Calc Object values corresponding to the final state of each Astrogator maneuver segment. Each Calc Object contained in the Component Browser is available for use, including user defined Calc Objects. The Calc Objects listed here are representative.
This data provider requires that the Satellite use the Astrogator propagator.
Interval data given specified evaluation intervals and step sizes. May supply data with duplicate times. Intended to be used only with elements from this same data provider.
| Name | Description |
|---|
| Top | Time measures. |
| Access | An Access calculation object that computes access between two objects. |
| Cartesian Elems | Calc Objects for the ephemeris of the object, expressed in Cartesian components. Each Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Constants | Constant values used in astrodynamic calculations. |
| Curvilinear Relative Motion | Calc Objects for relative ephemeris between the satellite and reference satellite, expressed in curvilinear coordinates.
The relative ephemeris is computed using a reference ellipse that is defined as being the instantaneous keplerian orbit for either the satellite or reference satellite.
Crosstrack is the (signed) distance between an object's position and the plane of the reference ellipse. Crossrange is the (signed) closest distance
to the reference ellipse from the projection of an object's position into the plane of the reference ellipse. This closest point on the reference ellipse is called the
downrange position of the object. Downrange is the (signed) distance along the reference ellipse between two downrange positions. See Also Relative Motion. |
| Delaunay Elems | A set of canonical angle-action variables commonly used in general perturbation theories. An orbit is defined by a set of conjugate angle-action pairs. |
| Environment | Calc Objects for the satellite environment. |
| Equinoctial Elems | Calc Objects for the ephemeris of the object, expressed in equinoctial elements. Each Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms). The default is osculating. Each Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Formation | Calc Objects for relative motion and close approaches with respect to the master satellite or a specified vehicle. See also Relative Motion. The close approach X axis is the unit vector in the direction of the cross product of the relative velocity vector with the orbit momentum vector of the reference vehicle. The close approach Y axis is the unit vector in the direction of the cross product of the X axis and the relative velocity vector. The close approach plane is the plane spanned by the X and Y axes. The close approach vector is the relative position vector from the reference vehicle. |
| GeoStationary | Calc Objects that are useful for station keeping of geostationary satellites. Each Calc Object allows a choice of a central body. The default is Earth. |
| Geodetic | Calc Objects for the ephemeris of the object, expressed in LLA elements. Each Calc Object allows a choice of a central body. The default is Earth. |
| Ground Track | Calc Objects for maintaining a repeating ground track. |
| Keplerian Elems | Calc Objects for the ephemeris of the object, expressed in keplerian (i.e., instantaneous two-body) elements. Each Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms). The default is osculating. |
| Maneuver | Maneuver related Calc Objects. |
| Math | Used to perform functions on other Calc Objects. |
| Mean Elems | Calc Objects for the ephemeris of the object, expressed in Keplerian elements. Each Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms).
The default is Kozai-Izsak mean elements. The mean elements are computed using mean element theory (not simply a numerical average of the element over a period), considering only gravity perturbations (J2 and for some theories J3 through J5). |
| MultiBody | Used for targeting a different central body. See also B-plane targeting under Astrogator help. |
| Other Orbit | Miscellaneous Calc Objects. |
| Power | Calc Objects that compute power. |
| Relative Motion | Calc Objects for relative ephemeris. The relative ephemeris is computed with respect to two rotating frames, the RIC
(Radial, In-Track, Cross-Track) frame and the NTC (Normal, Tangential, and Cross-Track) frames, that are defined using the primary's ephemeris.
Cross-track refers to the direction perpendicular to the position and inertial velocity; in-track refers to the direction perpendicular to both the radial
and cross-track (positive in the direction of motion); tangential refers to the direction along the velocity vector; and normal refers to the direction
perpendicular to the velocity and cross-track directions (positive outward along radial). Each Calc Object allows a choice of a central body. The default is Earth. See Also Formation. |
| SEET | Calc Objects utilizing computations provided by SEET. |
| Scalar | Scalar calculation component. |
| Scripts | Values from Astrogator plugin scripts. |
| Spacecraft Properties | Included are Drag, Radiation Pressure, and Solar Radiation Pressure coefficient and area values of a spacecraft. You can use these objects to report how a propagator plugin changes these values over time. When the value of one these objects changes, Astrogator applies the new value to subsequent propagation steps and segments in the MCS.
For built-in models that introduce time-varying areas and coefficients, namely the Variable Area and N-Plate models, the Drag and SRP calculation objects take on particular meanings as described below. Variable Area Drag and SRP models: The DragArea and SRPArea calculation objects reflect the associated areas used for a given time step in the ephemeris as prescribed by the corresponding file(s). Behavior of the Cd and Cr coefficients is unchanged from prior patterns by these models. Astrogator does not back-compute any quantities from the Variable Area Drag and SRP models; it keeps the values for area as per the original input. N-Plate Drag: For reporting purposes, Astrogator computes the DragArea calculation object by taking the "velocity-facing" area at a particular time step. Astrogator back-computes the Cd coefficient calculation object from the acceleration produced by the model only in the direction opposed to the velocity. Although such accounting generally captures the majority of the associated drag effects, neither of these scalar parameters completely reflect the contribution of the N-Plate Drag model to the total acceleration as experienced by the spacecraft under the numerical propagation. Astrogator neglects the perpendicular components in this reporting process. N-Plate SRP: Astrogator produces the SRPArea calculation object as the "Sun-facing" area for a particular ephemeris point. It back-computes the Cr coefficient calculation object only from the acceleration in the direction opposite to the Sun. Such accounting for reporting purposes in these scalar parameters does not capture the entire vector acceleration experienced by the spacecraft during numerical propagation. Unlike the case of a plugin changing the values, the various drag and coefficient values for these built-in models are applicable only for segments in which these models are active. Take the case, for example, where Astrogator propagates three subsequent segments in order. The first and third segments both use the DragArea parameter defined at the MCS level in some Initial State (or Update, etc.) segment. The second segment, between the first and third segments, uses the Variable Area Drag model. No plugins or other methods for changing the DragArea parameter are employed. In such a case, Astrogator will apply the constant MCS-level DragArea value to the first segment. For the second segment, it will use the Variable Area Drag model and report a varying value for DragArea. For the third segment, it will revert to the value of DragArea used in the first segment regardless of the DragArea value in effect at the end of the second segment. The behavior described in the Variable Area Drag model example — reverting parameters when the associated model is not employed — is consistent with how Astrogator reports all of the noted calculation objects for each of the built-in time-varying models described above. It is also consistent with the time of effect for the underlying models when Astrogator computes the full-vector accelerations consistent with constituent parameters (plates, coefficients, etc.). To have any value set by one of these models to persist into a subsequent segment, introduce an Update segment as appropriate. The effective drag and SRP area, as well as the effective Cd and Cr values, will be zero when the satellite altitude is outside the bounds of the density model, nominally -100 km to 2500 km. The effective Cr is also zero when the satellite is in shadow. |
| Spherical Elems | Calc Objects for the ephemeris of the object, expressed in spherical elements. |
| Target Vector | Data for incoming and outgoing asymptotes as well as C3 energy. |
| Time | Time related Calc Objects. |
| UserValues | User Variable related Calc Objects. |
| Vector | Vector-related Calc Objects. |
| Segment Data | Properties of each MCS segment in the Astrogator satellite. |
| Curvilinear Relative Motion |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| Crossrange_Position | Distance | Real Number | The crossrange position of location source relative to reference ellipse (i.e., the point on the reference ellipse closest
to the point corresponding to the projection of the position into the plane of the reference ellipse). The location source may be specified as being the satellite or the reference satellite.
The reference ellipse may be specified as being the instantaneous keplerian ellipse determined from the satellite's or reference satellite's orbit.
The sign convention may be specified as being positive or negative when the location source is outside of the reference ellipse. |
| Crossrange_Velocity | Rate | Real Number | The time derivative of crossrange position. |
| Crosstrack_Angle | Angle | Real Number or Text | The angle between the position of the location source and the plane of the reference ellipse. The location source
may be specified as being the satellite or the reference satellite. The reference ellipse may be specified as being the instantaneous keplerian ellipse
determined from the satellite's or reference satellite's orbit. The sign convention may be specified as being positive or negative when the position
has a positive dot product with the orbit plane normal. |
| Crosstrack_Angle_Rate | AngleRate | Real Number | The time derivative of crosstrack angle. |
| Crosstrack_Position | Distance | Real Number | The position of location source relative to the plane of the reference ellipse (i.e., the signed perpendicular distance between the
position and the plane of the reference ellipse). The location source may be specified as being the satellite or the reference satellite. The reference ellipse
may be specified as being the instantaneous keplerian ellipse determined from the satellite's or reference satellite's orbit. The sign convention may be specified
as being positive or negative when the position has a positive dot product with the orbit plane normal. |
| Crosstrack_Velocity | Rate | Real Number | The time derivative of crosstrack position. |
| Downrange_Angle | Angle | Real Number or Text | The relative angle between the downrange position of location source and the downrange position of the satellite
being used to define the reference ellipse. The location source may be specified as being the satellite or the reference satellite. The reference ellipse may be specified
as being the instantaneous keplerian ellipse determined from the satellite's or reference satellite's orbit. The sign convention may be specified as being positive
or negative when the location source is ahead of the downrange position of the satellite being used to define the reference ellipse. |
| Downrange_Angle_Rate | AngleRate | Real Number | The time derivative of downrange angle. |
| Downrange_Position | Distance | Real Number | The downrange position of location source relative to the downrange position of the satellite being used to define the reference ellipse.
The downrange position of an object is the point on the reference ellipse closest to the object. Distance is measured along the the curved path of the reference ellipse.
The location source may be specified as being the satellite or the reference satellite. The reference ellipse may be specified as being the instantaneous keplerian ellipse
determined from the satellite's or reference satellite's orbit. The sign convention may be specified as being positive or negative when the location source is ahead of
the downrange position of the satellite being used to define the reference ellipse. |
| Downrange_Time | Time | Real Number | The time offset between the downrange position of location source and the downrange position of the satellite being used to
define the reference ellipse, computed using keplerian motion along the reference ellipse. The location source may be specified as being the satellite or the reference satellite.
The reference ellipse may be specified as being the instantaneous keplerian ellipse determined from the satellite's or reference satellite's orbit.
The sign convention may be specified as being positive or negative when the location source is ahead of the downrange position of the satellite being used to define the reference ellipse. |
| Downrange_Velocity | Rate | Real Number | The time derivative of downrange position. |
| Formation |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| CloseApproachBearing | Angle | Real Number or Text | The angle from the relative velocity vector to the reference vehicle. The Calc Object allows a choice of a central body. The default is Earth. |
| CloseApproachMagnitude | Distance | Real Number | The magnitude of close approach vector. The value is sqrt(x^2 + y^2). The Calc Object allows a choice of a central body. The default is Earth. |
| CloseApproachTheta | Angle | Real Number or Text | The angle from X to close approach vector. The Calc Object allows a choice of a central body. The default is Earth. |
| CloseApproachX | Distance | Real Number | The X component of close approach vector. The Calc Object allows a choice of a central body. The default is Earth. |
| CloseApproachY | Distance | Real Number | The Y component of close approach vector. The Calc Object allows a choice of a central body. The default is Earth. |
| CosineOfCloseApproachBearing | Unitless | Real Number | The cosine of the close approach bearing. The Calc Object allows a choice of a central body. The default is Earth. |
| RelativeAtAOL | Time | Real Number | The relative value (i.e., difference between the value computed for this satellite and the reference vehicle) of a specified calculation object. The value for the satellite is computed at the current state; the value for the reference is computed at either the previous or next state where the reference vehicle's argument of latitude is the same as the satellite's current value. |
| RelativeValue | Time | Real Number | The relative value (i.e., difference between the value computed for this satellite and the reference vehicle) of a specified calculation object. Both values are computed at the given epoch. |
| RelGroundTrackError | Distance | Real Number | Ground track error compared to the reference vehicle. The value for the satellite is computed at the current state; the value for the reference is computed at either the previous or next state where the reference vehicle's argument of latitude is the same as the satellite's current value. The ground track error can be unsigned or signed based on RxV. |
| Rel_Mean_Arg_of_Lat | Angle | Real Number or Text | The relative mean argument of latitude compared to the reference vehicle. |
| Rel_Mean_Arg_of_Perigee | Angle | Real Number or Text | The relative mean argument of perigee compared to the reference vehicle. |
| Rel_Mean_Eccentricity | Unitless | Real Number | The relative mean eccentricity compared to the reference vehicle. |
| Rel_Mean_Inclination | Angle | Real Number or Text | The relative mean inclination compared to the reference vehicle. |
| Rel_Mean_Mean_Anomaly | Angle | Real Number or Text | The relative mean mean anomaly compared to the reference vehicle. |
| Rel_Mean_Period | Time | Real Number | The relative mean orbit period compared to the reference vehicle. |
| Rel_Mean_RAAN | Angle | Real Number or Text | The relative mean RAAN compared to the reference vehicle. |
| Rel_Mean_Semimajor_Axis | Distance | Real Number | The relative mean semimajor axis compared to the reference vehicle. |
| Keplerian Elems |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| Altitude_Of_Apoapsis | Distance | Real Number | The difference between the radius of apoapsis and the central body's equatorial radius. The Calc Object allows a choice of a central body. The default is Earth. |
| Altitude_Of_Periapsis | Distance | Real Number | The difference between the radius of apoapsis and the central body's equatorial radius. The Calc Object allows a choice of a central body. The default is Earth. |
| Argument_of_Latitude | Angle | Real Number or Text | The sum of the argument of periapsis and true anomaly. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Argument_of_Periapsis | Angle | Real Number or Text | The angle from the ascending node to the periapsis vector measured in the orbit plane in the direction of the object's motion.
The periapsis vector locates the closest point of the orbit. For a circular orbit, the value is defined to be zero (i.e., periapsis at the ascending node).
The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Eccentricity | Unitless | Real Number | A measure of the shape of the orbit. Values <1 indicate an ellipse (where zero is a circular orbit) and values >1 indicate a hyperbola. |
| Eccentric_Anomaly | Angle | Real Number or Text | An angle used for converting between true and mean anomaly. Has a geometrical definition as the angle between the line of apsides
and a line running from the center of the ellipse to a point Q on a circle circumscribed about the ellipse. The point Q is a projection of the satellite along a line parallel to the
minor axis of the ellipse. The Calc Object allows a choice of a central body. The default is Earth. |
| Inclination | Angle | Real Number or Text | The angle between the orbit plane and the XY plane of the coordinate system. |
| Longitude_Of_Ascending_Node | Angle | Real Number or Text | A measure of the right ascension of the ascending node, made in the Fixed frame. The value is the detic longitude of the orbit's ascending node. The ascending node crossing is assumed to be at, or prior to, the current position in the orbit in the same nodal revolution. The Calc Object allows a choice of a central body. The default is Earth. |
| MeanAnomaly | Angle | Real Number or Text | A measure of the time past periapsis passing, expressed as an angle. The Calc Object allows a choice of a central body. The default is Earth. |
| Mean_Motion | AngleRate | Real Number | A measure of the osculating period of the orbit, expressed as an angular rate. The value is 2pi rad / orbit_period.
The Calc Object allows a choice of a central body. The default is Earth. |
| Orbit_Period | Time | Real Number | Time required for a complete revolution as computed from osculating semi-major axis length. The Calc Object allows a choice of a central body. The default is Earth. |
| RAAN | Angle | Real Number or Text | The angle in the XY plane from the X axis to the ascending node, measured in a right-handed sense about the Z axis. in the equatorial plane.
For equatorial orbits, the ascending node is defined to be directed along the positive X axis, and thus the value is 0.0.
The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Radius_Of_Apoapsis | Distance | Real Number | The magnitude of the apoapsis vector. The apoapsis vector (defined only when the eccentricity is <1) locates the position in the orbit furthest from the central body. The Calc Object allows a choice of a central body. The default is Earth. |
| Radius_Of_Periapsis | Distance | Real Number | The magnitude of the periapsis vector. The periapsis vector locates the position in the orbit closest to the central body. The Calc Object allows a choice of a central body. The default is Earth. |
| Semimajor_Axis | Distance | Real Number | A measure of the size of the orbit. Orbits with eccentricity less than 1 are ellipses, with major and minor
axes identifying the symmetry axes of the ellipse, the major axis being the longer one. The value is half the length of the major axis.
The Calc Object allows a choice of a central body. The default is Earth. |
| Time_Past_Asc_Node | Time | Real Number | The elapsed time since passing the last ascending node crossing based on assumed two-body motion.. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Time_Past_Periapsis | Time | Real Number | The elapsed time since passing the last periapsis crossing based on assumed two-body motion.. The Calc Object allows a choice of a central body. The default is Earth. |
| True_Anomaly | Angle | Real Number or Text | The angle from the periapsis vector, measured in the orbit plane in the direction of motion, to the position vector.
The Calc Object allows a choice of a central body. The default is Earth. |
| Maneuver |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| DeltaV | Rate | Real Number | Delta-V magnitude integrated along the trajectory path. |
| DeltaV_Squared | Speed Change Squared | Real Number | Square of DeltaV integrated along path. |
| FuelMass | Mass | Real Number | Fuel mass remaining. |
| Fuel_Density | SmallDensity | Real Number | Density of the fuel. |
| Fuel_Used | Mass | Real Number | Fuel used since the initial state of the spacecraft. |
| Inertial_DeltaVx | Rate | Real Number | The X component of accumulated Delta-V integrated in inertial coordinates. |
| Inertial_DeltaVy | Rate | Real Number | The Y component of accumulated Delta-V integrated in inertial coordinates. |
| Inertial_DeltaVz | Rate | Real Number | The Z component of accumulated Delta-V integrated in inertial coordinates. |
| Inertial_DeltaV_Magnitude | Rate | Real Number | The magnitude of accumulated Delta-V integrated in inertial coordinates. Computed by integrating the thrust acceleration over time. |
| MCS_DeltaV | Speed Change | Real Number | Sum of DeltaV magnitude for all maneuvers in MCS. |
| MCS_DeltaV_Squared | Speed Change Squared | Real Number | Sum of squares of DeltaV magnitude for all maneuvers in MCS. |
| Specific_Impulse | SpecificImpulse | Real Number | The specific impulse during the maneuver, accounting for all engines, computed using the rocket equation. |
| Tank_Pressure | Pressure | Real Number | Fuel tank pressure. |
| Tank_Temperature | Temperature | Real Number | Fuel tank temperature. |
| Thrust_Vector_X | Force | Real Number | The X component of the total thrust vector. The Calc Object allows a choice of coordinate systems. The default is Earth ICRF. |
| Thrust_Vector_Y | Force | Real Number | The Y component of the total thrust vector. The Calc Object allows a choice of coordinate systems. The default is Earth ICRF. |
| Thrust_Vector_Z | Force | Real Number | The Z component of the total thrust vector. The Calc Object allows a choice of coordinate systems. The default is Earth ICRF. |
| Total_Mass | Mass | Real Number | Total mass (fuel plus dry mass). |
| Total_Mass_Flow_Rate | Mass Per Time | Real Number | The total mass flow rate, accounting for all engines, during a maneuver. |
| Mean Elems |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| Mean_Argument_of_Latitude | Angle | Real Number or Text | The sum of the argument of periapsis and true anomaly, where the angles are computed using Kozai-Izsak mean elements.
The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Mean_Argument_of_Perigee | Angle | Real Number or Text | The angle from the ascending node to the periapsis vector measured in the orbit plane in the direction of the object's motion.
The periapsis vector locates the closest point of the orbit. For a circular orbit, the value is defined to be zero (i.e., periapsis at the ascending node).
The ascending node and periapsis vector are computed using Kozai-Izsak mean elements. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Mean_Eccentricity | Unitless | Real Number | A measure of the shape of the orbit. Values <1 indicate an ellipse (where zero is a circular orbit) and values >1 indicate a hyperbola.
The value is computed using Kozai-Izsak mean elements. The Calc Object allows a choice of a central body. The default is Earth. |
| Mean_Inclination | Angle | Real Number or Text | The angle between the orbit plane and the XY plane of the coordinate system, where the orbit angular momentum vector
is perpendicular to the orbit plane. The orbit angular momentum vector is computed using Kozai-Izsak mean elements. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Mean_Mean_Anomaly | Angle | Real Number or Text | A measure of the time past periapsis passing, expressed as an angle. The periapsis direction is computed using Kozai-Izsak mean elements.
The Calc Object allows a choice of a central body. The default is Earth. |
| Mean_Orbit_Period | Time | Real Number | Time required for a complete revolution as computed from the mean semi-major axis length, computed using Kozai-Izsak mean elements.
The Calc Object allows a choice of a central body. The default is Earth. |
| Mean_RAAN | Angle | Real Number or Text | The angle in the XY plane from the X axis to the ascending node, measured in a right-handed sense about the Z axis. in the equatorial plane.
For equatorial orbits, the ascending node is defined to be directed along the positive X axis, and thus the value is 0.0. The ascending node vector is computed using Kozai-Izsak mean elements.
The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Mean_Semimajor_Axis | Distance | Real Number | A measure of the size of the orbit. Orbits with eccentricity <1 are ellipses, with major and minor axes identifying the
symmetry axes of the ellipse, the major axis being the longer one. The value is half the length of the major axis. The value is computed using Kozai-Izsak mean elements.
The Calc Object allows a choice of a central body. The default is Earth. |
| Mean_True_Anomaly | Angle | Real Number or Text | The angle from the periapsis vector, measured in the orbit plane in the direction of motion, to the position vector.
The periapsis vector and position vector are computed using Kozai-Izsak mean elements.
The Calc Object allows a choice of a central body. The default is Earth. |
| MultiBody |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| BDotR | Distance | Real Number | Dot product of B-Plane vectors B and R. B-vector is defined as the intersection of the B-plane and the trajectory plane, starting on the targeted central body and ending at the spot where the incoming asymptote crosses the B-plane. R is one of the axes of the B-plane. |
| BDotT | Distance | Real Number | Dot product of B-Plane vectors B and T. B-vector is defined as the intersection of the B-plane and the trajectory plane, starting on the targeted central body and ending at the spot where the incoming asymptote crosses the B-plane. T is one of the axes of the B-plane. |
| BMagnitude | Distance | Real Number | Magnitude of the B-plane B-vector. B-vector is defined as the intersection of the B-plane and the trajectory plane, starting on the targeted central body and ending at the spot where the incoming asymptote crosses the B-plane. |
| BTheta | Angle | Real Number or Text | B-Plane theta angle is the angle between the B-vector and the T-axis of the B-plane. |
| Delta_Declination | Angle | Real Number or Text | Delta Declination is the difference between the declination of the target body and that of the satellite with respect to the target body's parent body. |
| Delta_Right_Asc | Angle | Real Number or Text | Delta Right Ascension is the difference between the right ascension of the target body and that of the satellite. The right ascension is measured with respect to the target body's parent body, in the parent body's inertial coordinate system. |
| JacobiConstant | Unitless | Real Number | The single integral of the motion of the circular restricted three-body problem. Requires a valid Astrogator CR3BP propagated ephemeris for correct evaluation. |
| Other Orbit |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| Apparent_Solar_Time | Angle | Real Number or Text | Apparent solar time expressed as an angle. The Calc Object allows a choice of a central body. The default is Earth. |
| Beta_Angle | Angle | Real Number or Text | The angle between the orbit plane and the apparent sun direction. The Calc Object allows a choice of a central body. The default is Earth. |
| Earth_Mean_Local_Time_of_Ascending_Node | Angle | Real Number or Text | The Mean Solar (Local) Time of the instantaneously evaluated ascending node. The ascending node is computed by converting the osculating right ascension of the ascending nodes to its equivalent longitude of ascending node. This value is then used to compute the associated instantaneous Mean Solar Time. The resulting evolution is a slowly varying smooth function between the nodes that matches the Mean Solar Time at the ascending node. The value is computed as an angle with units of degrees by default with 0/360 degrees being directly opposite the Mean Sun in shadow and 180 degrees aligned with the Mean Sun in light. Units of HMS for the angle are also available. |
| Earth_Mean_Solar_Time | Angle | Real Number or Text | Apparent solar time modified for earth's equation of time, expressed as an angle. The Calc Object allows a choice of a central body. The default is Earth. |
| Local_Apparent_Solar_Longitude | Angle | Real Number or Text | Apparent solar longitude minus vehicle longitude. The Calc Object allows a choice of a central body. The default is Earth. |
| Longitude_of_Periapsis | Angle | Real Number or Text | The sum of the right ascension of the ascending node and the argument of periapsis. The Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms). The default is osculating. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Orbit_State_Value | Date | Real Number or Text | Computes the value of the specified Calc Object given the specified input values of position and velocity. |
| SignedEccentricity | Unitless | Real Number | The eccentricity multiplied by either 1.0 or -1.0. The value is positive if the mean anomaly is within pi/2 radians of the periapsis, else it is negative. The Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms). The default is osculating. |
| SignedInclination | Angle | Real Number or Text | The inclination multiplied by either 1.0 or -1.0. The value is positive if the argument of latitude is within pi/2 radians of the ascending node, else it is negative. The Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms). The default is osculating. |
| True_Longitude | Angle | Real Number or Text | The sum of the right ascension of the ascending node, the argument of periapsis, and the true anomaly. The Calc Object allows a choice of element type (Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms, and Brouwer-Lyddane Mean elements using both short and long period terms). The default is osculating. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Relative Motion |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| CrossTrack | Distance | Real Number | The cross-track component of the relative position vector. |
| CrossTrackRate | Rate | Real Number | The cross-track component of the relative velocity vector as observed in the RIC rotating frame. |
| InTrack | Distance | Real Number | The in-track component of the relative position vector. |
| InTrackRate | Rate | Real Number | The in-track component of the relative velocity vector as observed in the RIC rotating frame. |
| Normal | Distance | Real Number | The normal component of the relative position vector. |
| NormalRate | Rate | Real Number | The normal component of the relative velocity vector as observed in the NTC rotating frame. |
| Radial | Distance | Real Number | The radial component of the relative position vector. |
| RadialRate | Rate | Real Number | The radial component of the relative velocity vector as observed in the RIC rotating frame. |
| Range | Distance | Real Number | The range (i.e., distance between the primary and secondary object) at the given time. |
| RangeRate | Rate | Real Number | The rate of change of the magnitude of the relative position vector. |
| Relative_Inclination | Angle | Real Number or Text | The angle between the orbit normals of the satellite and reference satellite. Each orbit normal allows a choice of orbit normal type
(Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms,and Brouwer-Lyddane Mean elements using both short and long period terms). |
| Relative_Position_Declination_Angle | Angle | Real Number or Text | The angle between the relative position and an orbit plane. The relative position may be specified as either from the satellite to the reference satellite or the reverse.
The orbit plane may be specified as belonging to the satellite or the reference satellite, and allows a choice of orbit normal type
(Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms,and Brouwer-Lyddane Mean elements using both short and long period terms). The sign
convention may be specified as being positive or negative when the relative position lies above the orbit plane. |
| Relative_Position_InPlane_Angle | Angle | Real Number or Text | The dihedral angle about the orbit plane normal from the reference direction to the relative position (i.e., angle to projection of relative position
into orbit plane from projection of reference direction into orbit plane). The relative position may be specified as either from the satellite to the reference satellite or the reverse.
The orbit plane may be specified as belonging to the satellite or the reference satellite, and allows a choice of orbit normal type
(Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms,and Brouwer-Lyddane Mean elements using both short and long period terms).
The reference direction may be specified as being the satellite's or reference satellite's position or its opposite. Counter-clockwise rotation about the orbit normal may be specified
as being either a positive or negative value for the angle. |
| RICAzimuth | Angle | Real Number or Text | The angle measured in the plane formed by the in-track and cross-track directions, positive from the In-Track direction toward the Cross-Track direction. |
| RICAzimuthRate | AngleRate | Real Number | The rate of change of the RIC azimuth. |
| RICElevation | Angle | Real Number or Text | The angle measured perpendicular to the plane formed by the in-track and cross-track directions, positive toward the Radial direction. |
| RICElevationRate | AngleRate | Real Number | The rate of change of the RIC elevation. |
| Solar_Beta_Angle | Angle | Real Number or Text | The angle between the relative Sun position and an orbit plane. The relative Sun position may be specified as either apparent or true, as measured
from the satellite or from the reference satellite. The orbit plane may be specified as belonging to the satellite or the reference satellite, and allows a choice of orbit normal type
(Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms,and Brouwer-Lyddane Mean elements using both short and long period terms). The sign
convention may be specified as being positive or negative when the relative Sun position lies above the orbit plane. |
| Solar_InPlane_Angle | Angle | Real Number or Text | The dihedral angle about the orbit plane normal from the reference direction to the relative Sun position (i.e., angle to projection of Sun
into orbit plane from projection of reference direction into orbit plane). The relative Sun position may be specified as either apparent or true, as measured
from the satellite or from the reference satellite. The orbit plane may be specified as belonging to the satellite or the reference satellite, and allows a choice of orbit normal type
(Osculating elements, Kozai-Izsak Mean elements, Brouwer-Lyddane Mean elements using only short period terms,and Brouwer-Lyddane Mean elements using both short and long period terms).
The reference direction may be specified as being the satellite's or reference satellite's position or its opposite. Counter-clockwise rotation about the orbit normal may be specified
as being either a positive or negative value for the angle. |
| Tangential | Distance | Real Number | The tangential component of the relative position vector. |
| TangentialRate | Rate | Real Number | The tangential component of the relative velocity vector as observed in the NTC rotating frame. |
| TimeDifference | Time | Real Number | Alternative measure for in-track position difference, computed as duration. The duration is computed by dividing the in-track component of the relative position vector by the inertial velocity of the primary object. |
| SEET |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| DamageFlux | Flux | Real Number | The total impact flux that cause damage, from all meteoroid particulates, found as a simple sum of the damaging impact flux of all particulates. |
| DamageMassFlux | MassFlux | Real Number | The total impact mass flux that cause damage, from all meteoroid particulates, found as the integral of the damaging particle impact flux distribution with respect to mass. |
| GeoMagFieldDipoleL | Unitless | Real Number | The L value for the field line passing through the vehicle's location computed using the dipole approximation to the magnetic field. |
| GeoMagFieldFieldLineSeparation | Angle | Real Number or Text | The centric angle between the north footprint of the field line containing the vehicle's location and the north footprint of the field line containing the target's location. The north footprint is the point of intersection of the field line with the earth's surface north of the magnetic equator. If either north footprint is not defined, then the south footprint is used. |
| ImpactFlux | Flux | Real Number | The total impact flux from all meteoroid particulates, found as a simple sum of the impact flux of all particulates. |
| ImpactMassFlux | MassFlux | Real Number | The total impact mass flux from all meteoroid particulates, found as the integral of the particle impact flux distribution with respect to mass. |
| SAAFluxIntensity | FluxIntensity | Real Number | The SAA flux intensity at the vehicle's location for the vehicle's channel specification. |
| VehicleTemperature | Temperature | Real Number | Vehicle temperature, computed assuming thermal equilibrium. |
| Spherical Elems |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| Cosine_of_Vertical_FPA | Unitless | Real Number | The dot product of the unit position and unit velocity vectors. The Calc Object allows a choice of a central body. The default is Earth. |
| Declination | Angle | Real Number or Text | The signed angle measured from the XY plane to the position vector, where positive angles are used for locations above the XY plane, and negative for those below. |
| Declination_Rate | AngleRate | Real Number | The rate of change in the declination. |
| Flight_Path_Angle | Angle | Real Number or Text | The angle between the position and velocity vectors. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Right_Asc | Angle | Real Number or Text | The signed angle measured from the X axis to the projection of the position vector into the XY plane. The angle increases in the direction found by the right hand rule about the Z axis. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Right_Asc_Rate | AngleRate | Real Number | Right Ascension Rate. |
| R_Mag | Distance | Real Number | The magnitude of the position vector (i.e. the radius vector). The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Velocity_Azimuth | Angle | Real Number or Text | The angle, measured in the plane perpendicular to the position vector, between the local north direction and the projection of the velocity vector onto that plane, measured as positive moving toward local east. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| V_Mag | Rate | Real Number | The magnitude of the velocity vector, as observed in the coordinate system. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Target Vector |
|---|
| Name | Dimension | Type | Description |
|---|
| Time | Date | Real Number or Text | Time. |
| C3_Energy | Rate Squared | Real Number | An energy defined as -(mu/semi-major-axis). The Calc Object allows a choice of a central body. The default is Earth. |
| Incoming_Asymptote_Dec | Angle | Real Number or Text | Declination of incoming asymptote or apsides. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Incoming_Asymptote_RA | Angle | Real Number or Text | Right Ascension of incoming asymptote or apsides. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Incoming_Vel_Az_at_Periapsis | Angle | Real Number or Text | Velocity azimuth at periapsis for incoming trajectory. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Outgoing_Asymptote_Dec | Angle | Real Number or Text | Declination of outgoing asymptote or apsides. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Outgoing_Asymptote_RA | Angle | Real Number or Text | Right Ascension of outgoing asymptote or apsides. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |
| Outgoing_Vel_Az_at_Periapsis | Angle | Real Number or Text | Velocity azimuth at periapsis for outgoing trajectory. The Calc Object allows a choice of coordinate systems. The default is Earth Centered Inertial. |