasonable basis for  our findings and conclusions based on our audit objectives. We believe  that the evidence obtained provides a reasonable basis for our findings  and conclusions based on our audit objectives.
subsections: section_title: Background
paragraphs: This section provides information on the use of RPS in NASA space  missions, NASA’s PSD mission portfolio and mission classes, DOE’s role  in RPS production, DOE’s Pu-238 Supply Project, RPS production across  DOE’s national laboratories, and NASA’s funding for RPS production.
subsections: section_title: Use of RPS in NASA Space Missions
paragraphs: RPS are long-lived sources of spacecraft electrical power and heating  that are rugged, compact, highly reliable, and relatively insensitive to  radiation and other effects of the space environment, according to NASA  documentation (see fig. 1). Such systems can provide spacecraft power  for more than a decade and can do so billions of miles from the sun. In  addition to providing electricity, heat generated by Pu-238 contained in  the RPS is used to keep spacecraft instruments and components warm in  the frigid environments of deep space. Waste heat is rejected into the  environment via radiator fins that are attached to the RPS. Twenty-seven  U.S. missions have used RPS over the past 5 decades. RPS produce  electrical power by converting the heat generated by the natural  radioactive decay of Pu-238. Pu-238 is the best possible fuel for RPS  because it emits radiation that is easily shielded for the spacecraft, is  producible in sufficient quantities from available material, and can be  made into stable chemical forms that will not be taken up into the  environment if accidentally released. The current RPS design, the Multi- Mission Radioisotope Thermoelectric Generator (MMRTG), converts heat  given off by Pu-238 into about 120 watts of electrical power at the  beginning of its life—a 6 percent power conversion efficiency. One  MMRTG contains 32 general purpose heat source (GPHS) fuel clads,  which are pressed Pu-238 pellets encapsulated in iridium. Four fuel clads  are encased in one GPHS module, and eight of these modules are used  to fuel one RPS under the current MMRTG design.
section_title: NASA’s PSD Mission Portfolio and Mission Classes
paragraphs: NASA’s PSD science portfolio includes a wide array of missions that seek  to address a variety of scientific objectives. PSD’s scientific objectives  aim to answer many questions about the solar system, from how life  began to how the solar system is evolving, through the study of the  planets and small bodies that inhabit the solar system. NASA’s missions  and associated mission objectives seek to address PSD’s scientific  objectives. Some potential mission objectives include returning samples  from the surface of a comet, more intensive observations of the planets  and previously unobserved small bodies, and planet surface exploration  using unmanned robotic surface rovers. Scientific and mission objectives  influence the types of equipment needed for the mission, including the  mission’s power source.
While NASA has used RPS in support of answering PSD’s scientific  objectives, NASA has not recently used RPS to pursue scientific  objectives for other divisions or directorates, such as HEO, which  oversees human spaceflight missions. The missions NASA conducts from  PSD’s portfolio are of two types—directed and competed. Directed  missions are planned and carried out by NASA or another project  management organization to accomplish a specific set of priority  objectives, while competed missions are competitively awarded and  carried out by principal investigators under NASA oversight. NASA  offers competed missions through announcements of opportunity, which  specify scientific objectives and mission requirements, including potential  mission destinations and projected launch dates, and what equipment will  be made available, such as RPS. According to NASA officials, missions in  NASA’s PSD portfolio are generally classified in three ways:
Flagship. Flagship missions are the largest and most expensive of  NASA’s mission classes, costing $2 billion or more, and are given the  highest priority for resources, including funding, infrastructure, and  launch support. Flagship missions are directed by NASA to fulfill  specific needs or gaps in scientific knowledge. Past Flagship missions  that have used RPS include Galileo, Cassini, and Curiosity, and Mars  2020 is a planned Flagship mission using RPS.
New Frontiers. Added to NASA’s budget in 2003, New Frontiers  missions are competed missions that focus on enhancing our  understanding of the solar system and that have a development cost  cap of $850 million. New Frontiers missions are awarded to principal  investigators. To date, there have been three New Frontiers  missions—New Horizons, which is RPS-powered and is observing  Pluto and the outer solar system; Juno, which uses solar power to  observe Jupiter; and the Origins-Spectral Interpretation-Resource  Identification Security-Regolith Explorer (OSIRIS-REx), which uses  solar power and batteries and is to return samples from an asteroid  back to Earth.
Discovery. Missions in the Discovery program, which was started in  1992, are also competed, have a development cost cap of $450  million to $500 million according to NASA officials and documentation,  and have the goal of enhancing our understanding of the solar  system. The Discovery program utilizes many smaller missions with  fewer resources and shorter development times. Discovery missions  have never been powered by RPS.
section_title: DOE’s Role in RPS Production
paragraphs: The Atomic Energy Act of 1954 authorizes DOE to provide systems that  meet the special nuclear material needs of other federal agencies, and  under an agreement with NASA, DOE is responsible for maintaining our  nation’s capability to support the development, production, and safety of  NASA’s space exploration missions that use RPS. According to DOE  officials, DOE’s Office of Nuclear Energy, Nuclear Infrastructure  Programs, manages and oversees RPS production and the Supply  Project and coordinates with NASA to ensure DOE can meet NASA’s  mission requirements. This includes designing, developing, fabricating,  testing, and delivering RPS to meet NASA’s overall systems  requirements, specifications, and schedules. DOE also maintains RPS  production infrastructure to sustain capabilities between NASA missions  and to support mission planning.
section_title: DOE’s Pu-238 Supply Project
paragraphs: DOE restarted efforts to establish domestic Pu-238 production at the end  of 2011, under its Supply Project, to provide fuel for RPS. DOE’s goal is  to reach a full Pu-238 production rate of 1.5 kg per year by 2023, at the  earliest, with a late completion date of 2026. Before this full production  rate is achieved, DOE established an interim production rate of 300 to  500 grams per year by 2019 in order to ensure an adequate supply of Pu- 238 for NASA’s near-term missions. Until March 2017, DOE divided work  associated with the Supply Project into discrete segments. The  segmented management approach associated with the Supply Project  was a short-term, incremental approach to managing a program with  uncertain funding levels, according to DOE officials. According to DOE  officials, the segmented approach was intended to allow DOE to establish  and reach near-term Supply Project goals while maintaining a base level  of trained staff as the project developed from its early stages to its full  production rate. In March 2017, DOE officials changed how they manage  the Supply Project, discontinuing the segmented approach. The new  management approach for the Supply Project is to align with how DOE  expects to manage RPS production, according to DOE officials.
DOE’s Technical Integration Office, based at INL, coordinates with other  DOE laboratories on Supply Project work. As shown in figure 2, the  Supply Project involves a number of steps across several DOE national  laboratories, including INL and ORNL. The production of new Pu-238  under the Supply Project begins with a shipment of neptunium-237  (neptunium) isotope from INL to ORNL. The neptunium is blended with  aluminum powder, pressed into pellets, and then placed into targets that  are inserted into a reactor to be irradiated in order to convert neptunium  into Pu-238 isotope. Under the Supply Project, DOE officials plan to use  two DOE research reactors—the High Flux Isotope Reactor (HFIR) at  ORNL, which is currently used, and the Advanced Test Reactor (ATR) at  INL, which is planned for use to convert the neptunium to Pu-238 in the  future. Targets for ATR will be shipped from ORNL to INL for irradiation  and then shipped back to ORNL for chemical processing, a necessary  step to separate the newly produced Pu-238 isotope from unconverted  neptunium and other byproducts from the process. Chemical processing  also involves converting Pu-238 isotope into its oxide form, which is the  form of Pu-238 used as fuel for RPS. Unconverted neptunium is recycled  to be reused in target fabrication, and other waste materials are disposed.
section_title: RPS Production across DOE’s National Laboratories
paragraphs: RPS production occurs across three of DOE’s national laboratories— ORNL, LANL, and INL. Until 2017, DOE officials managed RPS  production across the national laboratories using a mission-specific  approach. In March 2017, DOE officials, in consultation with NASA,  moved from mission-specific production of GPHS fuel clads to a constant  production rate. According to DOE officials, this change was made to  provide stable staffing levels and maintain production capabilities across  DOE’s laboratories, among other things. Work at these laboratories  requires specialized facilities, such as hot cells and glove boxes, and  highly trained and qualified staff, because Pu-238 is highly radioactive.  These laboratories submit monthly reports to provide updates on RPS  and Supply Project activities to DOE’s Office of Nuclear Energy. Figure 2,  above, provides an overview of DOE’s RPS production process at ORNL,  LANL, and INL. For example:
ORNL is responsible for many of the processes related to DOE’s  efforts to reestablish a domestic supply of Pu-238. As such, Supply  Project management is based at ORNL. ORNL designs, tests, and  qualifies neptunium targets for the Supply Project. Under the Supply  Project, ORNL intends to ship newly produced Pu-238 to LANL for  storage and use in new GPHS fuel clads.
LANL maintains capability for Pu-238 processing and GPHS fuel clad  production, among other mission support activities. This work is  conducted at LANL’s Plutonium Facility PF-4 and involves Pu-238  storage, chemical processing, analysis, fuel processing, and  encapsulation of Pu-238 into GPHS fuel clads used in RPS.
INL maintains capability for RPS assembly, testing, storage, and  delivery of RPS for NASA. INL is also responsible for the transport  equipment and logistics related to delivering RPS to NASA’s Kennedy  Space Center in Florida, as well as for supporting NASA at the launch  site. Figure 3 shows an MMRTG being prepared for use in the  Curiosity rover at Kennedy Space Center in 2011.
section_title: NASA Funding for RPS Production
paragraphs: In 2011, NASA began fully funding DOE’s Supply Project, and since  2014, NASA has been responsible for funding all aspects of RPS  production operations and analysis to support launch safety and approval,  according to NASA documents. NASA funds DOE’s efforts to build, test,  and fuel RPS, as well as to update equipment and sustain staffing levels  associated with RPS production between missions. Specifically, NASA  has provided, on average, approximately $50 million per year to support  DOE’s ongoing operations and maintenance of RPS production  equipment. NASA provides additional funding related to specific missions  that require RPS. According to NASA and DOE officials, DOE provides  direct input during NASA’s annual budgeting process, giving NASA  officials information on DOE’s capabilities and resource needs as they  relate to the Supply Project and RPS production. See table 1 for NASA  and DOE funding of RPS production activities, including the Supply  Project.
NASA’s and DOE’s general RPS production roles and responsibilities are  established in a memorandum of understanding agreed to in 1991 and  revised in October 2016. The 2016 memorandum of understanding  delineates the authorities and responsibilities of each agency related to,  among other things, research, development, design, and production with  respect to RPS. Under the framework of the memorandum of  understanding, NASA and DOE have set up interagency agreements to  establish high-level milestones and funding profiles for specific RPS and  Pu-238 related work. For example, an April 2014 interagency agreement  was issued that included NASA’s request that DOE maintain the unique  program, facility, and safety capabilities required to produce RPS and  RPS components and provide related services in support of NASA  missions. The agreement also specified that DOE will coordinate with  NASA at least annually on the short- and long-range planning of  resources, including possible allocations of hardware, facilities, staff, and  Pu-238 to potential NASA missions. Another interagency agreement from  January 2015 identified commitments for the planned Mars 2020 mission  that, among other things, specified the number of RPS required and their  expected power requirements and described expected coordination  responsibilities. In addition, according to DOE officials, DOE and NASA  have established periodic reporting requirements and management  meetings to report progress and challenges related to RPS production  and the Supply Project.
section_title: NASA Selects RPS for Missions Based Primarily on the Agency’s Scientific Objectives, and Additional Factors Could Affect Demand for RPS and Pu-238
paragraphs: NASA selects RPS to power missions based on the agency’s scientific  objectives and mission destinations. Multiple factors, including costs  associated with RPS and missions, could affect demand for RPS and Pu- 238.
subsections: section_title: NASA Selects RPS to Power Missions Based on the Agency’s Scientific Objectives and Mission Destinations, and Power Source Selections are Made Early in NASA’s Mission Review Process
paragraphs: According to the NASA officials we interviewed, NASA selects RPS to  power its missions based on the agency’s scientific objectives and  mission destinations. Generally, the need for RPS is apparent based on  the mission’s scientific objectives and destination, according to NASA  officials we interviewed. For instance, an RPS is more likely to be needed  for a mission to a distant planet or permanently shadowed crater where  there is minimal sunlight.
According to NASA officials we interviewed, NASA prioritizes missions  identified in the National Academy of Sciences’ decadal survey report,  which include missions that respond to NASA’s scientific objectives and  may require the use of RPS. In addition, the National Aeronautics and  Space Administration Transition Authorization Act of 2017 states that the  NASA Administrator should set science priorities by following guidance  provided in this decadal survey report. The most recent decadal survey  report identified 16 potential missions, as shown in appendix II. Ten of  these potential missions were suggested as options for the decade from  2013 to 2022, and RPS was the recommended power source for 7 of the  10 missions. The decadal survey report also identified 6 missions for the  decade beginning in 2022 and recommended using RPS as the power  source for 3 of these missions.
NASA officials said that in some cases it is not immediately clear whether  RPS or a different power source would be appropriate for a mission’s  destination—e.g., Jupiter and its moons and, to a lesser extent, Saturn. In  such cases, an independent review team would look at aspects of a  proposed mission that are unique or require further evaluation. For  example, NASA used an independent review team to further evaluate  whether the Europa Clipper mission could be successfully accomplished  using solar power because typically a mission to one of Jupiter’s moons  would require the use of RPS. From March 2012 to August 2014, NASA  officials examined and assessed the baseline power requirements for the  Europa Clipper mission and worked with an independent review team to  determine whether solar power was a feasible power option and would  not compromise the mission’s scientific objectives. NASA officials we  interviewed said they were surprised that solar power was determined to  be feasible for the Europa Clipper mission.
After NASA chooses a mission, the power source for that mission is  typically considered and selected many years before a mission is  launched. Generally, NASA conducts mission concept studies to  demonstrate why using RPS or another power source is most appropriate  to meet a given mission’s scientific objectives. Subsequently, the power  source for a mission is also considered early in NASA’s formal mission  review process—the lifecycle review process (see fig. 4). Specifically,  NASA officials said that many aspects of a mission, including power  sources, are considered during pre-Phase A, which is the first step of  NASA’s lifecycle review process. At the conclusion of pre-Phase A,  NASA’s mission teams present the Mission Concept Review to a review  board for consideration and to seek formal agency approval. A Mission  Concept Review presentation outlines the preferred power source for a  mission.
NASA officials we interviewed said that while power source decisions are  reassessed throughout the lifecycle review process, once they are made,  changes to mission power source decisions are rare. In one instance,  NASA officials said that the Solar Probe mission originally called for the  use of RPS, but a decision was made to choose another power source  due to cost constraints and mission objective downsizing. More  specifically, following a narrowing of the scope of the Solar Probe  mission, RPS is no longer required, and the mission will instead rely on  solar power.
NASA officials said they also use review boards to provide independent  assessments of mission planning at the end of each phase of the lifecycle  review, including an assessment of power sources and margins. NASA  conducts these assessments at the conclusion of Phases B through E.  These assessments address questions about the electrical power system  for the mission and consider whether the selected power source can  provide sufficient electrical power margins, based on the current  spacecraft design, for example.
While NASA officials generally decide on a mission’s power source at the  end of pre-Phase A of its lifecycle review process, NASA officials  emphasized that the official decision to use RPS is contingent on a final  environmental impact statement and record of decision, in accordance  with National Environmental Policy Act of 1969 requirements. In addition  to its lifecycle review process, NASA officials added that, consistent with  the National Space Policy, RPS are used when they enable or  significantly enhance a mission, such as when a power alternative, such  as solar power, significantly compromises mission objectives. The  National Space Policy specifically states that RPS shall be developed and  used only when it significantly enhances space exploration or operational  capabilities. Prior to the establishment of DOE’s Supply Project in fiscal  year 2011, mission selections were influenced by the limited amount of  available Pu-238, NASA officials said. These same officials told us that  missions are now selected independently from decisions about how they  will be powered. However, projected availability of Pu-238 is factored into  whether it is offered for a specific mission opportunity.
section_title: Multiple Factors Could Affect Demand for RPS and Pu-238
subsections: section_title: Costs Associated with RPS and Missions Can Affect RPS Demand
paragraphs: NASA officials we interviewed said that the demand for RPS is driven by  a mission’s cost. Based on NASA’s expected funding levels, these  officials said, NASA can support no more than one mission using RPS  about every 4 years—or two to three missions per decade. NASA’s  current plans for solar system exploration—one RPS on the Mars 2020  mission and up to three RPS to support the selected New Frontiers #4  mission—is consistent with this mission frequency over the next decade.  NASA officials said that they try to work within their budget to pursue and  complete the right number of missions to meet the needs of the scientific  community and to be consistent with the agency’s scientific objectives.  According to NASA officials we interviewed, when NASA selects a  mission that requires RPS, the cost of the RPS must be supported by the  mission’s budget.
According to NASA officials, RPS have typically been used on Flagship  missions that cost $2 billion or more. Flagship missions are generally very  challenging, require more power for scientific instruments, and have  larger budgets that can accommodate the costs of RPS. NASA estimates  that a single RPS costs about $77 million, which would account for less  than 5 percent of a Flagship mission’s overall cost. Up to four RPS have  been used in past missions; however, planned missions are projected to  use one to three RPS per mission. Flagship mission planning and  development occurs over multiple years, and the costs, including those  related to RPS, are spread across that time frame. NASA officials we  interviewed said that they are currently in the development phase for one  Flagship mission—Mars 2020—and the formulation phase for a second  Flagship mission—Europa Clipper. NASA officials said that regardless of  the availability of RPS, NASA cannot support additional Flagship missions  until after the expected launch of Mars 2020 in July 2020, given their  expense relative to NASA’s overall budget. Mars 2020 has an estimated  total cost of $2.44 billion and will use one RPS.
According to NASA officials we interviewed, New Frontiers missions,  which are selected through a competitive process, may be good  candidates to use RPS given the types of instruments needed to address  the scientific questions these missions seek to answer. However, New  Frontiers missions have a development cost cap of $850 million, which  could restrict the use of RPS. A single RPS would represent about 9  percent of the development cost of a New Frontiers mission. NASA  documents indicate that the principal investigator chosen to develop a  New Frontiers mission is responsible for fitting the cost of the RPS into  the mission’s budget. In December 2016, NASA issued an announcement  of opportunity for the New Frontiers #4 mission, offering up to three  RPS.
RPS have not been used for previously completed Discovery-class  missions because these missions had smaller budgets—about $450  million—and shorter mission planning cycles—no more than 36 months— according to the National Academy of Sciences’ most recent decadal  survey report and NASA officials we interviewed. According to NASA  officials, Discovery-class missions are small, relatively quick missions that  typically rely on solar panels and not RPS as a power source. The cost of  RPS would represent a large portion of a Discovery mission budget,  according to NASA officials. A single RPS, at a cost of $77 million dollars,  would represent more than 17 percent of a Discovery mission’s $450  million development cap. Furthermore, the amount of time DOE takes to  build an RPS generally exceeds Discovery-class mission development  time frames of no more than 36 months and so it is unlikely that  Discovery-class missions can use RPS unless limitations from cost and  schedule can be reduced.
section_title: DOE’s RPS Production Capability Can Limit RPS Use
paragraphs: In addition to budget factors, DOE’s RPS production capability can limit  NASA’s ability to use RPS to power missions. According to DOE officials  we interviewed, it can take up to 6 years to acquire, fuel, test, and deliver  a new RPS for a NASA mission. According to both DOE and NASA  officials we interviewed, DOE only has the capacity to produce three to  four RPS at a time, given the current floor space dedicated to RPS  development at INL and limits on staff exposure to radiation at LANL.  NASA officials said that they would need to provide additional resources  to scale up RPS production beyond its current levels. To accommodate  DOE’s current RPS production capability, NASA officials said they will not  select two consecutive missions requiring RPS. For example, if NASA  officials know that a Flagship mission will require RPS, they will not offer  RPS for a competed mission that will launch around the same time.  NASA officials we interviewed said that they provide DOE with a mission  forecast, which provides prospective dates for missions offering RPS  flight opportunities and gives DOE the associated power requirements for  the missions.
section_title: Expected RPS and Solar Technological Advances Could Reduce NASA’s Demand for RPS and Pu-238
paragraphs: NASA’s Glenn Research Center is developing new RPS and solar power  technology that may reduce NASA’s demand for Pu-238 and thus RPS.  NASA officials we interviewed said that they are working on technology  advancements in order to preserve Pu-238, which they described as a  scarce and expensive resource. Furthermore, the National Academy of  Sciences’ most recent decadal survey report advocates for RPS  technology developments, stating that it is imperative that NASA invest in  technology for likely future missions, with the goals of reducing costs and  improving scientific capability and reliability.
According to a report to Congress, in 2010, NASA anticipated using a  dynamic RPS design, such as the Advanced Stirling Radioisotope  Generator (ASRG), for future missions. This design, according to NASA  documentation, would have provided a more efficient power system than  the MMRTG RPS design currently in use. DOE’s initial Pu-238  production goal of up to 5 kg per year from 2001 was reduced to 1.5 kg  based on the assumption that a dynamic system like the ASRG would be  available. The ASRG was projected to be more than four times as  efficient as the MMRTG and would have required just one-fourth as much  Pu-238. However, according to NASA officials, in 2013, the agency  ceased ASRG development due to the cost to complete the project under  reduced PSD funding (see table 1 for NASA’s prior funding of RPS  production activities, including ASRG). Although the 1.5 kg-per-year Pu- 238 production goal was based on the improved efficiencies of the ASRG  and a reduction in the amount of Pu-238 needed for missions, NASA  officials said that the projected production from the Supply Project will  nonetheless meet their demands using the MMRTG, based on PSD’s  current mission frequency. Furthermore, NASA’s fiscal year 2018 budget  estimate indicated that NASA will again invest in dynamic power  conversion systems. Specifically, NASA’s Glenn Research Center  officials said that current work to advance RPS technology would reduce  the amount of Pu-238 needed. Officials told us that they plan to invest $8  million in dynamic RPS technology beginning in fiscal year 2018 and  increase funding to $10 million by fiscal year 2022.
In addition to dynamic RPS design, NASA’s Glenn Research Center  officials said that they are researching advancements in thermoelectric  technologies that could also increase RPS efficiency. According to these  officials, NASA is currently funding this effort in fiscal year 2017 at $8  million and plans to increase funding to $9 million per year by fiscal year  2022. NASA officials said that new thermoelectric materials can lead to  improved power conversion efficiency and reduce the degradation of  thermoelectric couples over time. Specifically, NASA officials said NASA  plans to update the current MMRTG design using a new thermoelectric  couple material called skutterudite. NASA officials said that this enhanced  MMRTG (eMMRTG) would have a 25 percent beginning-of-life efficiency  improvement and a 50 percent increase of end-of-life power output. The  power output for the MMRTG is about 120 watts, while the eMMRTG is  expected to produce from 120 to 160 watts. According to NASA officials,  for a mission requiring 300 watts of power, only two eMMRTGs would be  needed instead of three MMRTGs. According to NASA officials, using one  less RPS unit would save about 3.5 kg of Pu-238 isotope and reduce the  mission’s overall mass by 45 kg. A NASA official said that the  thermoelectric couple technology for the eMMRTG is currently assessed  to be at a technical readiness level 3 and will be assessed for technical  readiness level 4 by the end of 2017. NASA will determine at a later  date if the technology is sufficiently advanced to use the new eMMRTG  for the New Frontiers #4 mission.
In addition, NASA officials we interviewed said that they are investigating  the next generation of RPS beyond the MMRTG and eMMRTG designs.  For example, these officials said that they are reviewing a modular RPS  device. A modular RPS would provide a smaller power output, but the  modular units could be bundled together to provide a specific power  output that meets mission requirements. This would allow NASA to use  smaller power increments for missions, thus requiring less Pu-238 to  provide that power. More specifically, NASA officials said that this type of  power system could have a reduced mass and use a more precise  amount of Pu-238 than is required for a mission, depending on the  mission’s power needs. According to NASA officials, the next generation  RPS would ideally achieve up to 600 watts if using two next-generation systems for New Frontiers missions and about 300 watts for Discovery-  class missions. Although NASA officials said that they anticipate the  Supply Project’s Pu-238 production rate goals to be sufficient to meet  their mission demands using the existing MMRTG, if advances in  conversion efficiency of future RPS designs come to fruition, NASA’s  future demand for Pu-238 may decrease. Table 2 compares the current  MMRTG with other potential RPS technologies.
According to NASA officials, advances in solar technology could increase  the distance from the sun at which missions can operate, making it  possible for missions that would otherwise require RPS to be powered,  instead, by solar panels. NASA officials said they are working with  contractors to focus on overcoming two of the main challenges with using  solar panels that are specific to deep space missions—low-intensity, low- temperature conditions and high-radiation environments. These officials  said that there have been advances in solar technology regarding how  much energy can be captured and converted into electricity, and these  advances could help address low levels of light intensity. NASA officials  said that because low temperatures can degrade some solar cells, the  agency is pursuing solar cells that are better suited for cold environments.  NASA officials said that advances in solar power technology have  realistically expanded the ability to use solar power for missions for which  it would not have been considered before. For example, these officials  noted that NASA’s current Juno mission and its planned Europa Clipper  mission—both with destinations being at Jupiter and its moons and which  would typically have used RPS—have demonstrated that solar power is a  viable power option.
section_title: NASA Does Not Anticipate RPS and Pu-238 Demand from Other Users
paragraphs: NASA does not anticipate other potential users to affect demand for RPS  or Pu-238. According to DOE planning documents and NASA officials,  expected RPS and Pu-238 production from the Supply Project is intended  to only meet PSD’s demand. The Supply Project goal of 1.5 kg of Pu-238  per year was established to support two to three PSD missions using  RPS each decade. NASA officials said that they did not account for  demand from other potential users within NASA or national security and  commercial sectors when establishing production goals for Pu-238. While  NASA does not expect other users to affect demand for Pu-238, there are  other potential uses for Pu-238 outside PSD, including precursor missions  in support of human exploration missions or to provide RPS for national  security uses.
Specifically, NASA Human Exploration and Operations (HEO) officials we  interviewed said that RPS could be used to power precursor missions to  Mars in advance of human exploration missions. As of now, HEO officials  have identified only one potential precursor mission—a prospecting rover  that would test equipment needed to convert atmospheric gas on Mars  into fuel—but the baseline power option for this mission would likely be  solar. In addition, NASA officials said that they do not anticipate using  RPS for primary power on missions involving manned surface rovers or  human inhabitants because, even with extreme production projections,  there cannot be enough Pu-238 to provide sufficient power. According to  NASA officials, however, they are in the early stages of planning for  potential future human exploration and precursor missions, and through  this planning process, they will determine whether RPS have a potential  role in these missions. Because such potential HEO missions are not  factored into the current production goal of 1.5 kg of Pu-238 per year, if  HEO officials determine that RPS are needed, such as for providing heat  or auxiliary power, HEO would need to coordinate with the PSD to make  mission prioritization decisions.
NASA officials said they have been approached in the past about RPS  availability for privately funded space missions, though not in several  years. If commercial entities were to require RPS for their missions, they  would need to develop a partnership with NASA and DOE to acquire  RPS. Additionally, despite being approached in the past, NASA officials  said they currently have no plans to offer RPS for privately funded space  missions. Similarly, DOE officials view the use of Pu-238 in these  contexts as unlikely. As a result, NASA officials did not account for this  potential use of RPS when establishing production goals for the Supply  Project. These officials said that if any significant quantity of Pu-238 was  to be offered to private industry, NASA planetary exploration would be  affected.
While DOE maintains a separate inventory of Pu-238 for national security  purposes, if that inventory degrades below usable levels or more quantity  is needed, according to NASA and DOE officials, NASA’s expected Pu- 238 from the Supply Project could be reallocated for national security  purposes. NASA officials said that DOE has the authority to govern the  allocations of the Pu-238 inventory, and that any reallocation for national  security purposes would be addressed by the executive branch and its  agencies. In such circumstances, NASA officials said that they would  work with the administration to address those priorities.
section_title: DOE Has Made Progress Reestablishing Pu- 238 Production but Faces Challenges that Could Affect Its Ability to Meet RPS and Pu-238 Demand
paragraphs: DOE has made progress reestablishing Pu-238 production to meet  NASA’s RPS demand, is in position to support NASA’s current plans for  solar system exploration, and anticipates being able to support two to  three RPS-powered missions per decade using new Pu-238 expected  from the Supply Project. However, DOE faces challenges with key  aspects of RPS and Pu-238 production that could put production goals at  risk.
subsections: section_title: DOE Has Made Progress Reestablishing Pu-238 Production to Meet NASA’s RPS Demand
paragraphs: DOE has made progress reestablishing Pu-238 production to meet  NASA’s future demand for Pu-238 to fuel RPS. DOE officials said that  they will be able to support NASA’s current plans for solar system  exploration and expect to be able to support two to three RPS-powered  missions per decade for the foreseeable future using new Pu-238  expected from the Supply Project. A selected chronology of key planned  DOE RPS and Pu-238 production activities, with NASA’s mission-related  activities, are shown in figure 5.
A critical component of meeting NASA’s expected RPS-related mission  requirements is the production of new Pu-238. NASA officials said that  they are confident that DOE will meet its Pu-238 production goals. DOE  demonstrated a proof of concept for new Pu-238 production and has  made approximately 100 grams of new Pu-238 isotope under its Supply  Project since its inception in 2011. As a result of the newly produced Pu- 238 isotope quality, it can be blended with Pu-238 that does not meet  NASA’s spaceflight power specifications in order to extend the usefulness  of NASA’s existing Pu-238 supply. Both DOE and NASA officials said that  they expect to develop and finalize a blending strategy after the quality of  Pu-238 produced under the Supply Project is fully assessed. Given  DOE’s current Supply Project and RPS production schedule, and NASA’s  space exploration plans, the existing Pu-238 supply will be exhausted by  2025 if four total RPS are used for NASA’s Mars 2020 and New Frontiers  #4 missions. Furthermore, until DOE and NASA develop and finalize a  blending strategy, the earliest RPS-powered mission using new Pu-238  would be in 2029, assuming delivery of 1.5 kg of Pu-238 to LANL for  GPHS fuel clad production at the start of fiscal year 2026, as shown in  figure 4, above. DOE’s progress in meeting NASA’s future Pu-238 and  RPS demand are illustrated in the following examples.
subsections: section_title: Using Existing Facilities and Automating Supply Project Steps at ORNL
paragraphs: For the Supply Project, as well as for RPS production, DOE officials said  that they are primarily leveraging existing facilities, equipment, and  previously proven processes. DOE officials said that it would be  prohibitively expensive to build new facilities for the Supply Project’s  chemical processing work. For example, DOE officials are using hot cells  at ORNL that are also used for other isotope work. In addition,  according to DOE officials we interviewed, new equipment is being  acquired at ORNL to modernize and automate some steps of the Supply  Project. For example, DOE has acquired equipment to automate  neptunium target production, which DOE officials said they expect will  increase Supply Project efficiency as well as reduce staff radiation  exposure. Preparing and pressing neptunium into pellets for use in  targets is currently a manual process done in gloveboxes, with a press  that was formerly used for iridium processing and that was built in the  1920s. DOE officials said that they are able to make about 40 neptunium  targets per year, equivalent to pressing one neptunium pellet about every  35 minutes. To achieve DOE’s interim goal of 300 to 500 grams of new  Pu-238 per year by 2019 and to build up an inventory of targets for full  production, DOE will need to make about 128 targets per year, or one  neptunium pellet about every 6 minutes. DOE officials said that the  automated system will help provide the necessary throughput to meet  interim production goals. Without automation, DOE officials determined  that they could produce from 120 to 150 grams of new Pu-238 per year.  DOE officials said that they intend to have neptunium pellet automation  implemented in 2017. The officials added that neptunium pellet  automation is expected to increase efficiencies with respect to meeting  documentation and quality control requirements prior to target irradiation  in a reactor.
section_title: Upgrading RPS Fuel Production Equipment at LANL
paragraphs: DOE officials said that investments and equipment upgrades are also  being undertaken at LANL in support of RPS production. Specifically,  LANL officials said that from 2010 through 2012, they carried out a  comprehensive programmatic equipment plan to maintain and upgrade  equipment related to RPS production work. The plan is now being  updated since major work has been completed, according to LANL  officials. As part of this plan, LANL officials said they are undertaking  efforts to revitalize and extend the life of gloveboxes and other equipment  at PF-4 in support of Pu-238 activities. For instance, LANL monthly  reports indicate that windows on a fuel production line have been  changed out—a necessary improvement because of degradation caused  by oxidation in the processing environment. According to LANL reports  and officials, they are installing a new Pu-238 fuel pellet hot press that will  be used after the current production run of Pu-238 fuel clads for NASA’s  Mars 2020 mission is complete. The Pu-238 fuel pellet hot press currently  in use is about 50 years old and needs frequent maintenance in order to  keep it operational. The hot press currently in use will serve as a backup  once installation of the new press is completed in 2019.
section_title: Testing and Fabricating RPS at INL
paragraphs: DOE officials told us that their main objective for RPS production at INL is  to maintain core capabilities to fabricate RPS units. DOE officials said  they maintain 30 pieces of equipment, totaling about $30 million in value,  that are replaced or refurbished on a rolling basis. For example, INL  maintains equipment to support RPS acceptance tests—vibration testing,  mass properties testing, magnetics testing, and thermal vacuum testing— to ensure that RPS are suitable for space flight. INL officials said that  they do not have backups for most of the equipment so it is imperative  that they enhance the equipment’s reliability through repair or  replacement. INL funding data show that INL sets aside about 5 percent  of its annual operations funding provided by NASA for RPS production  work to update equipment at INL. These officials said that over the last 12  years they have nearly completed updates to existing equipment related  to RPS production.
section_title: Stabilizing Staff Levels with a Constant GPHS Production Rate
paragraphs: DOE officials we interviewed said that staff retention between missions  has been a challenge and that hiring and training new staff to support  new missions can take up to 2 years because of the highly technical  nature of the job. According to DOE officials and documents, under the  previous management approach, DOE retained some staff to support  ongoing Pu-238 and RPS work at INL, ORNL, and LANL but would need  to hire more staff to support mission-specific work. Specifically, according  to INL documentation, there are 40 staff members who support ongoing  maintenance and operation of RPS equipment during off-peak times. INL  officials said that they would need to hire 15 to 20 people, to reach 55 to  60 staff members, to support mission-related activities under the mission- specific production rate at their laboratory.
DOE officials said that the constant GPHS fuel clad production rate will  provide stable staffing levels, removing the need to ramp up hiring and  training of qualified staff for mission-specific RPS production. However,  according to DOE officials, there are limits on how much DOE can  increase GPHS fuel clad production. DOE may only be able to produce  10 to 15 GPHS fuel clads per year—consistent with DOE’s current  production rate when preparing for a NASA mission and a sufficient  quantity to meet currently planned NASA missions. According to DOE  officials, if NASA were to require additional GPHS fuel clads for RPS—for  example, from 15 to 20 per year—DOE would face challenges in  increasing production due to risks to staff from potential radiation  exposure at LANL. Additionally, LANL officials said that if NASA requires  an increase in the GPHS fuel clad production rate, the current Pu-238  supply would be depleted by 2022, before the Supply Project is fully  operational. DOE has instructed its facilities to develop plans to carry  out constant rate production and to begin transitioning to the constant  production rate model by June 2017. DOE anticipates that NASA will  sign new interagency agreements and will provide funding to implement  constant GPHS fuel clad production in fiscal year 2017.
section_title: DOE Faces Challenges with Key Aspects of Pu- 238 and RPS Production
paragraphs: DOE officials from INL, LANL, and ORNL identified several challenges  that need to be overcome for DOE to be able to meet its projected Supply  Project goal of 1.5 kg per year of Pu-238 by 2026, at the latest.  Otherwise, DOE may not able to reach its full production rate or may  need to delay its delivery of 1.5 kg of Pu-238 per year. Specifically, these  officials identified perfecting and scaling up chemical processing, the  availability of reactors, and the qualification of targets for irradiation as  challenges that need to be overcome.
subsections: section_title: Perfecting and Scaling Up Chemical Processing
paragraphs: DOE faces challenges perfecting and scaling up chemical processing  that, if not overcome, could result in delays in producing Pu-238 to  support future NASA missions. According to DOE officials, DOE is still in  the experimental stage and has not perfected the chemical processing  required to extract new Pu-238 isotope from the irradiated targets, which  creates a bottleneck in the Supply Project and puts production goals at  risk. ORNL monthly reports and DOE officials state they are continuing to  develop the process to chemically separate newly produced Pu-238  isotope from unconverted neptunium and other materials resulting from  irradiation in the reactor. According to officials, DOE is exploring chemical  processing methods to effectively recycle neptunium for reuse in the  process, convert Pu-238 isotope into its oxide form for use in RPS, and  improve methods to reduce radioactive liquid waste.
According to ORNL monthly reports and officials we interviewed, two 5-  gram samples of Pu-238 taken from the first 50 grams of new Pu-238  from the Supply Project were shipped to LANL and tested in January and  February 2016. These initial samples, however, did not meet space flight  specifications. Office of Nuclear Energy officials said that samples from  a second 50-gram batch were tested at both ORNL and LANL in October  2016 and met flight specifications. According to DOE officials, chemical  processing cannot be done in a linear fashion—that is, the chemicals  used in the process are not all increased in the same quantities when  making increasing amounts of new Pu-238. As a result, DOE officials said  that they need to develop a chemical processing model that will help  identify bottlenecks and provide information to help DOE officials improve  the Pu-238 production process. However, ORNL officials said that  chemical processing needs to be scaled up to meet interim and final  production goals for Pu-238. For example, ORNL officials said they have  sufficient staff to process one batch of irradiated targets at a time to  extract new Pu-238 isotope, though multiple batches would need to be  run simultaneously to achieve production goals.
According to ORNL documents and officials, to reduce the risk of failing to  achieve Pu-238 production goals, additional resources for staff and  equipment are needed to increase chemical processing operations.  Specifically, to achieve interim production of 300 to 500 grams of Pu-238  per year by 2019, ORNL officials said they would require additional  funding of $3 million to 4 million per year for staff and other process  improvements. In addition, to reach full-scale operation of 1.5 kg of Pu- 238 per year by the end of fiscal year 2023, even more staff and funding  are needed. However, these officials did not specify how many new hires  would be needed to meet interim and full-scale operations. ORNL officials  said that because of the highly technical nature of the job, it can take 2  years to train staff to use specialized equipment. Furthermore, DOE  officials we interviewed at ORNL said that the laboratory needs  infrastructure improvements for chemical processing, including additional  storage tanks, transfer lines, and glove boxes, in order to increase Pu- 238 production beyond current sample-sized levels. DOE’s ability to meet  its production goal and support future NASA missions is at risk if the  chemical processing steps in the Pu-238 production process are not  improved and scaled up.
section_title: Availability of Reactor Positions for Target Irradiation
paragraphs: Officials we interviewed at INL and ORNL also said that achieving 1.5 kg  of Pu-238 per year is contingent on the availability of positions within both  the High Flux Isotope Reactor (HFIR) and the Advanced Test Reactor  (ATR) to irradiate neptunium targets for conversion to Pu-238 isotope.  DOE officials stated that ATR must be used, as projected in DOE’s initial  plans, to reach the production goal of 1.5 kg of Pu-238 per year.  However, ATR has not been qualified for Supply Project work because  NASA has decided to wait until the reactor returns to service in 2021,  after a yearlong scheduled maintenance shutdown beginning in 2020.  Until ATR is qualified, it is not available for new Pu-238 production. DOE  officials responsible for the Supply Project have utilized HFIR at ORNL to  irradiate targets, but the forecasted Pu-238 production from this reactor is  anticipated to be less than initially planned because target positions within  HFIR are limited so as to not interfere with other reactor activities. DOE’s  2013 analysis of Pu-238 production projected that HFIR could produce 2  kg of Pu-238 per year, but according to DOE officials, to avoid  interference with HFIR’s other missions, they subsequently determined  that HFIR would produce approximately 600 grams of Pu-238 isotope  with the current target design. According to DOE officials, they plan to use  positions within ATR to achieve full production goals.
In addition, deferring ATR’s use could put achieving production goals at  risk because accessing positions within ATR is highly competitive. DOE  officials at INL have said that ATR’s availability for the Supply Project may  be limited due to competition from other users, such as the U.S. Navy,  universities, medical researchers, and other DOE programs. Specifically,  DOE officials at INL said that the positions most useful for irradiating  neptunium targets to create Pu-238 isotope are over-utilized, and of the  nine available positions for target irradiation, six are dedicated for Navy  use. Despite this, Office of Nuclear Energy officials said that they do not  foresee an impact on meeting Pu-238 production goals from deferring the  use of ATR. These officials said that DOE conducted a trade study to  identify positions within ATR that are not currently being used by the Navy  or other ATR users, in order to determine whether they are suitable for  Pu-238 isotope production. According to the study, several such positions  could be suitable for Pu-238 production, but DOE officials said that  additional verification testing would be conducted in fiscal year 2017 to  confirm such findings. However, DOE officials said that if positions in ATR  are not available for Pu-238 isotope production, they do not have a plan  to address this longer-term challenge and will be unable to meet full Pu- 238 production goals.
section_title: Target Design and Qualification
paragraphs: While DOE officials said that they expect to meet Pu-238 production  goals with the existing target design, they have not qualified the existing  target for use in ATR, which is needed to reach 1.5 kg of Pu-238 per year.  In addition, DOE is pursuing a new target design with a higher expected  Pu-238 yield. However, the new target design has not been developed  and qualified for either HFIR or ATR. Furthermore, because the target  has not been fully developed, its expected yield—double the amount of  Pu-238 as the current target in certain reactor positions—remains  theoretical. According to Office of Nuclear Energy officials, DOE and  NASA have agreed to complete research and development efforts to  support a decision on the new neptunium target by 2019 that can be used  in both HFIR and ATR. ORNL documentation from July 2016 indicated  that the laboratory’s initial task is to test and assess the new target design  on a small scale. According to DOE officials at ORNL, upon successful  small-scale testing, they will scale up a prototype target for further testing.
DOE officials said that the higher yield from the new target design could  allow DOE to meet or exceed interim and final production time frames  and goals because they were calculated using the current target design  as the baseline. Officials from the Office of Nuclear Energy said that the  established Pu-238 production goals used the existing neptunium target  design as their baseline and that any increased Pu-238 production  expected with the new target design represents an opportunity. However,  officials we interviewed at ORNL and INL said that the anticipated  production from the new neptunium target design may be necessary in  order to mitigate the effects of other challenges, such as limited reactor  space, as discussed above. Office of Nuclear Energy officials said that  the existing Pu-238 inventory and planned NASA missions will allow them  time to finalize the target design and begin using ATR to provide  irradiation capability starting in 2021. According to DOE estimates, it  would take from 1 to 2 years to begin irradiating targets at ATR for new  Pu-238 isotope production.
section_title: Prioritizing Pu-238 for NASA at Plutonium Facility 4
paragraphs: Another challenge DOE must overcome to achieve its RPS and Pu-238  production goals relates to potential competition for space between Pu- 238 and nuclear weapons pit production activities at LANL, which could  significantly affect a key step in the RPS production process within the  next decade, and thus delay the delivery of RPS for NASA missions.  Specifically, LANL officials said that Pu-238 work must compete with  other priorities for facility space at LANL’s Plutonium Facility PF-4. As we  stated in an August 2016 report, the National Nuclear Security  Administration—a semiautonomous agency within DOE that is  responsible for the management and security of the nation’s nuclear  weapons, nuclear nonproliferation, and naval reactor programs—through  its plutonium strategy is focused primarily on the fabrication of plutonium  pits for nuclear weapons and has not coordinated with the Pu-238  program about potential modifications planned for PF-4. A May 2015  Congressional Research Service report suggested that moving Pu-238  operations outside of the current LANL PF-4 facility could free up floor  space for pit production operations, and also reduce the amount of  nuclear material at risk in the facility due to the very high radioactivity of  Pu-238. However, LANL officials told us that such a move would be  unlikely because of cleanup costs and difficulties in transporting  contaminated equipment. In addition, DOE’s Office of Nuclear Energy  officials said that they do not anticipate pit production to impact RPS  production. However, LANL officials told us that they have begun  preliminary discussions on this issue but are awaiting the results of a  National Nuclear Security Administration plutonium strategy study that is  focused on nuclear weapons needs. DOE officials added that they have  discussed moving Pu-238 capabilities out of PF-4, where they would seek  to move the capability to another DOE site. According to DOE officials, a  move of this nature would likely be an expensive, disruptive, and time- consuming effort.
section_title: Challenges May Put RPS and Pu-238 Production Goals at Risk
paragraphs: The challenges noted above—chemical processing, availability of reactor  positions, target design and qualification, and prioritizing Pu-238 at PF- 4—may put DOE’s RPS and Pu-238 production goals at risk, in part  because of the short-term and incremental segmented management  approach DOE has used to manage the Supply Project through early  2017. In this approach, DOE established short-term segments of Supply  Project work to be connected to time frames over which DOE could more  reliably predict funding from NASA. While DOE officials have known the  general tasks required to achieve full production goals for the Supply  Project, they have been relying on the developments of each segment to  inform specific tasks and activities of subsequent segments. For example,  up until March 2017, when DOE changed its management approach for  the Supply Project, if challenges, such as delays in scaling up chemical  processing, were to be realized, DOE officials said that they would have  shifted Supply Project activities from one segment to the next. DOE’s own  work, however, demonstrates the risks in this approach. For example, an  October 2016 DOE independent cost estimate for another DOE program  showed that deferring activities to later stages in that program may result  in program delays or, if delays are undesirable, future activities may be  compressed and would likely be less technically mature. Delays in the  Supply Project, or the use of less technically mature processes, could put  DOE’s ability to meet NASA’s Pu-238 demands at risk. DOE officials said  in June 2017 that the Supply Project’s early completion of full Pu-238  production was initially planned for 2023. However, DOE officials said  they now expect to reach full production no earlier than 2025 with a late  completion date remaining in 2026.
DOE officials, acknowledging that some long-term challenges to the  Supply Project exist, said that they recognized that the segmented  management approach was not well suited to dealing with those  challenges. As previously noted, in March 2017, DOE officials said that  the change to a constant GPHS production rate approach was expected  to help provide funding flexibility and stabilize RPS production staffing  levels between NASA missions. In June 2017, DOE officials said that the  constant GPHS production rate approach would also address other  identified challenges associated with RPS production and the Supply  Project and decided to discontinue the segmented management  approach. According to DOE officials, the constant GPHS production rate  approach is designed to ensure stable and predictable funding levels and  allow DOE more flexibility in how these funds are to be used. This  approach, according to DOE officials, will allow the agency to address  high-priority challenges by providing flexibility to use NASA funding  throughout the RPS supply chain, including for the Supply Project, and  will better enable them to sequence work. For example, DOE officials  described how a constant GPHS production rate approach allowed DOE  to prioritize funding for shipping containers to transport Pu-238 between  laboratories. DOE officials did not describe, however, how this new  approach would help address some of the other longer-term challenges  identified, such as scaling up and perfecting chemical processing.  Furthermore, DOE officials provided basic details about the new  approach as well as a memorandum dated March 7, 2017, with  deliverables that DOE states that the new approach will achieve.
However, DOE does not yet have an implementation plan under the new  constant GPHS production rate approach with milestones and interim  steps for the Supply Project or for RPS production that can be used to  show progress toward implementing efforts, show how risk is being  addressed or mitigated, or make adjustments to those efforts when  necessary. Our body of work has shown that without defined tasks and  milestones, it is difficult for an agency to set priorities, use resources  efficiently, measure progress, and provide management a means to  monitor this progress. By developing an implementation plan with  milestones and interim steps for the department’s management approach  for Pu-238 and RPS production, DOE can show progress toward  implementation, show how risk is being addressed or mitigated, or make  adjustments to its efforts when necessary.
In addition, DOE’s new approach still does not improve the agency’s  ability to assess the long-term effects of the challenges associated with  Pu-238 and RPS production, such as chemical processing, availability of  reactor positions, target design and qualification, and prioritizing Pu-238  at PF-4. DOE’s previous segmented management approach did not  require that DOE officials assess the potential long-term effects of these  challenges, and it allowed them to defer addressing challenges to later  segments of the Supply Project. The new approach also does not allow  for DOE to adequately communicate long-term challenges to NASA, and  it is unclear how DOE will use this approach to communicate these  challenges. According to DOE officials we interviewed, DOE and NASA  are to develop reports and hold management meetings to communicate  identified challenges. In addition, Standards for Internal Control in the  Federal Government states that agency management should use quality  information to achieve the entity’s objectives and communicate quality  information externally through reporting lines so that external parties can  help the entity achieve its objectives and address related risks. DOE  officials said they believe the new constant GPHS production rate  approach will aid DOE in identifying and addressing challenges  associated with RPS production and the Supply Project, as well as  communicating such challenges to NASA. DOE officials we interviewed,  however, provided few details on how they would address identified  challenges. Without adequately assessing the long-term effects of  existing challenges identified by DOE officials, DOE cannot develop the  quality information it needs to understand the effects of these challenges,  and this may affect its ability to achieve its Pu-238 production goal or to  communicate that information to NASA.
Moreover, because DOE does not maintain a comprehensive risk tracking  system for RPS production and, instead, defers to its individual  laboratories to track and manage their specific risks, DOE officials may  not have the necessary information needed to inform NASA about the  effects of these challenges. These potential effects may result in DOE not  meeting its Pu-238 production goal, which could cause NASA to delay  future RPS-powered missions. DOE officials said that they do not  maintain a risk tracking system for the RPS program and that this is  maintained by NASA. However, according to NASA officials we  interviewed, NASA only tracks high-level risks that could directly affect  NASA. Standards for Internal Control in the Federal Government states  that agency management should identify, analyze, and respond to risks  related to achieving defined objectives. Management is to identify risk  throughout the agency to provide a basis for analyzing risks. With a more  comprehensive risk tracking system that allows DOE to identify more  systemic risks beyond the specific technical risks identified by individual  laboratories, DOE will be better positioned to adequately assess the long- term effects of all of the identified challenges associated with Pu-238 and  RPS production objectives.
section_title: Conclusions
paragraphs: NASA is entirely dependent on DOE to supply Pu-238 and RPS for space  missions, and future missions requiring RPS are at risk if DOE is unable  to fuel and provide these RPS. To meet NASA’s demand for new Pu-238,  DOE’s Supply Project goal of 1.5 kg per year was initially established  assuming the use of a more efficient RPS design, which has yet to be  realized. While NASA officials subsequently said that the full production  rate under DOE’s Supply Project would be sufficient using existing RPS  designs, any Pu-238 production shortage, coupled with the use of less  efficient RPS technology, could present a challenge to carrying out  NASA’s future RPS-powered missions. In addition, if any of NASA’s Pu- 238 supply is needed for national security or other applications, NASA  may not have sufficient Pu-238 to support future missions or will have to  delay such missions until more Pu-238 is provided under the Supply  Project. Finally, if NASA intends to launch an additional RPS-powered  mission before the end of the 2020s, NASA officials would have to make  such a decision by 2023, before full-scale Pu-238 production under the  Supply Project is achieved, because it takes multiple years between the  time a mission and its power source are selected to the time of launch.
DOE has taken steps to reestablish domestic production of Pu-238 under  its Supply Project, and has produced small quantities of new Pu-238. In  addition, DOE has identified key challenges to the Supply Project—such  as scaling up chemical processing and qualifying targets—that put  achieving Supply Project production goals at risk. However, DOE has not  fully assessed the potential long-term effects of these challenges on  production goals. While DOE officials anticipate that their new approach  to managing RPS and Pu-238 production will better help address these  challenges, DOE is in the very early stages of implementing this approach  and has not identified details, including milestones and interim steps, for  how it would address them. In addition, DOE’s plans for nuclear weapons  pit production activities have not taken into account their potential effects  on RPS production and the Supply Project. Federal standards for internal  control state that agency management should use and communicate  quality information externally to help the entity achieve its objectives and  address related risks. While DOE and its laboratories have identified  existing challenges to RPS and Pu-238 production, the effect of these  challenges on expected Pu-238 production goals have not been fully  assessed and thus not fully communicated with NASA. Moreover, DOE’s  risk tracking system for RPS does not track systemic risks, but rather  relies on individual laboratories to track and manage specific risks. Better  information about risks would allow DOE officials to inform NASA about  the effects of these challenges. Supply Project challenges, if not  addressed, may result in DOE not meeting, or being delayed in meeting,  the Supply Project goals, and DOE may not be able to fully support NASA  missions to deep space using RPS after New Frontiers #4 in 2025.
section_title: Recommendations for Executive Action
paragraphs: To help ensure the availability of Pu-238 and RPS for space exploration,  we recommend that the Secretary of Energy take the following three  actions: develop an implementation plan with milestones and interim steps for  the department’s management approach for Pu-238 and RPS  production; assess the long-term effects that known challenges may have on  production quantities, time frames, or required funding, and  communicate these potential effects to NASA; and develop a more comprehensive system to track more systemic risks,  beyond the specific technical risks identified by individual laboratories.
section_title: Agency Comments and Our Evaluation
paragraphs: We provided a draft of this report to DOE and NASA for review and  comment. In response, we received written comments from DOE, which  are summarized below and reprinted in appendix III. NASA did not  provide a formal response because the report made no recommendations  to NASA; instead, NASA provided technical comments, which we  incorporated as appropriate.
DOE concurred with our three recommendations, stating that it is in the  process of implementing a new approach, termed Constant Rate  Production, for the RPS supply chain that is more responsive to NASA’s  needs, among other things. In response to our first recommendation,  DOE said that the agency is developing an integrated program plan to  implement the Constant Rate Production strategy that will document the  management approach for Pu-238 and RPS production. DOE expects to  complete this plan in September 2018. We believe that the development  of an integrated program plan is an important step, and reiterate that any  such plan documenting DOE’s management approach should include  milestones and interim steps so DOE can show progress toward  implementation, among other things. In response to our second  recommendation, DOE said that the agency will work with NASA to  identify, assess, and develop plans to address known challenges to the  RPS program and expects to complete this effort in September 2019. In  response to our third recommendation, DOE said that as part of the  integrated program plan it intends to develop in response to our first  recommendation, the agency will include steps to ensure the current risk  system includes comprehensive programmatic risks to support NASA’s  risk management activities. We believe that implementing these actions  will help DOE better ensure the availability of Pu-238 and RPS in support  of NASA’s space exploration missions.
As agreed with your offices, unless you publicly announce the contents of  this report earlier, we plan no further distribution until 30 days from the  report date. At that time, we will send copies to the appropriate  congressional committees, the Secretary of Energy, the Administrator of  the National Aeronautics and Space Administration, and other interested  parties. In addition, the report will be available at no charge on the GAO  website at http://www.gao.gov.
If you or your staff members have any questions about this report, please  contact me at (202) 512-3841 or oakleys@gao.gov. Contact points for our  Offices of Congressional Relations and Public Affairs may be found on  the last page of this report. GAO staff who made key contributions to this  report are listed in appendix IV.
section_title: Appendix I: Objectives, Scope, and Methodology
paragraphs: This report examines the National Aeronautics and Space  Administration’s (NASA) process for considering and selecting power  sources for missions, in particular the use of radioisotope power systems  (RPS), and the Department of Energy’s (DOE) ability to maintain the  necessary infrastructure and workforce for RPS and plutonium-238 (Pu- 238) production. Our objectives were to (1) describe how NASA selects  RPS for missions and what factors affect RPS and Pu-238 demand; and  (2) evaluate DOE’s progress in meeting NASA’s RPS and Pu-238  demand and what challenges, if any, DOE faces in meeting the demand.
To describe how NASA selects RPS for missions and what factors affect  RPS and Pu-238 demand, we reviewed NASA documents, including  procedural requirements, key decision documentation for specific  missions, and agreements between NASA and DOE. Specifically, we  reviewed NASA’s procedural requirements, including the NASA Space  Flight Program and Project Management Handbook, and reviewed how  those requirements were applied to recent missions that used or  considered RPS as a power source. We also reviewed documentation  related to NASA’s key decisions for specific missions—including Mars  Space Laboratory, Mars 2020, and the Europa Clipper—to identify  NASA’s power source decisions and when they were made under  NASA’s review process. To determine how NASA and DOE collaborate  on RPS and Pu-238 development, we reviewed interagency agreements  and memoranda of understanding between these two agencies. We also  met with NASA officials to discuss how mission decisions related to  power sources are made and the impact of technological advances on  NASA’s demand for RPS. In addition, we conducted interviews with  officials from the Planetary Science Division (PSD) of NASA’s Science  Mission Directorate to determine how NASA selects its missions and how,  if at all, the availability of Pu-238 has affected mission selection. In  addition, we asked PSD officials about the process NASA uses when  making decisions on how to power missions, including the timing of when  such decisions are made. We also met with officials from NASA’s Human  Exploration and Operations Mission Directorate to learn whether NASA  expects future human exploration missions to use RPS. We interviewed  officials at NASA’s Glenn Research Center to discuss how, if at all,  advancements in RPS and solar technology could affect future demand  for Pu-238-fueled missions. We also interviewed members of the  scientific community and representatives from a commercial entity to  obtain their perspectives on the use of RPS for future NASA missions.
To evaluate DOE’s progress in meeting NASA’s RPS and Pu-238  demand and what challenges, if any, DOE faces in meeting the demand,  we reviewed DOE documentation, including DOE’s program management  guidelines, Pu-238 Supply Project (Supply Project) plans, monthly  reports, and RPS and Supply Project management presentations. We  reviewed DOE Order 413.3B to evaluate its applicability to the Supply  Project. In addition, we reviewed the Plutonium-238 Production Program  Management Plan and the Pu-238 Supply Project - Project Execution  Plan to gain an understanding of the planning, management, and  execution of the Supply Project. We obtained and reviewed additional  documents associated with the Supply Project, such as DOE’s risk  management plan and risk register, to determine how DOE is managing  new Pu-238 production and the extent to which DOE identifies and  mitigates risks. In addition, we reviewed Idaho National Laboratory (INL),  Los Alamos National Laboratory (LANL), and Oak Ridge National  Laboratory (ORNL) monthly reports to assess periodic updates from each  laboratory on the Supply Project and RPS production. We also reviewed  presentations from DOE officials who oversee RPS production and the  Supply Project. In addition, we interviewed officials from DOE’s Office of  Nuclear Energy to determine the extent to which DOE is prepared to meet  NASA’s demand for RPS using Pu-238 for planned and future missions.  We also discussed with these officials how DOE prioritizes Pu-238 work  within its plutonium strategy and how DOE integrates RPS production  with other DOE activities. We interviewed officials at DOE’s national  laboratories involved in RPS production—INL, LANL, and ORNL—to  discuss the Supply Project and RPS production. We conducted site visits  to ORNL, the laboratory responsible for the Supply Project, and INL, the  laboratory primarily responsible for overseeing RPS production, to meet  with officials and examine facilities involved in the Supply Project and  RPS production. Finally, we compared DOE’s efforts to collect and  assess quality information about challenges associated with RPS and Pu- 238 production and to communicate these challenges against criteria  outlined in federal internal control standards. We also evaluated DOE’s  management approach for RPS and Pu-238 production against key  management practices established in prior GAO work.
We conducted this performance audit from March 2016 to September  2017 in accordance with generally accepted government auditing  standards. Those standards require that we plan and perform the audit to  obtain sufficient, appropriate evidence to provide a reasonable basis for  our findings and conclusions based on our audit objectives. We believe  that the evidence obtained provides a reasonable basis for our findings  and conclusions based on our audit objectives.
section_title: Appendix II: National Academy of Sciences Decadal Survey Recommended Missions and Power Sources, 2013-2022
paragraphs: Power Source Type (number  of units proposed)  Ultraflex (2)
MMRTG (5)
ASRG (1)
New Frontiers (4 or 5)
Ultraflex (1)
New Frontiers (4 or 5)
New Frontiers (4 or 5)
ASRG (2)
New Frontiers (4 or 5)
ASRG (2)
New Frontiers (4 or 5)
New Frontiers (5)
ASRG (2)
New Frontiers (5)
ASRG (1)
Gimbaled (1)
ASRG (3)
Ultraflex (1) + Fetch Rover (1)
Ultraflex (1)
ASRG (5) + MMRTG (1)
ASRG (3 to 6)
section_title: Appendix IV: GAO Contact and Staff Acknowledgments
subsections: section_title: GAO Contact
section_title: Staff Acknowledgments
paragraphs: In addition to the contact named above, Jonathan Gill (Assistant Director),  Samuel Blake, Kevin Bray, John Delicath, Jennifer Echard, Cindy Gilbert,  Timothy Guinane, John Hocker, Michael Kaeser, Jason Lee, Danny  Royer, Aaron Shiffrin, Kiki Theodoropoulos, Kristin VanWychen, and John  Warren made key contributions to the work.