> ## 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. # Attitude Transitions > Schedule and manage attitude mode transitions for your spacecraft > For the complete documentation index, see [llms.txt](/llms.txt). Use this page to schedule when your spacecraft switches between attitude modes, pick the **default mode** the spacecraft falls back to between transitions, and configure free-drift dynamics for an uncontrolled, torque-free orientation. For attitude mode concepts — what a mode is, body axes, target families, and the unified workspace catalog — see [Attitude modes overview](/features/attitude/overview). **Route:** `/attitude/modes` ## The Transition Schedule The **Transition Schedule** card lives in the main column of the attitude modes page, below the mode carousel and the Euler-angle plot. It lists every scheduled mode transition for the selected spacecraft in chronological order, alongside any CUSTOM-mode windows imported from AEM files. Each row shows: * The **target mode** the spacecraft will adopt at the transition time. CUSTOM rows (created by AEM imports) display **File Import** in place of a mode name, with a small badge naming the source `.aem` or `.txt` file. * The **scheduled time**, formatted as `MMM DD, HH:MM` in UTC (for example, `Apr 14, 08:56`). * An actions menu with **Edit** and **Delete** entries. CUSTOM rows handle these differently — see [CUSTOM Windows from AEM Imports](#custom-windows-from-aem-imports) below. By default the table hides past events and shows upcoming transitions only. Open the gear menu in the card header and tick **Show past events** to include scheduled times that have already elapsed. ### The right-hand modes panel The attitude modes page has a second column on the right that lists every attitude mode in your workspace catalog. The header carries a panel-toggle icon (the right-panel glyph next to the **Import** and **Export** buttons) — click it to hide or show the modes panel and reclaim screen space for the schedule and plots. ### Empty state When no transitions are scheduled and no AEM imports have been added, the **Transition Schedule** card replaces the row list with a centered **No transitions scheduled** message and a single **Add transition** button. Clicking the button opens the same scheduling dialog as the **Add transition** action in the card header. ## Scheduling a Transition Click **Add transition** in the **Transition Schedule** card header to open the **Add Transition** dialog. Every scheduled transition is time-anchored: it activates at a single UTC instant and remains active until the next transition (or until the schedule returns to the default mode). To schedule a transition: Type the time of day into the `HH:MM` input — the dialog auto-inserts the colon as you type. Then pick the date from the 7-day MiniCalendar carousel below the input. Use the left and right chevrons to navigate the carousel one week at a time. The carousel only allows dates between **today** and **today + 30 days**; days outside that window are disabled. Open the **Target mode** dropdown and pick any mode from the workspace catalog. CUSTOM is not selectable — CUSTOM windows can only be added via [AEM import](/features/attitude/ephemeris). If you pick **Free drift**, the dialog reveals an extra section for the torque-free dynamics needed to integrate the spacecraft's tumble. See [Free-Drift Dynamics](#free-drift-dynamics) below for the field reference. Click **Create**. The dialog closes on success and the new row appears in the **Transition Schedule** card, sorted by transition time. If the chosen time falls inside an existing AEM-imported CUSTOM window, the dialog stays open and surfaces an inline message naming the conflicting file and its time range — pick a different time, or delete the conflicting import first and retry. To change a previously scheduled transition, open the row's actions menu and click **Edit**. The dialog re-opens with the existing values pre-filled and a **Update** button in place of **Create**. CUSTOM rows do not expose **Edit** because their times are bound to the AEM import. ## The Default Mode Each spacecraft has exactly one **default attitude mode** — the orientation the spacecraft holds whenever no scheduled transition is active. The default is the fallback the schedule returns to between operations: * **No transitions scheduled:** the spacecraft holds the default mode at all times. * **One transition scheduled at time `T`:** the spacecraft holds the default before `T` and switches to the scheduled mode at `T`. * **Multiple transitions:** the spacecraft switches at each transition time in order; the default fills any gap before the first transition. You set and change the default from the **Attitude Modes** panel on the right of the page. Each mode card carries an actions menu — click **Set as default** on the mode you want to become the new fallback. The current default is marked with a **Default** badge. Selecting **Free drift** as default reveals the [free-drift dynamics form](#free-drift-dynamics) inline on the card. Setting the default mode rewrites which mode is active **between** scheduled transitions. It does not modify the rows in your transition schedule. ## CUSTOM Windows from AEM Imports When you import a CCSDS AEM file from the attitude modes page header, every attitude sample window in the file is added to the **Transition Schedule** card as a **CUSTOM** row. CUSTOM rows coexist with manually scheduled transitions and are sequenced into the same chronological list using the file's `START_TIME` and `STOP_TIME`. CUSTOM rows behave a little differently from manually scheduled transitions: * The mode column displays **File Import** with a file-name badge instead of a regular mode name. * The actions menu hides **Edit** — the time and duration of a CUSTOM window are fixed by the source AEM file. * Clicking **Delete import** on a CUSTOM row opens a confirmation dialog that warns the deletion will remove both the AEM import and its associated transitions. * New manually scheduled transitions cannot land inside an existing CUSTOM window. If the **Add Transition** dialog detects a collision, it surfaces an inline error naming the conflicting file. For the full AEM ingest flow, supported file types, validation messages, and the export counterpart, see [Import & Export Attitude Ephemeris](/features/attitude/ephemeris). ## Free-Drift Dynamics The **Free drift** mode disables active control and lets the spacecraft tumble under torque-free dynamics. Because two spacecraft running the same Free-drift mode have different inertias and different initial spin states, the physical inputs that drive the torque-free integration are configured **per spacecraft**, not per workspace mode. The free-drift form is rendered inline in two places, with identical fields: * Inside the **Add Transition** dialog, whenever you pick **Free drift** as the target mode of a scheduled transition. * Inside the **Attitude Modes** panel on the right of the page, when you select **Set as default** on the **Free drift** card. The form has three groups of three fields each: | Group | Fields | Unit | | -------------------------------- | ---------------------------------------------------- | ---------------------------------- | | **Principal Moments of Inertia** | Ixx, Iyy, Izz | kg·m² | | **Inertia Axis Assignments** | Inertia axis Ixx, Inertia axis Iyy, Inertia axis Izz | Body axis (+X, -X, +Y, -Y, +Z, -Z) | | **Initial Angular Velocity** | ωx, ωy, ωz | rad/s | The three principal moments describe the spacecraft's resistance to rotation about its own inertia axes; the three axis assignments tell the platform which body face each principal moment is aligned with; the three initial angular velocity components seed the torque-free integration at the transition's start time. A footnote at the bottom of the form reads **Free drift is computed using torque-free dynamics**. All nine values are validated as you edit, and the **Create**, **Update**, or **Set as Default** button stays disabled until every input is valid. *** Understand attitude modes, body axes, target types, and the unified workspace catalog Browse, create, edit, and delete modes in the workspace catalog Exchange attitude ephemeris with external partners and tools Inspect quaternion and Euler angle plots over time