In Stage II, a web-based system will be created to allow subject matter experts from around the globe, and from the span of relevant disciplines, to enter the information needed to have their concepts assessed in the context of interstellar flight. This will involve iterations to ensure that the questions being asked match what information is determinable. The starting points are the tables throughout this report. The overall intent is to collect enough information to assess the span of prospects under equitable conditions, so that ultimately the most impactful technologies can be identified along with research plans to advance those technologies. To get through that process, the information lists will be at four levels of scope:
• Mission-propulsion architecture concepts (and mission choices), e.g. table 3 • Power and propulsion prospects, e.g. table 4 • Key technologies within those systems • Research needs to deliver the envisioned performance abilities Mission-Propulsion Architecture Concepts List: Compiling a list of mission-propulsion architectures, like that of table 3 in Section 5.2, will be done in two contexts. First, the proponents of a given propulsion and power concept have the opportunity to document their concept in a mission context of their choosing—typically where their technology has an advantage. Second, to insure that the information needed for equitable comparisons is collected, the questions for the mission architecture will require explicit specification of core details such as the assumed data rates, data volume, payload power, etc, as outlined in Section 7 and the variables in table 6.
More General Mission Choices: Recall that the premise of this analysis allows the mission choices to be varied to assess their impact, so the ultimate mission candidates might be quite different than those originally proposed. In addition to those missions already listed in table 3, this assessment process will examine the propulsion concepts in different mission contexts, and for equitable comparisons, will use identical mission and payload baselines, such as those outlined in Section 8.2, and spanning the specific questions of Section 7.
Power and Propulsion Prospect List: The prospects list, similar to table 4 of Section 5.3, is where the power and propulsion concepts are described as a system—specifying all components of the system that are necessary for its success. The information provided here will feed into the analysis methods specified in Section 8.3 and 8.4, and thus must provide all the required information.
To insure that the information needed for equitable comparisons is collected, the questions for the prospects list will require explicit specification of core details such as the subject columns outlined in Section 5.3. This includes the level of details where design parameters used for the subsystems are revealed (such as tankage fraction, conversion efficiency for power sources, specific masses, etc.). In addition, the TRL levels associated with the projected performance values must be listed. This includes the variables outlined in table 6.
Key Technologies List: Within all power and propulsion system prospects, there are key technology elements. Some of these will be unique to a particular system, but many will be common across many systems. For example, different laser-sail concepts might use the same laser and power conversion technology, or different fusion rockets might require similar magnetic nozzle technology. Another common element is the thermal radiators needed to dissipate unusable energy.
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Millis 2018 Grant NNX17AE81G_for_CR.docx To insure that the information needed for equitable comparisons is collected, the claimed performance levels, associated TRL levels, and the critical make-break issues for each technology will need to be specified.

This also feeds into the next list—the research tasks required to answer those issues and deliver those performance projections.
One of the key technology areas for which more substantive estimations are sought are for trends of available energy and infrastructure (table 10), and trends of common design parameters (table 16).
Required Research: The advocates for power and propulsion concepts will also be asked to specify the nextstep research required to advance their concept. It is anticipated that these research tasks will focus on only the key points of interest from the advocated concept, instead of covering all the key issues needing to be resolved. Any possible differences between what the technologist proposes to work on, and what might actually need to be worked on, is what this study hopes to reveal.