diff --git a/exe/space_shoes b/exe/space_shoes
index e839ac3..c82c2e9 100755
--- a/exe/space_shoes
+++ b/exe/space_shoes
@@ -118,7 +118,11 @@ when "build-default"
   include SpaceShoes::Packaging
 
   location = build_default_wasm_package
-  puts "Built default Ruby Wasm package to #{location.inspect}"
+  sp_location = File.join(SpaceShoes::Packaging::PACKAGING_ROOT, "spacewalk.js")
+  sp_location = write_spacewalk_file(out_file: sp_location)
+
+  puts "Built default Ruby Wasm package to #{location}"
+  puts "Copied spacewalk.js to #{sp_location}"
 when "src-package"
   include SpaceShoes::Packaging
 
diff --git a/packaging/.gitignore b/packaging/.gitignore
index d62e5bc..e67174d 100644
--- a/packaging/.gitignore
+++ b/packaging/.gitignore
@@ -2,3 +2,4 @@ build
 rubies
 ruby.wasm
 packed_ruby.wasm
+spacewalk.js
diff --git a/test/test_space_shoes.rb b/test/test_space_shoes.rb
index 6c3c644..ad1742e 100644
--- a/test/test_space_shoes.rb
+++ b/test/test_space_shoes.rb
@@ -61,6 +61,8 @@ class TestSpaceShoesBuild < SpaceShoesCLITest
   def test_space_shoes_build_ruby_default
     Dir.chdir(ROOT_DIR) do
       out_or_fail "exe/space-shoes --dev build-default"
+      assert File.exist?("packaging/packed_ruby.wasm"), "In build-default, didn't create packed_ruby.wasm"
+      assert File.exist?("packaging/spacewalk.js"), "In build-default, didn't create spacewalk.js"
     end
   end
 end