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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.

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Create and save an objective

In 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. Choose a reference mode: 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 earliest start and choose flexible completion or a required complete-by date. Phasing reuses configured independent mission success criteria. Enter missing values under Success criteria and tightening overrides. Optional path, fuel and duration bounds are under Advanced restrictions; blank adds no extra restriction. Mean SMA and osculating perigee/apogee conditions are distinct requirements. The common numerical assessment interval is resolved automatically and counts in complete time. The existing spacecraft/device and selected state supply thrust, Isp, dry mass, initial mass and maximum continuous firing duration. There is no supplemental command-resource setup. Modeled consumption cannot exceed mass above dry mass, accounting for existing approved recovery holds. This model ceiling is not independently measured usable tank inventory. Retired precision, ignition, inventory, reserve and review-lead settings do not constrain new computations. Save and review Phasing retains the target/reference and opens a summary of the effective inputs. Compute fuel and time plans compares complete Min-fuel and Fastest alternatives under that same reviewed problem. Use Modify / Replan on a producing plan to reopen its request. Relevant edits require a new save and Review before computation. 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.

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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 exact producing numerical timing precision. Select Explicitly revise 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.

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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. The nominal target’s required terminal mean orbit follows the same saved trajectory at each alternative’s actual completion. A separately retained historical terminal reference remains inspectable. Phase, size/shape, plane and residual-drift requirements apply together.

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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. In the plan Overview, ΔMass (spacecraft) is signed (negative for fuel spent), while Fuel consumed is the positive amount spent. Both use kg for values at least 1 kg and g for smaller values, with three decimal places; these come from the producing Phasing run, not a rounded command aggregate. Initial State shows the selected source/display ID and mass source retained with that plan, alongside the run-frozen epoch, mass and saved reference source. The reference source identifies the target anchor; after replanning it may differ from the selected initial state. Older-plan limitation: plans computed before initial-state selection was retained can still show their frozen physical state and fuel evidence, but the selected source, mass source and State Vector display N/A when the original selection is absent. This update does not backfill that historical ID from the reference anchor, plan metadata or the spacecraft’s current state. A new computation records its own selection; it cannot recover which record an older run selected. Latest state vector (at run time) means a retained latest-state selection policy, not a known record ID. N/A for a missing or unfinished result is not a measured zero; an actual zero is shown as 0.000 g. 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. 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.