This is the second part of my article on Ad Astra space drives. Part 1 is here. Today, TL9 – TL11.
Tech Level 9 (without antimatter)
The perfection of deuterium/tritium fusion rockets revolutionises space travel. It is finally possible for a shuttle to take off from Earth, fly to the Moon and back, all without refuelling. Interplanetary travel becomes truly practical. Cheap VASIMR thrusters powered by fusion electric plants can haul large loads, even to the outer planets – although travel times are measured in months or years. For those in a hurry, fusion rockets with drop tanks can halve travel times.
D/T fusion drives use tonnes of hydrogen propellant, but also need hundreds of kilos of deuterium & lithium fuel. Deuterium is widely available, or can be purified from large quantities of plain hydrogen, given time. Lithium must be mined or filtered from sea water. D+Li typically costs Cr300/kg.
Nuclear salt water drives are even more capable – putting Mars only 2 weeks away. Unfortunately their highly toxic exhausts restrict them to military use, or uninhabited volumes.
Jump drives can be constructed at this tech level, although they are not discovered until TL10. Some interstellar travel is conducted by TL9 craft, even though a journey typically takes a whole year. Star ships at this tech level almost invariably place passengers in low berth, even for journeys of a single jump.
TL9 Moon shuttle 200t, MCr89, 37t cargo
200t streamlined cone configuration, with high thrust D/T fusion rockets. Hydrogen propellant tanks fill 50% of the hull, which is enough for 27.7km/s of delta-V. This ship can launch from Earth, fly to the Moon and back in 3 days, and land – all without refuelling. (Note the heat radiator fins.)
TL9 Mars ship 200t, MCr45, 9 months, 130t cargo
200t dispersed structure, with VASIMR thrusters capable of 0.00016G. A D/T fusion plant generates the necessary 52MW. Hydrogen propellant tanks fill 15% of the hull, which is enough for 52km/s of delta-V. A round trip to Mars (closest approach, no landing) takes 9 months.
TL9 NSW Mars ship 200t, MCr160*, 4 weeks, 106t cargo
200t dispersed structure, with a nuclear salt water drive capable of 1G. Water propellant tanks fill 20% of the hull, which is enough for 223km/s of delta-V. A round trip to Mars (no landing) takes between 4 weeks and 5 months, depending on the season. Cargo capacity is 106t.
* – This ship is highly capable, but has significant disadvantages. Firstly, refuelling is ruinously expensive. MCr100 of the MCr160 price tag is the 2000kg of highly enriched uranium that the ship burns during its round trip. Secondly, the exhaust is very toxic. Fortunately the propellant is expelled at many times solar escape velocity, but extreme care must be taken to ensure that it is never pointed at inhabited bodies. The drive would be quite capable of launching from a planet’s surface, but using it in an atmosphere is universally illegal.
Tech Level 10 (without antimatter)
Fusion drives continue to evolve. Highly efficient thrusters reduce the minimum time for an Earth-Mars journey to less than 3 weeks. These drives are so efficient that waste heat is now a serious problem. Thruster-driven ships have huge radiator fins. Many also employ trans-dimensional heat sinks, which store excess heat in foamed higher dimensions.
Rockets are now able to use the deuterium/helium-3 fusion reaction, which produces more energy, and requires much less heavy shielding. Shuttles can move around planetary systems with ease, and interplanetary craft can use much more energetic transfer vectors.
Helium-3 fusion drives & power plants CANNOT burn pure deuterium as they lack the proper shielding. He3 is usually only available at high-tech A- or B-class starports. It typically costs Cr10,000/kg. He3 may be manufactured from deuterium, but this process is slow and costly. Alternatively it may be collected from gas giants or mined on airless inner-system worlds.
TL10 is the usual capability level of interstellar civilizations. These ships can be found working in every inhabited, civilized system. They are widely traded, easy to use, cheap to run, and well understood.
TL10 shuttle 200t, MCr59, 82t cargo.
200t streamlined wedge configuration, with high thrust He3 fusion rockets. Hydrogen propellant tanks fill 35% of the hull, which is enough for 34.5km/s delta-V. A round trip to the Moon takes only 3 days.
TL10 Mars ship 200t, MCr81, 86t cargo.
200t dispersed structure, with D/T fusion thrusters capable of 0.01G. Hydrogen propellant tanks fill 30% of the hull, which is enough for 178km/s of delta-V. A round trip to Mars (no landing) takes between 6 weeks and 7 months, depending on the distance.
TL10 interplanetary shuttle 200t, MCr118, 52t cargo.
200t streamlined wedge configuration, with He3 fusion rockets, and a D/T fusion thruster. Hydrogen propellant tanks fill 40% of the hull, which is enough for 18km/s of high-thrust delta-V AND 112km/s of delta-V at 0.01G. This ship can launch from Earth, fly to Mars, land, and return – all in 2 months, without refuelling. A round trip to the Moon takes only 2 days.
TL10 jump courier 200t, MCr130, 40t cargo.
200t spherical configuration, with He3 fusion rockets (6G), and a D/T fusion thruster (0.01G). Hydrogen propellant tanks fill 40% of the hull, which is enough for 41km/s of high-thrust delta-V OR 255km/s of delta-V at 0.01G. The ship is designed to take advantage of drop tanks
Affordable antimatter enables a quantum leap in space craft technology. Suddenly, interplanetary journeys can be completed in days, rather than weeks.
Tech Level 9 with antimatter
TL9’s usual fusion rockets can be supercharged by injecting small (0.1%) amounts of antimatter into the fuel stream. Antimatter-catalysed fusion rockets can be used for interplanetary travel – often supplemented by drop tanks. Antimatter can be purchased at most A- and B-class starports, but prices can be very variable. MCr10/kg is typical. Pre-mixed deuterium/antimatter fuel pellets are often available for about Cr20,000/kg.
Pure antimatter rockets also become available at TL9. Whilst useless for long journeys, they enable highly manoeuvrable military fighter craft. Engines that can pull 6G for a whole hour are possible, although they would normally be used at lower thrusts, or for many shorter burns. Antimatter-rocket driven missiles are even faster.
TL9 interplanetary antimatter shuttle 200t, MCr75, 70t cargo.
200t streamlined wedge configuration, with antimatter catalysed fusion rockets (no thrusters). Hydrogen propellant tanks fill 40% of the hull, which is enough for 82km/s of high-thrust delta-V. This ship can launch from Earth, fly to Mars, land, and return in 3 months, without refuelling. A round trip to the Moon takes 15 hours.
Tech Level 10 with antimatter – torch ships.
Finally, at TL10 with antimatter, interplanetary travel becomes an every day convenience. Antimatter catalysed fusion thrusters have both super-high efficiency and high thrust – so there is no need for separate rockets for launch or landing. One “torch” ship, can do everything.
TL10 interplanetary antimatter shuttle 200t, MCr75, 76t cargo.
200t streamlined wedge configuration, with an antimatter catalysed fusion torch drive. Hydrogen propellant tanks fill 40% of the hull, which is enough for 1022km/s of delta-V at 1G. This ship can launch from Earth, fly to Mars, land, and return in a week, without refuelling. A round trip to the Moon takes 6 hours. Even a trip to Jupiter takes 9 days (with drop tanks).
Tech Level 11
Even without antimatter, fusion drive technology continues to develop. Procyon’s space fleet is largely limited to this capability level, because of the Commonwealth’s antimatter blockade.
Efficient Helium-3 fusion thrusters are now available, even though journey times are still measured in weeks. These drives are not powerful enough to launch or land, so ships still tend to be specialised between long-haul space-only craft – equipped with thrusters, and streamlined landing craft equipped with rockets.
Monopole catalysed fusion is the one TL11 innovation that might compete with antimatter, if only magnetic monopoles were easier to obtain. Monopoles make it far easier to manipulate the powerful magnetic fields required to initiate fusion, and can also be held in the mixture to help compress it. The result is every bit as efficient as antimatter catalysation, with the added advantage that the monopoles are not used up during the reaction, so fuel costs are minimal. Unfortunately monopoles are so rare that a single gram costs up to a million credits. Drives require hundreds or thousands of grammes.
TL11 interplanetary ship 200t, MCr38, 90t cargo.
200t close structure, with a Helium-3 fusion torch drive. Hydrogen propellant tanks fill 35% of the hull, which is enough for 431km/s of delta-V at 0.1G. A round trip to Mars takes just over two weeks, Jupiter and back is only 6 months.
(Thank you to conceptships.blogspot.co.uk for many of the space craft images used here.)