Added masse depletion delay effect.

src/main/java/org/orekit/forces/maneuvers/jacobians/MassDepletionDelay.java

+/* Copyright 2002-2021 CS GROUP
+ * Licensed to CS GROUP (CS) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * CS licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.orekit.forces.maneuvers.jacobians;
+
+import org.hipparchus.geometry.euclidean.threed.Vector3D;
+import org.orekit.forces.maneuvers.Maneuver;
+import org.orekit.propagation.SpacecraftState;
+import org.orekit.propagation.integration.AdditionalDerivativesProvider;
+import org.orekit.time.AbsoluteDate;
+
+/** Generator for effect of delaying mass depletion when delaying a maneuver.
+ * @author Luc Maisonobe
+ * @since 11.1
+ */
+public class MassDepletionDelay implements AdditionalDerivativesProvider {
+
+    /** Prefix for state name. */
+    public static final String PREFIX = "Orekit-depletion-";
+
+    /** Name of the mass depletion additional state. */
+    private final String depletionName;
+
+    /** Start/stop management flag. */
+    private final boolean manageStart;
+
+    /** Maneuver that is delayed. */
+    private final Maneuver maneuver;
+
+    /** Indicator for forward propagation. */
+    private boolean forward;
+
+    /** Simple constructor.
+     * <p>
+     * The generated additional state and derivatives will be named by prepending
+     * the {@link #PREFIX} to the name of the date trigger parameter.
+     * </p>
+     * @param triggerName name of the date trigger parameter
+     * @param manageStart if true, we compute derivatives with respect to maneuver start
+     * @param maneuver maneuver that is delayed
+     */
+    public MassDepletionDelay(final String triggerName, final boolean manageStart, final Maneuver maneuver) {
+        this.depletionName = PREFIX + triggerName;
+        this.manageStart   = manageStart;
+        this.maneuver      = maneuver;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public String getName() {
+        return depletionName;
+    }
+
+    /** Get the dimension of the generated column.
+     * @return dimension of the generated column
+     */
+    public int getDimension() {
+        return 6;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void init(final SpacecraftState initialState, final AbsoluteDate target) {
+        forward = target.isAfterOrEqualTo(initialState);
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public double[] derivatives(final SpacecraftState state) {
+
+        // retrieve current Jacobian column
+        final double[] p = state.getAdditionalState(getName());
+        final double[] pDot = new double[6];
+
+        if (forward == manageStart) {
+
+            // current acceleration
+            final double[] parameters   = maneuver.getParameters();
+            final Vector3D acceleration = maneuver.acceleration(state, parameters);
+
+            // we have acceleration Γ = F/m and m = m₀ - q (t - tₛ)
+            // where m is current mass, m₀ is initial mass and tₛ is maneuver trigger time
+            // a delay dtₛ on trigger time induces delaying mass depletion
+            // we get: dΓ = -F/m² dm = -F/m² q dtₛ = -Γ q/m dtₛ
+            final double minusQ = maneuver.getPropulsionModel().getMassDerivatives(state, parameters);
+            final double m      = state.getMass();
+            final double ratio  = minusQ / m;
+
+            pDot[0] = p[3];
+            pDot[1] = p[4];
+            pDot[2] = p[5];
+            pDot[3] = ratio * acceleration.getX();
+            pDot[4] = ratio * acceleration.getY();
+            pDot[5] = ratio * acceleration.getZ();
+
+        }
+
+        return pDot;
+
+    }
+
+}
+

src/main/java/org/orekit/forces/maneuvers/jacobians/package-info.java

+/* Copyright 2002-2021 CS GROUP
+ * Licensed to CS GROUP (CS) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * CS licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * Generators for columns of Jacobian matrices related to maneuver parameters.
+ */
+package org.orekit.forces.maneuvers.jacobians;
+