> ## 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.

# LEO disposal screening

> Compare preliminary disposal studies using your precise orbit, selected propulsion device and editable study requirements.

<Note>
  This capability is available only to enabled Operations audiences. Studies are
  preliminary screening results. They cannot be operationally approved or exported
  as OCM commands, even when a nominal target is met.
</Note>

## Create a study

1. Open **Maneuvers → Planner → New Plan**. In **Overview**, choose
   **LEO disposal** in **Maneuver Type**.
2. Name the plan, select a spacecraft and one chemical or electric propulsion
   device, then choose **Next**. In **Disposal study**, select an existing precise
   state or orbit solution. The selected device carries forward from Overview.
3. Enter your maximum modeled propellant spend and campaign start/end in UTC.
   The calculation uses mass from the selected state, plus catalogue dry mass,
   drag properties and the chosen device's thrust, Isp and maximum burn duration.
4. Declare the coast from the source epoch to your campaign start. If known
   intervening maneuvers exist, select a later state through the existing state-data
   workflow. Review any existing orbit-freshness notices.
5. Declare your jurisdiction/authorization context, ESA baseline adoption,
   constellation population, operational duration and relevant lifecycle dates.
   Leave unknown optional values blank.
6. Select **Lowering + natural decay** or **Nominal controlled return**. Controlled
   studies additionally require your nominal surface-region center and radius.
7. **Review recommendations**, adjust study targets if needed, then choose
   **Calculate preliminary study**. You can cancel a queued or running calculation.

A TLE/GP conversion is not a precise starting orbit. Missing essential catalogue
data must be completed in the existing spacecraft workflows; launch mass is not
substituted for current state mass.

## Recommendations and your targets

The initial five-year target runs from your **declared end of mission**, including
the powered campaign. It is a Valar good-practice preference, not a universal
European law. Attributed sources can have different or stricter deadlines and
different clocks. For example, French mission-duration and megaconstellation
conditions differ, and an adopted ESA baseline uses strictly-less-than-five-year
wording with its own lifecycle clock and probabilistic assessment method.

You may change the lifetime, maximum post-burn apogee and study mode. Source
requirements remain visible and unchanged. Choosing a less stringent target does
not demonstrate a waiver. Country selection alone does not determine every licence
or contractual obligation; coverage and unknown applicability remain explicit.

## Review a retained study

Select the study in the shared **Planner plan list**, alongside other plans.
Disposal rows are labelled **Preliminary** and show their calculation outcome.
The study opens in the Planner details pane; its URL can be reopened directly.
Spacecraft filtering applies to disposal rows, and the time filter uses their
creation date. Use **Load older disposal plans** to retrieve earlier retained
studies. The currently opened study remains visible across the time filter.
Review:

* **Trajectory:** nominal altitude/perigee/apogee history, active campaign time,
  passive or ballistic time, total time from end of mission, consumption and
  remaining modeled inventory. A qualifying natural-decay result may need no burn.
* **Maneuvers & coasts:** actual timestamped intervals, device, thrust/Isp,
  consumed mass and propulsion delta-v. Coasts and fractional epochs are retained.
* **Assessments:** numerical consistency, selected modeled targets and unresolved
  requirements. Incomplete search or no candidate does not prove physical infeasibility.
* **Requirements:** source versions, clocks, applicability/evidence limits and
  your selected targets.
* **Frozen inputs:** the chosen source, state mass, original/transformed frames,
  device and physical settings. Later orbit/catalogue edits do not change the study.

To investigate different dates, requirements or settings, use **New Plan** again.
Each calculation is retained separately; the earlier study is preserved. No
operational approval or OCM export is available for disposal studies.

## What the numbers mean

The result is the best numerically consistent candidate found in a bounded search,
not a guaranteed global minimum. Natural lifetime uses a fixed atmospheric
reference scenario and stops at a **120 km perigee proxy**; it is not a forecast or
a legally equivalent definition of reentry. A 100-year estimate can be censored.

Nominal controlled studies must satisfy the selected device's actual terminal
capability and return promptly to a computed surface point inside your selected
region. An electric device may be unable to do this; the study will not silently
switch devices or turn a slow spiral into a controlled result.

Density factors **0.5, 1 and 2** are displayed as scenarios. Factor 1 governs the
nominal trade; the others are advisory sensitivities, not calibrated probability
bounds. Numerical refinement checks stability, not real-world accuracy.

<Warning>
  A nominal intact-body surface intersection is not an actual surviving-debris
  footprint or a conservative casualty-risk bound. Casualty probability,
  fragmentation, hardware reliability and statistical footprint confidence remain
  indeterminate without the necessary evidence. Fleet collision risk, passivation
  and toxicity are also not certified by this study.
</Warning>