diff --git a/CHANGELOG.md b/CHANGELOG.md
index a8207bc..edaca14 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## Changelog
 
+### 4.1.2 (2020-10-13)
+
+- Expose `error` in TypeScript definition of `SatRec`.
+- Fix TypeScript definition for `PositionAndVelocity` to allow error handling.
+
 ### 4.1.1 (2020-09-15)
 
 - Fix TypeScript definition for `gstime` (#73).
diff --git a/README.md b/README.md
index 82ce090..f53085e 100644
--- a/README.md
+++ b/README.md
@@ -28,6 +28,8 @@ Special thanks to all contributors for improving usability and bug fixes :)
 - [dangodev (Drew Powers)](https://github.com/dangodev)
 - [thkruz (Theodore Kruczek)](https://github.com/thkruz)
 - [bakercp (Christopher Baker)](https://github.com/bakercp)
+- [Kyle G. Maxwell](https://github.com/kylegmaxwell)
+- [Chad Johnston](https://github.com/iamthechad)
 - [drom (Aliaksei Chapyzhenka)](https://github.com/drom)
 - [PeterDaveHello (Peter Dave Hello)](https://github.com/PeterDaveHello)
 - [nhamer](https://github.com/nhamer)
diff --git a/package.json b/package.json
index cb9f781..5d8c79c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "satellite.js",
-  "version": "4.1.1",
+  "version": "4.1.2",
   "description": "SGP4/SDP4 calculation library",
   "main": "lib/index.js",
   "jsnext:main": "dist/satellite.es.js",
diff --git a/types/index.d.ts b/types/index.d.ts
index 24f4dea..aabe99a 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -55,6 +55,10 @@ declare module 'satellite.js' {
      * Mean motion in radians per minute.
      */
     no: number;
+    /**
+     * Error code indicating propagation failure type.
+     */
+    error: number;
   }
 
   /**
@@ -95,10 +99,11 @@ declare module 'satellite.js' {
   /**
    * The position_velocity result is a key-value pair of ECI coordinates.
    * These are the base results from which all other coordinates are derived.
+   * If there is an error the position and velocity will be false.
    */
   export interface PositionAndVelocity {
-    position: EciVec3<Kilometer>;
-    velocity: EciVec3<KilometerPerSecond>;
+    position: EciVec3<Kilometer>|boolean;
+    velocity: EciVec3<KilometerPerSecond>|boolean;
   }
 
   /**