Antimatter catalysed nuclear pulse propulsion is a variation of nuclear pulse propulsion based upon the injection of antimatter into a mass of nuclear fuel which normally would not be useful in propulsion. The anti-protons used to start the reaction are consumed, so it is a misnomer to refer to catalyzation. An artists conception of a spacecraft powered by nuclear pulse propulsion Nuclear pulse propulsion (or External Pulsed Plasma Propulsion, as it is termed in one recent NASA document) is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. ...

Traditional nuclear pulse propulsion has the downside that the minimum size of the engine is defined by the minimum size of the nuclear bombs used to create thrust. With conventional technologies nuclear explosives can scale down to about 1/100 kiloton (10 tons, 42 TJ; W54), but making them smaller seems difficult. Large nuclear explosive charges require a heavy structure for the spacecraft, and a very large (and heavy) pusher-plate assembly. Small nuclear explosives are believed to stop shrinking in overall size and required fissile nuclear materials at around 25 kilograms weight, so smaller pulse units are much more expensive per delivered unit energy, and much less mass efficient than larger ones. The mushroom cloud of the atomic bombing of Nagasaki, Japan, in 1945 lifted nuclear fallout some 18 km (60,000 feet) above the epicenter. ... The W54 was a small nuclear warhead designed by the United States Government. ...

By injecting a small amount of antimatter into a subcritical mass of fuel (typically plutonium or uranium) fission of the fuel can be forced. An anti-proton has a negative electric charge just like an electron, and can be captured in a similar way by a positively charged atomic nucleus. The initial configuration, however, is not stable and radiates energy as gamma rays. As a consequence the anti-proton moves closer and closer to the nucleus until they eventually touch, at which point the anti-proton annihilates with a proton. This reaction releases a tremendous amount of energy, of which some is released as gamma rays and some is transferred as kinetic energy to the nucleus, causing it to explode. The resulting shower of neutrons can cause the surrounding fuel to undergo rapid fission or even nuclear fusion. Antimatter is matter that is composed of the antiparticles of those that constitute normal matter. ... A sphere of plutonium surrounded by neutron-reflecting blocks of tungsten carbide. ... General Name, Symbol, Number plutonium, Pu, 94 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white Atomic mass (244) g/mol Electron configuration [Rn] 5f6 7s2 Electrons per shell 2, 8, 18, 32, 24, 8, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... An induced nuclear fission event. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interactions. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... A semi-accurate depiction of the helium atom. ... This article is about electromagnetic radiation. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... Properties In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ...

The lower limit of the device size is determined by anti-proton handling issues and fission reaction requirements, but the concept appears to be feasible using today's technology and infrastructure, unlike either the Orion-type system, which requires large numbers of nuclear explosive charges, or the various anti-matter drives, which require impossibly expensive amounts of antimatter.

Tuning of the performance to the mission is also possible. Rocket efficiency is strongly related to the mass of the working mass used, which in this case is the nuclear fuel. The energy released by a given mass of fusion fuel is several times larger than that released by the same mass of a fission fuel. For missions requiring short periods of high thrust, such as manned interplanetary missions, pure microfission might be preferred because it reduces the number of fuel elements needed. For missions with longer periods of lower thrust, such as outer-planet probes, a combination of microfission and fusion might be preferred because it reduces the total fuel mass. Working mass is a mass against which a system operates in order to produce acceleration. ...

The concept was invented at Pennsylvania State University before 1992. Since then, several groups have studied antimatter-catalyzed micro fission/fusion engines in the lab (sometimes antiproton as opposed to antimatter). The Pennsylvania State University The Pennsylvania State University (commonly known as Penn State) is a state-related land-grant university with a main campus located in State College, Pennsylvania, and 23 other campuses (some called Commonwealth Campuses) located throughout Pennsylvania. ...

Work has been performed at Lawrence Livermore National Laboratory on antiproton-initiated fusion. In contrast to the large mass, complexity and recirculating power of conventional drivers for inertial confinement fusion (ICF), antiproton annihilation offers a specific energy of 90 MJ per µg and thus a unique form of energy packaging and delivery. In principle, antiproton drivers could provide a profound reduction in system mass for advanced space propulsion by ICF. Antiproton-driven ICF is a speculative concept, and the handling of antiprotons and their required injection precision—temporally and spatially—will present significant technical challenges. The storage and manipulation of low-energy antiprotons, particularly in the form of antihydrogen, is a science in its infancy and a large scale-up of antiproton production over present supply methods would be required to embark on a serious R&D programme for such applications. Aerial view of the lab and surrounding area. ... Inertial confinement fusion using lasers rapidly progressed in the late 1970s and early 1980s from being able to deliver only a few joules of laser energy to a fusion target to being able to deliver tens of kilojoules to a target. ... Antihydrogen is the antimatter counterpart of hydrogen. ...

External links

• Antimatter Catalyzed Micro Fission/Fusion (ACMF)
• Antiproton-Catalyzed Microfission/Fusion Propulsion Systems For Exploration Of The Outer Solar System And Beyond (one of the early Penn-State articles)
• "On the Utilty of Antiprotons as Drivers for Inertial Confinement Fusion" (Nuclear Fusion journal article of work performed at LLNL)