1   /* Copyright 2022-2025 Luc Maisonobe
2    * Licensed to CS GROUP (CS) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * CS licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *   http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.orekit.attitudes;
18  
19  import org.hipparchus.geometry.euclidean.threed.Vector3D;
20  
21  /** Container for inertial axis.
22   * <p>
23   * Instances of this class are immutable
24   * </p>
25   * @author Luc Maisonobe
26   * @since 12.0
27   */
28  public class InertiaAxis {
29  
30      /** Moment of inertia. */
31      private final double i;
32  
33      /** Inertia axis. */
34      private final Vector3D a;
35  
36      /** Simple constructor to pair a moment of inertia with its associated axis.
37       * @param i moment of inertia
38       * @param a inertia axis
39       */
40      public InertiaAxis(final double i, final Vector3D a) {
41          this.i = i;
42          this.a = a;
43      }
44  
45      /** Reverse the inertia axis.
46       * @return new container with reversed axis
47       */
48      public InertiaAxis negate() {
49          return new InertiaAxis(i, a.negate());
50      }
51  
52      /** Get the moment of inertia.
53       * @return moment of inertia
54       */
55      public double getI() {
56          return i;
57      }
58  
59      /** Get the inertia axis.
60       * @return inertia axis
61       */
62      public Vector3D getA() {
63          return a;
64      }
65  
66  }