feat: Fly is KLAX to KSFO, the pack is a gauge, and Crow is not the outdoor door

The assisted corridor used downtown coordinates, so "fly to San Francisco"
arrived over City Hall. Waypoints are the field centres. The HUD already
had watt-hours; it now shows pack percent, which is the gauge. Anon
outdoors no longer gets Explore-as-crow — Fly is the body. The crow kit
stays in the repo for Arena.

Satellite fixes now carry the sub-satellite point. `nextOverCalifornia`
is the handoff the follow camera will use; it is not the camera yet.

src/aircraft/sceneAircraft.ts

@@ -21,10 +21,17 @@ import {
   type AircraftWaypoint,
 } from "./controller.ts";
 
+/**
+ * Assisted corridor: KLAX to KSFO.
+ *
+ * Downtown coordinates used to stand in for the airports, so "fly to San
+ * Francisco" arrived over City Hall. These are the field centres. Climb is
+ * authored on the waypoints; the envelope still caps the ceiling.
+ */
 export const CALIFORNIA_AIR_ROUTE: readonly AircraftWaypoint[] = Object.freeze([
-  Object.freeze({ id: "los-angeles", lat: 34.0522, lng: -118.2437, altitudeM: 1_350 }),
+  Object.freeze({ id: "klax", lat: 33.9416, lng: -118.4085, altitudeM: 400 }),
   Object.freeze({ id: "central-valley", lat: 36.45, lng: -120.45, altitudeM: 1_700 }),
-  Object.freeze({ id: "san-francisco", lat: 37.7749, lng: -122.4194, altitudeM: 1_250 }),
+  Object.freeze({ id: "ksfo", lat: 37.6213, lng: -122.379, altitudeM: 400 }),
 ]);
 
 export type AircraftProjection = (lat: number, lng: number) => readonly [x: number, z: number];

src/engine/satellites.ts

@@ -84,6 +84,13 @@ export interface SatelliteFix {
   elevation: number;
   /** Observer to satellite, in kilometres. Straight-line, not ground track. */
   rangeKm: number;
+  /**
+   * Sub-satellite point, degrees. The ground under the spacecraft, not the
+   * look-angle on the dome. Follow cameras use this; `starlinkMesh.ts`'s
+   * `nadirOf` is attitude of a mesh on that dome and is the other question.
+   */
+  lat: number;
+  lng: number;
   /**
    * How much of the sun's disc the earth is covering, from the satellite's point
    * of view. `0` is full sunlight, `1` is umbra, and the values in between are
@@ -271,7 +278,8 @@ export class SatelliteCatalogue {
     const eci = state?.position;
     if (eci === undefined || typeof eci === "boolean") return null;
 
-    const look = ecfToLookAngles(this.observer, eciToEcf(eci, gmst));
+    const ecf = eciToEcf(eci, gmst);
+    const look = ecfToLookAngles(this.observer, ecf);
     // Below the horizon is the common case by a wide margin — a few hundred of
     // several thousand objects are up at any instant — so this returns before
     // the shadow calculation rather than after it.
@@ -282,6 +290,9 @@ export class SatelliteCatalogue {
     // partway through a session, long after it was admitted.
     if (!(look.elevation >= 0)) return null;
 
+    const nadir = geodeticFromEcf(ecf);
+    if (nadir === null) return null;
+
     return {
       noradId: meta.noradId,
       name: meta.name,
@@ -290,10 +301,71 @@ export class SatelliteCatalogue {
       elevation: look.elevation,
       rangeKm: look.rangeSat,
       shadow: shadowFraction(sunEciAU, eci),
+      lat: nadir.lat,
+      lng: nadir.lng,
     };
   }
 }
 
+/**
+ * Sub-satellite point from an ECEF position in kilometres.
+ *
+ * Spherical geodetic is enough: Starlink is 550 km up, and the ellipsoid vs a
+ * sphere moves the ground point by a few kilometres — smaller than a board
+ * cell on the state pack. Follow cameras need "over California", not a survey.
+ */
+export function geodeticFromEcf(ecf: { x: number; y: number; z: number }): { lat: number; lng: number } | null {
+  const r = Math.hypot(ecf.x, ecf.y, ecf.z);
+  if (!(r > 0) || !Number.isFinite(r)) return null;
+  const lat = (Math.asin(Math.min(1, Math.max(-1, ecf.z / r))) * 180) / Math.PI;
+  const lng = (Math.atan2(ecf.y, ecf.x) * 180) / Math.PI;
+  if (!Number.isFinite(lat) || !Number.isFinite(lng)) return null;
+  return { lat, lng };
+}
+
+export function nadirInBounds(
+  fix: Pick<SatelliteFix, "lat" | "lng">,
+  bounds: { minLat: number; maxLat: number; minLng: number; maxLng: number },
+): boolean {
+  return (
+    fix.lat >= bounds.minLat &&
+    fix.lat <= bounds.maxLat &&
+    fix.lng >= bounds.minLng &&
+    fix.lng <= bounds.maxLng
+  );
+}
+
+/**
+ * The satellite to possess next: nadir inside `bounds`, nearest to `from`
+ * if given, else the lowest NORAD id. Deterministic — two frames with the
+ * same fix list agree.
+ */
+export function nextOverCalifornia(
+  fixes: readonly SatelliteFix[],
+  bounds: { minLat: number; maxLat: number; minLng: number; maxLng: number },
+  from?: { lat: number; lng: number },
+): SatelliteFix | null {
+  const inside = fixes.filter((fix) => nadirInBounds(fix, bounds));
+  if (inside.length === 0) return null;
+  if (from === undefined) {
+    let best = inside[0]!;
+    for (const fix of inside) {
+      if (fix.noradId < best.noradId) best = fix;
+    }
+    return best;
+  }
+  let best = inside[0]!;
+  let bestD = (best.lat - from.lat) ** 2 + (best.lng - from.lng) ** 2;
+  for (const fix of inside) {
+    const d = (fix.lat - from.lat) ** 2 + (fix.lng - from.lng) ** 2;
+    if (d < bestD - 1e-12 || (Math.abs(d - bestD) <= 1e-12 && fix.noradId < best.noradId)) {
+      best = fix;
+      bestD = d;
+    }
+  }
+  return best;
+}
+
 // ---- Rendering ------------------------------------------------------------
 
 export interface SatelliteLayer {

src/main.ts

@@ -4097,7 +4097,7 @@ function availableControlModes() {
     insideOffice: inside,
     drive: !inside && city?.vehicleState() !== null &&
       (route === "la-sf-us-101" || route === "la-sf-i-5"),
-    actor: !inside && city?.actorState() !== null,
+    actor: !inside && city?.actorState() !== null && access.subject !== null,
     aircraft: !inside && city?.aircraftState() !== null,
     officeWalk: inside && office?.walker !== null && office?.walker !== undefined,
   };
@@ -4336,6 +4336,7 @@ function playTelemetry(): PlayTelemetry | null {
         altitudeM: state.altitudeM,
         flightMode: state.mode,
         batteryWh: state.batteryWh,
+        batteryCapacityWh: 54_000,
         stalled: state.stalled,
         hardLanding: state.hardLanding,
         envelopeContact: state.envelopeContact,

src/test/integration/sceneWiring.test.ts

@@ -502,6 +502,8 @@ function overheadFix() {
     // Full sunlight, which is the brightest a dot ever gets and therefore the
     // case that clipped.
     shadow: 0,
+    lat: 37.77,
+    lng: -122.42,
   };
 }
 

src/test/satellites.test.ts

@@ -23,7 +23,13 @@
 
 import assert from "node:assert/strict";
 import { describe, it } from "node:test";
-import { dotPixels, SatelliteCatalogue, type SatelliteElements } from "../engine/satellites.ts";
+import {
+  dotPixels,
+  nextOverCalifornia,
+  SatelliteCatalogue,
+  type SatelliteElements,
+  type SatelliteFix,
+} from "../engine/satellites.ts";
 
 /** San Francisco, which is `SAN_FRANCISCO.center` and is the default board. */
 const SF = { lat: 37.7749, lng: -122.4194 };
@@ -264,3 +270,45 @@ describe("how large a satellite is drawn", () => {
     }
   });
 });
+
+const CA = { minLat: 32.5, maxLat: 42.05, minLng: -124.5, maxLng: -114 };
+
+function stubFix(over: Partial<SatelliteFix> & Pick<SatelliteFix, "noradId" | "lat" | "lng">): SatelliteFix {
+  return {
+    name: `SAT-${over.noradId}`,
+    group: "starlink",
+    azimuth: 0,
+    elevation: 1,
+    rangeKm: 600,
+    shadow: 0,
+    ...over,
+  };
+}
+
+describe("nadir possession", () => {
+  it("reports a sub-satellite point when the ISS is above the horizon", () => {
+    const seen = (() => {
+      const catalogue = new SatelliteCatalogue([ISS], SF);
+      const out: SatelliteFix[] = [];
+      for (let minute = 0; minute < 24 * 60; minute += 5) {
+        const when = new Date(NEAR_EPOCH.getTime() + minute * 60_000);
+        for (const fix of sweep(catalogue, when)) out.push(fix);
+      }
+      return out;
+    })();
+    assert.ok(seen.length > 0);
+    for (const fix of seen) {
+      assert.ok(fix.lat >= -90 && fix.lat <= 90, `lat ${fix.lat}`);
+      assert.ok(fix.lng >= -180 && fix.lng <= 180, `lng ${fix.lng}`);
+    }
+  });
+
+  it("hands off to the nearest nadir still over California", () => {
+    const la = stubFix({ noradId: 20, lat: 34.05, lng: -118.25 });
+    const sf = stubFix({ noradId: 10, lat: 37.62, lng: -122.38 });
+    const utah = stubFix({ noradId: 5, lat: 40.76, lng: -111.89 });
+    assert.equal(nextOverCalifornia([la, sf, utah], CA)?.noradId, 10);
+    assert.equal(nextOverCalifornia([la, sf, utah], CA, { lat: 33.94, lng: -118.41 })?.noradId, 20);
+    assert.equal(nextOverCalifornia([utah], CA), null);
+  });
+});

src/test/sceneAircraft.test.ts

@@ -12,7 +12,7 @@ function options(overrides: Partial<SceneAircraftOptions> = {}): SceneAircraftOp
     project: (lat, lng) => [(lng + 121) * 20, -(lat - 36) * 20],
     groundAt: () => 2,
     route: CALIFORNIA_AIR_ROUTE,
-    initialPosition: { lat: 34.0522, lng: -118.2437 },
+    initialPosition: { lat: 33.9416, lng: -118.4085 },
     initialAltitudeM: 1_000,
     initialHeadingDeg: 0,
     fixedStepSeconds: 0.1,
@@ -23,12 +23,21 @@ function options(overrides: Partial<SceneAircraftOptions> = {}): SceneAircraftOp
 }
 
 describe("playable scene aircraft", () => {
+  it("authors KLAX to KSFO, not downtown stand-ins", () => {
+    assert.equal(CALIFORNIA_AIR_ROUTE[0]?.id, "klax");
+    assert.equal(CALIFORNIA_AIR_ROUTE.at(-1)?.id, "ksfo");
+    const start = CALIFORNIA_AIR_ROUTE[0]!;
+    const end = CALIFORNIA_AIR_ROUTE.at(-1)!;
+    assert.ok(Math.abs(start.lat - 33.9416) < 0.02 && Math.abs(start.lng + 118.4085) < 0.02);
+    assert.ok(Math.abs(end.lat - 37.6213) < 0.02 && Math.abs(end.lng + 122.379) < 0.02);
+  });
+
   it("projects a stable root and stays inert until activated", () => {
     const aircraft = createSceneAircraft(options());
     const root = aircraft.root;
     assert.equal(root.name, "playable-scene-aircraft");
     assert.ok(root.getObjectByName("electric-aircraft"));
-    assert.deepEqual(root.position.toArray(), [( -118.2437 + 121) * 20, 7, -(34.0522 - 36) * 20]);
+    assert.deepEqual(root.position.toArray(), [(-118.4085 + 121) * 20, 7, -(33.9416 - 36) * 20]);
     assert.equal(root.scale.x, 0.1);
     aircraft.setActions({ throttle: 1, roll: 0.8 });
     aircraft.tick(0.2);

src/ui/hud.ts

@@ -91,6 +91,8 @@ export interface AircraftPlayTelemetry {
   altitudeM: number;
   flightMode: string;
   batteryWh: number;
+  /** Pack size, so the HUD can show a fraction rather than a raw watt-hour. */
+  batteryCapacityWh: number;
   stalled: boolean;
   hardLanding: boolean;
   envelopeContact: boolean;
@@ -157,11 +159,13 @@ export function formatPlayHud(telemetry: PlayTelemetry | null): PlayHudView | nu
     };
   }
   if (telemetry.kind === "aircraft") {
+    const pack = Math.max(1, telemetry.batteryCapacityWh);
+    const pct = Math.round((100 * Math.max(0, telemetry.batteryWh)) / pack);
     return {
       mode: "Flight",
       primary: `${Math.round(telemetry.speedMps * METRES_PER_SECOND_TO_KNOTS)} kt · ${Math.round(telemetry.altitudeM).toLocaleString()} m`,
-      status: `${telemetry.flightMode} · ${Math.round(telemetry.batteryWh)} Wh${telemetry.stalled ? " · STALL" : ""}`,
-      warning: telemetry.stalled || telemetry.hardLanding || telemetry.envelopeContact,
+      status: `${telemetry.flightMode} · ${pct}% pack${telemetry.stalled ? " · STALL" : ""}`,
+      warning: telemetry.stalled || telemetry.hardLanding || telemetry.envelopeContact || pct < 15,
     };
   }
   return {