From df5ad4ca4a9e1606334ae787bfddc3ddddf7b36b Mon Sep 17 00:00:00 2001
From: Sameh Khamis <sameh@halfpixel.ai>
Date: Sat, 17 Oct 2026 13:46:00 -0700
Subject: [PATCH] Pair TLE lines through the shared decoder and add the
 changelog fragment

---
 changelog.d/1101-tle-catalog-number-match.md |  3 +++
 docs/CURRENT-STATE.md                        |  5 ++++-
 src/tools/queries/space.test.mjs             | 15 +++++++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/1101-tle-catalog-number-match.md

diff --git a/changelog.d/1101-tle-catalog-number-match.md b/changelog.d/1101-tle-catalog-number-match.md
new file mode 100644
index 000000000..d1e2aa407
--- /dev/null
+++ b/changelog.d/1101-tle-catalog-number-match.md
@@ -0,0 +1,3 @@
+- Skip TLE sets whose line 1 and line 2 carry different catalog numbers, so a
+  spliced catalog cannot pair one satellite's elements with another's; the next
+  valid set still parses (VG31OP, #1101).
diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index 458c44c6e..6d066a475 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -1474,7 +1474,10 @@ access. Callers retain validation, transport and response policy.
 
 The shared TLE text parser skips incomplete named sets and resumes at the next
 complete set. A missing orbital line does not discard the later satellites in
-the catalog; satellite layers and next-pass tools use the same parser.
+the catalog. A set whose two lines carry different catalog numbers, or a
+malformed catalog number, is skipped the same way, so a spliced catalog cannot
+pair one satellite's elements with another's. Satellite layers and next-pass
+tools use the same parser.
 
 ## Build configuration and local provider boundaries
 
diff --git a/src/tools/queries/space.test.mjs b/src/tools/queries/space.test.mjs
index 5b0fa5837..0eb5ce346 100644
--- a/src/tools/queries/space.test.mjs
+++ b/src/tools/queries/space.test.mjs
@@ -90,6 +90,21 @@ SAT ALPHA5
   assert.equal(tleCatalogNumber(entries[0].line2), 100000);
 });
 
+test('TLE parsing rejects a pair whose catalog fields are malformed and resumes', () => {
+  // Read as digits up to the first non-digit, both fields would be 2554.
+  const text = `SAT MALFORMED
+1 2554AU 98067A   24001.50000000  .00016717  00000-0  30270-3 0  9994
+2 2554B  51.6416 247.4627 0006703 130.5360 325.0288 15.50377579432414
+SAT HALF MALFORMED
+1 2554AU 98067A   24001.50000000  .00016717  00000-0  30270-3 0  9994
+2 02554  51.6416 247.4627 0006703 130.5360 325.0288 15.50377579432414
+${TLE}`;
+  assert.deepEqual(
+    parseTleText(text).map((entry) => entry.name),
+    ['ISS (ZARYA)', 'CSS (TIANHE)'],
+  );
+});
+
 test('Alpha-5 catalog numbers decode, skipping I and O', () => {
   for (const [field, id] of [
     ['A0000', 100000],