[HN Gopher] NASA solved a $100M vibration problem cheaply by str...
       ___________________________________________________________________
        
       NASA solved a $100M vibration problem cheaply by strobing the
       display
        
       Author : dharmaturtle
       Score  : 30 points
       Date   : 2021-08-08 19:35 UTC (3 hours ago)
        
 (HTM) web link (gizmodo.com)
 (TXT) w3m dump (gizmodo.com)
        
       | e_y_ wrote:
       | Designing and testing it would have cost them more than $5, but
       | substantially less than $100M. Nice solution.
        
       | andi999 wrote:
       | What amplitude of oszillations are we talking here?
        
         | dharmaturtle wrote:
         | > vibration amplitude classified into low (< 0.3 g) or high
         | (>0.5 g) (i.e., into 2 levels) were performed to assess the
         | significance of these findings
         | 
         | https://ntrs.nasa.gov/api/citations/20150000242/downloads/20...
         | 
         | I was hoping to find something like "5cm", but it looks like
         | "g" is all they offer.
        
         | cratermoon wrote:
         | http://www.spaceref.com/news/viewnews.html?id=1244
        
       | 71a54xd wrote:
       | This is such an awesome fix! I'm curious as to what portion of
       | the aero / solid rocket motor causes these violent vibrations,
       | specifically in the 10-12Hz range? Maybe I should've just
       | finished my mechanical engineering degree instead of switching to
       | EE / CS haha...
        
         | cratermoon wrote:
         | All of it. Solid rockets have what's called "resonant burning"
         | https://blogs.nasa.gov/Constellation/2009/04/17/post_1239311...
        
       | cratermoon wrote:
       | Ares 1 was a terrible idea. Putting humans on top of solid rocket
       | motors is bad enough when they are boosters alongside a more
       | traditional liquid fueled stage that can smooth out the
       | oscillations, but that still does nothing about the fact that you
       | can shut down solids, and all abort scenarios involve just
       | waiting until the SRBs burn out. Having humans riding a rocket
       | that's just a giant firecracker is insanity.
        
       ___________________________________________________________________
       (page generated 2021-08-08 23:02 UTC)