diff --git a/scico/linop/xray/astra.py b/scico/linop/xray/astra.py
index 8c97ac69f..0d6cff41c 100644
--- a/scico/linop/xray/astra.py
+++ b/scico/linop/xray/astra.py
@@ -185,7 +185,11 @@ def _proj(self, x: jax.Array) -> jax.Array:
         # apply the forward projector and generate a sinogram
 
         def f(x):
-            x.setflags(write=True)
+            if not x.flags.writeable:
+                try:
+                    x.setflags(write=True)
+                except ValueError("cannot set WRITEABLE flag"):
+                    x = x.copy()
             if self.num_dims == 2:
                 proj_id, result = astra.create_sino(x, self.proj_id)
                 astra.data2d.delete(proj_id)
@@ -199,7 +203,11 @@ def f(x):
     def _bproj(self, y: jax.Array) -> jax.Array:
         # apply backprojector
         def f(y):
-            y.setflags(write=True)
+            if not y.flags.writeable:
+                try:
+                    y.setflags(write=True)
+                except ValueError("cannot set WRITEABLE flag"):
+                    y = y.copy()
             if self.num_dims == 2:
                 proj_id, result = astra.create_backprojection(y, self.proj_id)
                 astra.data2d.delete(proj_id)