Launch GUI
Contents
Introduction
This GUI enables you to quickly design a launch trajectory to orbit for a multi-stage launch vehicle. You can select the vehicle model from a database, specify the type of launch and some parameters, then run it through an open-loop simulation. The tool will show you how much delta-v will be required in the upper stage to circularize at the specified orbit altitude.
The GUI is divided into two panels: The parameter inputs are defined in the left-side panel, while the results of the simulation are displayed in the right-side panel.
Load / Save
The menubar of the GUI has options to Load and Save.
Press "Save" to save your current input data to a mat-file for later use.
Press "Load" to find and load mat-files storing data from previous sessions.
Two example mat-files are provided with the Launch Vehicle Toolbox. They can be found in LaunchVehicle/LVData/.
Launch Method
Two launch methods are supported: Direct and Indirect.
- Direct: A direct launch follows a gravity turn for all stages. The thrust is directed along the velocity vector.
- Indirect: An indirect launch allows for a fixed control angle during the last stage. The first stage follows a gravity turn. For a three stage vehicle, the second stage also follows a gravity turn. For a four stage vehicle, the second stage follows a gravity turn and the third stage fires horizontally - i.e. the control angle is opposite the flight path angle. These control options will be selectable by the user in a future version.
Launch parameters
Several different parameters may be modified to customize your launch trajectory. The selections are summarized below.
- Launch Vehicle: Select the launch vehicle from the popup menu. This is the list of vehicles found in LVDatabase.csv. Launch vehicles with parallel solid booster stages in the SRB fields will be serialized with LVCombineSRB.
- Initial Altitude: The initial altitude of the vehicle when the launch starts, measured in km.
- Initial Velocity: The intial velocity of the vehicle when the launch starts, measured in km/s. If the vehicle fails to ascend, try giving it a small initial velocity.
- Initial Gamma: The initial flight path angle of the vehicle when the launch starts, measured in degrees.
- Final Stage Coast Time: The coast time for the final stage before it fires, measured in minutes. This parameter is only used for Direct launches.
- Final Stage Thrust Angle: The thrust elevation angle above local horizontal for the final stage. This parameter is only used for Indirect launches.
- Final Stage Mass Ratio: A parameter to scale up or down the total mass (structure and propellent) of the final stage.
- Payload Mass: The mass of the payload. This is separate from the final stage mass. Measured in kg.
- Drag Coeff. X Area: The drag coefficient multiplied by cross-sectional area. The same number is applied to all stages.
- Desired Altitude: The target altitude for orbit insertion. Measured in km.
Simulate
Press the "Simulate" button once you've entered parameters to define your launch trajectory. This will run a 2D Earth-fixed simulation of the selected vehicle with your specified parameters, and compute the delta-v required to circularize the orbit at your desired altitude. See GuidedLaunch2DSim and GuidedLaunch2DRHS for the simulation code.
Results will be displayed in the right-side panel and a time history plot will appear in a new figure.
The time history plot will add background shading to distinguish the time windows when each stage of the vehcile is firing. If the vehicle has SRBs firing with the first stage, this will be noted.
Back to Index.html