diff --git a/json-schema/schema.json b/json-schema/schema.json
index 4e489b7..26e28d0 100644
--- a/json-schema/schema.json
+++ b/json-schema/schema.json
@@ -158,7 +158,8 @@
         "sat:orbit_state_vectors": {
           "type": "object",
           "patternProperties": {
-            "^.*$": {
+            "$comment": "The key is a date-time string, and the value is an array of numbers.",
+            "^([\\+-]?\\d{4}(?!\\d{2}\b))((-?)((0[1-9]|1[0-2])(\\3([12]\\d|0[1-9]|3[01]))?|W([0-4]\\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\\d|[12]\\d{2}|3([0-5]\\d|6[1-6])))([T\\s]((([01]\\d|2[0-3])((:?)[0-5]\\d)?|24\\:?00)([\\.,]\\d+(?!:))?)?(\\17[0-5]\\d([\\.,]\\d+)?)?([zZ]|([\\+-])([01]\\d|2[0-3]):?([0-5]\\d)?)?)?)?$": {
               "type": "array",
               "items": {
                 "type": "number"