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SpaceX

Discussion in 'General' started by flyboy, Dec 21, 2015.

  1. Knotcher

    Knotcher Well-Known Member

    Is it a suppository?
     
  2. Only time will tell if I should cram it up my ass or if this gets us to stop hitching rides up to the ISS with Russia.
     
  3. mpusch

    mpusch Well-Known Member

    That's pretty amazing. Guessing that's for DM-1 then?

    Hurry up and get that thing done already :D
     
  4. I worked on about 80% of DM-1 and then I moved to DM-2. For the people who don't know the difference, DM-2 is the actual capsule that will hold astronauts. DM-1 will only be proof of concept.
     
  5. Banditracer

    Banditracer Dogs - because people suck

    That's me, glad you explained it. I've been following along but you nerds lose me. :crackup:
     
  6. :crackup:

    If you guys have any questions I can try and answer them to the best of my ability within reason. I’m no rocket scientist though.
     
  7. Sweatypants

    Sweatypants I am so smart! S-M-R-T... I mean S-M-A-R-T!

    why does air feel colder as you move faster thru it... say on a motorbike or airplane (ie. windchill), but then something re-entering the atmosphere generates intense heat due to friction and needs heat shields so that the astronauts don't die?

    i assume its because of the speed differential, but then that leads me to believe that there's some crossover point where things stop getting "colder feeling" and start getting "hotter feeling." what is the calculation or breaking point where surface temps of an object start getting hotter instead of colder as their move thru air?
     
  8. Hyperdyne

    Hyperdyne Indy United SBK

    Humidity maybe?
     
  9. peakpowersports

    peakpowersports Well-Known Member

    It heats up because it is going from no atmosphere and no resistance into an atmosphere filled with particles, gasses, elements ect creating friction.
     
  10. It's about speed and friction. You break the sound barrier a few of times over when you're re-entering and it goes from zero friction/atmosphere to denser and denser air. So you're falling and it just blasts this wall of air that the vehicle needs to burn through. That's pretty much it. It IS colder up there but speed and friction coefficient over come temperature.

    There's a crossover point somewhere below the karman line ~100km from earth's surface where you start aerodynamic heating.
     
  11. I should get off the beeb. My son was just born 2 hours ago. :crackup:
     
  12. Boman Forklift

    Boman Forklift Well-Known Member

    Congratulations, man. Very happy for you guys, and happy you got a good job and made it back here.
     
    R Acree likes this.
  13. Sweatypants

    Sweatypants I am so smart! S-M-R-T... I mean S-M-A-R-T!


    But at what speed would it still feel cold up there? Or neutral? Or hot?

    Hahaha congrats buddy i'm calling you.
     
  14. peakpowersports

    peakpowersports Well-Known Member

    I think up there it does not matter. With no atmosphere to create friction you won't feel anything no matter what speed. No wind no wind chill, no atmosphere no friction.
     
  15. OGs750

    OGs750 Well-Known Member

    It's because you're experiencing evaporative/convection cooling when you're on a bike or sticking your hand out the window of an airplane. The air is either evaporating the sweat off your body or the ambient air is pulling temperature away from you. Either way the wind is pulling heat away from your body at a faster rate then it's creating heat due to friction.

    You can probably calculate the crossover point, but you would need to know a few things about the liquid that's evaporating off the surface.
     
    badmoon692008 and Sweatypants like this.
  16. OGs750

    OGs750 Well-Known Member

    Congrats Alex!
     
  17. Mongo

    Mongo Administrator

    Speed. Not sure what the turning point is.
     
  18. Sweatypants

    Sweatypants I am so smart! S-M-R-T... I mean S-M-A-R-T!

    yea i mean... i'm sure the material, altitude, ambient air temp, humidity, density, speed, coefficient of drag on the object, height from ground level... all play into it, and change depending on the type of object or all those other factors. i was just curious if there was a relative ballpark or somebody knew the equation.

    like... we know an SR-71 heats up so much that it needed different materials for being at speed. but i wanted to get an idea of when friction took over compared to the wind + air temp. i always wondered about that.

    i figured he could just walk over and ask a nerd in a lab coat haha
     
  19. rd49

    rd49 Well-Known Member

    Obviously you did not go to a prominent university. :D
     
  20. Mongo

    Mongo Administrator

    You have to keep in mind windchill is a made up thing for humans too - there is no physical drop in temperature due to movement at lower speeds. So there's really just the turning point when you get fast enough for friction to overcome the ambient temp.
     

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