Nuclear Fusion Rocket
The Internal Fusion Drive
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Nuclear Fusion RocketThe Internal Fusion Drive |
| Nuclear Fusion Rocket - Data Panel
Summary: The Fusion drive uses heat from a fusion reactor to heat and eject the fuel. Depending on the type and efficiency, that gives a specific impulse of anywhere from a few thousand to a hundred thousand or more. These ships were quite important during the Interplanetary Age, especially among the Genetekker and Space Adapted tweak cultures Fusion rockets are huge and heavy devices, but, in systems where amat is scarce or unavailable, they are the only drive systems that give enough Δv for truly practical for System-wide operations. See also Fusion pulse Basic Propulsion: Reaction Specific Impulse [sec]: 104 to 105 Thrust-to-Weight Ratio: 10-5 to 10-2 Fuel: D-T or D-3He Reaction Mass: usually hydrogen; sometimes water Minimum Technology Required: Middle to High Tech (Information/Interplanetary Age Equivalent) Matter Manipulation: microscale/nanoscale (precision materials) Controller required: advanced non-sentient or sentient computers First Introduced: Information Age Used by: Many polities, clades, individuals and groups away from the Nexus, in low resource solar systems and among members of the Deeper Covenant, out on the periphery, and among some anti-ai luddite groups Used in: medium speed interplanetary transport Construction Costs: Autofac: high (bulky, precision materials); Hylonano: reasonably cheap assuming presence of component materials Running cost: depends on availability of fuel Advantages: reasonably reliable, reasonably good performance, can be made with materials in most solar systems; doesn't require amat Disadvantages: Interplanetary only. Normal Acceleration: 0.05 to 0.1 g Normal Top/Cruising Speed 100 - 150 km/sec (interplanetary haulers) |
The standard fusion rocket uses the D-3He fuel cycle, with bucking coils to extract a magnetic flux tube from a toroidal magnetic fusion reactor and exhaust the thrust. There were many technical difficulties to be overcome, especially involving magnetic field strength and the size and weight of the coils, and this engine only became practical with the invention of lightweight supercompact fusion reactors during the mid 2nd century. They very quickly became standard, until being supplanted in the inner solar system by the anti-matter fusion hybrid drive that became economical with increased output by the big amat cartels.
Historically, D-3He magnetic fusion has advantages for space applications in societies where antimatter production is limited, expensive, or unavailable. The high fusion power density in the plasma favors D-T fuel, but the reduced neutron power fraction favors D-3He fuel. This trade-off exemplifies the competition between physics and engineering that has always shaped fusion energy development. For space applications, D-3He fuel has usually been the most attractive. The key reason for this is that the most important factor is not the fusion power density in the plasma (kW-fusion/plasma volume) but is the engineering power density (kW-thrust/mass of reactor and radiators). Several factors contribute to the dominance of D-3He fuel over D-T:Even so, there are still a few clades that prefer D-T fusion, the fuel of which is more easily extracted
See also: Fusion pulse and Amat Catalysed Fusion