For the more general suite of interstellar concepts that presume the existence of in-space infrastructure, the two major questions are" "When will the needed infrastructure be ready to support the mission?" and "How much will it cost in energy and time to use that infrastructure to build and launch the mission hardware?" Currently, there are no substantive predictions about in-space infrastructure capacity and growth. As a starting point, the author sought the opinions from a number of subject matter experts (discussions with Brandt, Lewis, and Lubin, and cited values from Hoffman, Klupar) and merged them together to produce table 10 (with subjective compromises for mismatched predictions). Note how many fields remain unspecified. The rest of this table will be populated with estimates in Stage II of this work.
To get a grounding reference to scale the situation, the growth of world energy production has been extrapolated to fill out the first row in table 10. The data behind those extrapolations span 1888 through 2017 [46-47]. In the second row those values are converted into equivalent power (J/yr into J/s=W). The third row contains estimates from subject matter experts.
Since these projections will be used for relative comparisons only, it is not necessary that these growth projections be accurate. They only need set an approximate scale and then have that scale used consistently throughout the rest of the analyses.

|  | 2020 | 2030 | 2040 | 2050 | 2060 | 2070 | 2080 | 2090 | 2100 | 2110 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| REFERENCE POINT: World Energy Production Extrapolation, | 5.3 x 1020 | 6.4 x 1020 | 7.6 x 1020 | 9.1 x 1020 | 1.0 x 1021 | 1.2 x 1021 | 1.5 x 1021 | 1.7 x 1021 | 2.0 x 1021 | 2.3 x 1021 |
| (J/ r) REF: World Equivalent Power Capacity, (W) | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 | 5.3 x 1013 |
| Predicted Infrastructure Available Power, (W) |  | 1 x 108 | 2 x 109 | 1 x 1010 |  |  |  |  | 3 x 1013 |  |
| Functionalities: |  |  |  |  |  |  |  |  |  |  |
| Mining Capacity (kg/yr) Specific Energy (J/kg) |  | 100 - | 105 - |  |  |  |  |  |  |  |
| Material Processing Capacity (kg/yr) Specific Energy (J/kg) |  |  |  |  |  |  |  |  |  |  |
| Manufacturing & Construction Capacity (kg/yr) Specific Energy (J/kg) |  |  |  |  |  |  |  |  |  |  |
| Connecting Transportation Capacity (kg/yr) Specific Energy (J/kg) |  |  |  |  |  |  |  |  |  |  |

The lower rows of table 10 refer to both the capacities (kg/yr) and specific energies (J/kg) of the various infrastructure functions:
• Mining raw materials (including propellants) • Processing the raw materials into usable stock [100 MJ/kg aluminum?] • Manufacturing components from stock • Constructing objects from components and stock • Transporting items within the infrastructure Infrastructure Use Specific Energy, Esi (J/kg): For the analyses that follow, the specific energies for each of those functions will need to be estimated during stage-II. The sum of those specific energies will then represents the
Millis 2018 Grant NNX17AE81G_for_CR.docx

pg 43 of 69 total Infrastructure Use Specific Energy, Esi, to be used when calculating the use of infrastructure.