System The propulsion system is: :1. Premade and, or, an onboard antimatter generator :2. Storage :3. A way to separate or extract a certain amount of antimatter from the storage mass at the necessary rate :4. Generation of motion of antimatter as transferal to the annihilation location :5. An annihilation chamber :6. Control or channel of antimatter products as thrust
Methods Theoretical antimatter inclusion
propellant methods: ::plasma core ::solid core :::annihilation particles contained within the propulsion generator and controlled for heating a rocket working fluid ::::using conventional propellants: carbon dioxide, hydrogen, methane, water One method to reach relativistic velocities uses a matter-antimatter GeV gamma ray laser photon rocket made possible by a relativistic proton-antiproton pinch discharge, where the recoil from the laser beam is transmitted by the
Mössbauer effect to the spacecraft. A new annihilation process has purportedly been developed by researchers from the University of Gothenburg, Sweden. Several annihilation reactors have been constructed in the past years which attempted to convert
hydrogen or
deuterium into relativistic particles through laser annihilation. The technology was explored by research groups led by Prof. Leif Holmlid and Sindre Zeiner-Gundersen, and a third relativistic particle reactor is currently being built at the University of Iceland. In theory, emitted particles from hydrogen annihilation processes could reach 0.94c and can be used in space propulsion. However the veracity of Holmlid's research is under dispute and no successful implementations have been peer reviewed or replicated.
Nuclear catalyzed fission/fusion or spiked fusion This is a hybrid approach in which antiprotons are used to
catalyze a fission/fusion reaction or to "spike" the propulsion of a
fusion rocket or any similar applications. The antiproton-driven
Inertial confinement fusion (ICF) Rocket concept uses pellets for the
D-T reaction. The pellet consists of a hemisphere of fissionable material such as
U235 with a hole through which a pulse of antiprotons and positrons is injected. It is surrounded by a hemisphere of fusion fuel, for example deuterium-tritium, or lithium deuteride. Antiproton annihilation occurs at the surface of the hemisphere, which ionizes the fuel. These ions heat the core of the pellet to fusion temperatures. The antiproton-driven Magnetically Insulated Inertial Confinement Fusion Propulsion (MICF) concept relies on self-generated magnetic field which insulates the plasma from the metallic shell that contains it during the burn. The lifetime of the plasma was estimated to be two orders of magnitude greater than implosion inertial fusion, which corresponds to a longer burn time, and hence, greater gain. A different approach was envisioned for
AIMStar in which small fusion fuel droplets would be injected into a cloud of antiprotons confined in a very small volume within a reaction
Penning trap. Annihilation takes place on the surface of the antiproton cloud, peeling back 0.5% of the cloud. The power density released is roughly comparable to a 1 kJ, 1 ns laser depositing its energy over a 200 μm ICF target. The
ICAN-II project employs the antiproton catalyzed microfission (ACMF) concept which uses pellets with a molar ratio of 9:1 of D-T:U235 for
nuclear pulse propulsion.
Thermal antimatter rocket: heating of a propellant This type of antimatter rocket is termed a
thermal antimatter rocket as the energy or heat from the annihilation is harnessed to create an exhaust from non-exotic material or propellant. The
solid core concept uses antiprotons to heat a solid,
high-atomic weight (
Z), refractory metal core. Propellant is pumped into the hot core and expanded through a nozzle to generate thrust. The performance of this concept is roughly equivalent to that of the
nuclear thermal rocket (I_{\text{sp}} ~ 103 sec) due to temperature limitations of the solid. However, the antimatter energy conversion and heating efficiencies are typically high due to the short
mean path between collisions with core atoms (
efficiency \eta_e ~ 85%). These methods resemble those proposed for
nuclear thermal rockets. One proposed method is to use positron annihilation gamma rays to heat a solid engine core.
Hydrogen gas is ducted through this core, heated, and expelled from a
rocket nozzle. A second proposed engine type uses positron annihilation within a solid
lead pellet or within compressed
xenon gas to produce a cloud of hot gas, which heats a surrounding layer of gaseous hydrogen. Direct heating of the hydrogen by gamma rays was considered impractical, due to the difficulty of compressing enough of it within an engine of reasonable size to absorb the gamma rays. A third proposed engine type uses annihilation gamma rays to heat an ablative sail, with the ablated material providing thrust. As with nuclear thermal rockets, the
specific impulse achievable by these methods is limited by materials considerations, typically being in the range of 1000–2000 seconds. The
gaseous core system substitutes the low-melting point solid with a high temperature gas (i.e. tungsten gas/plasma), thus permitting higher operational temperatures and performance (I_{\text{sp}} ~ 2 × 103 sec). However, the longer mean free path for thermalization and absorption results in much lower energy conversion efficiencies (\eta_e ~ 35%).
Relative powers Efficiency :
Beam: 100% mass=energy though estimated 70% available. Catalysticalized anti-protonic neutron output is a range of a six-multiple of the power of conventional process. :Schmidt
et al 1999: 13600 - 67000s ==See also==