diff --git a/aiapy/__init__.py b/aiapy/__init__.py
index 1eb0a5c..86e5839 100644
--- a/aiapy/__init__.py
+++ b/aiapy/__init__.py
@@ -3,7 +3,10 @@
 
 from .version import version as __version__
 
-_SSW_MIRROR = "https://sohoftp.nascom.nasa.gov/solarsoft/"
+_SSW_MIRRORS = [
+    "https://soho.nascom.nasa.gov/solarsoft/",
+    "https://hesperia.gsfc.nasa.gov/ssw/",
+]
 
 
 def _get_bibtex():
@@ -23,4 +26,4 @@ def _get_bibtex():
 
 
 __citation__ = __bibtex__ = _get_bibtex()
-__all__ = ["__version__", "__citation__", "_SSW_MIRROR"]
+__all__ = ["__version__", "__citation__", "_SSW_MIRRORS"]
diff --git a/aiapy/calibrate/uncertainty.py b/aiapy/calibrate/uncertainty.py
index 42e4c08..50d4f15 100644
--- a/aiapy/calibrate/uncertainty.py
+++ b/aiapy/calibrate/uncertainty.py
@@ -34,7 +34,7 @@ def estimate_error(
     contributions from the photometric calibration and errors in the atomic data.
 
     .. note:: This function is adapted directly from the
-              `aia_bp_corrections.pro <https://sohoftp.nascom.nasa.gov/solarsoft/sdo/aia/idl/response/aia_bp_estimate_error.pro>`_
+              `aia_bp_estimate_error.pro <https://sohoftp.nascom.nasa.gov/solarsoft/sdo/aia/idl/response/aia_bp_estimate_error.pro>`_
               routine in SolarSoft.
 
     Parameters
diff --git a/aiapy/calibrate/util.py b/aiapy/calibrate/util.py
index aed96e8..3a87967 100644
--- a/aiapy/calibrate/util.py
+++ b/aiapy/calibrate/util.py
@@ -14,7 +14,7 @@
 from sunpy.data import manager
 from sunpy.net import attrs, jsoc
 
-from aiapy import _SSW_MIRROR
+from aiapy import _SSW_MIRRORS
 from aiapy.util.decorators import validate_channel
 from aiapy.util.exceptions import AiapyUserWarning
 
@@ -24,19 +24,17 @@
 # This needs to be incremented as the calibration is updated in JSOC.
 CALIBRATION_VERSION = 10
 # Error table filename available from SSW
-AIA_ERROR_FILE = urljoin(_SSW_MIRROR, "sdo/aia/response/aia_V{}_error_table.txt")
+AIA_ERROR_FILE = "sdo/aia/response/aia_V{}_error_table.txt"
 # Most recent version number for error tables; increment as new versions become available
 ERROR_VERSION = 3
 # URLs and SHA-256 hashes for each version of the error tables
-# The URLs are left as a list so that possible mirrors for these files
-# can be specified
 URL_HASH = {
     2: (
-        (AIA_ERROR_FILE.format(2)),
+        [urljoin(mirror, AIA_ERROR_FILE.format(2)) for mirror in _SSW_MIRRORS],
         "ac97ccc48057809723c27e3ef290c7d78ee35791d9054b2188baecfb5c290d0a",
     ),
     3: (
-        (AIA_ERROR_FILE.format(3)),
+        [urljoin(mirror, AIA_ERROR_FILE.format(3)) for mirror in _SSW_MIRRORS],
         "66ff034923bb0fd1ad20e8f30c7d909e1a80745063957dd6010f81331acaf894",
     ),
 }
diff --git a/aiapy/response/channel.py b/aiapy/response/channel.py
index 2aced04..f084a36 100644
--- a/aiapy/response/channel.py
+++ b/aiapy/response/channel.py
@@ -11,7 +11,7 @@
 from sunpy.io.special import read_genx
 from sunpy.util.metadata import MetaDict
 
-from aiapy import _SSW_MIRROR
+from aiapy import _SSW_MIRRORS
 from aiapy.calibrate import degradation
 from aiapy.calibrate.util import _select_epoch_from_correction_table, get_correction_table
 from aiapy.util import telescope_number
@@ -20,23 +20,17 @@
 __all__ = ["Channel"]
 
 # TODO: Work out what changes with version.
-AIA_INSTRUMENT_FILE = urljoin(_SSW_MIRROR, "sdo/aia/response/aia_V{}_{}_fullinst.genx")
+AIA_INSTRUMENT_FILE = "sdo/aia/response/aia_V{}_{}_fullinst.genx"
 VERSION_NUMBER = 8  # Most recent version number for instrument response data
 # URLs and SHA-256 hashes for each version for the EUV and FUV files
-# The URLs are left as a list so that possible mirrors for these files
-# can be specified
 URL_HASH = {
-    2: {"fuv": None, "euv": None},
-    3: {"fuv": None, "euv": None},
-    4: {"fuv": None, "euv": None},
-    6: {"fuv": None, "euv": None},
     8: {
         "fuv": (
-            (AIA_INSTRUMENT_FILE.format(VERSION_NUMBER, "fuv")),
+            [urljoin(mirror, AIA_INSTRUMENT_FILE.format(VERSION_NUMBER, "fuv")) for mirror in _SSW_MIRRORS],
             "8635166d8f6dde48da4f135925f4e8f48a0574f129c2c2ca24da6628550f5430",
         ),
         "euv": (
-            (AIA_INSTRUMENT_FILE.format(VERSION_NUMBER, "all"),),
+            [urljoin(mirror, AIA_INSTRUMENT_FILE.format(VERSION_NUMBER, "all")) for mirror in _SSW_MIRRORS],
             "3940648e6b02876c45a9893f40806bbcc50baa994ae3fa2d95148916988426dd",
         ),
     },
diff --git a/changelog/322.doc.rst b/changelog/322.doc.rst
new file mode 100644
index 0000000..deddb56
--- /dev/null
+++ b/changelog/322.doc.rst
@@ -0,0 +1 @@
+Fixed incorrect IDL routine reference in the `aiapy.calibrate.uncertainty.estimate_error` documentation.
diff --git a/changelog/322.feature.rst b/changelog/322.feature.rst
new file mode 100644
index 0000000..90e6fe7
--- /dev/null
+++ b/changelog/322.feature.rst
@@ -0,0 +1 @@
+Added extra mirrors to fetch files from SSW.