1   /* Copyright 2002-2025 CS GROUP
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.propagation.numerical;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
21  
22  /** Interface summing up the contribution of several forces into orbit and mass derivatives.
23   *
24   * <p>The aim of this interface is to gather the contributions of various perturbing
25   * forces expressed as accelerations into one set of time-derivatives of
26   * {@link org.orekit.orbits.Orbit} plus one mass derivatives. It implements Gauss
27   * equations for different kind of parameters.</p>
28   * <p>An implementation of this interface is automatically provided by {@link
29   * org.orekit.propagation.integration.AbstractIntegratedPropagator integration-based
30   * propagators}, which are either semi-analytical or numerical propagators.
31   * </p>
32   * @see org.orekit.forces.ForceModel
33   * @see org.orekit.propagation.numerical.NumericalPropagator
34   * @author Luc Maisonobe
35   * @author Fabien Maussion
36   * @author V&eacute;ronique Pommier-Maurussane
37   * @param <T> type of the field elements
38   */
39  public interface FieldTimeDerivativesEquations<T extends CalculusFieldElement<T>> {
40  
41      /** Add the contribution of the Kepler evolution.
42       * <p>Since the Kepler evolution is the most important, it should
43       * be added after all the other ones, in order to improve
44       * numerical accuracy.</p>
45       * @param mu central body gravitational constant
46       */
47      void addKeplerContribution(T mu);
48  
49      /** Add the contribution of an acceleration expressed in some inertial frame.
50       * @param gamma acceleration vector in the same inertial frame the spacecraft state is defined in (m/s²)
51            * @since 9.0
52       */
53      void addNonKeplerianAcceleration(FieldVector3D<T> gamma);
54  
55      /** Add the contribution of the flow rate (dm/dt).
56       * @param q the flow rate, must be negative (dm/dt)
57       * @exception IllegalArgumentException if flow-rate is positive
58       */
59      void addMassDerivative(T q);
60  
61  
62  }