"Extra Stout" Megalith class heavy space tug TECHNICAL SPECS: --------------- Overall length: 34m (85 studs) Overall width: 36m (90 studs) Fuselage width: 8m (20 studs) Mass: 1260t (6.3 kg) dry weight Crew: 4 Lifeboat capacity: 4 Propulsion: Primary: 22.8MN (4 x J-33 cylindrical pump assembly fusion torches) (MN = MegaNewtons. 1kg weighs 9.8 Nwetons in 1G) Fuel: Primary: 27200MN hours Power: Main: 1.2MW (Side-loop heat bleed from #2 fusion torch) Auxiliary: 108kW (Auxiliary Nuclear-thermal plant) Decks: 6 + 2 modules Deck 0 - Bridge Deck 1 - Rotation cuff Deck 2 - Cargo and storage Deck 3 - Vehicle Access and Workshop Deck 4 - Crosslink Access and Medbay Deck 5 - Engine Room Deck M1- Living Quarters and Mess (rotating module) Deck M2- Hydroponics and Recreation (rotating module) BACKGROUND: ---------- It is 2138. Earth celebrates its first century of commercial space exploration and exploitation. Out here in the far reaches of the solar system, megacorporations and small, independent ship operators thrive side by side as they harness the vast mineral wealth of the planets and asteroids. Solitary, half-crazed prospectors in scratch-built, jury rigged vessels ply the fringes of the asteroid belt, searching with their magnectic anomaly sensors and gravimeters for the claim which will make them wealthy beyond belief. Every so often, one of them does strike a mother lode - a heavy, nickel-iron rock amidst the jumble of silicate and ice. Then the lucky prospector scurries back to one of the big corporate headquarters - Ceres Mining Corp, or Trans-Solar Industries - and sells their claim for a slim percentage and a bit of company scrip. If the asteroid is big enough, the mining corp will send a factory ship, and build a smelter on-site. But for the small rocks on the fringes - asteroids under 200 MegaTonnes, say - they're more likely to hire an independent space tug captain to bring in the rock for processing at the big orbital smelters. Captain Jack Hargreaves is one such tug operator - and his "Extra Stout" is typical of the sort of rock-hopper you get on the belt fringes. Jack and his crew of three run a tight ship - winning the early delivery bonuses makes R&R at Luna all that much more appealing... TECHNOLOGIES: ------------ The "Extra Stout" is based on near-future technologies: No warps drives or reactionless engines: Fusion torch engines, top acceleration 1 or 2 Gs; in-system interplanetary travel. No force fields, so you have to use hatches and airlocks to keep the breatheable stuff inside. No artificial gravity, so if you want to keep your feet on the floor, you either have to accelerate hard, or spin the hull to provide pseudo-gravity. DESIGN REQUIREMENTS: ------------------- I made every effort to design a "real" ship - one that's workable and to-scale for its purpose. Here are some of the things I considered: GRAVITY or LACK THEREOF: ----------------------- The "Extra Stout" was designed to push asteroids or other very heavy objects, such as space factories or extremely large cargo packages. She is designed around this concept; she has very large engines for her size - enough to generate nearly 2 Gs of acceleration when unburdened. However, when she's pushing a 200m diameter asteroid, that acceleration is cut down to barely 1/50th of a G. In order to make the weeks or months-long transit back to the factory more livable, the "Extra Stout" is equipped with a pair of centrifugal living quarters modules to provide pseudo-gravity when she is not under rapid acceleration. However, this poses a problem when the "Extra Stout" *is* accelerating quickly, such as when she is headed out for a pickup. For these occasions, the rotating module arms fold back against the hull, and hatches are opened between "4" deck and the modules. This gives a large, convenient living space with "up" oriented toward the nose of the ship - the direction of acceleration. It also prevents stress to the long rotating arms, and keeps the living quarters from being "sideways" for the duration. The remainder of the decks are oriented with "up" toward the nose - they only have "gravity" when the ship is under rapid acceleration. When drifting or pushing a rock, they are effectively null-G. KEEPING the AIR IN: ------------------ There are two types of access doors on the "Extra Stout": Hatches and Airlocks. Hatches are for use when docking to another vessel (or mating the living modules to the hull). They consist of a single door, which opens "in", against air pressure. In order to operate, they need to seal to another matching hatchway. Once the pressure is equalized, the hatchway can be opened to provide access. There are 9 external hatchways on the "Extra Stout" - one on each living module for mating to the crossover deck, two on "4" deck, and one on "3" deck for vehicle docking. There is one in each module for sealing the rotation arm before it is folded; and two in the rotation cuff for sealing the arms at the top ends when they are folded. There are two internal hatchways in the "Extra Stout", which serve to prevent complete decompression in the event of the hull being damaged. They separate the bridge from the rotator cuff, and the rotator cuff from the aft part of the ship. Airlocks have two doors - an inner and outer door. Since only one door is opened at a time, there is no danger of the air rushing from the ship as you exit! There is one airlock on the "Extra Stout": at the nose of the ship. THE SHIP that NEVER COMES to SHORE: ---------------------------------- The "Extra Stout" was built in space, and operates there. She is not aerodynamic, and is not intended to land, even on an airless world. Hence, she has no landing gear. However, she *is* meant to push heavy objects, which means butting into them (no tractor beams, remember?) Consequently, she is equipped with a "bustle" which looks a lot like landing gear, but is intended to prevent both damage to her own hull, and to the object she is pushing. THE BUSTLE: ---------- The "bustle" is the buffer equipment of a tug which comes between it and the object it's pushing. The "Extra Stout" is currently outfitted for rock-hopping, so it has large contact pads on its bustle to spread the force from the tug over a wider area. Contrary to popular belief, most asteroids are at least partly comprised of dust and gravel, which is only very loosely bound to the "rock". The "Extra Stout" carries a quantity of "SCE" (Surface Conditioning Equipment) in its cargo bay. SCE includes compressors and plasticrete spray hoses which can be used to firm up a dangerous surface before the tug is nestled up to the rock. THE FRAME: --------- The "Extra Stout" has a very strong internal frame, on which the engines, hull, decks, and equipment are hung. Although the "Extra Stout" was not designed to land on a planetary surface, it is capable of transferring twice its own "weight" (on Earth) through the bustle to the object it is pushing. (In real terms, the "Extra Stout" model can be picked up and waved around, and it *can* stand on its bustle. Really. It is *very* sturdy.) VIBRATION ISOLATION: ------------------- The engines, at the aft of the ship, are isolated from the remainder of the vessel by large vibration-damping struts. Besides damping the roar of the engines to a tolerable level for the crew, these struts are a key safety feature: Excessive vibration, when transferred to an unstable asteroid, can result in a "gravelanche", where the loose pebbles and dust of the asteroid surface are knocked loose and threaten the ship and her crew, as well as destabilizing the mooring point. THE ROTATION CUFF: ----------------- The rotation cuff provides smooth rotation of the living modules and their arms when they are deployed. In Lego terms, a pair of technic turntables were used to allow the cuff to rotate freely with respect to the bridge and with respect to the aft portions of the ship. The two turntables were then rotationally locked to one another, which synchronizes the rotation of the bridge and the aft decks. The end result is that the front and back of the ship appear to be locked solid to one another, when really there is no direct connection. At the same time, the 24-tooth gear hole at the centre of each turntable is large enough to permit a minifig to pass through the center of rotation. They also provide convenient points for hatch placement. The rotation cuff, despite allowing free rotation, is solid enough to support the mass of the rotation modules, and sturdy enough to permit the model to be handled freely. ROTATION ARM HINGES: ------------------- Each rotation arm hinges partway along, to permit the living modules to be brought adjacent to the mating hatches on deck "4". The hinges are able to bear the strain of rotation, and the weight of the modules when folded alongside the hull. ACCESS CRAWLWAYS: ---------------- In keeping with the scale of the model, the "Extra Stout" has crawlways and access passages throughout. Minifigs *can* get everywhere they need to in the vessel, and ladders are provided anywhere that they might prove necessary. Safety grip rails are provided along with the ladders in most places. Some of the more interesting passageways: Engineering access: Travels between decks "4" and "5", inbetween the fuel tanks and communications array. It is the aft end of the access tunnel which runs the length of the "Extra Stout" Rotation Arms: Lead from the rotation cuff out to the modules. Each is hexagonal in cross section, with 1x1 round bricks detailing the "grooves" between the bricks, and to prevent unsightly "see-throughs". Each is reinforced to support the weight of the module at its end. Rotation cuff hatchways: The central access tunnel running the length of the ship passes through the rotation cuff at a pair of technic turntables. These holes are never blocked at any point in the rotation, and can readily pass a minifig. VIEWING the MODEL: ----------------- In order to be able to photograph the model, the following features were added: Engines: The four engines may be detached, to reveal the viewports into the engine control room (deck "5"). Normally these viewports would be used by the engineer to monitor the fusion torches. Engine room deck separation: The engine room deck (deck "5") may be easily detached from the rest of the frame to permit viewing and photography. Handy!