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What's in the control room? The most important things are the instruments for Flight Path Control, that is, the controls for the rocket engine and for pointing the spacecraft's nose in the proper direction. This will probably take the form of joystick, er, ah, Translational Hand Controllers. In addition, the control panel will include a radarscope, accelerometer, gyroscope platform, periscope, and chronometer. And maybe an integrating accelerograph. This will display elapsed time, velocity, and distance in dead-reckoning for empty space. If the spacecraft is under programmed controls, the programmed values for the three items will be displayed below the actual values, so the pilot can see how results matched prediction. There might be a brennschluss timer. When a burn is initiated, this is pre-set to count-down to burn stop time.
As far as guidance goes, the accelerometers, combined with the gyros, tell you your exact position, velocity, and orientation during a burn. The pilot's job during a burn is to try and keep those values matching the pre-computed values.
  Upper top label: Flywheel Controls. Upper bottom Label: Firing Controls. Lower top label: Television Pickup
from Destination Moon
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Under high acceleration, the pilot might use controls in a lap panel. |
Rocky X of the Rocketeers,Boy Comics #80, 1952
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 Maltron ergonomic keyboard
 Kinesis ergonomic keyboard
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from the introduction to the wargame BATTLEFLEET MARS by Redmond Simonsen "Vesta acquisition." In response to the verbal from the autopilot, Dieter Ulans flipped his datavisor in front of his eyes and prepared to take direct command of the massive ring of lasers and reaction engines that was Hercules. He hit the juicer button and felt the rush as the drugs began to wash into his veins. "Com'monn jockey juice!" he whispered and then began to croon: "All my thoughts of you, you, you -- all that I've sought is you, you, you." The tiny green symbols on the datavisor began to zip past his eyes at an increasing speed. His subconscious easily absorbed and processed the information even as his conscious mind took in the blue numbers and symbols on the main screen that showed the gross situation as Hercules and five other ships of the Martian battlefleet began their final approach to Vesta Main Station. "Joey Kolnichok, I know you're here and I'm going to personally fry your tender little parts." The ship thrummed as the main three o'clock engine cut in and changed vector in response to a movement of Dieter Ulan's right ring finger. It was his former classmate he sought -- Josip V. Kolnichok - the one who had beaten him out his bid for a cushy transport command and who had also cast aspersions on his loyalty to the company. This had cost Ulans two points on his profit sharing plan and that was a deficit he intended to make up by turning J.V. Kolnichok and the DesJardin into a bright, glowing gas. |
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"80-80. Ready track. Ready main. On my mark FC to you and...mark!" A second green line began streaming across the datavisor as Ulans took control of the main laser fire control systems. Every time he blinked, the little green symbols paused. Every time he squinted his eyelids, a bright blue bullseye magically appeared where he looked on the main screen. Just tap your foot when your buddy shows, he thought, and you'll make him a star. He began to click his teeth together. His finger tips sweated in the close-fitting control caps. Only eighteen k-k's from Vesta and still no Company. What had they done -- written the station off? The entire ship reached into his heightened awareness. The awesome engines designed to hurl inert cargo on multi-million-kilometer tracks through space. The heavy mining laser converted into a terrifying main weapon now slung in the cargo grapples. The thousands of bits of information from the ship's computers and sensing radars. Where the hell were they? "Come on, you Company fish, swim out into the pan." |
  Datahand ergonomic keyboard
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Another important item is the control panel lock. When the lock engaged, all the other controls are locked in place. So the pilot can sleep in their chair and not have to worry about accidentally brushing a toggle switch. This also comes in handy if the pilot is forced to allow into the control room a bratty kid who just happens to be the son of the boss. A control of dubious utility is the three-position control switch. It is available if one has duplicate sets of controls for pilot and co-pilot. The control switch is labeled "Pilot & Co-Pilot", "Pilot only" and "Co-Pilot only". It determines which sets of controls are live. One would expect to find this only on a training spacecraft, or if you would commonly expect a non-pilot to be riding in one of the control seats. There may also be repeater indicators. Such as a red indicator light from the power room which will change to green when the power officer unlocks the safety on the reactor damper. |
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 Artwork by Rick Sternbach
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The three types of instrument displays are Analog, Digital, and Binary. Analog are typically circular like a clock with hands, semicircular like a multimeter or some automobile speedometers, or tape-like similar to a ruler. Digital displays numbers, such as an automobile odometer or a pocket calculator. Binary are "idiot lights" that are either on or off. The advantage of analog is in displaying the relationship between the current reading and any "red-line" minimum or maximum. The gas (petrol) gauge on an automobile typically has a red area adjacent to "Empty" as a warning that you'd better fill your tank soon. Analog displays are also good at showing the rate of change. You can tell at a glance if the temperature is rising too quickly. The disadvantage of analog displays is that they can seldom be read with more than three figures of accuracy. |
The advantage of digital displays is that it can be read with as many figures of accuracy as there are digits in the display. Disadvantages include having memorize what the red-line values are, and not being able to read the display if the figures change so rapidly as to be a blur.
The advantage of binary displays is the simplicity of an immediate warning. Disadvantages include the necessity of a test mode (so you can tell if an indicator light has burnt out) and the lack of extra information. Airplane pilots have many worries when they hit the "lower the landing gear" button and the "landing gear down" binary display fails to light up. Is the gear still up, or is gear actually down but the light is burnt out or the sensor wiring connection loose? All you can do is make a low pass by the control tower so they can look at the status of your landing gear. An analog or digital indicator with the angle of gear would avoid that worry.
  Top: Apollo CM control panel
Top: Space Shuttle control panel
images courtesy of NASA
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Heinlein short stories have rockets with a coelostat on the control panel. This is a series of prisms used for navigation. For each burn of the engine, the astrogator will calculate the direction of the axis of acceleration (i.e., where the ship's nose points). Then they will calculate how to set the prisms on the coelostat. When the pilot sets the coelostat, each prism will reflect a "guide star" onto a screen with cross hairs. (say, three prisms using Vega, Antares, and Regulus) When the ship is pointed in the correct direction, all the guide stars will be dead center in the cross hairs. G. Harry Stine calls this instrument an "astrostat". During the burn, the pilot will [a] keep the stars in the astrostat centered, [b] ensure that the burn starts and stops at the proper time according to the chronometer or brennschluss timer, [c] keep the thrust at the pre-calculated rate according to the accelerometer, and [d] keep an eye on the radar to be sure that space is clear. Remember that the spacecraft has to be balanced or it will tumble. Any crewmember who unstraps and upsets the balance by walking around will receive a free trip out the airlock sans spacesuit when the pilot catches up with them. |
 From When Worlds Collide
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From Spacehounds of IPC by E.E. "Doc" Smith (1931) The computer, his calculations complete, watched the pilot with interest, for, accustomed as he was to traversing the depths of space, there was a never-failing thrill to his scientific mind in the delicacy and precision of the work which Breckenridge was doing -- work which could be done only by a man having had long training in the profession and possessed of almost instantaneous nervous reactions and of the highest degree of manual dexterity and control. Under his right and left hands were the double-series potentiometers actuating the variable-speed drives of the flight-angle directors in the hour and declination ranges (ed note: in the "hours" of Right Ascension and the "degrees" of Declination, which is the longitude and lattitude of celestial navigation.); before his eyes was the finely-marked micrometer screen upon which the goniometer threw its needle-point of light; powerful optical systems of prisms and lenses revealed to his sight the director-angles, down to fractional seconds of arc. It was the task of the chief pilot to hold the screened image of the cross hairs of the two directors in such position relative to the ever-moving point of light as to hold the mighty vessel, precisely upon its course, in spite of the complex system of forces acting upon it. |
From MegaTraveller Starship Operator's Manual by Digest Group Publications
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Whoever invented dynamic configs deserves a medal - I'd give him all of mine. Imagine the chaos we'd have without them. A kid joins the Navy on Viand, learns the ropes, and then musters out and joins a merchant company operating out of the Marches. So what happens? The merchant vessel he's on was built by a company light-years away from the yard that fabbed the dreadnought. All the controls are different: the power switch that was under the thumb of his left hand is now under the third finger of his right. The heads-up attitude display is now flat on the board, and the blue light that signaled a problem is an amber one on the merchant. If he doesn't scuttle her first time out of the dock, you're lucky. |
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With a dynamic config, he keys in the layout he likes, and if he wants to further customize the panel, he moves the controls around and logs it in the computer so he can call it up any time he wants. There are moments on the bridge, too many moments, that call for split-second thinking. You set that panel up to your liking - you live with that panel - you marry that panel - and it will always be right there when you need it. Your fingers (and feet, if you use them, but I never do) learn every inch of the board, and you can fly a ship in your sleep. A skilled crewman never looks at the controls - his eyes are on the tell tales and other displays. |
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If a man's skilled with the configs, too, he can handle any board in a crisis. Commo needs help set ting up a line-of-sight during a battle? Fine, if he's not tied up it takes him a second to pull up commo's board at his station. That's why it's so critical that your bridge crew be skilled at several tasks. Personally, when I configure a panel I always ignore the leg controls. I don't stop my crew from using them, because a man knows what he likes or he doesn't know anything. But I was never much of a dancer, either, and I feel like my legs just flail around under the console. |
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I keep the most common controls under my index fingers, but I won't overlap. If there's two things I need to do at once, they've got to lie under different fingers. I'm left handed, so I put anything I need quick under those fingers. I use my thumbs as anchors, mostly. If controls need locked, sure, I'll put in a toggle where I want it, but if the control needs a sensitive touch but still must be held down, l put it under a thumb so the rest of my hand can still swivel around to all the positions. Another good place for anchors is the little fingers. Little fingers are good, too, to set up alternative controls. For example, on my commo board I like my left index to handle fine tuning of radio frequency, but once I've zeroed in on what I want, that spot's wasted. So when I'm ready to transmit the burst, my right pinkie holds what I call my "second set". Then the burst pad is under my left index where fine tuning normally is. Once the burst is through, I let up my pinkie and I can reset the frequency if I want to. (ed note: In other words, the "second set" button is like the shift key on a computer keyboard.) |
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I keep any displays I want in front of me, using heads-up holo. If the station can't handle a holo, I'll use a data-display/recorder headpiece, but I don't like to because I get tired faster. The main displays are right in front all the time. I map telltales to the center in a contrasting color - for the important ones, I use a mixture of red and green, chosen so they clash with each other. I don't like `em to blink, because I want to look at them and catch the info at any time. The split second between blinks might be the split second I need to make the decision. Choose your own colors; your eyes are different from mine. |
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I use my right third finger to move the telltale once I've spotted it, and I never use this finger for any other purpose on any board. The warning light appears, in the center as I said, then once I've noted it I punch the board and the light moves off to one side. They're all set so that if the condition lasts over a certain time, the telltale will reappear, and I'll just punch it over to the side again if I'm handling it. I want to know, but once it's in my brain I don't need to keep staring at the light all the time. |
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Burn start and stop might be under autopilot control. But the pilot will still keep their hand hovering over the manual start key (or cut-off switch), as they never quite trust the auto-pilot. The co-pilot and the power officer will also have their hands hovering over their manual keys, since they never quite trust the auto-pilot nor the pilot.
Acceleration depend upon the ship's mass. However, the ship's mass will be decreasing during the burn (as propellant is expended) so the acceleration will go up. The amount of thrust will have to be reduced in proportion in order to keep the acceleration constant. There will be some sort of control that will do this automatically.
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How do you keep the ship from spinning, tumbling, or otherwise stationary? Equip the ship with a massive stabilizing gyroscope. If you cannot construct or otherwise use a single massive gyroscope, you can use a series of smaller ones. The International Space Station can limp along with only two, but three is preferred, and the fourth is a back up. The technical term is "control moment gyroscope." You mount each inside a spherical framework which rotates inside a slightly larger spherical framework. This larger framework is anchored to the ship's structure. The ISS gyros spin at about 6,600 revolutions per minute and take eight hours to rev up to full speed.
Once you spin up a given gyro, the inner framework will stay in one orientation. If the gyro frame is "unclutched", the inner frame can freely rotate (actually it stays stable while the ship rotates around it). When you "clutch" the gyros, the inner frame is clamped onto the outer frame, and the gyro cage will do its best to keep the ship from changing orientation. Aerospace Engineer Bill Kuelbs Jr corrected an error on an earlier version of this page. I mistakenly stated that the control moment gyroscopes had to be mounted at the center of gravity of the ship. Mr. Kuelbs pointed out that due to a force known as a 'moment couple' the the translative forces are balanced out (i.e., you can mount the gyros anywhere inside the ship and they will work). Some spacecraft designers will try to economize by specifying gyros that are too light for the spacecraft's moment of inertia (i.e., the rotational analogue to mass ). Such ships will tend to wobble under acceleration. This will also happen if a gyro's bearings start to go bad. |
First image from the
Aerospace Corporation.
Second image courtesy of NASA.
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Since gyros heavy enough to stabilize the entire spacecraft are rather massive, a more elegant solution is to use tiny gyros to detect changes in the spacecraft's orientation and connect this to an attitude control system to automatically counteract it. In the old Heinlein novels ships had gyros massive enough to keep a landed ship from tipping over, but this might not be realistic.
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How does the pilot aim the ship? The Apollo spacecraft used attitude jets. A more elegant way is with a large precessing flywheel on a gimbal (these are also called reaction wheels or momentum wheels) Aim the axis of the flywheel so it is parallel to the desired axis of rotation, start spinning it, and the spacecraft will start to yaw, pitch, or roll in the opposite direction. Keep an eye on the astrostat to see when the stars overlap, telling you that the ship is pointed in the correct direction. Stop the flywheel and so will the ship. Be sure to unclutch the gyros first. Trying to use the precessing flywheel while the gyros are clutched is like trying to drive a car with the emergency brake on. |
 image courtesy of NASA
 Artwork by Don Davis
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Hop David has an exceedingly clever arrangement of attitude jets on his Tetrahedral spaceship concept. This takes the "jet on a long lever arm" arrangement of Babylon-5 Starfuries to the logical ultimate.
 Artwork by Ed Emshwiller for Original Science Fiction Stories September 1957.
Mike White points out that as a model for the boy Mr. Emshwiller
used a young neighbor
named Bill Griffith,
who now draws the cartoon Zippy The Pinhead. Bill's father was the
model for the general on the view screen.
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Since the spacecraft has far more mass that the flywheel, the ship will rotate far more slowly than the flywheel does. So if you want the ship to rotate faster than the hour hand on an analog watch the flywheel will have to spin like a x100 CD-ROM drive. It might be prudent to put an armored cage around the flywheel, in case of "explosive delamination". This will ensure that the deadly shrapnel from the delaminating flywheel will shred the armored cage instead of shredding the unlucky crewmembers who happened to be in the plane of the flywheel. Unfortunatly the mass of the armor cuts into payload mass. Also note that for certain types of inertial reference platforms, one cannot rotate the ship through certain directions or you will send the platform into gimbal lock and tumble it. A flywheel is too slow to be used during a burn. For that one will use gyros, either massive ones to prevent tumbling by brute force or a tiny ones connected to gimbaled nozzles on the propulsion system. |
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For complicated maneuvers, one programs the controls with an autopilot. Nowadays one uses computers. In pre-computer days, they "cut a cam". A cam operates in a similar fashion to the paper roll on a player piano. When I was little they were all the rage in motorized toys, to program various movement patterns. But those have gone the way of eight track tapes and slide rules. Currently the only place one is likely to encounter a cam in on the camshaft in the engine of your automobile. Each cam is a "program" that controls the state of the intake and exhaust valves, synchronizing them to the position of the pistons. |
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 Two-dimensional cam
 Three-dimensional cam
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From Rocket Ship Galileo by Robert Heinlein, 1947 Cargraves yelled, "Hang on to your hats, boys! Here we go! He turned full control over to Joe the Robot pilot. That mindless, mechanical-and-electronic worthy figuratively shook his non-existent head and decided he did not like the course. The image of the moon swung "down" and toward the bow, in terms of the ordinary directions in the ship, until the rocket was headed in a direction nearly forty degrees further east than was the image of the moon. Having turned the ship to head for the point where the moon would be when the Galileo met it, rather than headed for where it now was, Joe turned his attention to the jet. The cadmium plates were withdrawn a little farther; the rocket really bit in and began to dig. Ross found that there was indeed a whole family on his chest. Breathing was hard work and his eyes seemed foggy. If Joe had had feelings he need have felt no pride in what he had just done, for his decisions had all been made for him before the ship left the ground. Morrie had selected, with Cargraves' approval, one of several three-dimensional cams and had installed it in Joe's innards. The cam "told" Joe what sort of a course to follow to the moon, what course to head first, how fast to gun the rocket and how long to keep it up. Joe could not see the moon -- Joe had never heard of the moon -- but his electronic senses could perceive how the ship was headed in relation to the steady, unswerving spin of the gyros and then head the ship in the direction called for by the cam in his tummy. |
The cam itself had been designed by a remote cousin of Joe's, the great "Eniac" computer at the University of Pennsylvania. By means of the small astrogation computer in the ship either Morrie or Cargraves could work out any necessary problem and control the Galileo by hand, but Joe, with the aid of his cousin, could do the same thing better, faster, more accurately and with unsleeping care -- provided the human pilot knew what to ask of him and how to ask it.
Joe had not been invented by Cargraves; thousands of scientists, engineers, and mathematicians had contributed to his existence. His grandfathers had guided the Nazi V-2 rockets in the horror-haunted last days of World War II. His fathers had been developed for the deadly, ocean-spanning guided missiles of the UN world police force. His brothers and sisters were found in every rocket ship, private and commercial, passenger-carrying or unmanned, that cleft the skies of earth.
Trans-Atlantic hop or trip to the moon, it was all one to Joe. He did what his cam told him to do. He did not care, he did not even know.
Last but not least is the pilot's logbook in the corner. Or log tape. Or DVD. Or holographic crystal. Or whatever.
