This question is motivated by an argument that arose in relation to this question.
We know there are decadal surveys recommending the priorities in planetary exploration. There is also a neat problem summarized by Andrew Kennedy (see wait calculation) for interstellar exploration probes.
Each mission study has the following hard-wired quantitative parameters:
- time to develop, test and launch the spacecraft (given by the launch window);
- maximum payload mass, power, and datarate that limit how much data can be collected and how fast the results can be transferred (given by the chosen trajectory and available launchers);
- time in transit from launch to destination (or destinations) when the scientific payoff is minimal;
- cost of launch campaign;
- cost of mission control over various mission phases;
- use of otherwise limited resources (like plutonium-238 for RTGs).
There are also "soft", less quantifiable parameters:
- expected value of scientific results;
- probability of missing the launch window due to the need for redesign;
- expected development costs.
A naive straightforward approach would be to calculate discounted net present value (NPV) of all the outlays and scientific results (somehow converted into money) and use it or the implicit rate of return to compare missions.
My question is twofold:
- Is there a widely-accepted handbook outlining theory to be used in top-level decision making while choosing the mission portfolio?
- Are there any studies that analyze how decisions are really made (by NASA or other agencies)? What discounting rates are implicitly used by decision-makers?