35 7.4. Motive ................................................................................................................................................... 37 7.5. Figures	
  of	
  Merit.................................................................................................................................. 37
8.	
   METHODS	
  FOR	
  EQUITABLE	
  COMPARISONS ......................................................................39
8.1. Distinct	
  Eras	
  of	
  Interstellar	
  Flight............................................................................................... 39 8.1.1. Era	
  of	
  Precursors........................................................................................................................................... 39
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8.1.2. Era	
  of	
  Infrastructure .................................................................................................................................... 39 8.1.3. Era	
  of	
  Breakthroughs................................................................................................................................... 40 8.2. Baseline	
  Mission	
  &	
  Payload	
  Scenarios....................................................................................... 40 8.2.1. Solar	
  Gravitational	
  Lens ............................................................................................................................. 41 8.2.2. Deep	
  Interstellar	
  Medium.......................................................................................................................... 41 8.2.3. Centauri	
  Flyby................................................................................................................................................. 41 8.2.4. Centauri	
  Slower	
  Flyby................................................................................................................................. 41 8.2.5. Centauri	
  Orbiter............................................................................................................................................. 41 8.3. Measuring	
  Infrastructure	
  Dependence ..................................................................................... 42 8.3.1. Earth-­‐Based	
  Beaming	
  Infrastructure.................................................................................................... 42 8.3.2. Estimating	
  In-­‐Space	
  Infrastructure	
  Availability	
  and	
  Growth..................................................... 43 8.3.3. Estimating	
  In-­‐Space	
  Infrastructure	
  Usage.......................................................................................... 44 8.4. Measuring	
  Disparate	
  Propulsion	
  &	
  Power............................................................................... 45 8.4.1. Type	
  IP-­‐OM:	
  Internal	
  Power	
  &	
  Onboard	
  Reaction	
  Mass.............................................................. 45 8.4.2. Type	
  RP-­‐OM:	
  Received	
  Power	
  &	
  Onboard	
  Reaction	
  Mass........................................................... 48 8.4.3. Type	
  RP-­‐XM:	
  Received	
  Power	
  &	
  External	
  Reaction	
  Mass............................................................ 49 8.4.4. Type	
  IP-­‐XM:	
  Internal	
  Power	
  &	
  External	
  Reaction	
  Mass ............................................................... 51 8.5. Estimating	
  Comparative	
  Rates	
  of	
  Advancement .................................................................... 53 8.5.1. Baseline	
  Performance	
  Trends.................................................................................................................. 53 8.5.2. Technology	
  Maturation	
  Rates.................................................................................................................. 54 8.5.3. Modeling	
  Technology	
  Advancement	
  Rates	
  in	
  General.................................................................. 56 8.5.4. Other	
  Methods	
  Under	
  Consideration.................................................................................................... 57
9.	
   SAMPLE	
  DATA	
  PLOTS ...............................................................................................................59
9.1. Technology	
  Comparisons............................................................................................................... 59 9.2. Mission	
  Comparisons....................................................................................................................... 60
10.	
   STAGE	
  II	
  PLANS ........................................................................................................................62
10.1. Collection	
  and	
  Display	
  of	
  Information	
  from	
  Subject	
  Matter	
  Experts............................ 62 10.2. Analysis	
  Portal................................................................................................................................. 63 10.3. General	
  Audience	
  Website .......................................................................................................... 63 10.4. Concluding	
  Remarks ..................................................................................................................... 63
11.	
   REFERENCES..............................................................................................................................64
11.1. Sequentially	
  Cited........................................................................................................................... 64 11.2. Bibliography..................................................................................................................................... 65
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