Orbit

The Orbit MFD shows your current trajectory, the selected target's trajectory, and a proposed maneuver around Vieneo. Use it to change your orbit, rendezvous with a station or another spacecraft, or pass over a selected surface point. DOR executes the selected valid orbital plan; circularizing is one possible plan.

The full-page instrument is installed in the E-10, E-11, P-13, W-6, T-19 and EVA displays. It is not installed in the A-4. Older clients may still show the small numerical Orbit readout.

About the illustrations: These are labeled scenario renders from the implemented instrument's layout, orbital planner and guidance code, using synthetic example conditions. They are not screenshots of live flights. Each uses the native 420 × 320 layout enlarged for reading. Example times, fuel and delta-V are not a performance promise for your vehicle. Some dated illustrations use earlier labels (MIN ROUTE ALT, TO GO / USED and ATM PASS) and omit the live MECO estimate; the current readouts are described below.

Ascent alpha: Clients with MODE ASCENT can perform VTOL liftoff and a powered climb to a selected parking orbit. See automated ascent. This is separate from ground-to-ground SURFACE PLAN and does not complete a station rendezvous automatically.

Client versions and limits: Orbital adjustment, rendezvous and overflight have executable plans. SURFACE PLAN remains planning-only for ground and low-atmospheric departures. The automated-entry alpha adds REENTRY execution from orbit to an atmospheric handoff, followed by altitude, heading and TAS hold. It does not fly the final descent or land. This requires the client with ENTRY READY; earlier calibration clients show REENTRY PLAN / PLAN ONLY and support manual REC capture only.

Open and operate the page

The page is identified as DOR at the upper left. While executing, EXEC at the upper right and the active phase (ALIGN, WAIT, BURN, COAST or ARRIVAL) blink together: one second visible, one second hidden. Normal active phases are green; a separate red warning does not turn BURN or ARRIVAL red. The phase and its MECO estimate blink together. The DOR page identifier, other numerical readouts and atmospheric warnings stay steady. ESTIMATE, NO PLAN and completion/fault indications do not use this execution blink.

Older orbital illustrations show ORB1 and DOR-prefixed phases. Static illustrations do not demonstrate the execution blink.

Select the Orbit page on a supported vehicle's MFD. Choose the station, spacecraft or surface waypoint on your usual target-selection instrument; Orbit reads that selection. You do not enter a second waypoint on this page.

Control	Action
Shift + Up / Down	Select a row in the side controls. The highlighted row's actions appear along the bottom.
Shift + Left / Right	Change the highlighted option or decrease/increase its value.
Shift + C, with the eccentricity row selected	Request a circular orbit (e = 0).
Your configured DOR on/off control	Engage or disengage a valid executable plan. SURFACE PLAN stays planning-only. The automated-entry alpha can execute an ENTRY READY reentry; after handoff, the same control cancels its TAS hold.

The controls require cockpit power and do not take these keys while text entry is active. Changing VIEW does not alter the plan or interrupt DOR. Changing a planning value does interrupt execution: review the new solution before engaging DOR again. In ASCENT, STEER AFCS / ORBIT is a live steering choice and can be changed without interrupting the climb.

Selecting Orbit does not replace or acknowledge EICAS indications. With EICAS powered and serviceable, its gear, engine, trim and crew-alert indications remain independent of the MFD page. If these disappear only while ORB1 is selected, that is a rendering fault, not evidence that the underlying condition has cleared.

Select an objective

MODE	Use
RENDEZVOUS	An orbiting station or free-flying vessel is selected. Reach a future point on its trajectory and match its velocity there.
OVERFLY	A surface waypoint or grounded vessel is selected. Pass above that rotating ground point at the requested altitude and time.
SURFACE PLAN	A surface target is selected for a ground or low-atmospheric departure. Compare atmospheric, suborbital and orbital journeys using TRIP duration before departure and a PASS countdown afterwards. Planning only.
REENTRY	The surface-arrival objective for an orbital/high-altitude departure, including while docked at a station. Compare direct powered entry with coast-then-entry, ending upstream of the waypoint at the selected HANDOFF altitude and TAS. The automated-entry alpha can execute a qualifying ENTRY READY plan after undocking.
ASCENT	In the ascent alpha, perform VTOL liftoff or take over an airborne climb to a selected circular parking orbit. Main-engine pitch guidance uses current mass and atmospheric conditions. Replan RENDEZVOUS after insertion.
ADJUST ORBIT	Change your own orbit independently of the selected target. Available through MODE even when a target is selected.

A newly selected surface target defaults to the surface-arrival objective. It is labeled SURFACE PLAN for a ground/low-atmospheric departure or REENTRY for an orbital/high-altitude departure. An entry keeps its identity through the atmospheric handoff rather than becoming a new ground-departure plan. Use MODE to choose OVERFLY for an orbital pass or ADJUST ORBIT to change your own orbit. An explicitly selected ADJUST ORBIT objective remains independent of the target.

With no target, select ADJUST ORBIT, ASCENT in the ascent alpha, or select a navigation target elsewhere. A docked or contained target is not treated as an independent free-flying spacecraft. An undocked spacecraft inside a station's reference bubble remains a valid target. An atmospheric-flight target may still have a predicted trajectory, but it is marked with an atmospheric warning.

Rendezvous is more than matching orbital size and shape. Two spacecraft can have identical orbital parameters and remain far apart. Rendezvous also solves for position and velocity at the same future time, including the difference between their orbital planes.

Read the picture and numbers

The graphic area stays the same size in every mode. Green is your current trajectory; cyan is the target; amber dashed lines show the proposed transfer. Dim amber shows the destination orbit, and gray dashed lines show a planned coast before departure. AP and PE mark apoapsis and periapsis. In orbital plans, numbered amber markers identify burns; T identifies the target's current position. Ground-departure surface previews instead number phase boundaries and mark the future arrival point B. REENTRY uses D for deorbit, E for the 100 km crossing and H for atmospheric handoff; the legend identifies them.

VIEW	What it helps you see
ORBIT	Your orbital plane viewed face-on: shape, apsides and transfer path.
PLANE 3D	Plane orientation, with Vieneo's equator and north axis as references. The NODE line indicates the intersection of the current and target orbital planes.
EDGE-ON	Your orbital plane viewed from its edge. Useful for seeing how far the target or transfer leaves that plane; it compresses the shape of your own orbit into a line.
TRACK	Latitude/longitude ground tracks, including Vieneo's rotation. Useful for a surface overflight. This is a schematic grid, not terrain imagery.

Readout	Meaning
AP / PE	Highest / lowest altitude of the orbit above the spherical Vieneo reference surface, in km. A negative PE means the unpowered trajectory intersects that surface.
e	Eccentricity: 0 is circular; larger values produce a more elongated ellipse.
SIZE … km MSL	Orbit size expressed as altitude above mean sea level. For a circle, this is the orbit altitude; for an ellipse, it is (AP altitude + PE altitude) / 2, not the time-average altitude. The planner adds Vieneo's 2939.6 km reference radius internally.
i / PLANE DIF	Inclination to Vieneo's equator, or the angle between your plane and the target's plane, in degrees.
TP / nu	Orbital period in seconds / true anomaly in degrees, locating you around the current orbit relative to periapsis.
CURRENT > FINAL	Current AP/PE/e followed by the proposed final orbit after all burns. Older captures say CURRENT > PLAN. This is not the transfer minimum. CURRENT > REQUEST is an editable goal for which no valid plan exists yet.
PLAN MIN ALT	Lowest checked planned-route altitude in km MSL above the spherical reference surface. Includes any waiting coast, transfer and continuing final orbit; an OVERFLY circularization check also includes its arrival-response allowance. This is separate from final PE and from the actual unpowered coast.
B1 / B2	Planned burn time and delta-V in m/s. The IDEAL line gives duration in seconds and fuel in kg for the main-engine maneuver; it does not include all attitude control, RCS trims or later corrections.
TOTAL / IDEAL FUEL	Total planned delta-V and ideal main-engine fuel. The calculation uses current vehicle mass and engine performance, with mass decreasing as fuel is consumed. Real execution can use more fuel for alignment, RCS, finite burns and corrections.
LEFT / ALL USED	During orbital DOR execution: the active guidance correction remaining, in m/s, and all fuel consumed since engagement, in kg. ALL USED includes alignment, both burns, coast and corrections; it is not a B1-only or B2-only measurement.
MECO ~mm:ss	Estimated time to cutoff of the current orbital burn, shown beside BURN or ARRIVAL. It follows measured convergence and throttle-down, not the original B1/B2 duration. It may increase after a correction. --- means no reliable recent convergence estimate. ALIGN, WAIT, COAST, continuous ascent and reentry do not show this timer. Cutoff is controlled by guidance, not by the countdown; another correction may subsequently fire.

Minimum route altitude

Read PLAN MIN ALT directly below the graphic before engaging DOR. The graphic retains its size, and the OWN / TARGET / PLAN legend sits alongside the readout. It appears in every orbital view, including ascent detail when an orbital route is available. It uses the planner's checked arc minima, not the lowest vertex of the drawn curve.

• Red means the planned minimum is below 100 km MSL.
• Amber means the minimum is at least 100 km but the planned route has an atmospheric warning or is blocked by the clearance check.
• Neutral gray is an unflagged estimate, not flight clearance. --- means no checked route minimum is available; it never substitutes the final PE or current-coast minimum.

CURRENT > FINAL distinguishes the destination AP/PE from this route minimum. A final PE of 118 km does not establish the approach's minimum altitude, and pressure warnings depend on air-relative speed as well as altitude. The pressure advisory threshold is 10 Pa; a 118 km orbit is not automatically atmospheric. Atmospheric and surface-planning policies remain those of the selected mode; this display change does not add a new restriction to RENDEZVOUS or ADJUST ORBIT. SURFACE PLAN keeps its separate phase legend and planning-only readouts.

During EXEC, PLAN MIN ALT continues to describe the committed instantaneous-burn plan. COAST MIN describes the current unpowered trajectory if no more burns occur; CORRECTION MIN describes the live powered-correction forecast. These are km MSL and need not agree: a planned minimum of 118 km can coexist with a negative COAST MIN while later burns are still needed. A negative value means the mathematical coast intersects Vieneo. These warnings remain separate from the green execution phase and any retained red abort reason. A fresh preview after an abort shows the new plan; the old abort reason remains available independently.

Finite-burn limitation: PLAN MIN ALT still describes the instantaneous-burn plan, not the live powered recovery. DOR checks a finite powered response separately, including alignment time rather than an unpowered coast for the entire correction. A negative current PE during a burn can therefore coexist with a viable recovery, while still warning what would happen if thrust stopped. A neutral planned minimum or final PE is not assurance that DOR can complete the whole maneuver. See Powered correction clearance.

Scenario 18: route minimum and final orbit. Fresh labeled render from the actual planner/display code. This synthetic rendezvous has a final PE and route minimum both at 118 km. With the 10 Pa advisory threshold, its route minimum is neutral gray; LONG BURN - ESTIMATE and the independent reversal caution remain visible. This is not a live flight, a reconstruction of player telemetry or a guarantee of execution.

Orbital direction cautions

A steady amber caution beside the graphic's view title identifies the direction of the proposed plan. It remains visible during EXEC, including the hidden half of the execution blink, and does not replace atmospheric, fuel or finite-burn cautions.

• ORBIT REVERSAL means a departure or arrival burn changes the orbital angular-momentum direction by more than 90 degrees. It compares the directions before and after the burn; it is not based on which way the nose or thrust vector points. An ordinary backward braking burn that preserves orbital direction does not trigger it.
• RETROGRADE ORBIT means the transfer or final orbit runs against Vieneo's modeled rotation. A ship that already travels retrograde can keep that direction without an ORBIT REVERSAL. Polar motion alone is not classified as retrograde.
• RETROGRADE / REVERSAL shows both conditions. An intermediate retrograde transfer still warns even if the final orbit returns to prograde. The committed plan retains its caution during execution.

The OVERFLY automatic initial PASS search excludes plans that reverse orbital direction. Manual previews remain available with the caution. Direction caution alone does not block DOR, but the independent OVERFLY atmospheric-clearance requirements still apply. Blocked atmospheric previews retain their direction caution. If reversal was unintended, change the arrival/departure time or the overflight exit behavior and inspect the resulting plan before engaging DOR. A large delta-V can suggest reversal, but the warning is calculated from the trajectories rather than a speed threshold.

See the updated blocked-overfly illustration under Overfly atmospheric clearance. It replaces the older example that allowed the same low-periapsis route as a warning-only plan.

Ground and ascent

• 

  Older-client scenario 1: on the ground. A station is selected, but there is no solved powered launch profile. Current orbital elements are unavailable.

• 

  Scenario 2: ascending through 75 km. The green curve is a measured-state ballistic coast. An in-flight vacuum transfer estimate can appear, with an atmospheric warning; this is not a powered ascent profile.

For orbital objectives, on the ground or while rising below 100 km, the graphic automatically becomes ASCENT DETAIL / COAST. It shows the local curved surface and altitude scale. The header says ASCENT / INSERTION, while MODE still describes your chosen objective, such as RENDEZVOUS.

For RENDEZVOUS or ADJUST ORBIT, ASCENT PROFILE REQUIRED means the orbital transfer solver has no executable powered launch. In the ascent alpha, choose MODE ASCENT for the separate powered climb described below. Older clients require manual ascent. Any ordinary vacuum transfer estimate starts from your measured position and velocity; it does not include lift or drag in that predicted path.

At 100 km while climbing, the graphic returns to the selected orbital view. This does not certify that you are in orbit: a trajectory whose periapsis intersects Vieneo remains ORBIT INSERTION or SUBORBITAL / ENTRY. A descending vehicle below 100 km is not automatically shown as ascending.

For SURFACE PLAN, the default view shows a fitting estimated powered ascent as ASCENT / PLAN ONLY. A rejected candidate is labeled ASCENT / INVALID PREVIEW. Change VIEW to PLANE 3D, EDGE-ON or TRACK to inspect the entire journey before takeoff; changing VIEW does not change the selected trip timing. The local surface view rotates with the departure location, so a vertical climb is not mistaken for sideways travel caused by Vieneo's rotation.

There is no hard atmospheric boundary at 75 or 100 km. The planner's warning estimate uses the client's density model and air-relative speed. The 100 km ascent-view transition is a display rule. OVERFLY separately uses 100 km as a minimum clearance policy and also checks dynamic pressure; neither use defines a physical atmospheric boundary.

Automated ascent alpha

Use this section only in a client offering MODE ASCENT. It provides continuous pitch and thrust guidance to a circular parking orbit, including VTOL liftoff. It is not a replay of a recorded pilot's control inputs and does not yet optimize launch windows or predict the whole ascent's time and fuel.

1. Select MODE ASCENT on DOR. A newly selected station or spacecraft while on the ground also selects it. Set ORBIT 200 km MSL for the first test; the range is 150–1000 km in 50 km steps.
2. Use STEER AFCS to follow the selected HDG or NAV heading for an assigned departure. DOR controls attitude and thrust while following that heading. The magenta orbital heading bug and ORBIT HDG … deg T show the desired orbital direction separately. Set the assigned heading or navigation route before engaging.
3. Start approximately level on a clear VTOL departure area, with sufficient vertical-thrust authority for the current loaded weight. Flaps and spoilers must be stowed; icing and open bays are unsupported. A runway takeoff remains manual; ASCENT can also take over an airborne climb.
4. Engage DOR when VTOL READY or ASCENT READY is shown. VTOL first lifts approximately level to 100 m AGL, then transitions to a climb using lift and pitch to direct the main engines. Retract the gear yourself after liftoff. DOR does not operate it.
5. When cleared to turn toward the orbital direction, change STEER to ORBIT. This is allowed during execution. No automatic turn is authorized merely by passing 17 km. AFCS may be selected again if needed; monitor the changed flight path.
6. Monitor IAS/Vne, AFT, pitch, thrust, fuel and AP/PE. The controller uses current mass and separate thrust limits, favors the main engines, and retains bounded translation RCS for liftoff and residual corrections. Its initial speed schedule leaves margin below Vne. A short-term forecast at 95% Vne or 200°C AFT removes positive main thrust and shows ASCENT LIMIT / IDLE; this is a controller margin, not a guarantee against disturbances.
7. After parking-orbit insertion settles, DOR disconnects with the usual sound and shows INSERTION COMPLETE / REPLAN. Select RENDEZVOUS and inspect a new plan to reach the station. ASCENT does not automatically complete rendezvous or switch to TVM.

GUIDANCE ONLY / NO ETA / NO BUDGET means there is no full-flight arrival-time or fuel estimate for this first ascent controller. USED records fuel actually consumed. The green line is the measured current coast, and the parking orbit is a goal; neither is a prediction of the entire powered climb. The controller has no terrain/obstacle avoidance and does not forecast weather along the route. Ground-to-ground SURFACE PLAN remains a separate preview-only objective.

Changing ORBIT altitude or MODE cancels the active ascent. VIEW and STEER can be changed without cancelling it. Manual attitude or thrust input overrides powered ascent; invalid/stale required data, unsupported configuration or loss of authority can stop execution. Retain control of the flight after a disconnect.

DOR automatically records an executed ascent. Keep both matching CSV files from OrbitLogs, including the new ascent commands, steering selection and actual engine/RCS response. REC remains available for a continuous flight capture through manual flight and later maneuvers. Use the procedure below when recording a manual profile.

Recording an ascent

In clients with REC ON (FLIGHT), REC is available in every objective, including when ASCENT PROFILE REQUIRED is displayed. Recording observes the flight; it does not engage DOR, supply an automatic ascent pitch/throttle schedule or change ATC routing. A recording is calibration evidence, not an executable profile loaded into the ship.

1. Before takeoff, select the intended station or spacecraft and open DOR. Select REC with Shift + Up/Down, then press Shift + Left/Right. With no proposed path, the row reads REC ON (FLIGHT).
2. Fly your normal comfortable ascent using manual controls or appropriate existing Autoflyte modes. Follow ATC headings/fixes and make your normal gear, flap, throttle and pitch changes. There is no required 15-degree or 60-degree test attitude.
3. Leave REC on through the thin-atmosphere transition and orbital insertion, including any later DOR maneuver. Changing target, planning controls, VIEW or MFD page does not stop a FLIGHT recording. It remains flight-only even if a plan subsequently becomes available.
4. Once established in the intended orbit, turn REC OFF. Keep both matching DOR-N.csv and DOR-N-plan.csv from OrbitLogs beside the running executable. Note the vehicle, starting load and any unusual weather or ATC interruption when returning the files.

The flight CSV records current mass/fuel, available and delivered thrust, actual pitch/roll/heading, angle of attack, air-relative flight-path angle, radial climb speed, tangential inertial and ground-relative speed, air-data freshness, IAS/TAS, dynamic pressure, AFT, configuration and Autoflyte modes. It distinguishes vehicle attitude from velocity direction. The companion file contains the capture origin and any available current/target trajectory context; it contains no invented reference ascent. Recording stops on REC OFF, vehicle/simulator state reset, client exit, a file error or the size cap. Copy both files before further tests reuse their slot.

If a proposed path exists when REC starts, the row instead reads REC ON (REF). That captures a frozen reference and follows the stop rules under manual reference recording. REF recordings end when the target or planning controls change, or when DOR execution begins.

Change or circularize your orbit

Scenario 3: circularize using MSL altitude. With e = 0, the selected SIZE of 937.0 km MSL matches the final AP and PE. The nearly circular starting orbit needs only a small correction. Fresh labeled scenario render from the instrument code, not a live flight.

1. Select MODE → ADJUST ORBIT.
2. Choose LOCK NONE, LOCK AP or LOCK PE. Locking an apsis preserves its selected radius while you change eccentricity. It does not mean “wait to burn at that apsis.”
3. Change e. With LOCK NONE, also change SIZE. Shift+C on the e row requests a circle; without an apsis lock it uses the planned first-burn radius when available, otherwise your current radius.
4. Choose the departure rule under START. Compare the green current orbit with the amber requested orbit, AP/PE, burn count, fuel and warnings.
5. Engage DOR when satisfied with a valid plan, or use the plan as a reference for manual flying.

START NOW asks for a solution from your current position; you do not have to wait for apoapsis or periapsis. START AUTO compares a limited set of candidate departure times, including apsides for orbital adjustment, and chooses the lowest delta-V among valid candidates. It is not a search of every possible launch window. START AT TIME exposes an IN countdown that you can adjust.

If the requested orbit does not pass through the departure point, the planner may propose a transfer and a second burn to establish the new shape. A request that intersects the surface is rejected. SIZE changes in 100 km MSL-altitude steps, from 100 to 50,000 km MSL; e changes in 0.01 steps. For example, SIZE 600.0 km MSL with e = 0 requests a 600 km circular orbit. You do not add the planetary radius. With nonzero e, SIZE is the midpoint of the AP and PE altitudes, so check both endpoints and PLAN MIN ALT before execution.

Rendezvous with a station or spacecraft

Orbital pressure advisories trigger above 10 Pa. This operating tolerance applies consistently to current-coast, transfer, target and live DOR pressure checks, including OVERFLY's pressure criterion. YSP at 118 km produces approximately 6.3 Pa in the existing client density model, so its orbit alone no longer raises ATMOSPHERIC TARGET. The separate red below-100-km warning and OVERFLY minimum altitude still apply. Targets explicitly in atmospheric-flight reference mode still receive a target warning. Fuel, thrust, orbital-direction and finite-burn checks remain separate; this threshold change does not alter station fuel use or simulate heating.

Scenario 4: a station in a different plane. PLANE DIF is about 38°. The cyan orbit and amber transfer leave the green orbital plane; the station does not need to be directly overhead.

1. Select the target on the navigation/target instrument, then choose RENDEZVOUS here.
2. Set MEET to the desired future arrival time. Each adjustment changes the requested interval by five minutes and establishes a new countdown. The adjustment uses the remaining time currently shown, with limits of 30 seconds to six hours.
3. Compare START NOW, AUTO or AT TIME. If no clear transfer is found, change the arrival or departure time.
4. Use PLANE 3D or EDGE-ON to inspect the plane change, and ORBIT to inspect the transfer shape. Review both burns and the fuel estimate.
5. Engage DOR to execute the selected solution. Continue monitoring the target and warnings.

The planned meeting point is approximately 5 km behind the target along its trajectory. It is a rendezvous staging point, not a docking port or a command to fly into the station's center. Stations follow their modeled motion. Another spacecraft is predicted to coast; if it maneuvers, the original prediction is no longer reliable.

After rendezvous, use the normal close-approach and docking procedures. The Orbit page does not obtain docking clearance or perform docking. TVM remains a separate target-relative velocity control.

Planning inside a station bubble

Scenario 11: undocked inside a station bubble. The ORBIT phase and maneuver estimate remain available. This labeled scenario uses a reconstructed station-relative position and velocity.

A station's nearby reference bubble is a coordinate frame used for smooth motion. Entering it does not mean the ship is docked. You can plan and execute orbital maneuvers while undocked inside it, and select another undocked spacecraft in a station bubble as a rendezvous target. Entering or leaving the bubble alone does not cancel DOR. Actual docking at a station permits planning but blocks DOR arming and execution. Previews use the ship's current position and velocity carried by the station. You can inspect RENDEZVOUS, ADJUST ORBIT, OVERFLY and SURFACE PLAN, including their time controls, while attached. Undock before engaging an executable orbital plan; undocking alone does not arm DOR. The selected deadline remains a countdown, so review the updated solution before engagement. Docking during execution cancels DOR.

Orbit reconstructs a ship's state from the station's modeled instantaneous motion plus the ship's measured relative motion. This avoids the jumping orbital elements caused by subtracting two rounded station positions to estimate velocity. It applies regardless of whether the selected target is a station, a spacecraft or a ground point; no display smoothing delays the values.

Follow DOR through the burns

DOR follows the selected executable orbital plan. SURFACE PLAN cannot engage DOR, even when a route says MODEL FIT. REENTRY in the automated-entry alpha has a separate powered-entry controller. During ALIGN and active burns of executable orbital plans, DOR steers pitch and yaw with rotational RCS, points the nose along the commanded burn direction for forward main-engine thrust, and rolls wings level relative to Vieneo's local horizon. The existing flight director receives burn pitch/heading targets and a level-roll reference; Orbit adds no separate attitude-command panel. In WAIT/COAST these remain guidance for the next burn, not a direction the ship must hold. Near a vertical burn, the horizon roll reference is ambiguous, so the controller preserves a stable roll orientation. DOR does not turn on the aircraft Autoflyte autopilot to do this.

• 

  Scenario 5: departure, 30 seconds after engagement. DOR BURN; TO GO is about 487 m/s. The B1/B2 rows retain the planned burn budgets.

• 

  Scenario 6: the same transfer coasting. B1 is DONE. DOR COAST applies no translation thrust and prepares guidance for the next burn; TO GO now refers to that next correction.

• 

  Scenario 7: arrival correction. DOR ARRIVAL has begun before the planned meeting time. Live TO GO differs from the original B2 estimate as guidance corrects the actual trajectory.

Scenario 19: ALIGN before thrust. A fresh, labeled scenario render from the actual executor, attitude controller and instrument drawing code, not a live client screenshot. DOR is engaged, EXEC and ALIGN are in their visible blink phase, and translation commands are held off while the ship turns. START NOW does not bypass alignment.

ALIGN uses rotational RCS before allowing a burn. It captures within 2 degrees with total angular rate below 0.5 degree/second for at least half a second; more than 5 degrees of attitude error or 2 degrees/second of angular rate returns it to ALIGN. The commanded slew rate is limited to 5 degrees/second per body axis, with braking based on available torque. These are Rise control settings, not an Earth aircraft envelope. Small velocity trims below 2 m/s within the same burn phase retain the established nose direction instead of chasing a reversing near-zero vector; bounded translation controls handle those trims.

The controller uses the vehicle's existing RCS force caps, inertia, lever arms, current mass, installed augmentation-system health, wing damage, electrical power and wear. Rotational effort consumes fuel through the existing propulsion model. DOR can use installed rotational RCS independently of the manual augmentation toggle and its IAS fade. It does not teleport attitude or grant extra torque. Main-engine spool-down and translation-RCS filtering still take time; holding commands off is not an instantaneous removal of residual thrust. The main engines do the bulk orbital acceleration. While aligned, transverse RCS supplies a proportional correction to the thrust direction; small terminal trims retain their separate translation authority. IDEAL duration/fuel and ALL USED measure different things: the former is a main-engine estimate, while the latter includes the fuel actually consumed by all thrusters and idle operation since engagement.

WAIT and COAST allow free attitude control. You may turn the ship in pitch, yaw and roll to look around while DOR remains engaged and the route stays armed. DOR does not force an immediate return to the next burn direction. With the controls released, gentle rotational RCS follows the changing local horizon, lowering the nose as a forward-facing ship travels around Vieneo. It preserves your chosen attitude relative to that changing horizon rather than forcing the nose onto the flight path or restoring level roll. This uses measured motion and planet rotation, not an Earth orbit rate or an altitude cutoff.

When the executor requests a departure, correction or arrival burn, DOR switches to ALIGN, reacquires the burn direction and level roll, and waits for pointing/rate capture before allowing translation thrust. WAIT/COAST alone never command translation thrust. START NOW or reaching a scheduled burn time does not bypass ALIGN. Looking away may therefore add alignment time before the next burn, and the clearance check can refuse that delay. During active burns, remaining delta-V is recalculated from the actual state; it need not decrease smoothly or equal the original burn budget. Completion requires the controller to settle near its goal, so finite burns can finish later than the initial estimate.

Rendezvous completion and TVM

After a successful RENDEZVOUS, DOR automatically hands control to TVM with TVM SET 0.000 km/s, keeping the same selected station or spacecraft. The page reports RENDEZVOUS COMPLETE / TVM and the normal Autoflyte disconnect sound plays once as DOR switches off. This happens when the final position and velocity correction settles, not simply when MEET reaches zero or B2 starts.

TVM commands a velocity match with the selected target; it does not hold the 5 km trail position or provide collision avoidance or automatic docking. Monitor separation and take control for the final docking approach. A manual DOR cancellation or an automatic abort does not engage TVM. ADJUST ORBIT and OVERFLY finish with their normal DOR disengagement.

Powered correction clearance

DOR rechecks each correction from the measured state using a finite powered forecast with Vieneo gravity and the same guidance retargeting law. It budgets alignment as unpowered coast, reserves engine spool and reverser response time, then credits bounded available thrust. Main-engine authority includes current mass, wear, engine health, power and the existing engine derating; small trims use the weaker translation limit. WAIT and COAST receive no hypothetical thrust credit.

This fixes a false CORRECTION MARGIN LOST rejection in which the old check coasted for the entire burn duration using the weakest translation axis. The new check retains surface clearance for RENDEZVOUS and ADJUST ORBIT and the stricter 100 km / 10 Pa requirements for OVERFLY. OVERFLY still checks the remaining approach and continuing orbit and reduces optional position-closing commands that would spoil clearance.

The forecast is a bounded two-body estimate with constant mass and ideal steering after alignment. It is not a complete actuator, drag, lift, terrain or heating simulation. DOR rechecks when actual measurements change; unavailable authority, inadequate alignment time, or an unsafe powered response can still disconnect it. Ground takeoff, atmospheric cruise, reentry and landing remain outside DOR execution.

Scenario 20: powered recovery remains engaged. Fresh labeled render from the actual planner, executor and drawing code. ADJUST ORBIT requests a 500 km circle from a slow suborbital state; the unrelated selected station is not the objective. The negative current PE and red ATM PASS warning describe the unpowered coast. The powered correction passes its separate check. An independent finite-thrust regression with ideal steering and engine spool completes above 419.3 km, despite repeated rejection by the old coast-only guard. Synthetic example, not a live flight or reconstructed player telemetry.

If no qualifying correction exists, DOR clears its thrust and attitude commands, disconnects with the existing sound, and retains a reason such as DOR: NO CLEAR CORRECTION, DOR: CORRECTION MARGIN LOST, DOR: FINAL ORBIT UNSAFE or DOR: COAST CLEARANCE LOST. A delayed departure can report DOR: DEPARTURE COAST UNSAFE. Alignment checks the measured unpowered path for the estimated turning time and engine response, followed by the powered correction: DOR: ALIGN MARGIN LOST means it cannot safely spend that time turning. OVERFLY retains its atmospheric-clearance requirement; other orbital objectives retain their existing surface-clearance checks and atmospheric cautions. DOR: NO ATTITUDE CONTROL means the attitude data or required rotational authority is unavailable. Disconnecting does not recover an unsafe trajectory. Inspect your actual PE and warnings, then take over or select a different valid recovery plan.

Use DOR off to take over. Manual thrust-increase/decrease key commands also disengage it. Pitch/yaw/roll inputs in WAIT or COAST leave DOR engaged. During ALIGN or either active burn (BURN or ARRIVAL), a pitch, yaw or roll key command disconnects DOR immediately; joystick pitch, roll or yaw input outside the configured dead zone also disconnects it. Those disconnects use the existing Autoflyte disconnect sound. Stale guidance, invalid control data and Flight Freeze suppress rotational commands. Normal control resumes through the existing manual controls after disconnect. Changing planning values, losing/changing a rendezvous target, losing cockpit power, docking/landing, or changing/resetting the vehicle's flight state cancels execution. After a cancellation, inspect the reason and solve again before re-engaging. VIEW changes alone are safe to make during execution.

Every transition from DOR on to off plays the existing Autoflyte disconnect sound once. This includes normal plan completion, automatic aborts, manual takeover, switching to TVM, and a disconnect caused by loss of cockpit power. Completion and abort messages remain visible so you can inspect the reason. Remaining off does not repeat the sound, and restoring power does not replay it; engaging DOR again re-arms the next disconnect. This behavior follows DOR engagement, without an altitude or airspeed cutoff, and also applies in the simulator.

Pass over a ground point

Scenario 8: overfly. A surface point is selected, with a 900 km pass in 40 minutes and EXIT COAST. The ground track accounts for Vieneo rotating beneath the flight path.

1. Select a surface waypoint, then choose OVERFLY.
2. Set ALT above the spherical reference surface, in 100 km steps, and PASS time, in five-minute steps.
3. Select EXIT COAST to continue on the transfer orbit after the crossing, or EXIT CIRCULARIZE to establish a circular orbit after passing the waypoint.
4. Set START, inspect the ground track and orbit views, and review the burn estimates before using DOR.

On entering OVERFLY, the planner searches for an early viable PASS time using the selected ALT, EXIT and START settings. It checks the route and continuing orbit against the OVERFLY clearance requirements below, available fuel and the preview's burn-duration limits. Automatic PASS suggestions also exclude orbital reversals. It searches up to six hours ahead in 30-second intervals, refines the first viable interval to one second, and adds up to 30 seconds of headroom when that later candidate also passes the checks. This is a useful starting estimate, not a guaranteed global minimum or a guarantee of flight performance. Very narrow windows can be missed. It does not minimize fuel.

While searching, FINDING PASS TIME replaces the plan and DOR cannot engage it. NO VIABLE PASS IN 6H means no candidate met these criteria in the bounded search; it does not prove that no possible route exists. Change ALT, EXIT or START, or choose a manual PASS time to inspect other estimates. Weather at the selected point is not an input to the transfer solver.

The initial countdown stays fixed once selected. Until you edit PASS directly, changes to ALT, EXIT or START/IN request a new suggestion. After a direct PASS edit, your chosen deadline is retained, including an invalid or warning-producing one; the planner does not silently move it back into a valid window. Decrease or increase the displayed remaining time in five-minute steps (30 seconds to six hours). To request another automatic starting estimate, leave OVERFLY and select it again. VIEW changes do not restart the search. Automatic suggestions never change an executing DOR plan; manually changing planning values still cancels execution.

The older illustration above demonstrates the layout, not automatic PASS initialization. The clearance illustration below is a labeled code-generated scenario, not a live-flight capture.

Why a low pass may have no clear transfer: Reaching 200 km above the point is not enough if the approach dips into the atmosphere or the continuing orbit returns there. EXIT COAST requires the full continuing orbit to remain bound and clear. EXIT CIRCULARIZE adds an arrival burn, but cannot make an earlier atmospheric dip acceptable. Changing PASS, ALT or EXIT may produce a valid route. Manual PASS retains your requested deadline and may display a blocked trajectory; it cannot override OVERFLY atmospheric clearance. Long-burn estimates can still be inspected manually.

Overfly meets a moving ground location at a chosen time; it does not hover above it. A circularization burn belongs after the crossing and can change where the spacecraft travels afterward. The pass altitude is not clearance above local terrain.

Overfly atmospheric clearance

OVERFLY checks the waiting coast, approach to the waypoint and continuing orbit. Each must stay at or above 100 km MSL and have a conservative dynamic-pressure bound of 10 Pa or less. EXIT CIRCULARIZE also checks the unbraked arrival path over an estimated response interval before crediting the final circular orbit. A clear later circle does not excuse an earlier low pass. The solver prefers a qualifying transfer over a cheaper atmospheric alternative.

The pressure estimate uses the client's 3.063 kg/m³ surface density, 7.5 km scale height and a conservative bound on air-relative speed at the lowest point of the checked arc. At orbital speed, this can require clearance higher than 100 km. These are operational planning checks, not a validated heating envelope, drag-integrated trajectory or guarantee of finite-burn performance. Vieneo's nitrogen/sulfur-dioxide/oxygen atmosphere is retained; no Earth heating coefficients or new atmospheric boundary are introduced. The published Vieneo scale height is 7.5 km, matching the client and server models.

Steady red PLAN MIN, COAST MIN or CORRECTION MIN identifies which trajectory falls below 100 km, with its minimum altitude in km MSL. EXEC PATH <100km identifies another low path checked by the executor. These can warn while your present altitude is much higher. The current-coast indication clears at 105 km to prevent flicker; its displayed number remains the actual predicted minimum during that hysteresis interval. This does not relax the solver's 100 km limit. Ground/reset state clears stale orbital warnings. Pressure advisories such as COAST ATM q>10Pa stay amber when there is no low-altitude warning. Warnings remain visible during both EXEC blink phases and after an abort.

A blocked preview shows NO PLAN, ATM PASS - NO PLAN and MIN … km / BLOCKED where a rejected trajectory is available. DOR cannot engage that preview. Atmospheric penetration remains possible to display for other orbital objectives, and the atmospheric stages of SURFACE PLAN remain planning-only; this OVERFLY restriction is not a blanket exclusion of atmospheric flight or reentry.

Cockpit Q is forward dynamic pressure in lb/ft²: Q = 2 is about 96 Pa, not 2 Pa. It is not a direct temperature or burn-up indication, and the planner's conservative arc-pressure bound is not the same as that instantaneous cockpit component.

Scenario 17: atmospheric overfly blocked. Fresh labeled render from the actual planner and instrument code. A synthetic 905 km orbit requests a 200 km COAST pass in 180 minutes, but the candidate falls to 65.3 km. The red MIN ROUTE ALT 65.3km MSL, atmospheric warning and NO PLAN identify the rejection before engagement; the independent retrograde/reversal caution remains visible. This is not a live client screenshot or a reconstruction of player telemetry.

Surface journey planning

For a ground or low-atmospheric departure, select point B on the normal target instrument. On this page choose MODE SURFACE PLAN, then ROUTE and TRIP while on the ground, or PASS when already airborne. For a departure from orbit or an orbital station, use the REENTRY controls below instead. Docking prevents execution, not planning. SURFACE PLAN remains planning-only after undocking; a qualifying REENTRY plan in the automated-entry alpha can be executed.

Local trips: SURFACE PLAN shows NO PLAN / TOO SHORT when the departure and destination are less than 5 km apart, including their height difference. It does not generate a climb path, fuel estimate or initial time search for these trips. A coincident destination on the ground shows ALREADY AT B. Fly the local hop using ordinary flight controls or suitable Autoflyte modes; changing TRIP/PASS or forcing ATM, SUB or ORB does not create a local takeoff/hover/landing profile. This is a limit of the surface planner, not a vehicle flight limit. Orbital REENTRY and an entry already in progress are exempt.

ROUTE	Proposed profile
AUTO	Compare the three route families at the selected TRIP duration or PASS deadline. Choose the lowest estimated fuel among candidates that pass the simplified model checks. AUTO may choose a different family when the selected time changes.
ATM	A powered atmospheric profile, climbing to 20 km MSL, traversing toward B, then descending. Only offered for departures at or below 40 km in this initial model. It is not a simulation of wing-borne cruise.
SUB	Powered climb and boost, a ballistic coast with a surface-intersecting osculating orbit, then powered braking and descent. The coast ends before the intersection.
ORB	Powered climb and boost, a circular coast nominally at 400 km MSL, then powered braking and descent. This need not complete a revolution.

TRIP is the requested travel duration before departure. While on the ground with REC off, it stays steady: TRIP 30:00 means a 30-minute journey starting when you depart. Waiting on the ground does not consume that allowance or make the same route require more thrust and fuel. At liftoff the deadline is fixed and the row becomes PASS, counting down to arrival. Starting REC also fixes the reference at capture start, even if you are still on the ground; it must not slide forward during a calibration recording. Ending REC while still grounded restores the selected TRIP duration. Landing with REC off also restores duration planning. An already-airborne surface preview uses PASS from the time it is selected.

Adjust TRIP/PASS in five-minute steps using the value shown (30 seconds to six hours). This is a timing constraint, not an AUTO preference switch. The comparison shows each family's estimated fuel and MODEL FIT, THRUST LIMIT, FUEL LIMIT, IAS LIMIT or another reason. A forced ATM/SUB/ORB choice is retained even when invalid; AUTO does not silently replace it. If nothing fits, AUTO can display a rejected candidate for inspection. The upper-right header says INVALID in red; PLAN ONLY is reserved for a fitting preview, and NO PLAN means no candidate is available. The rejected path and estimates remain visible to help you adjust the timing; they are not achievable flight commands. Longer times are not guaranteed to help: gravity support consumes fuel and the search covers only a limited family of profiles.

On first selecting this objective, the module searches for an initial model-fitting trip time up to six hours: two-minute trial spacing, ten-second refinement of the first fitting bracket, and up to 30 seconds of headroom if that candidate also fits. FINDING TRIP TIME identifies the grounded search; NO FITTING TRIP IN 6H means this bounded search found none, not that every possible trajectory is impossible. Airborne previews use FINDING INITIAL PASS / NO FITTING PASS IN 6H. A manual edit keeps your chosen duration or deadline, including an invalid one. Changing ROUTE requests a new suggestion only before the time has been edited manually. Leaving and reselecting SURFACE PLAN restarts automatic initialization. The search never rewrites an executing orbital plan.

The amber path joins the measured initial state to B's position at PASS, accounting for Vieneo's rotation. PLANE 3D and TRACK can show the whole journey even before takeoff. For space profiles, markers 1–4 indicate the end of climb, start of coast, start of braking and start of descent/entry; B is the future destination. These are preview phase boundaries, not flight-director commands. ATM has only its final B marker. The top flight-phase label describes your current state, independently of the proposed route.

Surface readout	Meaning
RANGE	Current great-circle distance to B, in km; not full path length. Below 10 km, one decimal place is shown (for example, 0.5 km).
TOP	Highest sampled profile altitude, km MSL above the spherical reference surface.
TOTAL	Integrated powered acceleration, expressed as delta-V in m/s, including gravity support and modeled body drag. This can greatly exceed the vehicle's speed; it is not a cruise-speed command.
FUEL	Estimated kg for the selected ideal profile, including idle flow during coasts.
THRUST	Peak fraction of available main-engine thrust. More than 100% is shown in red and invalidates the candidate. If IAS also exceeds its limit, the reason reads IAS / THRUST LIMIT so neither failure is hidden.
MAX q	Highest sampled dynamic pressure in kPa, based on mass density and air-relative speed. It is informational, not a validated heating or structural limit.

MODEL FIT is not flight clearance. The preview uses Vieneo gravity and rotation, the client's 3.063 kg/m³ surface density and 7.5 km density scale height, vehicle main thrust, altitude efficiency, fuel flow, wear and empirical body drag. The published Vieneo scale height matches the 7.5 km used by both client and server. Cruise at 20 km, the 100 km powered-segment interface and nominal 400 km orbital coast are planning choices, not atmospheric boundaries.

These ground-departure powered segments assume ideal thrust direction. They do not simulate RCS-axis limits, vehicle attitude changes, spool response, wing lift, wing/tail/wave drag, wind, clouds, weather avoidance, heating or terrain. ATM supports weight with thrust, so its fuel estimate is not a prediction of ordinary wing-borne Autoflyte cruise. Sampled geometry checks a reference sphere; it does not establish terrain clearance or that point B is a suitable landing site. Fuel comparisons and AUTO's choice are therefore comparisons within this simplified model, not a global optimum or a recommendation to fly the displayed path. Direction reversals remain visibly cautioned.

PLAN ONLY / ATM HANDOFF means the atmospheric stages require separate pilot/Autoflyte operation. SURFACE PLAN provides no automatic mode handoff, takeoff, atmospheric guidance, hover or landing. Orbital REENTRY has its own alpha controller described below. The end-state is an ideal planning endpoint at B, not a landing command. Pressing DOR on a surface preview leaves execution off and plays the Autoflyte disconnect cavalry sound once to acknowledge the refusal. Holding the key does not repeat the sound. Existing executable ADJUST ORBIT, RENDEZVOUS and OVERFLY plans remain separate.

The dated scenario illustrations below use the earlier PASS label before takeoff; current ground previews display TRIP.

• 

  Scenario 13: ATM, 500 km in 60 minutes. Local ascent preview and route comparison. The large TOTAL includes ideal powered gravity support. Labeled synthetic render, not a live flight.

• 

  Scenario 14: SUB at the same PASS. Whole-route PLANE 3D view while still on the ground, with ballistic coast and numbered phase boundaries. Labeled synthetic render.

• 

  Scenario 15: AUTO, 4000 km in 90 minutes. ORB fits the simplified model while ATM and SUB exceed thrust. This demonstrates the PASS constraint, not certified flight performance. Labeled synthetic render.

Reentry and atmospheric entry

Select the intended surface waypoint on the usual navigation instrument. For an orbital departure, choose REENTRY. Planning is available while docked; undock before engaging DOR. The automated-entry alpha can fly an ENTRY READY profile from at least 100 km MSL to its atmospheric handoff. It requires current air data, main/reverse and translation thrust, and a clean configuration: gear, flaps and spoilers retracted, bay closed and no significant icing. A plan lacking those inputs, or newly planned below 100 km, remains PLAN ONLY. Earlier calibration clients label this mode REENTRY PLAN and cannot execute it.

The initial handoff is 30 km MSL at 0.5 km/s TAS, upstream of the selected surface point. These are adjustable test conditions, not universal safe limits. The handoff is level flight aimed toward the surface point; it is not touchdown. HANDOFF counts down to that atmospheric transition, not touchdown at the waypoint. The planner estimates the remaining glide reach using the vehicle's clean-air aerodynamic data. FINAL HOLD retains that general-purpose handoff. The arrival-planning alpha also offers runway/hover previews described below. None establishes obstacle clearance or an achievable unpowered glide all the way to B.

Control	Meaning
ROUTE AUTO	Compare direct powered entry and coast-then-entry at the selected handoff time. Among model-fitting candidates, choose the lower estimated fuel requirement. This is a bounded search, not a global optimum.
ROUTE ORB	Remain on the measured current orbit for a selected coast, then enter. The preview does not first force the ship into a nominal 400 km orbit.
ROUTE SUB	Begin a direct powered entry after allowing time to align, without a discretionary orbital coast. Its feasibility depends on the requested time, position, velocity, weight and available thrust.
H ALT	Atmospheric handoff altitude, km MSL. Adjust in 5 km steps, from 15 to 60 km.
H TAS	Air-relative handoff speed, km/s. Adjust in 0.1 km/s steps, from 0.1 to 1.5 km/s. This is not IAS or orbital speed.
HANDOFF	Requested remaining time, adjusted in five-minute steps. A shorter time may require greater powered acceleration or braking, or have no fitting candidate.
REC	Record a manual test and the selected reference plan without engaging DOR. See below.

ATM remains an atmospheric-departure option in SURFACE PLAN. It is not offered as an orbital entry shortcut. Ground/low-atmospheric SURFACE PLAN retains its separate AUTO / ATM / SUB / ORB route families and TRIP/PASS arrival at B; the new entry controls describe an atmospheric handoff before B.

D marks deorbit/start of the powered profile, E the sampled crossing of 100 km, and H the atmospheric handoff. The 100 km marker is an operating reference, not a hard atmosphere boundary. Gray is the planned coast on the current orbit; amber is the proposed powered entry. The graphic area remains the same size in every view.

REV and RCS show peak required fractions of the corresponding available thrust. The entry model uses current loaded mass, fuel consumption, main-engine condition, separate forward/reverse and up/down/side limits, engine response, Vieneo gravity/rotation/density, and the client's clean wing/tail/body and Mach-dependent aerodynamic model. It estimates AFT from the client's heat-transfer model. MAX q is the modeled effective aerodynamic pressure in kPa, including the client's Mach augmentation; it is distinct from ambient-density dynamic pressure. Cockpit Q is in lb/ft². LOAD is estimated non-gravitational acceleration in standard Earth g units.

The alpha's preview reports peak IAS as a percentage of Vne and peak predicted AFT. It requires at most 95% of Vne, 200°C predicted AFT and 95% of each available thrust axis, plus its engine-response and attitude-rate checks. These are controller settings for validation, not newly established vehicle limits. AFT forecasting uses Vieneo's model and the current measured temperature/wind; it does not forecast changing weather, clouds or turbulence along the route. ALPHA / NO TERRAIN CHECK remains a limitation: the profile has no terrain or obstacle database and no automated final-descent or landing controller. Keep entry procedures, AFT, IAS/Vne and flight path in view.

Entry readiness and configuration: A route can fit the fuel, thrust and temperature limits while the ship is not ready to execute it. PLAN ONLY with an amber CONFIG LANDING GEAR, CONFIG FLAPS, CONFIG SPOILERS, CONFIG AIRFRAME ICE or CONFIG CARGO BAY identifies the configuration that must be corrected. Air, thermal or performance data problems have their own messages. Retract gear, flaps and spoilers fully, close the bay and clear icing before entry. Landing gear must also have confirmed status: a GEAR DISAGREE condition or unknown gear status prevents entry even if the gear appears retracted. The DOR page continues to show CONFIG LANDING GEAR. READY / ENTRY READY and ARM DOR TO EXECUTE indicate that the entry readiness checks pass; selecting AUTO does not engage DOR.

If gear prevents engagement, DOR remains off, announces its disconnect sound and queues "Config. Landing gear." The refusal is also shown in red. Extending gear or losing confirmed gear status during an executing entry invalidates the clean profile and disconnects DOR, releasing its attitude and thrust commands with the same specific alert. Take control after a disconnect; DOR does not retract gear or automatically re-engage. A new entry still requires an origin at or above 100 km MSL. The queued gear phrase is discarded if the gear is confirmed fully retracted, power is lost, or the relevant vehicle/plan changes before playback. Normal gear use after the achieved atmospheric handoff does not trigger this entry-specific warning; the ordinary aircraft-mode limits still apply.

Automated entry alpha

1. Start with a clean ship in orbit and select the surface destination. Use AUTO, H ALT 30 km and H TAS 0.5 km/s for the initial test.
2. Adjust HANDOFF until the preview says ENTRY READY. Shortening it asks for a faster journey; IAS RESERVE, AFT RESERVE, THRUST RESERVE, ATTITUDE RATE or SPOOL LIMIT identifies why a candidate is rejected. A longer time is not guaranteed to fit every geometry. Check fuel and the whole proposed path.
3. Undock if necessary, then engage DOR. AUTO selects a route; it does not engage DOR by itself. An accepted entry starts a CSV capture automatically, so REC is not required for this test.
4. During coast DOR pre-aligns for entry. During POWERED ENTRY it keeps the nose into the air-relative direction of travel with a small positive angle of attack, using forward or reverse mains and bounded translation RCS. Braking does not require pointing the tail into the airflow. Manual attitude input during ALIGN or powered entry disconnects DOR.
5. ENTRY LIMIT / BRAKING means the short-term forecast predicts excessive IAS or AFT. DOR gives braking and descent control priority over the requested time; HANDOFF may be missed. This is active protection, not a guarantee against every disturbance or an instruction to ignore warnings.
6. At the achieved handoff, expect the ordinary DOR disconnect sound once. FINAL HOLD transfers to ALT/HDG/TAS hold; a valid runway FINAL selection transfers to ALT/NAV/TAS hold on the inbound course. The autopilot holds the selected MSL altitude and the entry autothrottle holds the selected TAS. It does not descend toward or land at B. HANDOFF PASSED alone is not completion: altitude, airspeed, descent rate, position and attitude must also converge.
7. To resume normal flight, cancel the entry TAS hold with the DOR control or by moving a physical throttle lever. The altitude and heading holds remain until changed or disconnected. Disconnecting the aircraft autopilot also ends the TAS hold. In the arrival/FPA alpha, TAS hold continues with HDG, NAV or LOC and PIT, VS, ALTm, ALTa, FPA or G/S. Selecting SpeedPitch, Roll, an off mode or TVM ends it. Ordinary gear/flap/spoiler changes after handoff retain TAS hold with updated drag compensation; icing, an open bay, unavailable/stale air data or lost authority still cancel it. Change H TAS on the DOR page to adjust the held speed. Take over for ATC routing, descent and approach; a fixed TAS can produce increasing IAS as you descend, so reduce it appropriately.

Automatic recording continues through the handoff holds until they are cancelled. Retain both matching CSV files for review of the actual response, predicted heat/IAS, force commands, available thrust and handoff modes. Start testing with a comfortable preview, then shorten the requested time on subsequent flights; the alpha is not a certified fastest possible entry.

Arrival planning and final approach

These controls require the arrival/FPA alpha, which is newer than the ascent-recording alpha. They are available on REENTRY, not on ground-departure SURFACE PLAN. Choose FINAL with the usual Shift + arrow controls before engaging DOR. A new surface target resets FINAL to HOLD; selecting a destination does not silently authorize an approach or landing.

FINAL	Preview and handoff
HOLD	The default: atmospheric entry followed by ALT/HDG/TAS hold.
ILS (PLAN)	Select a live, fully serviceable runway ILS or an outer-marker/LOM waypoint with one unambiguous associated inbound runway. The preview uses the marker's distance when available, otherwise the selected final distance (initially 10 km). Its final gate is 50 m below the nominal 3° beam for an eventual level intercept. The displayed ≤30° intercept is a planning objective for the manual final, not an automatically enforced capture condition.
VISUAL (PLAN)	Select a runway threshold with a published inbound heading. A second FINAL row adjusts the extended-centerline distance from 6 to 30 km in 2 km steps; the initial value is 10 km. The gate follows a 3° ray above the runway's local tangent plane, corrected for Vieneo's curvature. Ten km is approximately 0.54 km above the runway; the readout is MSL, so runway elevation is added.
VTOL (PLAN)	Preview a hover gate 100 m above the selected surface point. Current vertical-thrust authority must exceed the weight-support requirement at the loaded mass. This is not a terrain-clearance check or a commanded hover/landing.

Runway selections position the atmospheric entry handoff upstream on the runway's extended centerline and point its ground-relative path inbound. The automated portion still ends at H ALT / H TAS (initially 30 km / 0.5 km/s), not at the low final gate. A successful runway entry transfers to ALT NAV SPD / FINAL MANUAL. The gray final line and FINAL … km MSL / MANUAL altitude are advisory geometry. DOR does not execute that line, descend to the LOM, arm LOC/G/S, flare or touch down. VTOL also retains the atmospheric altitude/heading/speed handoff; it does not switch to TVM or descend automatically.

After handoff, manage the remaining energy and descent with the aircraft controls. For an instrument approach, select the correct runway/radio course and use the normal LOC/G/S controls when appropriately positioned below the glidepath, within a 30° inbound intercept and at a suitable speed. A LOM is a fix, not the runway threshold or the origin of the ILS beam. Airport names and proximity alone do not identify a runway. SELECT RUNWAY / LIVE ILS or SELECT RUNWAY THRESHOLD means the required data are absent or ambiguous. Changing associated approach data during DOR entry stops execution with APPROACH DATA CHANGED.

Flight path angle (FPA)

The normal vertical flight-director cycle is PIT → FPA → VS → SPD → ALTm → ALTa → PIT. FPA follows Pitch directly. ALTa is skipped when the required ground-height data are unavailable; G/S remains separately armed. FPA captures the current ground-relative climb/descent angle. Use the existing vertical-target increase/decrease controls to adjust it; the selected signed angle appears in the flight-mode display. The selectable range is −15° to +20°. For a descending 3° path, select −3°.

FPA is the angle of travel relative to the local ground tangent, not nose pitch or angle of attack. The controller adjusts pitch as the measured path changes; its pitch command changes by at most 3°/s. Aircraft response, wind, lift and available thrust still determine whether it can achieve the selected path. FPA controls neither lateral course nor speed, and does not provide terrain avoidance, a flare or touchdown. It can be used as a flight-director cue or with the normal aircraft autopilot; it is not an orbital insertion solver or a DOR ascent profile.

At ground contact, below 0.010 km/s horizontal groundspeed, or with invalid path data, FPA returns to PIT at the current pitch. It does not automatically re-arm: select FPA again after establishing forward flight. This prevents a hover or nearly vertical trajectory from being treated as an ordinary forward flight path. Ground-relative geometry remains defined at high speed, but selecting FPA does not establish atmospheric control authority in suborbital coast or orbit.

The CSV records selected FPA/course, AFCS ground/vertical speeds, arrival choice, final-gate geometry and its advisory status. The companion plan file labels the final line final_advisory_not_executed. Actual lateral/vertical thruster output remains recorded; a human's recorded firings are not replayed as the optimal control sequence.

Recording a manual entry test

1. Select the target, route, handoff time, altitude and TAS; wait for an inspectable proposed path.
2. Select REC and press Shift + Left/Right once to turn recording on. With the proposed path available, the row reads REC ON (REF). This does not engage DOR or command the ship.
3. Fly the test manually or with appropriate existing Autoflyte modes. Changing VIEW or leaving the MFD page does not stop recording. The CSV reference stays fixed at recording start even while the live preview updates.
4. Turn REC off to finish. Changing planning controls, changing target, resetting/changing the vehicle, or engaging an executable DOR plan also ends the manual capture. A new test requires REC on again.
5. Return both matching files from the OrbitLogs directory beside the running executable: DOR-N.csv and DOR-N-plan.csv. The first contains actual flight data and timed comparison values; the second contains the frozen reference trajectory.

Four reusable file slots bound retention; older captures can be replaced by subsequent starts. A slot stops at 128 MiB rather than discarding its beginning. REC FILE ERROR or REC FILE FULL means capture has stopped. Current clients can start REC ON (FLIGHT) without a reference; older entry-calibration clients instead display REC WAIT FOR PLAN. Copy the pair you want to keep before beginning more tests. No automatic upload occurs.

New captures separately integrate main-engine, translational-RCS, attitude-RCS and idle fuel consumption, and record the available orbital MECO estimate. The tank-based ALL USED remains the measure of fuel actually lost; integrated component totals can differ slightly because of fuel-tank rounding.

The CSV includes time, target, mass/fuel, position/velocity, engine and RCS outputs, air-relative velocity, IAS, Mach, dynamic pressure, measured AFT and reference errors. The automated-entry alpha also records the predicted AFT/IAS reference, the live protection forecast, controller limits, force requests and handoff holds. Earlier calibration captures contain measured AFT but no predicted temperature reference. An expired HANDOFF or end of recording does not prove that the entry was completed successfully.

Warnings and unavailable plans

Message	Meaning / next action
VACUUM ESTIMATE	An orbital estimate is available. It assumes two-body coasting between instantaneous planned burns.
LONG BURN - ESTIMATE / FINITE BURN NOT CORRECTED	The preview's instantaneous-burn approximation is weak for the estimated duration. Live DOR corrects from actual state, but the original time, path and fuel are estimates.
PLAN ATM PASS / COAST ATM q>10Pa / CORRECTION ATM q>10Pa / CURRENT ATM q>10Pa / ATMOSPHERIC PASS / ATMOSPHERIC TARGET	Pressure advisory above 10 Pa, or a target explicitly in atmospheric-flight reference mode. The actual predicted coast is refreshed during execution. Other orbital modes can retain atmospheric estimates; OVERFLY must satisfy its stricter clearance requirements.
PLAN MIN / COAST MIN / CORRECTION MIN / EXEC PATH <100km	Steady red low-altitude warning identifying the affected trajectory. The numerical minima are km MSL. COAST MIN assumes no further burns and can differ from PLAN MIN ALT. The current-coast warning clears at 105 km; this is annunciation hysteresis only.
ATM PASS - NO PLAN / MIN … km / BLOCKED	An inspectable OVERFLY candidate fails atmospheric clearance. Change PASS, ALT or EXIT; DOR cannot execute it.
DOR: NO CLEAR CORRECTION / CORRECTION MARGIN LOST / FINAL ORBIT UNSAFE / COAST CLEARANCE LOST / DEPARTURE COAST UNSAFE	Execution stopped because the updated trajectory or correction fails its checks. Thrust commands are cleared and the disconnect sounds once. The existing trajectory still needs pilot attention.
SURFACE INTERSECTION / NO CLEAR TRANSFER	The requested shape intersects Vieneo, or no acceptable transfer was found. Raise the requested periapsis or change the timing/objective.
INSUFFICIENT FUEL / PERFORMANCE UNAVAILABLE	Fuel or propulsion data do not support execution. A geometric estimate alone is not an executable DOR plan.
BURN TIME PASSED / ARRIVAL TIME PASSED	The selected deadline has passed. Edit the time to request a new one; these are real countdowns, not indefinitely rolling delays.
SELECT NAV TARGET / NO TARGET TRAJECTORY	Select a usable target, or choose ADJUST ORBIT.
DOR: UNDOCK TO EXECUTE	An orbital plan can be previewed while attached to a station, but DOR cannot arm or execute it until undocked. Undocking does not engage DOR automatically. SURFACE PLAN remains planning-only. A qualifying automated-entry REENTRY still requires undocking before execution.
NO DEPARTURE STATE / POWER OFF	The departure reference is unavailable or unsupported, or cockpit power is off. A valid station attachment permits previews; an unsupported containment frame does not.
ASCENT PROFILE REQUIRED	The selected vacuum orbital objective has no powered launch solution. Choose MODE ASCENT in the ascent alpha, or fly and record a manual ascent.
VTOL READY / ASCENT READY	ASCENT can engage with the current inputs. This is not a full-flight fuel, time or terrain-clearance guarantee.
VTOL LIFT / ATTITUDE LIMIT / ASCENT DATA INVALID	Check loaded vertical-thrust authority, level ground attitude, configuration and valid current air data.
ASCENT LIMIT / IDLE	The short-term ascent forecast is at its IAS or AFT guard. Positive main thrust is reduced; monitor the actual path.
INSERTION COMPLETE / REPLAN	Parking-orbit ascent has ended. Select and review RENDEZVOUS separately to continue to the target.
PLAN ONLY / ATM HANDOFF	The displayed candidate is preview-only; DOR cannot execute it. Ground-departure SURFACE PLAN remains preview-only. REENTRY needs a qualifying ENTRY READY profile in the automated-entry alpha.
INVALID / MODEL FIT / THRUST LIMIT / FUEL LIMIT / IAS LIMIT / IAS / THRUST LIMIT	Result of the surface preview’s simplified checks. MODEL FIT does not certify terrain, heating, weather, maneuverability or landing.
NO TERRAIN / HEAT CHECK	SURFACE PLAN and older calibration previews omit these checks. Automated-entry REENTRY predicts heat but still displays ALPHA / NO TERRAIN CHECK.
ENTRY READY / IAS RESERVE / AFT RESERVE / THRUST RESERVE / ATTITUDE RATE / SPOOL LIMIT	Automated-entry preview result. READY passes the modeled checks; other messages identify a rejection. None certifies terrain clearance or landing.
ENTRY DATA / CONFIG	Entry cannot execute with the current air data, configuration or departure altitude. Check clean configuration, valid measurements and an orbital departure.
ENTRY LIMIT / BRAKING	Active entry protection prioritizes braking and arresting descent over the requested handoff time. Monitor the actual trajectory.
MODEL FIT / HEAT UNCHECKED	Older calibration-client preview; it does not support automated entry.
HANDOFF BELOW TARGET	Raise H ALT above the destination elevation.
ENTRY DATA UNAVAILABLE / ENTRY GEOMETRY / NO COAST / ENTRY FIT	Required performance data or a fitting entry candidate is unavailable. Inspect the selected time, route and handoff settings.
REC FILE ERROR / REC FILE FULL	Capture stopped because of a file error or size cap. See recording instructions.
ENTRY FIRST / NO ROUTE AT THIS PASS	Direct ATM is outside its initial departure-height range, or no candidate was available at this deadline. Change ROUTE/PASS or use separate entry procedures.