diff --git a/scripts/track-regression.mjs b/scripts/track-regression.mjs
index e00dadfc3..16c345db5 100644
--- a/scripts/track-regression.mjs
+++ b/scripts/track-regression.mjs
@@ -409,6 +409,15 @@ async function main() {
             status: 'ready',
           }));
         }
+        // CelesTrak SATCAT, which the satellite classes read beside the TLEs.
+        // An empty CSV (header only) keeps the run hermetic: the classes fall
+        // back to names and groups, as they do when SATCAT is unavailable.
+        if (isAppRequest && url.pathname.startsWith('/api/celestrak-satcat/')) {
+          return Promise.resolve(new Response(
+            'OBJECT_NAME,OBJECT_ID,NORAD_CAT_ID,OBJECT_TYPE,OPS_STATUS_CODE,LAUNCH_DATE\n',
+            { status: 200, headers: { 'Content-Type': 'text/csv' } },
+          ));
+        }
         // CelesTrak TLE groups. Served from a fixed two-satellite catalog so
         // the satellite assertions are deterministic and the run never depends
         // on an upstream that rate-limits (it was answering 403 the night this
diff --git a/src/layers/satellites/ingestion.js b/src/layers/satellites/ingestion.js
index c69b14f30..dc20968a3 100644
--- a/src/layers/satellites/ingestion.js
+++ b/src/layers/satellites/ingestion.js
@@ -12,6 +12,13 @@ import { classifySatellite, parseSatcatCsv } from './classes.js';
  */
 export const SATCAT_WAIT_MS = 3000;
 
+/**
+ * How long a complete, current SATCAT read is kept before the layer asks
+ * again, ms. SATCAT changes daily and the proxy caches it a day, so the
+ * five-minute TLE update does not read all eleven groups each time.
+ */
+export const SATCAT_KEEP_MS = 6 * 60 * 60 * 1000;
+
 export function createIngestion({
   state: layerState,
   services,
@@ -42,6 +49,12 @@ export function createIngestion({
    */
   function _readSatcat(signal) {
     if (typeof source.readSatcat !== 'function') return Promise.resolve([]);
+    // A complete, current read is kept; a stale or failed one is asked again.
+    if (
+      layerState._satcatState === 'current' &&
+      Date.now() - layerState._satcatReadAtMs < SATCAT_KEEP_MS
+    )
+      return Promise.resolve([]);
     return Promise.all(
       CATALOG_GROUPS.map((groupDef) =>
         source
@@ -86,6 +99,7 @@ export function createIngestion({
     if (!groups.length) return;
     const changed = layerState._satcatState !== satcatState;
     layerState._satcatState = satcatState;
+    layerState._satcatReadAtMs = Date.now();
     if (satcatState !== 'current')
       console.warn(`[Data:Satellites] SATCAT ${satcatState}: classes may lag`);
     // The row's info line says so (getRowControls).
diff --git a/src/layers/satellites/ingestion.test.mjs b/src/layers/satellites/ingestion.test.mjs
index c25b90158..3871e57a3 100644
--- a/src/layers/satellites/ingestion.test.mjs
+++ b/src/layers/satellites/ingestion.test.mjs
@@ -1,7 +1,11 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { parseTleText, tleLineLaunchYear } from '../../sources/tle.js';
-import { SATCAT_WAIT_MS, createIngestion } from './ingestion.js';
+import {
+  SATCAT_KEEP_MS,
+  SATCAT_WAIT_MS,
+  createIngestion,
+} from './ingestion.js';
 import { createOrbits } from './orbits.js';
 import { createControls } from './controls.js';
 
@@ -178,7 +182,9 @@ test('a satellite in visual and resource is imaging, whichever group shows it',
   t.mock.method(console, 'warn', () => {});
   // A name no pattern knows, no UCS record and no SATCAT: only its groups.
   const { state, update } = ingestionFor((path) =>
-    path === 'visual' || path === 'resource' ? tleSet('ZZ TESTSAT', '50001') : '',
+    path === 'visual' || path === 'resource'
+      ? tleSet('ZZ TESTSAT', '50001')
+      : '',
   );
   await update();
   const sat = state._catalog.get(50001);
@@ -247,3 +253,40 @@ test('a failed SATCAT read is told on the layer row, not only the console', asyn
   });
   assert.equal(current.methods.getRowControls().info, '');
 });
+
+test('a current SATCAT read is kept between updates; a failed one is asked again', async (t) => {
+  t.mock.method(console, 'log', () => {});
+  t.mock.method(console, 'warn', () => {});
+  const header =
+    'OBJECT_NAME,OBJECT_ID,NORAD_CAT_ID,OBJECT_TYPE,OPS_STATUS_CODE\n';
+  let reads = 0;
+  let ok = true;
+  const { state, update } = ingestionFor(tleSet('ZZ TESTSAT', '50003'), {
+    source: {
+      readSatcat: async () => {
+        reads++;
+        return ok
+          ? { ok: true, text: `${header}ZZ TESTSAT,2015-001A,50003,PAY,-` }
+          : { ok: false, text: '' };
+      },
+    },
+  });
+  await update();
+  const perUpdate = reads;
+  assert.ok(perUpdate > 0);
+  await update();
+  assert.equal(reads, perUpdate, 'a fresh read is not asked again');
+  assert.equal(
+    state._catalog.get(50003).satelliteClass,
+    'debris',
+    'the held records still class the rebuilt catalog',
+  );
+
+  state._satcatReadAtMs -= SATCAT_KEEP_MS;
+  ok = false;
+  await update();
+  assert.equal(reads, 2 * perUpdate, 'an old read is asked again');
+  assert.equal(state._satcatState, 'unavailable');
+  await update();
+  assert.equal(reads, 3 * perUpdate, 'a failed read is asked again');
+});
diff --git a/src/layers/satellites/state.js b/src/layers/satellites/state.js
index 16c210a77..42823ee00 100644
--- a/src/layers/satellites/state.js
+++ b/src/layers/satellites/state.js
@@ -48,6 +48,9 @@ export function createState({ services }) {
   // How current the SATCAT records behind the classes are: null before any
   // read, then 'current' | 'stale' | 'unavailable' (see ingestion.js).
   state._satcatState = null;
+  // When _satcatState was last set (Date.now()); a current read is kept
+  // SATCAT_KEEP_MS (src/layers/satellites/ingestion.js).
+  state._satcatReadAtMs = Number.NEGATIVE_INFINITY;
   state._denseStale = false;
 
   state._activeUpdateControllers = new Set();