Editor: Orbit Maneuvers with Thrusters
Description
This guide showcases how to use thrusters to perform an orbit-raising maneuver. This example scenario can be found at the Dynamics/Demo_DVFunctionalChain level. It uses a propellant tank and thruster to model the application of thrust to raise the semi-major axis of a spacecraft’s orbit while tracking propellant consumed during the maneuver.
Creating the Spacecraft
Start by configuring a level with a spacecraft spawned in orbit. The spacecraft must have the following components for this example:
- Reaction Wheels (
BP_ReactionWheel_Quad) - Computer (
BP_NS_Computer) - Fuel Source (BP_NS_FuelTank_1U_Spherical)
- Thruster (BP_NS_Thruster_1U_Small)
The spacecraft shown below is used for this guide. It is provided within the example spacecraft blueprints (BP_Spacecraft_DVFC_3U).
Setting up the Thruster
The physical properties of the thruster can be set within the Details panel of the Thruster component of the BP_Spacecraft_DVFC_3U. The properties can be found by expanding the Child Actor Components as can be seen below. Ensure that the Max Thrust, Max Impulse, Exit Area and other thruster properties are as depicted below.
Setting up the Fuel Tank
Similarly the properties of the fuel tank can be set within the Details panel within the BP_Spacecraft_DVFC_3U object by first highlighting the Fuel Source in the Components tree. Set the properties of the values to the same values as depicted below.
Setting Up Velocity Pointing Mode
In this scenario, it is assumed that the spacecraft is in a near-circular orbit such that if we fire the thruster in the spacecraft’s inertial velocity direction, we will increase the semi-major axis of the spacecraft’s orbit. For instructions on how to set velocity pointing for a spacecraft please refer to the velocity pointing guide Editor: Velocity Pointing Chain.
Adding a Fuel Node Model
Within the level blueprint, a fuel node model can be added to the thruster via the Add Fuel Node Model block as shown below. The physical properties of the fuel node, associated with the Thruster, can be input. Set the input properties to the following:
| Specific Heat Ratio | 1.41 |
|---|---|
| Total Temperature | 250 |
| Total Pressure | 2750 |
Firing the Thruster
To fire the thruster, the fire request input message has to be set for the thruster. This can be done as per the image below. The start value of the Fire Request Message indicates the number of elapsed seconds in the simulation when the thruster will begin firing. The duration will be the number of seconds that the thruster will be fired for.
