diff --git a/src/mpclookup/handlers/external.py b/src/mpclookup/handlers/external.py
index 28eaab8..b33804b 100644
--- a/src/mpclookup/handlers/external.py
+++ b/src/mpclookup/handlers/external.py
@@ -1,9 +1,10 @@
 """Handlers for the app's external root, ``/mpc-lookup/``."""
 
 from typing import Annotated
+from urllib.parse import urlencode
 
-from fastapi import APIRouter, Depends, Query
-from fastapi.responses import RedirectResponse
+from fastapi import APIRouter, Depends, Query, Request
+from fastapi.responses import PlainTextResponse, RedirectResponse
 from safir.dependencies.logger import logger_dependency
 from safir.metadata import get_metadata
 from structlog.stdlib import BoundLogger
@@ -60,6 +61,7 @@ async def get_index(
 async def search(
     designation: Annotated[str, Query()],
     logger: Annotated[BoundLogger, Depends(logger_dependency)],
+    request: Request,
 ) -> str:
     """
     Request a redirect to the MPCORB record for a given designation.
@@ -68,14 +70,37 @@ async def search(
     -----
     Example request:
 
-    /mpc-lookup/search?designation=2011+1001+T-2
+    `/mpc-lookup/search?designation=2011+1001+T-2`
 
+    In this case, the "2011 " prefix, which is present in the DP0.3 data, will
+    be stripped out automatically so that the designation is valid.
+
+    Any designations containing spaces will be redirected to an endpoint that
+    will return a text response indicating that the object is synthetic.
     """
     logger.info("Request for designation URL", designation=designation)
     fd = designation.replace(_DESIGNATION_PREPEND, "")
-    redirect_url = (
-        "https://www.minorplanetcenter.net/db_search/"
-        f"show_object?object_id={fd}"
-    )
-    logger.info("Redirecting to designation URL", redirect_url=redirect_url)
+    if " " not in fd:
+        redirect_url = (
+            "https://www.minorplanetcenter.net/db_search/"
+            f"show_object?object_id={fd}"
+        )
+        logger.info("Redirecting to MPC URL", redirect_url=redirect_url)
+    else:
+        base_url = str(request.url_for("get_synthetic_object"))
+        query_string = urlencode({"designation": designation})
+        redirect_url = base_url + "?" + query_string
+        logger.info(
+            "Redirecting synthetic object to", redirect_url=redirect_url
+        )
     return redirect_url
+
+
+@external_router.get("/synthetic_object", response_class=PlainTextResponse)
+async def get_synthetic_object(
+    designation: Annotated[str, Query()],
+) -> str:
+    return (
+        f"{designation} "
+        "appears to be a synthetic object from the DP0.3 input simulation."
+    )