> ## 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.

# Phasing

> Save a fixed phase objective, compute finite chemical or electric corrections, and review orbit, drift and resource achievement.

Phasing changes one spacecraft's position along its orbit relative to a saved reference.
It accounts for the entry maneuver, drift, recovery and measurement coast together.
The result must meet the phase target, terminal orbit and residual relative drift on
the same assessed trajectory.

## Create and save an objective

In **Operations → Planner → New Plan**, select a spacecraft and thruster, choose
**Phasing**, review **Initial State** to choose the operational TLE/state vector and
mass, then continue to **Phasing objective**. Operations Flight plans can also
link a saved Phasing intent to a phase. In Mission Analysis, select **Add Phasing**
in the existing Flight plan editor.

Choose a reference mode:

| Mode             | Meaning                                                                                                                                      |
| ---------------- | -------------------------------------------------------------------------------------------------------------------------------------------- |
| Signed change    | A signed advance or delay relative to the anchored unmanoeuvred trajectory. Complete relative laps are retained: 390° is different from 30°. |
| Reference offset | An offset from a versioned virtual or leader trajectory, modulo one revolution. The result identifies the selected direction and winding.    |

Positive phase is ahead in the direction of travel. It does not prescribe the first
burn direction. The authoritative observable is mean phase in degrees, not true anomaly,
ground-track longitude or three-dimensional separation.

Supply the phase tolerance, earliest burn and latest completion, temporary orbital
excursion limits, terminal mean-orbit tolerances, permitted plane mismatch, residual
drift bound and measurement-coast duration. Distances identify their representation:
mean SMA and osculating perigee/apogee radii are different requirements.

The selected catalog device supplies thrust, Isp and its maximum continuous firing
duration. Declare remaining ignitions, minimum command, timing precision, restart gaps,
propellant cap/reserve, rolling duty, sunlight eligibility and blackouts. Prograde and
retrograde settings declare the ability to track those RTN directions throughout a firing.
Identify the source of these command limits; the editor does not infer mission values.

**Save Phasing intent** retains the target and reference. Select it from **Saved Phasing
intent** when reopening. Computation uses the saved revision shown in the panel; save
edits before computing them.

Expand **Saved reference state and resources** to inspect the frozen GCRF/UTC state,
its source, mass, and selected propulsion. Changing the controlled-state selection
for a later computation does not replace the saved reference.

## Keep the target when replanning

A saved 10° correction with 4° already gained still targets 10°, leaving 6° to achieve.
It does not request another 10° from the updated state.

For a signed correction at a later entry epoch, provide continuous unwrapped phase
history, the matching epoch and its evidence source. A wrapped state alone cannot
prove completed relative laps, and a proposed burn is not evidence that it executed.
Operations retains its existing future, whole-second planning-window requirement;
history must be resolved to the selected planned-start state. Finite commands retain
their finer declared timing precision.

Select **Explicitly replace the saved reference** when revised intent should adopt a
new anchor. A new correction or changed reference is explicit and versioned. Older
proposals remain tied to their producing snapshots.

## References and terminal orbit

The default is an unmanoeuvred reference from the resolved selected state. Mission
Analysis uses its explicit analysis initial orbit and frozen assets. The controlled
spacecraft always enters a composed phase with the preceding phase's achieved state,
epoch and remaining mass.

Advanced reference records use GCRF/UTC state data, source/version, model/data identity,
coverage and maneuver assumptions. A leader ephemeris needs ordered knots, an
interpolation-gap limit and declared thrust-free coverage of the measurement interval.
Missing coverage is not extrapolated, and unknown future leader burns are not assumed.
An unavailable saved model/data revision is reported rather than silently replaced.

By default, the required terminal mean orbit follows the phase reference at arrival.
A separate **Terminal orbit reference** can specify another return orbit. All authored
phase, size/shape, plane and residual-drift requirements still apply together.

## Review the result

The review shows the saved target, selected branch/winding, achieved phase and error,
residual drift, terminal orbit residuals, propellant used, remaining propellant and
required reserve. **Complete elapsed time** includes coasts and the measurement interval;
**Total firing time** counts only actual firings.

Use the aligned charts to inspect unwrapped phase or selected-branch error, mean SMA,
mean eccentricity and osculating perigee/apogee. Firing boundaries and authored limits
remain visible. Phase tolerance is an endpoint condition; excursion limits hold along
the full trajectory.

Outcomes distinguish unsupported input/capability, conflicting requirements, an
unsuccessful bounded search and insufficient numerical qualification. A verified
candidate can remain usable when further optimization reaches its budget. Minimum
propellant is the objective, not a promise of a global optimum.

Operations approval uses the retained finite commands through the existing review
lifecycle. Changed or unqualified proposals cannot be approved/exported. A coast-only
achievement creates no artificial burns. Mission Analysis results remain isolated and
cannot be approved as operational proposals.

Initial and terminal mean orbits cover near-circular Earth LEO through 2,000 km
mean-SMA altitude and eccentricity 0.01. Temporary excursions have separate authored
bounds and model-applicability checks. Numerical achievement is modeled evidence;
it does not establish indefinite spacing, rendezvous or conjunction clearance.
