Astrogator makes a number of Calculation Objects available for use in constructing other components, such as stopping conditions, or for use as results, target sequence constraints and report and graph elements. Also, you can create new Calculation Objects using the Component Browser. The types of Calculation Objects provided with Astrogator include the following:

Type | Description |
---|---|

Epoch | The epoch of a given state in the Mission Control Sequence. |

Access | Access between objects. |

Cartesian Elements | X, Y, and Z components of position and velocity vectors. |

Constants | Provides constant values that are accessible to in-line calculation objects and scripting tool scripts. Gravitational Parameter, Gravity Coefficient, Reference Radius, Speed of Light. |

Delaunay Elements | Delaunay G, H, L, and Semi-Latus Rectum. |

Environment | Atmospheric density, pressure and temperature. |

Equinoctial Elements | Equinoctial h, k, p, q and Mean Longitude. |

Formation | Select relative values for use in formation flying. |

Geostationary | Longitude drift rate in angle/time, positive toward East. |

Geodetic | Latitude, longitude, altitude, height above terrain, latitude rate, longitude rate, altitude rate. |

Ground Track | Repeating Ground Track Error to be measured at the equator (as a distance). |

Keplerian Elements | Classical elements specifying an orbit by its size, shape and three-dimensional orientation in space. |

Maneuver | V (integrated along orbit path), FuelMass, Fuel Density, Fuel Used, Inertial V Magnitude, Inertial Vx, Inertial Vy, Inertial Vz, Specific Impulse, Tank Pressure, Tank Temperature, Thrust Vector X, Thrust Vector Y, Thrust Vector Z, Total Mass, Total Mass Flow Rate. |

Math |
Absolute Value, Difference, Maximum Value, Minimum Value, and Negative.
An A Difference object expresses the difference of the
reference calculation object between two points in time, the first
being the beginning of the segment where the difference object is
placed and the second being the current time at the end of the
segment.
A
A |

Mean Elements | Various Kozai-Izsak and Brouwer-Lyddane means. |

Multibody | B-plane elements, delta declination and right ascension. |

Other Orbit | Including beta angle, C3 energy, true longitude, etc. |

Power | Internal, Processed, Solar Array. |

Relative Motion | Various relative values compared to reference satellite. |

Scalar | A scalar value, based on any Calculation component from the Analysis Workbench. |

Scripts | Custom functions and MATLAB,
VBScript, Perl, or JScript in-line functions. To use any MATLAB
function - even an in-line function - you must be able to connect
to MATLAB; STK will automatically start a session and connect when
required. In-line functions are used for very simple computations
that are not presently available as Calculation Objects in the
Component Browser. They have three attributes -
CalcArguments, InlineFunc, UnitDimension. When
an in-line Calculation Object is used, STK creates a function with
the inputs listed in CalcArguments, returning the value
computed by the InlineFunc, with a name derived from the
Calculation Object name itself. |

SEET | Space environment components (SEET license required): DamageFlux, DamageMassFlux, GeoMagFieldDipoleL, GeoMagFieldFineLineSeparation, ImpactFlux, ImpactMassFlux, SAAFluxIntensity, VehicleTemperature. |

Segments |
A A A A |

Spacecraft Properties | Drag, Radiation Pressure, and Solar Radiation Pressure coefficient and area values of a spacecraft. These objects can be used to report how a propagator plugin changes these values over time. When these properties are changed by a propagator evaluation plugin, they keep the new value in subsequent steps in the propagation, and in subsequent segments in the MCS. |

Spherical Elements | Cosine of vertical FPA, declination, declination rate, flight path angle, R magnitude, right ascension, right ascension rate, magnitude of the velocity vector, velocity azimuth. |

Target Vector | C3 Energy, Incoming and Outgoing Asymptotes and other Target Vector elements. |

Time | Duration from a given epoch. |

UserValues | User variable values. |

Vector | Vector components, dot products, angles between vectors, etc. |

A brief description of a Calculation Object is displayed when you highlight it in the Component Browser. To view the elements of a Calculation Object (and edit them, if the variable is a copy), double-click it in the Component Browser, bringing up its Component Edit window.