Mark reads a statement by an industrial valve expert regarding the international space station. Johnathan and Sean join the discussion.
Think about the fuel pumps, the air exchange, and the seal replacement programs. Valves are maintained and changed out frequently. Now consider the
ISS in this light. One little
pumps change out in
2010 and a little repair in
2013?
Does NASA have valves that
function in impossible environments and seals made of un-obtainium and unicorn tears? I am guessing…
no.
Actuators (air cylinders)-
Actuators (or air cylinders) are the muscles of moving machinery.
Pumps are the hearts of machinery that pump fluids and gases to drive the machines. Valves control the pressures and quantities of the fluids and gases. Actuators push and pull to give the machines
movement. They have been used for decades to drive the industrial revolution forward. They are the muscles of robots that move their limbs. They hold the hood open on your car so you can check the oil. They open and close the hatches on submarines. They drive needles that weave carpets. They are all around us in every mechanical system. Some are driven with pneumatic air pressure, some use hydraulic fluids and some are electrical.
Let us look at the
types.
Pneumatic (air driven) – On the ISS how would these work? The seal issue is certainly a big problem. Actuators need valves. We covered these problems already.
Piston rods rely on dynamic seals and are prone to leakage.
Temperature is an issue.
Ice cream makers and metal forges struggle with actuators due to the extreme temperatures that they deal with, but consider that they only deal with their end of the temperature range. Ice cream makers
deal only with extreme cold.
Metal forges deal with only extreme heat. What kind of
Vulcan technology is NASA using to handle both temperature extremes, let alone in a vacuum?
Hydraulic (fluid driven) – The same problems as Pneumatic s apply here as well. In addition,
Hydraulic actuators drip and “weep” oil. The ISS would become uninhabitable without constant maintenance. Where would the fluid be stored, disposed of, replaced, etc.
Electronic - This is probably the most probable type NASA would claim that they use.
They are clean and function without the exchange of pressurized substances. What about maintenance, Lubrication, degaussing, replacing motors, drives, belts, circuits, panels?
Certainly they would be prone to shorting out and requiring constant care, especially since they cannot be grounded (consider satellites, but that’s another topic).
Changing out components is not like changing the brush heads on a vacuum cleaner.
Maintenance and installation –
Lastly and probably the most important problem, no machine shop.
All dynamic systems require installation and maintenance. No matter how carefully designed and how advanced a system is, something will require machining. All large
Navy craft have
onboard machine shops. The reason that I use ships and subs as examples is that they are the most similar systems to the ISS that we can relate. They are moving, large, self contained and functioning in hostile environments. Navy vessels must be able to repair, modify or replace anything onboard. Even under the best conditions, metal will warp, screw threads will strip out, seals will leak, welds will break, metal sealing surfaces will get
scratched, tubes will crack, electronics will short out, motors will overheat, motors will freeze up, critical tools will break, belts will break, cables will snap, etc., etc, etc, ad infinitum. The ISS appears to not have a machine shop what so ever. How are repairs done?
Are we to believe that all the replacement parts are flawless modules that snap together perfectly every time like Legos? Are there sea containers full of replacements parts floating
next door? Is there never a time that a critical threaded
hole is stripped out and needs to be re-tapped? Do parts never warp in the extreme temperatures and need to be re-surfaced? Is
there welding equipment up there?
Submarines have welding equipment. They can even weld underwater. What happens in the event of a structural event that requires welding? I know that
Captain Kirk and
Spock repaired the
Enterprise using a
Phazer as a welder, but this is supposed to be real. Of course, the chance of fire is too great to weld, but structural damage happens and has to be calculated into the plan. As far as I know, it is not. Regarding
fire hazards, machine shops throw sparks, lots of sparks. Even if you could haul a lathe,
Bridgeport and drill press up to the ISS the danger would be too extreme. This is where NASA “shot themselves in the foot”. For short missions (days, even weeks) this would not be an issue, but when missions are years long….uh no.
The ISS is great theater but not reality.
- published: 14 Oct 2015
- views: 16148