diff --git a/resources/sql/autopatches/20150610.spaces.3.archive.sql b/resources/sql/autopatches/20150610.spaces.3.archive.sql
new file mode 100644
index 0000000000..8dd55959a3
--- /dev/null
+++ b/resources/sql/autopatches/20150610.spaces.3.archive.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_spaces.spaces_namespace
+  ADD isArchived BOOL NOT NULL;
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index e3ba379280..079819f657 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -2577,6 +2577,7 @@ phutil_register_library_map(array(
     'PhabricatorSortTableUIExample' => 'applications/uiexample/examples/PhabricatorSortTableUIExample.php',
     'PhabricatorSourceCodeView' => 'view/layout/PhabricatorSourceCodeView.php',
     'PhabricatorSpacesApplication' => 'applications/spaces/application/PhabricatorSpacesApplication.php',
+    'PhabricatorSpacesArchiveController' => 'applications/spaces/controller/PhabricatorSpacesArchiveController.php',
     'PhabricatorSpacesCapabilityCreateSpaces' => 'applications/spaces/capability/PhabricatorSpacesCapabilityCreateSpaces.php',
     'PhabricatorSpacesCapabilityDefaultEdit' => 'applications/spaces/capability/PhabricatorSpacesCapabilityDefaultEdit.php',
     'PhabricatorSpacesCapabilityDefaultView' => 'applications/spaces/capability/PhabricatorSpacesCapabilityDefaultView.php',
@@ -6089,6 +6090,7 @@ phutil_register_library_map(array(
     'PhabricatorSortTableUIExample' => 'PhabricatorUIExample',
     'PhabricatorSourceCodeView' => 'AphrontView',
     'PhabricatorSpacesApplication' => 'PhabricatorApplication',
+    'PhabricatorSpacesArchiveController' => 'PhabricatorSpacesController',
     'PhabricatorSpacesCapabilityCreateSpaces' => 'PhabricatorPolicyCapability',
     'PhabricatorSpacesCapabilityDefaultEdit' => 'PhabricatorPolicyCapability',
     'PhabricatorSpacesCapabilityDefaultView' => 'PhabricatorPolicyCapability',
diff --git a/src/applications/people/storage/PhabricatorUser.php b/src/applications/people/storage/PhabricatorUser.php
index aa93485dd2..55ade255a7 100644
--- a/src/applications/people/storage/PhabricatorUser.php
+++ b/src/applications/people/storage/PhabricatorUser.php
@@ -759,7 +759,7 @@ final class PhabricatorUser
     // for now just use the global space if one exists.
 
     // If the viewer has access to the default space, use that.
-    $spaces = PhabricatorSpacesNamespaceQuery::getViewerSpaces($this);
+    $spaces = PhabricatorSpacesNamespaceQuery::getViewerActiveSpaces($this);
     foreach ($spaces as $space) {
       if ($space->getIsDefaultNamespace()) {
         return $space->getPHID();
diff --git a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
index 5d0f79e170..453b965034 100644
--- a/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
+++ b/src/applications/search/engine/PhabricatorApplicationSearchEngine.php
@@ -149,6 +149,10 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
     if ($object instanceof PhabricatorSpacesInterface) {
       if (!empty($map['spacePHIDs'])) {
         $query->withSpacePHIDs($map['spacePHIDs']);
+      } else {
+        // If the user doesn't search for objects in specific spaces, we
+        // default to "all active spaces you have permission to view".
+        $query->withSpaceIsArchived(false);
       }
     }
 
diff --git a/src/applications/spaces/application/PhabricatorSpacesApplication.php b/src/applications/spaces/application/PhabricatorSpacesApplication.php
index 380f80569e..0e25120626 100644
--- a/src/applications/spaces/application/PhabricatorSpacesApplication.php
+++ b/src/applications/spaces/application/PhabricatorSpacesApplication.php
@@ -38,6 +38,15 @@ final class PhabricatorSpacesApplication extends PhabricatorApplication {
     return true;
   }
 
+  public function getHelpDocumentationArticles(PhabricatorUser $viewer) {
+    return array(
+      array(
+        'name' => pht('Spaces User Guide'),
+        'href' => PhabricatorEnv::getDoclink('Spaces User Guide'),
+      ),
+    );
+  }
+
   public function getRemarkupRules() {
     return array(
       new PhabricatorSpacesRemarkupRule(),
@@ -51,6 +60,8 @@ final class PhabricatorSpacesApplication extends PhabricatorApplication {
         '(?:query/(?P<queryKey>[^/]+)/)?' => 'PhabricatorSpacesListController',
         'create/' => 'PhabricatorSpacesEditController',
         'edit/(?:(?P<id>\d+)/)?' => 'PhabricatorSpacesEditController',
+        '(?P<action>activate|archive)/(?P<id>\d+)/'
+          => 'PhabricatorSpacesArchiveController',
       ),
     );
   }
diff --git a/src/applications/spaces/controller/PhabricatorSpacesArchiveController.php b/src/applications/spaces/controller/PhabricatorSpacesArchiveController.php
new file mode 100644
index 0000000000..82cf19e9e8
--- /dev/null
+++ b/src/applications/spaces/controller/PhabricatorSpacesArchiveController.php
@@ -0,0 +1,76 @@
+<?php
+
+final class PhabricatorSpacesArchiveController
+  extends PhabricatorSpacesController {
+
+  public function handleRequest(AphrontRequest $request) {
+    $viewer = $request->getUser();
+
+    $space = id(new PhabricatorSpacesNamespaceQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($request->getURIData('id')))
+      ->requireCapabilities(
+        array(
+          PhabricatorPolicyCapability::CAN_VIEW,
+          PhabricatorPolicyCapability::CAN_EDIT,
+        ))
+      ->executeOne();
+    if (!$space) {
+      return new Aphront404Response();
+    }
+
+    $is_archive = ($request->getURIData('action') == 'archive');
+    $cancel_uri = '/'.$space->getMonogram();
+
+    if ($request->isFormPost()) {
+      $type_archive = PhabricatorSpacesNamespaceTransaction::TYPE_ARCHIVE;
+
+      $xactions = array();
+      $xactions[] = id(new PhabricatorSpacesNamespaceTransaction())
+        ->setTransactionType($type_archive)
+        ->setNewValue($is_archive ? 1 : 0);
+
+      $editor = id(new PhabricatorSpacesNamespaceEditor())
+        ->setActor($viewer)
+        ->setContinueOnNoEffect(true)
+        ->setContinueOnMissingFields(true)
+        ->setContentSourceFromRequest($request);
+
+      $editor->applyTransactions($space, $xactions);
+
+      return id(new AphrontRedirectResponse())->setURI($cancel_uri);
+    }
+
+    $body = array();
+    if ($is_archive) {
+      $title = pht('Archive Space: %s', $space->getNamespaceName());
+      $body[] = pht(
+        'If you archive this Space, you will no longer be able to create '.
+        'new objects inside it.');
+      $body[] = pht(
+        'Existing objects in this Space will be hidden from query results '.
+        'by default.');
+      $button = pht('Archive Space');
+    } else {
+      $title = pht('Activate Space: %s', $space->getNamespaceName());
+      $body[] = pht(
+        'If you activate this space, you will be able to create objects '.
+        'inside it again.');
+      $body[] = pht(
+        'Existing objects will no longer be hidden from query results.');
+      $button = pht('Activate Space');
+    }
+
+
+    $dialog = $this->newDialog()
+      ->setTitle($title)
+      ->addCancelButton($cancel_uri)
+      ->addSubmitButton($button);
+
+    foreach ($body as $paragraph) {
+      $dialog->appendParagraph($paragraph);
+    }
+
+    return $dialog;
+  }
+}
diff --git a/src/applications/spaces/controller/PhabricatorSpacesViewController.php b/src/applications/spaces/controller/PhabricatorSpacesViewController.php
index 46e82627ec..511d853151 100644
--- a/src/applications/spaces/controller/PhabricatorSpacesViewController.php
+++ b/src/applications/spaces/controller/PhabricatorSpacesViewController.php
@@ -37,6 +37,12 @@ final class PhabricatorSpacesViewController
       ->setHeader($space->getNamespaceName())
       ->setPolicyObject($space);
 
+    if ($space->getIsArchived()) {
+      $header->setStatus('fa-ban', 'red', pht('Archived'));
+    } else {
+      $header->setStatus('fa-check', 'bluegrey', pht('Active'));
+    }
+
     $box = id(new PHUIObjectBoxView())
       ->setHeader($header)
       ->addPropertyList($property_list);
@@ -112,6 +118,26 @@ final class PhabricatorSpacesViewController
         ->setWorkflow(!$can_edit)
         ->setDisabled(!$can_edit));
 
+    $id = $space->getID();
+
+    if ($space->getIsArchived()) {
+      $list->addAction(
+        id(new PhabricatorActionView())
+          ->setName(pht('Activate Space'))
+          ->setIcon('fa-check')
+          ->setHref($this->getApplicationURI("activate/{$id}/"))
+          ->setDisabled(!$can_edit)
+          ->setWorkflow(true));
+    } else {
+      $list->addAction(
+        id(new PhabricatorActionView())
+          ->setName(pht('Archive Space'))
+          ->setIcon('fa-ban')
+          ->setHref($this->getApplicationURI("archive/{$id}/"))
+          ->setDisabled(!$can_edit)
+          ->setWorkflow(true));
+    }
+
     return $list;
   }
 
diff --git a/src/applications/spaces/editor/PhabricatorSpacesNamespaceEditor.php b/src/applications/spaces/editor/PhabricatorSpacesNamespaceEditor.php
index 3b6c7bb6e6..caa45f28c2 100644
--- a/src/applications/spaces/editor/PhabricatorSpacesNamespaceEditor.php
+++ b/src/applications/spaces/editor/PhabricatorSpacesNamespaceEditor.php
@@ -17,6 +17,7 @@ final class PhabricatorSpacesNamespaceEditor
     $types[] = PhabricatorSpacesNamespaceTransaction::TYPE_NAME;
     $types[] = PhabricatorSpacesNamespaceTransaction::TYPE_DESCRIPTION;
     $types[] = PhabricatorSpacesNamespaceTransaction::TYPE_DEFAULT;
+    $types[] = PhabricatorSpacesNamespaceTransaction::TYPE_ARCHIVE;
 
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
@@ -40,6 +41,8 @@ final class PhabricatorSpacesNamespaceEditor
           return null;
         }
         return $object->getDescription();
+      case PhabricatorSpacesNamespaceTransaction::TYPE_ARCHIVE:
+        return $object->getIsArchived();
       case PhabricatorSpacesNamespaceTransaction::TYPE_DEFAULT:
         return $object->getIsDefaultNamespace() ? 1 : null;
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
@@ -61,6 +64,8 @@ final class PhabricatorSpacesNamespaceEditor
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         return $xaction->getNewValue();
+      case PhabricatorSpacesNamespaceTransaction::TYPE_ARCHIVE:
+        return $xaction->getNewValue() ? 1 : 0;
       case PhabricatorSpacesNamespaceTransaction::TYPE_DEFAULT:
         return $xaction->getNewValue() ? 1 : null;
     }
@@ -84,6 +89,9 @@ final class PhabricatorSpacesNamespaceEditor
       case PhabricatorSpacesNamespaceTransaction::TYPE_DEFAULT:
         $object->setIsDefaultNamespace($new ? 1 : null);
         return;
+      case PhabricatorSpacesNamespaceTransaction::TYPE_ARCHIVE:
+        $object->setIsArchived($new ? 1 : 0);
+        return;
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
         $object->setViewPolicy($new);
         return;
@@ -103,6 +111,7 @@ final class PhabricatorSpacesNamespaceEditor
       case PhabricatorSpacesNamespaceTransaction::TYPE_NAME:
       case PhabricatorSpacesNamespaceTransaction::TYPE_DESCRIPTION:
       case PhabricatorSpacesNamespaceTransaction::TYPE_DEFAULT:
+      case PhabricatorSpacesNamespaceTransaction::TYPE_ARCHIVE:
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
       case PhabricatorTransactions::TYPE_EDIT_POLICY:
         return;
@@ -128,13 +137,27 @@ final class PhabricatorSpacesNamespaceEditor
           $error = new PhabricatorApplicationTransactionValidationError(
             $type,
             pht('Required'),
-              pht('Spaces must have a name.'),
+            pht('Spaces must have a name.'),
             nonempty(last($xactions), null));
 
           $error->setIsMissingFieldError(true);
           $errors[] = $error;
         }
         break;
+      case PhabricatorSpacesNamespaceTransaction::TYPE_DEFAULT:
+        if (!$this->getIsNewObject()) {
+          foreach ($xactions as $xaction) {
+            $errors[] = new PhabricatorApplicationTransactionValidationError(
+              $type,
+              pht('Invalid'),
+              pht(
+                'Only the first space created can be the default space, and '.
+                'it must remain the default space evermore.'),
+              $xaction);
+          }
+        }
+        break;
+
     }
 
     return $errors;
diff --git a/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php b/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php
index 710972e8f4..6645c7edbd 100644
--- a/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php
+++ b/src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php
@@ -39,6 +39,10 @@ final class PhabricatorSpacesNamespacePHIDType
       $handle->setName($name);
       $handle->setFullName(pht('%s %s', $monogram, $name));
       $handle->setURI('/'.$monogram);
+
+      if ($namespace->getIsArchived()) {
+        $handle->setStatus(PhabricatorObjectHandle::STATUS_CLOSED);
+      }
     }
   }
 
diff --git a/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php b/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php
index 77cb8aee5e..51ac66130a 100644
--- a/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php
+++ b/src/applications/spaces/query/PhabricatorSpacesNamespaceQuery.php
@@ -9,6 +9,7 @@ final class PhabricatorSpacesNamespaceQuery
   private $ids;
   private $phids;
   private $isDefaultNamespace;
+  private $isArchived;
 
   public function withIDs(array $ids) {
     $this->ids = $ids;
@@ -25,38 +26,32 @@ final class PhabricatorSpacesNamespaceQuery
     return $this;
   }
 
+  public function withIsArchived($archived) {
+    $this->isArchived = $archived;
+    return $this;
+  }
+
   public function getQueryApplicationClass() {
     return 'PhabricatorSpacesApplication';
   }
 
   protected function loadPage() {
-    $table = new PhabricatorSpacesNamespace();
-    $conn_r = $table->establishConnection('r');
-
-    $rows = queryfx_all(
-      $conn_r,
-      'SELECT * FROM %T %Q %Q %Q',
-      $table->getTableName(),
-      $this->buildWhereClause($conn_r),
-      $this->buildOrderClause($conn_r),
-      $this->buildLimitClause($conn_r));
-
-    return $table->loadAllFromArray($rows);
+    return $this->loadStandardPage(new PhabricatorSpacesNamespace());
   }
 
-  protected function buildWhereClause(AphrontDatabaseConnection $conn_r) {
-    $where = array();
+  protected function buildWhereClauseParts(AphrontDatabaseConnection $conn) {
+    $where = parent::buildWhereClauseParts($conn);
 
     if ($this->ids !== null) {
       $where[] = qsprintf(
-        $conn_r,
+        $conn,
         'id IN (%Ld)',
         $this->ids);
     }
 
     if ($this->phids !== null) {
       $where[] = qsprintf(
-        $conn_r,
+        $conn,
         'phid IN (%Ls)',
         $this->phids);
     }
@@ -64,17 +59,23 @@ final class PhabricatorSpacesNamespaceQuery
     if ($this->isDefaultNamespace !== null) {
       if ($this->isDefaultNamespace) {
         $where[] = qsprintf(
-          $conn_r,
+          $conn,
           'isDefaultNamespace = 1');
       } else {
         $where[] = qsprintf(
-          $conn_r,
+          $conn,
           'isDefaultNamespace IS NULL');
       }
     }
 
-    $where[] = $this->buildPagingClause($conn_r);
-    return $this->formatWhereClause($where);
+    if ($this->isArchived !== null) {
+      $where[] = qsprintf(
+        $conn,
+        'isArchived = %d',
+        (int)$this->isArchived);
+    }
+
+    return $where;
   }
 
   public static function destroySpacesCache() {
@@ -156,6 +157,21 @@ final class PhabricatorSpacesNamespaceQuery
     return $result;
   }
 
+
+  public static function getViewerActiveSpaces(PhabricatorUser $viewer) {
+    $spaces = self::getViewerSpaces($viewer);
+
+    foreach ($spaces as $key => $space) {
+      if ($space->getIsArchived()) {
+        unset($spaces[$key]);
+      }
+    }
+
+    return $spaces;
+  }
+
+
+
   /**
    * Get the Space PHID for an object, if one exists.
    *
diff --git a/src/applications/spaces/query/PhabricatorSpacesNamespaceSearchEngine.php b/src/applications/spaces/query/PhabricatorSpacesNamespaceSearchEngine.php
index 9b4014c3dd..c12ad9e098 100644
--- a/src/applications/spaces/query/PhabricatorSpacesNamespaceSearchEngine.php
+++ b/src/applications/spaces/query/PhabricatorSpacesNamespaceSearchEngine.php
@@ -11,28 +11,39 @@ final class PhabricatorSpacesNamespaceSearchEngine
     return pht('Spaces');
   }
 
-  public function buildSavedQueryFromRequest(AphrontRequest $request) {
-    $saved = new PhabricatorSavedQuery();
-
-    return $saved;
+  public function newQuery() {
+    return new PhabricatorSpacesNamespaceQuery();
   }
 
-  public function buildQueryFromSavedQuery(PhabricatorSavedQuery $saved) {
-    $query = id(new PhabricatorSpacesNamespaceQuery());
+  public function buildCustomSearchFields() {
+    return array(
+      id(new PhabricatorSearchThreeStateField())
+        ->setLabel(pht('Active'))
+        ->setKey('active')
+        ->setOptions(
+          pht('(Show All)'),
+          pht('Show Only Active Spaces'),
+          pht('Hide Active Spaces')),
+    );
+  }
+
+  public function buildQueryFromParameters(array $map) {
+    $query = $this->newQuery();
+
+    if ($map['active']) {
+      $query->withIsArchived(!$map['active']);
+    }
 
     return $query;
   }
 
-  public function buildSearchForm(
-    AphrontFormView $form,
-    PhabricatorSavedQuery $saved_query) {}
-
   protected function getURI($path) {
     return '/spaces/'.$path;
   }
 
   protected function getBuiltinQueryNames() {
     $names = array(
+      'active' => pht('Active Spaces'),
       'all' => pht('All Spaces'),
     );
 
@@ -40,11 +51,12 @@ final class PhabricatorSpacesNamespaceSearchEngine
   }
 
   public function buildSavedQueryFromBuiltin($query_key) {
-
     $query = $this->newSavedQuery();
     $query->setQueryKey($query_key);
 
     switch ($query_key) {
+      case 'active':
+        return $query->setParameter('active', true);
       case 'all':
         return $query;
     }
@@ -72,6 +84,10 @@ final class PhabricatorSpacesNamespaceSearchEngine
         $item->addIcon('fa-certificate', pht('Default Space'));
       }
 
+      if ($space->getIsArchived()) {
+        $item->setDisabled(true);
+      }
+
       $list->addItem($item);
     }
 
diff --git a/src/applications/spaces/storage/PhabricatorSpacesNamespace.php b/src/applications/spaces/storage/PhabricatorSpacesNamespace.php
index 5b1098b1f8..f728d22dfa 100644
--- a/src/applications/spaces/storage/PhabricatorSpacesNamespace.php
+++ b/src/applications/spaces/storage/PhabricatorSpacesNamespace.php
@@ -12,6 +12,7 @@ final class PhabricatorSpacesNamespace
   protected $editPolicy;
   protected $isDefaultNamespace;
   protected $description;
+  protected $isArchived;
 
   public static function initializeNewNamespace(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
@@ -28,7 +29,8 @@ final class PhabricatorSpacesNamespace
       ->setIsDefaultNamespace(null)
       ->setViewPolicy($view_policy)
       ->setEditPolicy($edit_policy)
-      ->setDescription('');
+      ->setDescription('')
+      ->setIsArchived(0);
   }
 
   protected function getConfiguration() {
@@ -38,6 +40,7 @@ final class PhabricatorSpacesNamespace
         'namespaceName' => 'text255',
         'isDefaultNamespace' => 'bool?',
         'description' => 'text',
+        'isArchived' => 'bool',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'key_default' => array(
diff --git a/src/applications/spaces/storage/PhabricatorSpacesNamespaceTransaction.php b/src/applications/spaces/storage/PhabricatorSpacesNamespaceTransaction.php
index ef7d8f210f..4c438537f1 100644
--- a/src/applications/spaces/storage/PhabricatorSpacesNamespaceTransaction.php
+++ b/src/applications/spaces/storage/PhabricatorSpacesNamespaceTransaction.php
@@ -6,6 +6,7 @@ final class PhabricatorSpacesNamespaceTransaction
   const TYPE_NAME = 'spaces:name';
   const TYPE_DEFAULT = 'spaces:default';
   const TYPE_DESCRIPTION = 'spaces:description';
+  const TYPE_ARCHIVE = 'spaces:archive';
 
   public function getApplicationName() {
     return 'spaces';
@@ -78,6 +79,16 @@ final class PhabricatorSpacesNamespaceTransaction
         return pht(
           '%s made this the default space.',
           $this->renderHandleLink($author_phid));
+      case self::TYPE_ARCHIVE:
+        if ($new) {
+          return pht(
+            '%s archived this space.',
+            $this->renderHandleLink($author_phid));
+        } else {
+          return pht(
+            '%s activated this space.',
+            $this->renderHandleLink($author_phid));
+        }
     }
 
     return parent::getTitle();
diff --git a/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php b/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php
index 046e3b0f4f..25951b53af 100644
--- a/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php
+++ b/src/applications/spaces/typeahead/PhabricatorSpacesNamespaceDatasource.php
@@ -21,9 +21,20 @@ final class PhabricatorSpacesNamespaceDatasource
     $spaces = $this->executeQuery($query);
     $results = array();
     foreach ($spaces as $space) {
-      $results[] = id(new PhabricatorTypeaheadResult())
-        ->setName($space->getNamespaceName())
+      $full_name = pht(
+        '%s %s',
+        $space->getMonogram(),
+        $space->getNamespaceName());
+
+      $result = id(new PhabricatorTypeaheadResult())
+        ->setName($full_name)
         ->setPHID($space->getPHID());
+
+      if ($space->getIsArchived()) {
+        $result->setClosed(pht('Archived'));
+      }
+
+      $results[] = $result;
     }
 
     return $this->filterResultsAgainstTokens($results);
diff --git a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
index b4d36b5513..2f36828b8a 100644
--- a/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
+++ b/src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php
@@ -310,6 +310,7 @@ abstract class PhabricatorApplicationTransactionEditor
             $space_phid = $default_space->getPHID();
           }
         }
+
         return $space_phid;
       case PhabricatorTransactions::TYPE_EDGE:
         $edge_type = $xaction->getMetadataValue('edge:type');
@@ -2011,6 +2012,8 @@ abstract class PhabricatorApplicationTransactionEditor
 
     $has_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpacesExist($actor);
     $actor_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpaces($actor);
+    $active_spaces = PhabricatorSpacesNamespaceQuery::getViewerActiveSpaces(
+      $actor);
     foreach ($xactions as $xaction) {
       $space_phid = $xaction->getNewValue();
 
@@ -2040,6 +2043,23 @@ abstract class PhabricatorApplicationTransactionEditor
             'You can not shift this object in the selected space, because '.
             'the space does not exist or you do not have access to it.'),
           $xaction);
+      } else if (empty($active_spaces[$space_phid])) {
+
+        // It's OK to edit objects in an archived space, so just move on if
+        // we aren't adjusting the value.
+        $old_space_phid = $this->getTransactionOldValue($object, $xaction);
+        if ($space_phid == $old_space_phid) {
+          continue;
+        }
+
+        $errors[] = new PhabricatorApplicationTransactionValidationError(
+          $transaction_type,
+          pht('Archived'),
+          pht(
+            'You can not shift this object into the selected space, because '.
+            'the space is archived. Objects can not be created inside (or '.
+            'moved into) archived spaces.'),
+          $xaction);
       }
     }
 
diff --git a/src/docs/user/userguide/spaces.diviner b/src/docs/user/userguide/spaces.diviner
new file mode 100644
index 0000000000..9026edf86e
--- /dev/null
+++ b/src/docs/user/userguide/spaces.diviner
@@ -0,0 +1,27 @@
+@title Spaces User Guide
+@group userguide
+
+Guide to the Spaces application.
+
+Overview
+========
+
+IMPORTANT: Spaces is a prototype application.
+
+Archiving Spaces
+================
+
+If you no longer need a Space, you can archive it by choosing
+{nav Archive Space} from the detail view. This hides the space and all the
+objects in it without deleting any data.
+
+New objects can't be created into archived spaces, and existing objects can't
+be shifted into archived spaces. The UI won't give you options to choose
+these spaces when creating or editing objects.
+
+Additionally, objects (like tasks) in archived spaces won't be shown in most
+search result lists by default. If you need to find objects in an archived
+space, use the `Spaces` constraint to specifically search for objects in that
+space.
+
+You can reactivate a space later by choosing {nav Activate Space}.
diff --git a/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php b/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php
index b48e1e5c46..4d0f96bde5 100644
--- a/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php
+++ b/src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php
@@ -25,6 +25,7 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
   private $edgeLogicConstraints = array();
   private $edgeLogicConstraintsAreValid = false;
   private $spacePHIDs;
+  private $spaceIsArchived;
 
   protected function getPageCursors(array $page) {
     return array(
@@ -1722,6 +1723,11 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
     return $this;
   }
 
+  public function withSpaceIsArchived($archived) {
+    $this->spaceIsArchived = $archived;
+    return $this;
+  }
+
 
   /**
    * Constrain the query to include only results in valid Spaces.
@@ -1760,6 +1766,11 @@ abstract class PhabricatorCursorPagedPolicyAwareQuery
       $viewer_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpaces(
         $viewer);
       foreach ($viewer_spaces as $viewer_space) {
+        if ($this->spaceIsArchived !== null) {
+          if ($viewer_space->getIsArchived() != $this->spaceIsArchived) {
+            continue;
+          }
+        }
         $phid = $viewer_space->getPHID();
         $space_phids[$phid] = $phid;
         if ($viewer_space->getIsDefaultNamespace()) {
diff --git a/src/view/form/control/AphrontFormPolicyControl.php b/src/view/form/control/AphrontFormPolicyControl.php
index 45bff0900e..58d06cc5de 100644
--- a/src/view/form/control/AphrontFormPolicyControl.php
+++ b/src/view/form/control/AphrontFormPolicyControl.php
@@ -265,7 +265,7 @@ final class AphrontFormPolicyControl extends AphrontFormControl {
 
     $select = AphrontFormSelectControl::renderSelectTag(
       $space_phid,
-      $this->getSpaceOptions(),
+      $this->getSpaceOptions($space_phid),
       array(
         'name' => 'spacePHID',
       ));
@@ -273,12 +273,20 @@ final class AphrontFormPolicyControl extends AphrontFormControl {
     return $select;
   }
 
-  protected function getSpaceOptions() {
+  protected function getSpaceOptions($space_phid) {
     $viewer = $this->getUser();
     $viewer_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpaces($viewer);
 
     $map = array();
     foreach ($viewer_spaces as $space) {
+
+      // Skip archived spaces, unless the object is already in that space.
+      if ($space->getIsArchived()) {
+        if ($space->getPHID() != $space_phid) {
+          continue;
+        }
+      }
+
       $map[$space->getPHID()] = pht(
         'Space %s: %s',
         $space->getMonogram(),