394 RWA IV Data Study Conclusions  

Executive- Level  RWA IV Study Conclusions :  Based on these overall  assessments, summary conclusions for state- of-the-art RWA IV values are (note  that, although not rigorously quantified, the values given are intended to represent ~ 2-sigma variation) :  • Test-to-test amplitude is generally within ~±35% of  the average dataset value for a specific  RWA.   • There is no evidence of large ( e.g., ~3-sigma) RWA -to-RWA m echanical noise/jitter variations  if all are   otherw ise flight -acceptabl e/spec -complia nt, no out-of-family /trending/anomalous  RWA  quality  issue s.  • IV LO S jitter analytical r esult variation for ambient -test-to-nominal -orbit-condition transiti ons is  approximately ±25% for  average RMS values and ± 50% for  peak RMS values.   • IV LOS j itter analytical res ult variation factor  for ambient -test-to-worst -orbit-condition- transitions is  approximately ±50% for av erage RMS values and ± 100% for  peak RMS values.  

Specific RWA IV Study Insights/Conclusions :  Based on the foreg oing evaluations and detailed investigations , the following detailed conclusions result:   • Qualitat ive analysis  and review of I V datasets substantiate their validity and confirmed in this study  effort basic  tenets  of RWA bearing- rotor construction, imperfections, a nd first -order physics.   • IV testing dataset variations, including both test -to-test and environment al-exposure variations, for key   (linked)  2.8 and 5.2 axial -direction harmonics show 1- sigma variances of approximately ± 0.6 and ±0.3  µinch ( ±0.015 and ± 0.007 µm) equivalent geometry error respectively:  equating to  ~±35% variance on   the all-RWA average value(s) . [Ref.  Ap. A tabular  data]   • IV testing data set variations, including both test -to-test and environment al-exposure variations, for key  (linked)  1.0 and 2.0 radial -direction harmonics show 1- sigma variances of approximately ± 2.0 and ± 0.4  µinch ( ±0.50 and ±0.10 µm) equivalent geometry error respectively:  equating to ~ ±35% variance on  the all -RWA average value(s) . [Ref.  Ap. A tabular  data]   • Total combined (via RSS summing)  expected variations due to transition from ground to nominal and  extreme orbital environment conditions in axial and radial direction 1.0 harmonics have the largest test  data basis; accounting for variations of roughly ± 1.5 and ± 3.0 µinch ( ±0.04 and ±0.08 µm) equivalent  geometry error respectively:  equating to ~ ±20% and  ~±40% variance on the all -RWA average value( s).  [Ref.  Ap. A tabular data]   • Total combined (via RSS summing)  expected variations due to transition from ground to nominal and  extreme orbital e nvironment conditions in other -direction higher key harmonics are not well  known/characterized and speculative, but are estimated to account for variations of roughly ±0.8 and  ±1.5 µinch (±0.02 and ± 0.04 µm) equival ent geometry error respectively: equating to ~ ±25% and  ~±50% variance on the all -RWA average value(s) . [Ref. Ap. A tables ]  • HST RWA LOS jitter analyt ical results variability estimate  for ambient -to-nominal -orbit-condition  transitions correspond to 0.74 to 1.16 milli -arcsecond average RMS val ues and 4.54 to 10.22 milli - arcsecond for peak RMS values for the overall noisiest -worst -case  RWA  dataset  (1005).   • HST RWA LOS jitter analyt ical results variability estimate  for ambient -to-extreme- limit-orbit-condition  transitions correspond to 0.62 to 1.40 milli -arcsecond average RMS val ues and 3.41 to 13.63 milli - arcsecond for peak RMS values for the overall noisiest -worst -case  RWA  dataset  (1005).   • Additional RWA harmonics should be evaluated in overall jitter analyses, depending upon general system fidelity required and engineering judgment on a potential for high frequency disturbances to  affect optical tra in elements . [Ref.  Ap. A tables  for comparison of relative harmonic magnitudes]  

Summary  

A RWA IV jitter optimization treatise, focused on an ultra- fine-pointing spacecraft utilizing stat e-of-the-art  RWA IV balancing/measurements along with system engineering aggregated efforts, is documented. Key  findings, methodologies, overviews, and intertwined details  for lower -level elements within HST’s designtest-analysis evolution, commonly with nuanced discoveries and counter -intuitive paradigm shifts in  approaches and resolution  path, are summarily discussed often within a background/historical context.  However, a clear focus is also maintained on how these multiple dependencies contribute to pr esent and