> ## 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 — the window in which that station can track or communicate with it. 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.