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 Effort required. We have not made a level of effort estimate for the PassPredict work. The existing relevant software suggests that the actual software development will be a smaller job than TrailMask; however, a robust system to manage and interface with the ephemeris data will likely take significant and continuing resource investment.

"Support selected detailed simulations of the effects on data analysis systematics and data reduction signal-to-noise impacts of masked trails on scientific programs affected by satellite constellations. Aggregation of results should identify any lower thresholds for the brightness or rate of occurrence of satellite trails that would significantly reduce their negative impact on the observations."

3.3.1. EphemSimulate

To model the effects of future constellations, we need to be able to go from a constellation description to a simulated ephemeris database; EphemSimulate would do this.

Inputs:  Constellation shell parameters Observation date 

Outputs


 * 1) Simulated ephemeris database

A typical constellation description defines a number of layers with fixed altitude and inclination (see Fig. 6 for an example). Each layer specifies the number of orbital planes and number of satellites per plane. We can assume that the planes are evenly spaced and that the satellites in a single plane are on average evenly spaced along the orbit (possibly with some rule for adding some randomness to the phases along the orbit). This allows us to instantiate a suitable set of orbital elements for each satellite in the constellation. For this purpose (to assess the impact of a particular new constellation design), perfect circular Keplerian orbits are likely a sufficiently accurate representation; detailed propagation models are not needed.

Since the deployment of Starlink it has become clear that satellites may spend a significant fraction of their lifetime in ascent and descent orbits and in plane-adjusting drift orbits at intermediate altitudes, so simulations may want to include these effects as well. Rh