diff --git a/astroquery/heasarc/core.py b/astroquery/heasarc/core.py
index e5cabd9d33..aeed1d068b 100644
--- a/astroquery/heasarc/core.py
+++ b/astroquery/heasarc/core.py
@@ -169,9 +169,11 @@ def query_region_async(self, position: Union[coordinates.SkyCoord, str],
         kwargs['equinox'] = 2000
 
         # Generate the request
+        # Fixed string representation of coordinates ensures that request payload
+        # does not depend on python/astropy version for the same input coordinates
         request_payload = self._args_to_payload(
             mission=mission,
-            entry="{},{}".format(c.ra.degree, c.dec.degree),
+            entry=f"{c.ra.degree:.10f},{c.dec.degree:.10f}",
             radius=u.Quantity(radius),
             **kwargs
         )
diff --git a/astroquery/heasarc/tests/data/0f36aba7.dat b/astroquery/heasarc/tests/data/10f92917.dat
similarity index 100%
rename from astroquery/heasarc/tests/data/0f36aba7.dat
rename to astroquery/heasarc/tests/data/10f92917.dat
diff --git a/astroquery/heasarc/tests/data/69b39684.dat b/astroquery/heasarc/tests/data/6ad7a587.dat
similarity index 100%
rename from astroquery/heasarc/tests/data/69b39684.dat
rename to astroquery/heasarc/tests/data/6ad7a587.dat
diff --git a/astroquery/heasarc/tests/data/31b1e555.dat b/astroquery/heasarc/tests/data/6df5af53.dat
similarity index 100%
rename from astroquery/heasarc/tests/data/31b1e555.dat
rename to astroquery/heasarc/tests/data/6df5af53.dat
diff --git a/astroquery/heasarc/tests/data/29872e7f.dat b/astroquery/heasarc/tests/data/eb62ea7d.dat
similarity index 100%
rename from astroquery/heasarc/tests/data/29872e7f.dat
rename to astroquery/heasarc/tests/data/eb62ea7d.dat
diff --git a/astroquery/heasarc/tests/data/26550aeb.dat b/astroquery/heasarc/tests/data/f3778475.dat
similarity index 100%
rename from astroquery/heasarc/tests/data/26550aeb.dat
rename to astroquery/heasarc/tests/data/f3778475.dat
diff --git a/astroquery/heasarc/tests/parametrization.py b/astroquery/heasarc/tests/parametrization.py
index e40de7655c..8cac67559b 100644
--- a/astroquery/heasarc/tests/parametrization.py
+++ b/astroquery/heasarc/tests/parametrization.py
@@ -1,3 +1,4 @@
+import json
 import os
 import glob
 import hashlib
@@ -40,7 +41,11 @@ def fileid_for_request(url, params):
 
 def filename_for_request(url, params, output=False):
     fileid = fileid_for_request(url, params)
-    return data_path(fileid, output=output)
+
+    filename = data_path(fileid, output=output)
+    log.debug(f'constructed filename {filename} for request: ' + json.dumps(dict(url=url, params=params), sort_keys=True, indent=4))
+
+    return filename
 
 
 def get_mockreturn(session, method, url, params=None, timeout=10, **kwargs):
diff --git a/astroquery/heasarc/tests/test_heasarc_remote.py b/astroquery/heasarc/tests/test_heasarc_remote.py
index e6f7455762..50693e1d63 100644
--- a/astroquery/heasarc/tests/test_heasarc_remote.py
+++ b/astroquery/heasarc/tests/test_heasarc_remote.py
@@ -24,6 +24,7 @@ def test_custom_args(self):
                                      time="2020-09-01 .. 2020-12-01",
                                      resultmax=10,
                                      good_isgri=">1000",
+                                     cache=False
                                      )
 
     def test_filter_custom_args(self):
diff --git a/astroquery/heasarc/tests/test_heasarc_remote_isdc.py b/astroquery/heasarc/tests/test_heasarc_remote_isdc.py
index c43cac094a..0f3765ec49 100644
--- a/astroquery/heasarc/tests/test_heasarc_remote_isdc.py
+++ b/astroquery/heasarc/tests/test_heasarc_remote_isdc.py
@@ -32,6 +32,7 @@ def test_custom_args(self):
                         time="2020-09-01 .. 2020-12-01",
                         resultmax=10,
                         good_isgri=">1000",
+                        cache=False
                     )
 
     def test_filter_custom_args(self):