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Why Does the International Space Station Have That Shape?
- rgawdzik 12y agoI'm sure if the budget was there, NASA would worry about aesthetics.
- Ezhik 12y agoWouldn't it be great if NASA got a budget so big they could actually start worrying about aesthetics, though?
- hueving 12y agoNo, that would mean they were allocated too much money. Too much money in a government agency is immediately consumed by bureaucracy and waste. NASA isn't paid to make pretty crap, they get paid to do really awesome research and push the boundaries of engineering and our knowledge of science.
- Ezhik 12y agoHmm, that is a very good point. Still, I look forward to the day when our ability to explore space gets far enough for focusing on aesthetics and making pretty crap to not be something unreasonable.
- ars 12y agoThat's how to tell if a technology is complete. When computers started they were beige boxes, now they are decorated and colorful - so we know they are done. People worry about how phones look, so those are done. The first smart watches were functional, now they worry more about aesthetics, but none are actually on the market. So that technology is not done, but is getting close. Cars have been all about aesthetics for decades now. Etc, etc. (Don't assume "complete" means they don't improve them, it just means any further changes are minor, and mostly unimportant.) Airplanes for example seem like they are done - but they are not sold on looks, so they are not actually done. (Maybe a little bit on the inside?)
- mrottenkolber 12y agoDisagree strongly. Computers are way uglier now than they were in the 90s (beige boxes). There is an arc in every art. It starts with the bare bone essentials, exposing the spirit and greatness. Then it becomes popular and amasses cruft until its unbearably overloaded and ugly. Then it gets stripped back to its original form, regaining its glory. And then we repeat.
- theandrewbailey 12y agoAgreed. I started noticing 5 years ago that laptops started getting really... I don't know, tacky? Not to mention the dozens of stickers that no one thinks to peel off. Also, anything marketed towards gamers tends to look like it has enough pieces and glow so much that it might be mistaken for a nuclear reactor.
- comex 12y agoDepends on the manufacturer, of course. Apple's laptop visual design over the last decade or so has been basically conservative, but you can really see the improvement from the original MacBook Pro from 2006: http://upload.wikimedia.org/wikipedia/commons/2/24/MacBook_Pro_situated_on_a_wooden_table.jpg http://upload.wikimedia.org/wikipedia/commons/2/24/MacBook_P... to the unibody one in 2008: http://upload.wikimedia.org/wikipedia/commons/2/2e/Unibody_MacBook_Pro.jpg http://upload.wikimedia.org/wikipedia/commons/2/2e/Unibody_M... Today's MacBook Pros look quite similar to that one (aside from being much thinner), but the light has been dropped, the power button has moved to the keyboard, and the "MacBook Pro" branding below the screen has been removed, resulting in a slightly cleaner look. The new MacBook is a more dramatic change: it will bring the branding back, offer three metal colors, and cram the keyboard into the body in a way that looks slightly awkward to me, but has the obvious advantage of minimizing the physical size of the device. Time will tell how well its design holds up. http://images.apple.com/v/macbook/b/overview/images/overview_keyboard_on_medium_2x.jpg http://images.apple.com/v/macbook/b/overview/images/overview... (No stickers, of course!)
- rthomas6 12y ago
- na85 12y agoI'm sure the shape is only weird to those who haven't pondered the economics of designing something to withstand the near-vacuum of low earth orbit.
- darklajid 12y agoWhich, incidentally, is probably the majority of the people, ~everyone~. Explaining the question quite well in my opinion?
- Ezhik 12y agoI don't know, I like the shape. It's actually kinda symmetrical, so it's great!
- Klathmon 12y agoThere was a portion of time where there were 2 solar arrays on one side, and one on the other. That was annoying...
- IvyMike 12y agoI always kinda wonder how much wiggle it has. I mean, like, if you bounce off a wall, how much does the thing vibrate?
- nialo 12y agoThis is actually a straightforward question to answer, I think: By conservation of momentum, the center of gravity of the entire ISS + astronaut system needs to stay on the same path before and after your wall bounce. So, the momentum change for the ISS is equal in magnitude but opposite in direction to the momentum change for the astronaut, and the velocity change will be the velocity change for the astronaut times astronaut mass/ISS mass Getting actual numbers to plug in left as an exercise for the reader.
- Thrymr 12y agoThat doesn't tell you whether you will start the station oscillating in some mode of vibration. For that you'd need a model of the stiffness and structure of the station.
- outworlder 12y agoI thought wobbly stations were a Kerbal problem.
- TeMPOraL 12y agoNot really. In fact, Kerbals can just bruteforce the problem with boatloads of struts. But then again, we don't get to meet the Space Kraken.
- sitharus 12y agoVibrations are a constant worry for the ISS. The structure is pretty stiff - each module is connected with a series of bolts (20 I think) and very stiff steel rings. One of the long term fatigue problems they have to worry about is the impact of space ship docking - the existing APAS-95 docking ports require a significant force to initiate mating which causes the whole structure to flex, especially the truss as it's perpendicular to most docking ports. NASA are planning to solve this with the low impact docking system (LIDS), but that's not going to be deployed until the Orion capsule flies, or perhaps the SpaceX crewed Dragon. Day-to-day all the exercise stations are mounted on special vibration reducing mounts, even the treadmill. Back in the Space Shuttle days there would be blackout periods for exercise to reduce the vibrations transmitted through the docking port to the shuttle. Space is a harsh mistress.
- tajen 12y agoI'm wondering about rotation and trajectory. Do they have engines on the craft to maintain its trajectory? But then if they thrust from one module, given all modules aren't aligned with each other, that implies thurst creates a rotation of the craft, so do they have two engines for each dimension? Same question for solar panels: Do they let them rotate so at odd times they're exactly flat in the plane of the sun and receiving 0% energy, or do they rotate other modules of the spacecraft so that the solar panels are always at the sun?
- coob 12y ago100kg flywheels help hold attitude. The Zvevzda module[1] has engines, used rarely. When Progress supply ships are docked, their engines are used for adjustment. [1] http://en.wikipedia.org/wiki/Zvezda_(ISS_module) http://en.wikipedia.org/wiki/Zvezda_(ISS_module)
- Already__Taken 12y agoI know NASa had a competition running for the public to see if anyone could find a more optimum way of rotating the solar arrays on the station to improve power. They detailed some crazy restrictions like how the panels have to be heated evenly so the thermal expansion does not rip them apart. ahh heres a link: http://www.topcoder.com/iss/challenge-details/ http://www.topcoder.com/iss/challenge-details/
- cesarb 12y ago> Same question for solar panels: Do they let them rotate so at odd times they're exactly flat in the plane of the sun and receiving 0% energy, or do they rotate other modules of the spacecraft so that the solar panels are always at the sun? I think I didn't quite get this question. The solar panels have two rotary joints; the alpha joint (https://en.wikipedia.org/wiki/Integrated_Truss_Structure#Solar_alpha_rotary_joint https://en.wikipedia.org/wiki/Integrated_Truss_Structure#Sol...) and the beta joint (related to the beta angle, see https://en.wikipedia.org/wiki/Beta_angle https://en.wikipedia.org/wiki/Beta_angle). With both joints operating together, I think there's no angle where the solar panels can't be pointed directly at the sun. They only get out of the sun when it's behind the Earth, or if they have to move the panels out of the way to avoid pluming from a docking or leaving spacecraft.
- mrottenkolber 12y agoWho called it ugly? I think its looking awesome.
- jkot 12y agoOther issue is de-orbiting and module replacement. Monolitic station would be very dangerous and maintenance nightmare.
- datsun 12y agoInteresting article. It's amazing how humans manage to engineer and build such complex systems.
- gregschlom 12y agoThe video at the end of the article is absolutely fascinating. Also, it's the first time I hear that rejecting heat is a big deal in space. If anything, I would have assumed that heating the station would have been a problem, rather than keeping it cold.
- matt4077 12y agoSame exposure to the sun, but no air convection.
- wmil 12y agoMost people assume that, and most sci-fi reinforces that opinion. But a generic Thermos is a vacuum flask. Space is an incredible insulator. The only way to cool things is to radiate heat.
- fsniper 12y agoThank you. TIL, actually not learned realized, space is actually a good insulator out of earth conditions too. Prejudices. We can never know what if something we thing is a reality or prejudice. Science and skepticism is that important.
- darkmighty 12y agoAlso of note is that while a vacuum doesn't necessarily have a temperature (it's just a medium), space does. Even if you go far away from anything else, you will still reach thermal equilibrium at the Cosmic microwave background (CMB) temperature, which is 2.7K -- it's essentially the "temperature of the universe", radiation which has been emitted as far back as the first moments of the universe. And of course, if you create a vacuum chamber on Earth, any object inside will always reach equilibrium at ambient temperature (in the lack of any heat engines on the body -- even then the fuel would deplete some time).
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- personjerry 12y agoI found it surprising how much of this I knew from my hours spent playing Kerbal Space Program!
- Already__Taken 12y agoA little bit of me would like to see that animation at the end with RTS like stats changing with regards to resource capacity,use and the cost going up. I see they added a solar array whilst for a period closing the one on top of the station. I wonder if they had to make do for a period or the new array was much improved it didn't matter much.
- aidos 12y agoAre solar array almost like a film? I thought they sort of folded but in the animation they look like they can almost roll them up (I know it's just an animation, but it left me wondering).
- adventured 12y agoHere's a great look at one set, that was damaged: http://upload.wikimedia.org/wikipedia/commons/2/25/STS120SolarPanel.jpg http://upload.wikimedia.org/wikipedia/commons/2/25/STS120Sol...
- sitharus 12y agoThey are rigid solar panels mounted on Kapton tape. There's a fan-fold mechanism to store them for transport - exactly like old tractor-feed printer paper. They can fold them back up, and they are an in-space replaceable component but there's no reason to ever do that. It was done once to move the P6 truss from a temporary position on top of the station to the end of the wing, but this resulted in (repairable) damage to the solar array. https://www.youtube.com/watch?v=-bTcodL0awg https://www.youtube.com/watch?v=-bTcodL0awg is a good view of the retraction.
- notahacker 12y agoI was hoping to see the famous story of path dependency that traces the dimensions of shuttles back through the history of rail gauges back to Roman chariots and the width of two horses http://www.astrodigital.org/space/stshorse.html http://www.astrodigital.org/space/stshorse.html
- bradleyland 12y agoFamous, but full of "fudged" facts that make that version of the story more interesting. Snopes has a full drill down. http://www.snopes.com/history/american/gauge.asp http://www.snopes.com/history/american/gauge.asp
- flinty 12y agoI was hoping to see the snopes link as a rebuttal.
- deleted 12y ago[deleted]
- BaconJuice 12y agoI'm not following the rejection of heat, can someone explain that to me? I thought it was cold out there and heat had to be generated?
- minikites 12y agoTemperature is more like "undefined" in a vacuum, since heat is the motion of matter and there isn't matter in a vacuum. Vacuum is a good insulator, which is why a Thermos is an effective storage vessel.
- smeyer 12y agoI don't think it's really fair to say there's no way to define a temperature in a vacuum. With radiation, it seems fair to call the temperature that to which a black body would be heated if placed in the vacuum.
- arielby 12y agoOuter space is very, very far from thermal equilibrium. The temperature of the interplanetary plasma is different from the temperature of the redshifted-big-bang-light (CMB) which is different from the temperature of sunlight. The temperature of a black body depends on how much of it is exposed to sunlight vs. CMB.
- smeyer 12y agoI'm well aware, but I was just talking about the easiest case (deep intergalactic space with the CMB and minimal other exposure to radiation). There's a lot more complication than that, as you indicated, but I still don't think it's fair to call it undefined due to the lack of matter (I'd grant calling it undefined in some areas due to the complication of the different sources of radiation and of the matter, but that's another story).
- murbard2 12y agoHeat conduction is very poor; you're practically in a vacuum, so you can only lose heat by radiating it. On earth, you can dump your heat into the atmosphere or the oceans, which are both gigantic heat sinks. The entire surface of the earth then radiates that heat out to space. In space, you only have your own surface to radiate the heat out.
- rwmj 12y agoCan someone explain what "pluming" means?
- danepowell 12y agoI'm guessing it refers to the problem when docking the shuttle or other spacecraft of making sure that thruster exhaust is never directed towards the station itself. I remember seeing a video that showed the shuttle approaching the station on a nautilus-shell sort of trajectory, so that thruster fire was always directed out and away from the station. Apart from the obvious danger of impact from ice and other debris from thrusters, unburnt hydrazine is nasty stuff- you don't want to deposit any on the station, only to have an astronaut on EVA scrape some off by accident and bring it back inside.
- termain 12y agoExhaust plume impingement.
- junto 12y agoLooking forward to the day when you can just deploy an army of mini robots that 3d print their way along building the hull as they go.
- neohaven 12y agoYou'd need to bring the metal up before anyway, in that case. It doesn't really solve the major problem. It would be easier to build them on earth still.
- junto 12y agoRecycled space junk! :)
- outworlder 12y agoOh, but it does. Parts and components usually aren't very space-efficient, specially when shipped together with other parts. Look at any toolbox, there is a lot of wasted empty space. Instead, you'd ship a lump of whatever material is required by your printer, and manufacture whatever is needed, on demand. It's more compact and more versatile, what's not to like? Weight is at a premium when you are talking about payloads, but so is space.
- Symmetry 12y agoYou could also, in theory, use the non-fuel part of the rocket stage that brought you up for building material. Some people have actually proposed using empty fuel tanks for living space but this would be better.
- mu_killnine 12y agoThe author makes a point about cooling the station through the use of radiators. How do radiators work in the vacuum of space?
- danepowell 12y agoThermal radiation is an order of magnitude less efficient than other forms of heat transfer, but it gets the job done. It helps that you're radiating to the dead of space, which is near absolute zero (efficiency is dependent on the black-body temperature of what you're radiating "to"). That's the why the radiators have to be so huge, and are kept out of direct sunlight.
- deleted 12y ago[deleted]
- ORioN63 12y agohttp://en.wikipedia.org/wiki/Heat_transfer#Radiation http://en.wikipedia.org/wiki/Heat_transfer#Radiation
- jccooper 12y agoThe sky is cold, the Earth is warm, and the Sun is hot. If you have heat you want to get rid of (and in a spacecraft you usually do, since vacuum is a great insulator), you put it into a panel with good heat radiation characteristics and point it at the sky, and arrange shades so it can't see the Earth and (especially) the Sun. The panel then being hotter than the sky, it sheds heat off into the universe, cooling itself, and the spacecraft. This is why you will usually see solar panels and radiator panels perpendicular to each other. The solar panels want to see the sun, the radiators don't.
- golergka 12y agoAs with many other questions regarding space exploration, it seems almost intuitive and obvious after playing KSP.
- TeMPOraL 12y agoExactly. Few dozen hours spent in that game will teach you more about space than... pretty much anything.
- scarygliders 12y agoFirst thing that popped into my head was "This might be an article about why we don't have a Rotating Wheel space station" (mostly cost and ability to transport the necessary parts into orbit, and some other technical details). The article itself explains the layout of the ISS nicely though. I'd still like to see the construction of a rotating wheel station some day ;)
- zkhalique 12y agoI always wondered why real-life space stations don't seem to have the sleek exteriors, pleasing or even consistent patterns, but seem to have a bunch of irregularities, and ugly-looking metal structures of different shades of beige protruding from the hull. How do you explain that?
- pchristensen 12y agoOff the top of my head: - no aerodynamic concerns - extreme weight concerns for launch - each component is a one-off custom module - it's a life support and research vessel - a smooth cover would make it harder to work on components during space walks
- jccooper 12y agoThe reason to have sleek exteriors or to look cool is because you need be aerodynamic (because you're in the air) or need to look cool (because you're in a movie, or you're a consumer good). Being neither in much air nor in a movie nor a consumer good, real spacecraft don't bother with expensive, constrictive, and (more importantly) heavy exterior shells. Instead, form follows function.
- zkhalique 12y agoI always wondered why real-life space stations don't seem to have the sleek exteriors, pleasing or even consistent patterns, but seem to have a bunch of irregularities, and ugly-looking metal structures of different shades of beige protruding from the hull. How do you explain that?
- peter303 12y agoDitto for the Mirs and Tiangongs. They only had 2 to 6 sausages. The ISS is more of a Swiss army knife.
- jccooper 12y agoOne factor in the shape of the station that's not commonly known is actually aerodynamics. The ISS is in a rather low orbit (mostly to make getting there easier) so aerodynamic drag is a noticeable (if small) force. The station is thus laid out kind of "flat" to present a reasonably compact frontal area. (This also helps with orbital debris encounters.) The solar array positioning does commonly conflict with the aerodynamics, but minimizing that is one of the factors in their positioning software. The fore/aft view is not very popular, because it doesn't look as impressive, but here's one: http://www.extremetech.com/wp-content/uploads/2011/06/ISS_Backdropped_by_Space_and_Earth.jpg http://www.extremetech.com/wp-content/uploads/2011/06/ISS_Ba... That's the orientation the ISS travels in--i.e., what "stationary" air sees as it zooms past.
- sitharus 12y agoIt's also the reason for Night Glider Mode: https://en.wikipedia.org/wiki/Night_Glider_mode https://en.wikipedia.org/wiki/Night_Glider_mode Laying the panels 'flat' with regards to the orbit saves significant amounts of fuel. There's also a mode where they do the same during the day if there's a critical shortage of fuel.
- smackfu 12y agoIt's remarkably close the Space Station Freedom design from 1987, nearly 30 years ago. http://www.astronautix.com/craft/spaeedom.htm http://www.astronautix.com/craft/spaeedom.htm
- rbanffy 12y agoThis is not surprising. ISS and Freedom are closely related and subject to the same engineering constraints.