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Text for pod exterior panel left of door.

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treddie		#21	[-]
Posts: 53 (10/21/08 11:18:59) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	At first thought that didn't seem possible. Then again...In one thought experiment, if you have two flywheels that are concentric and counter-rotating where the momentum of each wheel is identical but reversed, one would want to precess in one direction, the other in the other direction. It doesn't seem logical that the whole system would remain fixed in space if you tried to rotate it. You're right. it probably would cancel out. But each flywheel would still want to precess, regardless, meaning that they must still be putting an angular load on their respective bearings. I think I'd like to play around with this with a couple of those toy gyroscopes held together by a short beam. They wouldn't be concentric, but at least it might shed light on the question. But now that I think about it, car wheels want to precess whenever the wheels are turned on their axes, and wheel bearings are very reliable. I imagine that they could engineer a huge bearing for the centrifuge to withstand all that. But it might be REALLY heavy. Then I think about all those slip rings that would be required to funnel data IO and power to and from the centrifuge. Maybe a very short range wireless would work for data.
EVAPOD man	Ladders in zero gee	#22	[-]
Posts: 89 (10/21/08 13:45:43) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The ladder was added because it was too dificult to simlate zero-gee inside the spaceship. Thats why all the pepole are walking around inside the shipswith velco shoes that wouldn't work anyways. A nuclear powered ship like the Discovery would have a maximum acceleration of about .1 gee. The difference is that this thrust could be maintained for weeks at a time to built a large amount of speed. a firemans pole would be suffecient to move in that space. Conservation of angular momentum will still aply but the counter rotating flywheel can be smaller and go at a higher to still balance it out.
AE35	Tech info from Fred Ordway	#23	[-]
Posts: 2 (11/17/08 05:33:22) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I ran across this ancient 2001 tech web site here, containing information attributed to Fred Ordway. The footnotes are from the author, not me. Does anyone have access to the original article from the British Planetary Association to verify this? If this is in fact from Ordway, it would explain a lot of the conjectures in this thread, such as the nature of the reaction control system propellant, main engine propellant, controller design (this would seem to confirm that the controllers do indeed rotate about the stem axis, for 6 degrees of control), and the Pod's capability of landing/taking off. Specifications (Detailed to Come Soon) Title: Grumman DC-5 EVA Craft Number Produced: 45 14 for Space Station Five, 11 for Space Station Four 7 for Space Station Three* 5 Replacement vehicles 4 test vehicles 3 for Discovery One 1 Replica 1 for Discovery Prototype**** Mass at Earth Gravity: 1,387 Kg. Overall Diameter: 1.98 m. Capacity: One Person Standard; Three Person Emergency Propulsion systems: Ten Mk 12 (140 Kgs. Thrust) for major course changes along all axes; Eight Mk 17 (35 Kgs. Thrust) for precision maneuvers; Eight Mk 8 micro-thrusters (10 Kgs.) for low-gravity station-keeping; Five Mk 14 (80 Kgs. Thrust) provide roll; One Mk 37 (500 Kgs. Thrust) for use in emergency. Life Support: 12 Hrs. (One Person) Radar: Grumman EPS-2D; Long Range; Active Pulse Other Equipment: Explosive Bolt Door Separation; Short-range Object Approach System and Transponder; Complete HAL 9000 Data link System; Automatic Thruster Control; Auto Hover; Eight-Channel communication system; Advanced Manipulator Control System; Two-hour Oxygen Reserve System. Notes: The Grumman DC-5 carries can carry little in the way of food and water stocks, due to short life support capacity. A single air conditioning vent is provided. Misc. Technical Information: (From Frederick Ordway and the British Interplanetary Association) Propulsion: A subliming solid system provides vernier propulsion, wherein the solid propellent sublimes at a constant pressure and is emitted from a nozzle. Such reaction jets will last for long periods of time, have great reliability and use no mechanical valves. The main propulsion system is powered from by storable liquids. Mechanical Hand Controls: Selection controls are placed on each side so that the appropriate hand must be removed from the manipulator to select a tool or to park. Selection of a tool returns the arm to the 'park' position, where it leaves the 'hand', then the arm goes to the appropriate tool and plugs in. In doing so, it inhibits the 'finger' controls on the manipulator, so that when the operator returns his hand into the glove he can only move a solid object, not individual fingers. Television: It was found possible to produce all-round TV coverage with eight fixed cameras. This, however, did not give a sufficiently accurate picture for docking or selecting a landing space. For this purpose, the field of view can be narrowed or orientated; controls are included for this purpose. Normally, the TV link is occupied by the internal camera, so that the parent craft can monitor the pod interior. The pilot can switch in any other camera for specific purposes (survey, etc.) reverting to interior camera for normal work. Proximity Detector: This is the safety system with omnidirectional coverage working from the main communication aerials. It gives audible warning when the pod approaches a solid object. This is necessary as a safety measure as the pilot cannot monitor seven or eight TV displays continuously. The system also detects an approach to an object, the speed of which is too high to be counteracted by the vernier thrust settings on the control system. In this event, full reverse thrust is applied, overriding the manual control setting. The system depends upon a frequency modulated transmission and under safe conditions results in a low, soft audible background signal. This continuous signal is considered necessary in order to provide a continuous check on a vital safety system. If the speed of an approach to an object becomes dangerous compared with the distance from it, the tone becomes louder and higher pitched, and, if unchecked, end in a shrill note accompanied by reverse thrust. The system also works in conjunction with a transponder (to the give the necessary increased range) to measure distance from the Discovery. Flying Controls: Manual controls are considered necessary both as a standby and for local maneuvers. Two hand control sticks, each with two degrees of freedom and fitted with twist grips, provide the necessary control about six axes. Analog information is presented for attitude, heading rate and distance; these can be referred to local ground (for landing, takeoff, etc.), course (which enables the pilot to face forward, head up, on any preselected course, or parent ship (for docking, local maneuvers, etc.) This data has to be presented, as the pilot has to act immediately on them. This is the most easily assimilated display. A variation in full scale rate, which can be applied by the control sticks, is included; this allows the full stick movements to result in any proportion of vernier motor thrust, thus giving a 'fine' control for local maneuvers. Notes: When I think about it, I don't think the door ever separated from the pod. It seems that it was simply opened extremely quickly by the explosive bolts. If the door actually WAS blown off, it would have smashed into the airlock's outer door; breaking into several pieces. This would fly back towards Dave, and as many people would put it, that would be a very bad thing. This is non-operational, and do not carry any functional systems. The single replica is currently on display at the NASM's "21st Century Space Flight" display. Earlier Space Stations are not capable of supporting the design. *** What's this about a Discovery prototype? You'll find out pretty soon, once I get the "fan designs" page up. Last Edited By: AE35 11/19/08 14:03:53. Edited 1 times.
treddie		#24	[-]
Posts: 57 (11/18/08 11:52:33) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Regarding the first note, explosive bolts do not propel by force. Explsive bolts are also known as frangible bolts, in that their sole purpose is to break in a well-defined way, via a small internal charge inside the hollow core of the bolt. Separation of the two planes then occurs via springs, small solid motors, or anything that gets the two surfaces away from each other in a controlled fashion. The pod door clearly has an inner hatch secured by ebolts in an outer frame (you can see it in many pictures). But in the production shots, it appears that they did not go through the trouble of showing the empty frame; they just opened the door all the way and left it at that. The puff of "smoke" in the scene is probably not smoke from the tiny explosions; it is most likely condensed atmosphere and moisture which had to "get small" by rapidly passing through the confined area of the door hole, then rapidly dissipating as it expanded quickly on the other side. The bits and pieces may not be so much bolt parts, but again, atmosphere and moisture that rapidly turned to ice and then sublimate back to vapor. The door getting in the way is still a big issue. Explosive bolts do not destroy anything except the bolt; they merely break the bolt into two or more parts. So the inner hatch would not get destroyed and it has to go somewhere.

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