17 January 2003
Project Prometheus
(formerly the Nuclear Systems Initiative)


UPDATE FEBRUARY 2004 - NASA is working with the science community via a Science Definition Team (SDT) to identify specific science objectives for the proposed Jupiter Icy Moons Orbiter (JIMO) mission and the measurements necessary to support these objectives. The team's report, which was recently completed and submitted to NASA, can be found at http://ossim.hq.nasa.gov/jimo/

In Greek mythology, Prometheus was the wisest of the Titans, and he gave the gift of fire to humanity. The name Prometheus means 'forethought.'

For NASA, the name “Prometheus” is indicative of our hope to establish a new tool for understanding nature and for expanding our exploration capabilities. The gift of fire to humans was a powerful gift. We believe that the knowledge that will be enabled by the technologies developed by Project Prometheus will also be a powerful gift. NASA intends that Project Prometheus will be a true gift that will enable the peaceful exploration of the Solar System and our ability to answer important questions about the origin of life in the universe. The Nuclear Systems Initiative was a useful title for the proposed program in that it was clear, concise and easily identifiable. As we move forward with the program, we believe that a name that also contains meanings related to our goals should be used, therefore, we have changed the name to “Project Prometheus.”

Project Prometheus will develop the means to efficiently increase power for spacecraft, thereby fundamentally increasing our capability for Solar System exploration. Increased power for spacecraft means not only traveling farther or faster, but it also means exploring more efficiently with enormously greater scientific return. High levels of sustained power would permit a new era of Solar System missions designed for agility, longevity, flexibility, and comprehensive scientific exploration. Some possibilities we envision are:

  • We could conduct comprehensive and detailed investigations creating comparative data sets of the outer planets-Jupiter, Saturn, Uranus and Neptune-and all their moons and associated objects. The knowledge we gain with these data sets would be vital to understanding other planetary systems recently discovered (we’ve discovered more gas giants than Earth-like planets to date).
  • The surfaces and interiors of comets could be comprehensively explored, and we could even return samples to better understand the building blocks of the universe.
  • At Mars, we could dramatically expand our capabilities for surface, on-orbit exploration and sample return.
  • At the edge of the Solar System, if we’re not limited by power, there is important knowledge about the origins of the Solar System to be gained from understanding Pluto and the Kuiper Belt.

Today, only nuclear power can enable these scientifically vital, but incredibly challenging missions.

Technology Focus

Pending approval by Congress, NASA’s Project Prometheus would develop the technologies needed to enable the above vision for the future. There are two basic types of technology under consideration for this program: (1) radioisotope-based systems and (2) nuclear fission-based systems.

Radioisotope Power System (RPS) development would focus on two technologies, the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and the Stirling Radioisotope Generator (SRG), that are expected to improve the efficiency and utility of systems that NASA has been using for 30 years. These essential improvements on our current technology would enable an “all weather, anywhere, anytime” exploration of planetary surfaces.

The fission power and propulsion research would focus on developing the nuclear systems needed for revolutionary new capabilities in space exploration. Project Prometheus would include research on reactors, advanced heat-to-power conversion, and power management and distribution technologies to provide spacecraft flexibility, long-mission durations, and orders of magnitude more power for science instruments. See the NASA Fact Sheet on Space Fission Reactor Power Systems for additional information.

Programmatic Focus

Project Prometheus will be a NASA program with substantial involvement of the U.S. Department of Energy (DOE). NASA would define the science requirements for future exploration missions and manage the RPS and fission-based programs, as well as the spacecraft systems engineering. A substantial portion of Project Prometheus research and development will be competitively awarded. The DOE will manage work awarded in the nuclear area, while NASA centers (Glenn Research Center and Marshall Space Flight Center) and the Jet Propulsion Laboratory will manage work awarded in the non-nuclear area.

The initial activity for the fission power and propulsion program will focus on defining the near-term technology research goals, and on identifying planetary science missions uniquely enabled by nuclear fission electric power and propulsion. The RPS program will concentrate on developing the MMRTG and SRG systems (either of which could be of potential use on the Mars Smart Lander Mission to be launched in 2009). The program has also identified a planetary science mission that will be uniquely enabled by nuclear fission electric power and propulsion: the Jupiter Icy Moons Orbiter. The Jupiter Icy Moons Orbiter would be an ambitious mission to orbit three planet-sized moons of Jupiter -- Callisto, Ganymede and Europa -- which may harbor vast oceans beneath their icy surfaces. The mission would orbit each of these moons for extensive investigations of their makeup, their history and their potential for sustaining life.

In addition, a range of technologies and system designs will be explored that may be prudent for NASA and DOE to invest in over the next several years, beyond the specific technologies already under consideration. NASA and DOE would also identify and recommend additional strategic technology investments to potentially enable future human exploration of the Solar System.

In keeping with NASA goals of openness and transparency, Project Prometheus would seek to ensure open, inclusive dialogue and engagement with the public, media, educators, legislators, and others; foster technology education and outreach programs; and make appropriate materials available on the Internet.

Focus on Safety

Project Prometheus would continue to emphasize the safe way we operate and design missions. For NASA, the key word in this sentence is “safe” -- safety is the primary operating principle for Project Prometheus. NASA has over 30 years’ experience in the successful management and operation of RPS missions. Working with the DOE, NASA will extend that safety experience to the design, manufacture, and flight of a fission reactor-based mission. The reactor will have multiple safety features including a design that will prevent criticality while the vehicle is still near Earth. Also, Project Prometheus will continue to engage expertise in continuous risk management and risk assessment and will fully comply with environmental and nuclear safety launch approval processes. For further information, see the NASA Fact Sheets on RPS safety and fission reactor power system safety.

Focus on the Future

Project Prometheus would enable the fulfillment of NASA’s most challenging scientific goals, and will provide the essential ability to answer our most intriguing questions: Is there life elsewhere in the Solar System? How was the Solar System created and what is its future? These questions can be answered when we are able to explore--with enough time and power-enabled by the ability to change course in mid-mission to take advantage of the opportunities presented by new discoveries. Providing these important capabilities is the focus of Project Prometheus.


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