Starships[]
The starships of the Galactia program will represent the pinnacle of spacecraft engineering in the Solaria phase and will, given the nature of NanoFoam as a basis of their construction and the use of anti-matter propulsion, likely employ a design radically different from the starships previously envisioned by space scientists and most recent science fiction authors.
Early notions of plausible interstellar spacecraft have tended toward extremely large complex and bulky structures, such as the Bussard Ramjet concept proposed in 1960 by physicist Robert Bussard (now generally considered infeasible but once very popular in less fanciful science fiction), Project Orion concept proposed by Ted Taylor and Freeman Dyson in the late 1960s, the Project Daedalus concept proposed by the British Interplanetary Society in early 1970s, and the Project Longshot concept proposed by NASA in the late 1980s. These were based largely on variations of proposed fusion propulsion and employed vast fuel storage tanking with vast beryllium shields as protection against forward particle impacts at relativistic speeds. Traveling around 10% the speed of light, their missions to nearby stars were projected to be in the 50 year range. The Project Longshot concept is interesting in that it’s design features a BeamShip architecture like most of the spacecraft anticipated for the Asgard phase of development. It also has characteristics of the dumbbell or ‘gamma’ spacecraft configuration favored by a number of past hard science fiction authors.
A more recent, and potentially more promising, concept from the early 1990s is the Valkyrie proposed by writer Charles Pellegrino and physicist Jim Powell. This is also a very long BeamShip-like structure based on a ten kilometer long tether or narrow truss featuring a towing engine configuration where a large forward-mounted toroidal magnetic confinement antimatter engine provides thrust with crew and payload modules further down the truss shielded by a dense but relatively small tungsten ‘shadow shield’. A spray of coolant droplets provides a combination of cooling and dust impact shielding and is recovered and recycled continuously during acceleration by the magnetic confinement field. A duplicate engine, at the opposite end of the tether is employed during deceleration, generating reverse thrust, while vast but extremely thin umbrellas of mylar in thousands of layer would be deployed in the front of the vessel to serve like a Whipple Shield for particle impacts. This would be further assisted by a ‘dust shield’ made from ground-up used fuel tanking and ejected in a plume in the direction of travel. (A bit of a hazard traveling as relativistic speeds…) This approach eliminates the need for the vessel to reverse direction mid-flight -it’s long flexible structure impossible to shield when turning- but does require that the crew module be able to climb the core tether or truss to an opposite position for distance from the braking engine’s radiation. This concept in intended to have three generations, the first using an antiproton-induced fusion propulsion system capable of 10% the speed of light, the second a scaled-down vessel using a proton-antiproton annihilation version of the engine for a fast interplanetary vessel, and the full scale proton-antiproton annihilation engine capable of a speculative 92% the speed of light. First featured in Pellegrino’s SF novel Flying to Valhalla, a visual analog to this form of starship also recently appeared in the James Cameron film Avatar, Pellegrino and Powell acting as consultants on its design. This is our most advanced plausible starship concept to date and if this form of propulsion is realized in the Asgard phase, it’s likely that this design approach may be use for the first interstellar probes.
However, in the original TMP Marshal Savage offered the radical suggestion of very streamlined starships of unified architecture, taking into account the need to minimize the angle of incidence of likely particle impacts as spacecraft velocities became great so as to reduce hull damage and erosion. In addition, his proposed spacecraft would employ active impact and induced radiation shielding in the form of a continuously operating laser spike powered by energy from the engines that would ionize onrushing hydrogen and other particles that would then be magnetically deflected out of the path of the vessel, creating a plasma halo. The elongated tetrahedron-shaped design Savage envisioned was certainly a great departure from the non-SciFi vessels proposed in the past. But it had one problem; it was not especially streamlined in the reverse position and a starship traveling at relativistic speeds would spend half its trip decelerating in the aft-forward position. Thus it would need to be symmetrically streamlined in profile. Savage also did not consider the impact of nanotechnology on the design and construction of spacecraft by this time in future history.
Thus for TMP2 we have arrived at an even more radical design concept and our model comes straight from Mother Nature and some of her most streamlined creations;
http://upload.wikimedia.org/wikipedia/commons/9/92/Fin_whale_from_air.jpg
Grown from NanoFoam, rather than assembled, like other spacecraft of the Solarian age and featuring a monolithic structure our new Galactia Starship would be a symmetrically tapered ovoid in shape, much like the form of the fin whale shown above, or rather like two of them merged head-to-head. This profile is as much for radiation shielding as it is for streamlining, the form in part dictated by the shadow of shield barriers at the engines. This shape would be organized into 5 basic sections; an aft propulsion system with integrated radiation shielding, a matching forward X-ray laser system, a central habitat sphere or payload section, an aft interstitial antimatter fuel reserve, and a fore ice fuel reserve doubling as additional induced radiation shielding surrounded by integral field coil shield system. Optionally, the fore section may mirror the aft section with a second deceleration engine and antimatter storage system, the thrust duct exposed at mid-flight, to preclude the need of turning the ship around at relativistic speeds. Though this might seem a heavy structure, like BeamShips of the Asgard phase, its architecture would be organized largely around a core internal ‘spine’ running the length of the ship which provides most of the structural integrity. Though light, highly efficient in terms of mass ratio, and with scales varying greatly according to mission concept, these vessels are still likely to be quite large -potentially kilometers long.
We assume that a more advanced proton-antiproton annihilation propulsion devised by the time of the Solarian age will be much more laser-like in its reaction control and more directional, collimated, and efficient. This possibility is already hinted at in contemporary trends in emergent fusion technology and research in nuclear X-ray laser weapons. This means that, instead of a large area omnidirectional explosive antimatter reaction needing very wide magnetic field toroids for confinement and thrust vectoring as suggested with the Valkyrie concept, our anticipated antimatter engine may be a relatively compact system more akin to the form factors of today’s emerging plasma thrusters. Thus our very unified design would internally integrate most of its features in this sleek hull form and its engine ducts may be little more than a relatively narrow tubular opening. The forward X-ray laser -possibly powered by a dedicated antimatter reactor- would function in combination with magnetic field coils in the tapering nose of the vessel as a deflection shield, ionizing atomic hydrogen and some nanoscale dust in the interstellar medium and deflecting them away from the vessel, creating a plasma shroud in front of the vessel in flight. A water mist deflection shield would also be used, creating an ionized plume ahead of the ship to reduce induced radiation and erosion during the brief period of rotation when the vessel switches from acceleration to deceleration.
Should our assumption on the nature of antimatter propulsion prove wrong, this same vehicle form would still function for an external reaction antimatter propulsion system like that of the Valkyrie concept. (and if the Valkyrie concept is employed in the late Asgard era, this may be a likely evolution for first generation Galactia vessels) The same grown hull shape would be employed -though likely narrower and much longer- with the toroidal field coil units placed on projecting spars at the ends, rather than employing a single internal engine at one end. The taper of the hull profile would thus be designed to follow the shadow produced by engine shielding using conical or domed tungsten nose and tail caps.
The Galactia starship hull would be a very light many-layered cellular structure of diamondoid composition. All along its surface it would be highly reflective and corrugated, greatly increasing its surface area so that the entire outer hull surface can be employed as a vast thermal radiator. Though our engine technology is anticipated to be highly efficient and directional in reaction, it would likely still produce much waste heat and, with its capillary channels filled with molten salts, the aft end of the hull would likely glow a dull red color constantly during flight. (the fore end likewise with the heat dumped by its massive X-ray laser system) Toward the wider section, the hull would also be able to integrate the elements of a phased array antenna which would serve for both communications and radar. This would be supplemented by ‘whisker’ antennas projected from the vessel’s middle section, each perhaps as thin as some tens of centimeters at the base but potentially kilometers long and regrown by the ship like a cat’s whiskers whenever damaged.
At the mid-section of the manned vessel there would be several large eye-like portals. Sealed during flight, these would open upon arrival to expose large bays for smaller utility and probe vessels. These points would also be at the equator of the spherical center habitat and would link by branches through that to the center spine. During initial fabrication of the ship, these may actually serve as the ‘navels’ of the vessel where umbilical connections linked the growing structure to a parent orbital habitat. The mid-section of the outer hull would also feature the same iridescent fly’s-eye array of cellular optical elements used to communicate light and view to the interior of the EcoSphere habitats and, in general, the central habitat section would function much the same as a smaller -though still quite large- EcoSphere.
Within the manned habitat sphere a light transmitting inner hull surface would provide artificial sky lighting and views of surrounding space enclosing an integral arcology formed around the central spine. Featuring elaborate low-mass grown-in-place organic architecture adapted for habitability in both microgravity and under 1g force during acelleration/deceleration, this variant of the Urban Tree habitat would have a variably profiled tower-like form sloping outward toward the polar ends and with several branches linking to the perimeter points hosting the mid-section portals and their vehicle bays. The scale of an entire town or small city, this core habitat would provide comfortable accommodations quite similar to that of both EcoSphere habitats and terrestrial arcologies and may feature a garden environment with extensive vegetation growing from integral hydroponics planting beds, pockets, and trellises designed for both microgravity and gravity conditions. The line between structure, landscape, and vegetation blurred by the organic design, the Urban Tree may be, very literally, a living tree integrated to the spacecraft.
Unmanned vessels would need no open interior space and the center payload section would be a largely solid mass dominated by data systems. Instead of eye-like portals, a broad continuous meridian bay with a continuous retracting lid would be used to house a fleet of probe and utility vehicles fabricated en-route and deployed on arrival to explore and pre-colonize a whole solar system by seeding its most promising natural bodies with RhiZome complexes.
One of the great quandaries of plausible starship design is the issue of mass-ratio when so much mass becomes necessary for cargo capacity to support the anticipated colonization of a new solar system. But with the advent of NanoFoam this is a much simpler prospect because a NanoFoam vessel would effectively need little cargo space in the convention sense. It’s physical structure would be its primary cargo, readily repurposed on arrival to make whatever the mission needed. Thus the Galactia starship is not just transportation. It is a permanent home and would, on arrival, immediately reform itself into an EcoSphere colony and vast communications array able to park in any desired location in the new star system and establish a civilization from there. All the tools needed to turn any solar system with any combination of natural bodies into a habitable place would be contained in any NanoFoam structure. Everything we need to live well anywhere in the universe in one self-transporting, self-repairing, self-transforming, self-replicating package. Marshal Savage envisioned mission schemes based on large slow cargo vessels being followed by smaller faster manned vessels, but with this virtue of NanoFoam composition no difference in sizes and speeds are necessary. In fact, pre-colonization vessels could be much smaller and faster than their manned counterparts as they need deliver very little NanoFoam material to a solar system to start its pre-colonization development -though we are likely still talking about very large vehicles compared to the spacecraft of the present.
And these vessels may also be self-aware. With vast data systems distributed throughout its NanoFoam structures, the Galactia starship could host the most advanced AI systems and may even serve host to communities of artilects with its own Virtual Habitat. In some mission scenarios, as we will discuss later, a crew might live in a virtual habitat while their bodies are maintained in suspended animation, though an artilect community would not need even that much of a contrivance and individual artilects might embody themselves as starships perpetually exploring the universe, seeding them for their fellow artilect settlers to follow by simple digital telecommunications transmission.
The starships originally envisioned by Marshal Savage were described as traveling at a potential 10% of the speed of light for slower and larger cargo vessels while the ‘fast clippers’ might achieve a 50% fraction of c. This would make the trip to Alpha Centauri about 45 years and 10 years respectively. With superior mass-ratio and potentially more efficient engines allowing it possible speeds akin to the Valkyrie concept, we anticipate the new Galactia starship could halve these transit times and perhaps, like the Valkyrie concept, be capable of a 90% of c.
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