The next question is about the duration of the mission, or more broadly the entire project. Since this study includes the research that predates the mission, those stages are also measured. Many stages have trades. The stages are:
Millis 2018 Grant NNX17AE81G_for_CR.docx

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Total Project Duration, Ttp (yrs): This term means the entire span encompassing all the other stages, from the point the research begins until receiving all of the data back from the probe.
Technology Maturation Duration, Trl (yrs): This is the time between the start of the research and when that research has advanced to approximately TRL-6, or advanced enough to allow planning and developing a mission. The trade here is whether to select less capable but more near term technology that will be ready sooner, or more capable technology that might be available later. This is related to the Incessant Obsolescence Postulate, which is mostly affected by subjective mission motives.
In the case of the "Precursor Era" missions, sufficient technology maturation exists to initiate trade studies, albeit the best projected performance can only reach 1,000 AU in 50 years with a 38 kg payload [32]. In the case of both the "Infrastructure Era" and "Breakthrough Era," the Technology Maturation Durations have not yet been estimated.
Devising a means to estimate the durations of technology maturation and mission development are part of the goals of this Stage I study. These details are discussed in Section 8.5 "Estimating Comparative Rates of Advancement." Mission Development Duration, Tdev (yrs): This is the time between the beginning of the mission trades studies and the launch of the mission. It will likely be different for each of the three interstellar eras and therefore estimated differently. The trade here is to use less complex systems that can be built faster, or more capable systems to launch later. Again, this is related to the Incessant Obsolescence Postulate, but this time the duration is also a function of how soon the infrastructure will be available.
For the precursor era missions, this duration will likely fall within the 6-12 year span of the development of the New Horizons missions and Cassini-Huygens, respectively.
In the case of mission architectures of the infrastructure era, this is dominated by the time for using the presumed preexisting infrastructure to build the spacecraft and any supporting new infrastructure (such as laser systems). Accordingly and per the methods in Section 8.3 "Measuring Infrastructure Dependence," these following two development times will be estimated:
Spacecraft Build Duration, Tscb (yrs): This is the time it takes to build the spacecraft and fully load it with propellant using the infrastructure available at the time. Base Hardware Build Duration, Tbd (yrs): This is the time it takes to build any of the supporting propulsion infrastructure such as anything that needs to beam energy or reaction mass to the vehicle.
Total Mission Duration, Tm (yrs): The time between launch and receiving all of the data back from the probe. It is the sum of these sub-stages:
Trip Time, Tt (yrs): The time between launch and arrival at the destination. This is a function of the payload mass, the energy available for propulsion, and the performance of the power and propulsion system. Signal Time, Ts (yrs): The lightspeed signal return time, a simple function of the destination distance and lightspeed. Data Transmission Time, Tx (yrs): The time it takes to transmit the full suite of the data back to Earth. This is a function of the communication system, its power, and apertures (both on the spacecraft and the receivers on Earth), where in principle smaller payloads with less power will have lower data rates and hence longer transmission times.
The demarcation points between these times are defined as: Research Commitment Year, Yrc (calendar year, cy): This is the calendar year when the commitment is made to begin advancing the required technologies up through TRL-6, initiating the development of the spacecraft and base hardware. Technology maturation is initiated at the start of the Research Commitment Year and extends to the Mission Commitment Year.
Mission Commitment Year, Ym (cy): The calendar year when the commitment to developing the mission is made. The required technology must be mature enough for reliable trade studies at this point, specifically TRL ≥ 6. Currently only the Precursor Era missions satisfy that condition. Mission development begins at the start of the Mission Commitment Year and extends to the Launch Year.
Launch Year, Yl (cy): The launch date is often cited as a primary mission goal, but the decisions needed to meet that goal are made years earlier. The challenge in developing the analysis is that sometimes this will be an
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