From 003b92f64a60af2f4681863f974a777bdc89ea2e Mon Sep 17 00:00:00 2001
From: VG31OP <vg.sdcet@gmail.com>
Date: Tue, 13 Oct 2026 16:57:55 +0530
Subject: [PATCH] fix(satellites): reject TLE pairs with mismatched catalog
 numbers (#906, #936)

---
 CHANGELOG.md                     |  7 ++++---
 src/sources/tle.js               | 15 +++++++++++----
 src/tools/queries/space.test.mjs | 17 +++++++++++++++++
 3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b24ac95ed..83b32baaa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -95,9 +95,10 @@
 
 ## [Unreleased]
 
-- Keep later satellites when a TLE catalog entry is missing an orbital line.
-  The parser skips the incomplete set and resumes at the next complete named
-  set, instead of losing the rest of the group (#906).
+- Keep later satellites when a TLE catalog entry is missing an orbital line or
+  pairs lines with mismatched NORAD catalog numbers. The parser skips corrupt sets
+  and resumes at the next complete named set, instead of losing the rest of the
+  group (#906, #936).
 
 - Add an experimental ChatGPT/Codex OAuth option for cloud voice in Provider
   Settings. API-key voice remains the default. Local sign-in can start from
diff --git a/src/sources/tle.js b/src/sources/tle.js
index ac7aedc2c..8f97e4eda 100644
--- a/src/sources/tle.js
+++ b/src/sources/tle.js
@@ -13,7 +13,14 @@ export function parseTleText(text) {
     const name = lines[i];
     const line1 = lines[i + 1];
     const line2 = lines[i + 2];
-    if (line1.startsWith('1 ') && line2.startsWith('2 ')) {
+    const cat1 = tleCatalogNumber(line1);
+    const cat2 = tleCatalogNumber(line2);
+    if (
+      line1.startsWith('1 ') &&
+      line2.startsWith('2 ') &&
+      cat1 !== null &&
+      cat1 === cat2
+    ) {
       result.push({ name, line1, line2 });
       i += 2;
     }
@@ -21,8 +28,8 @@ export function parseTleText(text) {
   return result;
 }
 
-/** The NORAD catalog number from TLE line 1, or null. */
-export function tleCatalogNumber(line1) {
-  const number = Number.parseInt(String(line1).slice(2, 7), 10);
+/** The NORAD catalog number from a TLE line, or null. */
+export function tleCatalogNumber(line) {
+  const number = Number.parseInt(String(line).slice(2, 7), 10);
   return Number.isInteger(number) ? number : null;
 }
diff --git a/src/tools/queries/space.test.mjs b/src/tools/queries/space.test.mjs
index f6c2a8df8..2b2586b45 100644
--- a/src/tools/queries/space.test.mjs
+++ b/src/tools/queries/space.test.mjs
@@ -51,6 +51,23 @@ for (const missingLine of [1, 2]) {
   });
 }
 
+test('TLE parsing rejects pairs with mismatched catalog numbers and resumes', () => {
+  const text = `SAT A
+1 25544U 98067A   24001.50000000  .00016717  00000-0  30270-3 0  9994
+2 48274  41.4697 175.8913 0005643 312.8370 141.6893 15.61287398150000
+SAT B
+1 48274U 21035A   24001.50000000  .00020137  00000-0  24481-3 0  9993
+2 48274  41.4697 175.8913 0005643 312.8370 141.6893 15.61287398150000
+`;
+  const entries = parseTleText(text);
+  assert.deepEqual(
+    entries.map((entry) => entry.name),
+    ['SAT B'],
+  );
+  assert.equal(tleCatalogNumber(entries[0].line1), 48274);
+  assert.equal(tleCatalogNumber(entries[0].line2), 48274);
+});
+
 test('the next pass defaults to the ISS and reports times, peak and direction', async () => {
   const catalog = composeCatalog({
     tools: coreTools,