> ## Documentation Index
> Fetch the complete documentation index at: https://docs.valar.space/llms.txt
> Use this file to discover all available pages before exploring further.

# Passes Overview

> Understand ground-station passes, coverage definitions, and how the Passes area's pages fit together

> For the complete documentation index, see [llms.txt](/llms.txt).

A **pass** is a period during which a spacecraft is above a ground station's applied horizon — a topocentric visibility window, not a guarantee of communication or mission readiness. The Passes area is where you configure the ground stations passes are computed against, and review the resulting coverage.

**Route:** `/passes`

Open the area via the **Passes** entry in the sidebar. Inside it, a shared tab bar switches between **Table**, **Timeline**, **Stations**, and **Coverage Map**.

## What Determines a Pass

Whether a spacecraft counts as visible from a station at a given moment comes down to that station's **coverage definition** — either a single constant minimum elevation, or an elevation mask that varies by azimuth to describe an uneven local horizon. The station's coverage definition, evaluated by the server, is called its **applied horizon**; it is what pass computation actually checks against, not a value you calculate by hand. See [Elevation Masks](/features/passes/elevation-masks) for how the two combine.

## Pages in This Area

| Page | What it's for |
| - | - |
| **[Elevation Masks](/features/passes/elevation-masks)** | Understand what an elevation mask is, why it matters, and how it combines with a station's minimum elevation into its applied horizon. |
| **[Stations](/features/passes/stations)** | Create and edit the ground stations passes are computed against — location, reference frame, and coverage definition, with a coordinate minimap and a live applied-horizon preview. |
| **[Timeline](/features/passes/timeline)** | Visualize computed passes per station, with a stated outcome for every station you asked about — including why a station shows nothing. |
| **[Coverage Map](/features/passes/coverage-map)** | A read-only geographic view of every station's coverage footprint at a shared reference altitude, so you can compare ground-segment coverage spatially. |

The **Table** tab lists computed passes themselves, alongside the other tabs in the same tab bar.

## Related Pages

* [Elevation Masks](/features/passes/elevation-masks) — the concept behind a station's applied horizon.
* [Ground Stations](/features/passes/stations) — the station-creation and editing flow, including the CSV format for uploading an elevation mask.
* [Timeline](/features/passes/timeline) — per-station pass outcomes, including excluded and not-evaluated stations.
* [Coverage Map](/features/passes/coverage-map) — see every station's coverage footprint on one map.


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