Gary L. Bennett (born January 17, 1940) is an American scientist and engineer, specializing in aerospace and energy. [1] He has worked for NASA and the US Department of Energy (DOE) on advanced space power systems and advanced space propulsion systems. His professional career has included work on the Voyager, Galileo, and Ulysses space missions, and is currently working as a consultant in aerospace power and propulsion systems. He is also a science fiction author (The Star Sailors).
Bennett was born in Twin Falls, Idaho. He joined the NASA headquarters in June 1988 as the Manager of Advanced Space Power Systems in the transportation division of the Office of Advanced Concepts and Technology. There, he managed a number of transportation technology programs including hybrid propulsion, electric propulsion, low-thrust chemical propulsion, and other advanced propulsion concepts (e.g., fusion, antimatter). He was also the first program manager of the advanced technology insertion program for the Pluto Fast Flyby (now New Horizons) mission and the TIMED space physics mission.
Prior to coming to NASA, Bennett held key positions in DoE's space radioisotope power program, including serving as Director of Safety and Nuclear Operations for the radioisotope power sources that were used on the Galileo mission to Jupiter and that are being used on the Ulysses mission to explore the polar regions of the Sun. This same radioisotope power source design was then flown on the Cassini mission to Saturn and on the New Horizons mission to Jupiter.
Previous positions included Chief of the Research Support Branch in the US Nuclear Regulatory Commission (NRC) where Bennett was instrumental in creating and managing NRC's reactor operational safety research program.
Bennett was the flight safety manager for the radioisotope power sources currently in use on the Voyager 1 and Voyager 2 spacecraft (which went to Jupiter, Saturn, Uranus, Neptune and beyond) and on Lincoln Laboratory's LES 8 and LES 9 communications satellites.
Bennett also worked as a physicist in the NERVA (Nuclear Engine for Rocket Vehicle Applications) program at what was then NASA's Lewis Research Center (now the John H. Glenn Research Center) in Cleveland, Ohio. He did fundamental reactor safety research at what is now the Department of Energy's Idaho National Laboratory (INL).
From 1980 to 1988, he was a member of or adviser to US delegations to the two subcommittees of the United Nations Committee on the Peaceful Uses of Outer Space and he prepared the official US position papers on the use of nuclear power sources in outer space.
From 1988 to 1990, Bennett chaired the Steering Group of the Interagency Advanced Power Group (IAPG), the national coordinating group for federally sponsored space and terrestrial power research. During his tenure and under his initiative the IAPG saw its greatest increase in membership.
Bennett received his PhD in physics from Washington State University in 1970; a Master of Nuclear Science degree in 1966, and a BSc degree in physics from the University of Idaho in 1962; and an Associate of Arts degree from Boise Junior College (now Boise State University) in 1960.
Since 1995, he has been active in promoting the teaching of science (specifically evolution) and received the Friend of Darwin Award. Bennett has also been a champion of the First Amendment and was elected to the National Advisory Council of Americans United for Separation of Church and State.
Bennett has authored or coauthored over 160 technical papers, reports and articles on power, propulsion, and space missions.
Science fiction
Chapters in:
Galileo was an American robotic space program that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the Italian astronomer Galileo Galilei, the Galileo spacecraft consisted of an orbiter and an atmospheric entry probe. It was delivered into Earth orbit on October 18, 1989, by Space ShuttleAtlantis on the STS-34 mission, and arrived at Jupiter on December 7, 1995, after gravity assist flybys of Venus and Earth, and became the first spacecraft to orbit Jupiter. The spacecraft then launched the first probe to directly measure its atmosphere. Despite suffering major antenna problems, Galileo achieved the first asteroid flyby, of 951 Gaspra, and discovered the first asteroid moon, Dactyl, around 243 Ida. In 1994, Galileo observed Comet Shoemaker–Levy 9's collision with Jupiter.
A nuclear electric rocket is a type of spacecraft propulsion system where thermal energy from a nuclear reactor is converted to electrical energy, which is used to drive an ion thruster or other electrical spacecraft propulsion technology. The nuclear electric rocket terminology is slightly inconsistent, as technically the "rocket" part of the propulsion system is non-nuclear and could also be driven by solar panels. This is in contrast with a nuclear thermal rocket, which directly uses reactor heat to add energy to a working fluid, which is then expelled out of a rocket nozzle.
A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby which makes use of the relative movement and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense.
A radioisotope thermoelectric generator, sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect. This type of generator has no moving parts and is ideal for deployment in remote and harsh environments for extended periods with no risk of parts wearing out or malfunctioning.
Project Prometheus was established in 2003 by NASA to develop nuclear-powered systems for long-duration space missions. This was NASA's first serious foray into nuclear spacecraft propulsion since the cancellation of the SNTP project in 1995. The project was planned to design, develop, and fly multiple deep space missions to the outer planets.
An interstellar probe is a space probe that has left—or is expected to leave—the Solar System and enter interstellar space, which is typically defined as the region beyond the heliopause. It also refers to probes capable of reaching other star systems.
The exploration of Jupiter has been conducted via close observations by automated spacecraft. It began with the arrival of Pioneer 10 into the Jovian system in 1973, and, as of 2024, has continued with eight further spacecraft missions in the vicinity of Jupiter and two more en route. All but one of these missions were undertaken by the National Aeronautics and Space Administration (NASA), and all but four were flybys taking detailed observations without landing or entering orbit. These probes make Jupiter the most visited of the Solar System's outer planets as all missions to the outer Solar System have used Jupiter flybys. On 5 July 2016, spacecraft Juno arrived and entered the planet's orbit—the second craft ever to do so. Sending a craft to Jupiter is difficult, mostly due to large fuel requirements and the effects of the planet's harsh radiation environment.
The advanced Stirling radioisotope generator (ASRG) is a radioisotope power system first developed at NASA's Glenn Research Center. It uses a Stirling power conversion technology to convert radioactive-decay heat into electricity for use on spacecraft. The energy conversion process used by an ASRG is significantly more efficient than previous radioisotope systems, using one quarter of the plutonium-238 to produce the same amount of power.
GPHS-RTG or general-purpose heat source — radioisotope thermoelectric generator, is a specific design of the radioisotope thermoelectric generator (RTG) used on US space missions. The GPHS-RTG was used on Ulysses (1), Galileo (2), Cassini-Huygens (3), and New Horizons (1).
The multi-mission radioisotope thermoelectric generator (MMRTG) is a type of radioisotope thermoelectric generator (RTG) developed for NASA space missions such as the Mars Science Laboratory (MSL), under the jurisdiction of the United States Department of Energy's Office of Space and Defense Power Systems within the Office of Nuclear Energy. The MMRTG was developed by an industry team of Aerojet Rocketdyne and Teledyne Energy Systems.
Stamatios (Tom) Mike Krimizis is a Greek-American scientist in space exploration. He has contributed to many of the United States' unmanned space exploration programs of the Solar System and beyond. He has contributed to exploration missions to almost every planet of the Solar System. In 1999, the International Astronomical Union named the asteroid 8323 Krimigis in his honor.
Nuclear power in space is the use of nuclear power in outer space, typically either small fission systems or radioactive decay for electricity or heat. Another use is for scientific observation, as in a Mössbauer spectrometer. The most common type is a radioisotope thermoelectric generator, which has been used on many space probes and on crewed lunar missions. Small fission reactors for Earth observation satellites, such as the TOPAZ nuclear reactor, have also been flown. A radioisotope heater unit is powered by radioactive decay and can keep components from becoming too cold to function, potentially over a span of decades.
Adriana C. Ocampo Uria is a Colombian planetary geologist and a Science Program Manager at NASA Headquarters. In 1970, Ocampo emigrated to California and completed her Master in Sciences at California State University, Northridge and finished her PhD at the Vrije Universiteit in the Netherlands. During high school and graduate studies she worked at the Jet Propulsion Laboratory, where she serves as the science coordinator for many planetary missions.
Robert Samuel Kraemer was an American aerospace engineer who served as Director of Planetary Programs at the National Aeronautics and Space Administration from 1971 to 1976.
Silicon-germanium (SiGe) thermoelectrics have been used for converting heat into electrical power in spacecraft designed for deep-space NASA missions since 1976. This material is used in the radioisotope thermoelectric generators (RTGs) that power Voyager 1, Voyager 2, Galileo, Ulysses, Cassini, and New Horizons spacecraft. SiGe thermoelectric material converts enough radiated heat into electrical power to fully meet the power demands of each spacecraft. The properties of the material and the remaining components of the RTG contribute towards the efficiency of this thermoelectric conversion.
Shuttle-Centaur was a version of the Centaur upper stage rocket designed to be carried aloft inside the Space Shuttle and used to launch satellites into high Earth orbits or probes into deep space. Two variants were developed: Centaur G-Prime, which was planned to launch the Galileo and Ulysses robotic probes to Jupiter, and Centaur G, a shortened version planned for use with United States Department of Defense Milstar satellites and the Magellan Venus probe. The powerful Centaur upper stage allowed for heavier deep space probes, and for them to reach Jupiter sooner, prolonging the operational life of the spacecraft. However, neither variant ever flew on a Shuttle. Support for the project came from the United States Air Force (USAF) and the National Reconnaissance Office, which asserted that its classified satellites required the power of Centaur. The USAF agreed to pay half the design and development costs of Centaur G, and the National Aeronautics and Space Administration (NASA) paid the other half.
Galileo was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989, by Space ShuttleAtlantis, during STS-34. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit an outer planet.