ORBITAL Orbital Simulation and Telemetric Data Collection Software Developed By: Aaron M. Rosenfeld

Specifications ORBITAL accurately simulates space flight of one spacecraft around a single planet. ORBITAL accurately simulates space flight of one spacecraft around a single planet. Displays a 2D view port of space which can be centered on different objects or be freely moved. Displays a 2D view port of space which can be centered on different objects or be freely moved. Collects telemetry data which can be displayed as graphs in real time or post-simulation. Collects telemetry data which can be displayed as graphs in real time or post-simulation.

User Interface

Autonomous Guidance ORBITAL currently supports only orbit- stabilization guidance. It can autonomously maintain LEO (Low Earth Orbit) and GEO (Geosynchronous Earth Orbit). ORBITAL currently supports only orbit- stabilization guidance. It can autonomously maintain LEO (Low Earth Orbit) and GEO (Geosynchronous Earth Orbit). In the future, ORBITAL will be able to complete more advanced orbital maneuvers such as Hohmann transfer orbits, direct transfer orbits, and “sling-shot” orbits around a planet. In the future, ORBITAL will be able to complete more advanced orbital maneuvers such as Hohmann transfer orbits, direct transfer orbits, and “sling-shot” orbits around a planet.

Firing System To accurately portray real-world manual guidance systems, a simple firing system was used. To accurately portray real-world manual guidance systems, a simple firing system was used. User selects a length of time to fire the engine (currently only max thrust). User selects a length of time to fire the engine (currently only max thrust). User can manually ignite the engine or set a pre- defined position to do so. These positions can be an angle with respect to the planet, a distance threshold, or at an apogee or perigee. User can manually ignite the engine or set a pre- defined position to do so. These positions can be an angle with respect to the planet, a distance threshold, or at an apogee or perigee.

Firing System Example The following demonstrates a very basic course correction to take a spacecraft from LEO to an orbit of just under 8,000 km. The following demonstrates a very basic course correction to take a spacecraft from LEO to an orbit of just under 8,000 km. The firing system was set to fire at full thrust for 100 seconds at the next occurring apogee. The firing system was set to fire at full thrust for 100 seconds at the next occurring apogee.

Firing System (Setup)

Firing System (Burn)

Firing System (Completion)

Firing System Example 2 This example shows how one can use ORBITAL’s firing system to cause a spacecraft to re-enter the Earth’s atmosphere. This example shows how one can use ORBITAL’s firing system to cause a spacecraft to re-enter the Earth’s atmosphere. Only one burn was used here in a retrograde orientation (the spacecraft is facing the opposite direction of travel) which slows the spacecraft, allowing it to descend. Only one burn was used here in a retrograde orientation (the spacecraft is facing the opposite direction of travel) which slows the spacecraft, allowing it to descend.

Firing System 2 (Setup)

Firing System 2 (Burn)

Firing System 2 (Completion)

Geosynchronous Orbit Stabilization The following is a demonstration of the Geosynchronous Orbit Stabilization system (GeoSync) included with ORBITAL. The following is a demonstration of the Geosynchronous Orbit Stabilization system (GeoSync) included with ORBITAL. No manual course corrections were made and time acceleration error was negligible (under.4%). No manual course corrections were made and time acceleration error was negligible (under.4%).

Geosynchronous Orbit Stabilization

To Do For Users For Users Add UI for intitial settings. Add UI for intitial settings. User-defined spacecraft setting such as weight, fuel, etc. User-defined spacecraft setting such as weight, fuel, etc. User-defined planet specifics such as radius, mass, etc. User-defined planet specifics such as radius, mass, etc. Make orbital maneuvers (LEO, GEO) buttons configure burn(s) to get the spacecraft into that orbit. Make orbital maneuvers (LEO, GEO) buttons configure burn(s) to get the spacecraft into that orbit. Allow more than one planet. This will require a complete re-working of the software's computational methodology so it may not be soon. Allow more than one planet. This will require a complete re-working of the software's computational methodology so it may not be soon. Add units for user-defined graphs. Add units for user-defined graphs. For Developers For Developers Complete re-orgazination of RenderFrame class structure. File is horribly messy. Complete re-orgazination of RenderFrame class structure. File is horribly messy. Create 'System' class for ship/planet. Create 'System' class for ship/planet. Create 'UI' class for all UI elements and functionality. Create 'UI' class for all UI elements and functionality. Create 'InputController' class to handle all user input via mouse, keyboard, etc. Create 'InputController' class to handle all user input via mouse, keyboard, etc. Find a better method of UIElement.Button invocation and boolean checking (Pointers?). Find a better method of UIElement.Button invocation and boolean checking (Pointers?). Possibly create a math class of some sort to deal with all the distance, drag, and trajectory calculations. Possibly create a math class of some sort to deal with all the distance, drag, and trajectory calculations.

Time Acceleration Computations If time is accelerated, acceleration, velocity, and position cannot be computed at every single moment in time. If time is accelerated, acceleration, velocity, and position cannot be computed at every single moment in time. Cannot simply evaluate these vectors at the few moments the time acceleration allows. Error would be too great. Cannot simply evaluate these vectors at the few moments the time acceleration allows. Error would be too great. Utilized a method called “Dynamic State Vector Propagation” developed by Martin Schwieger, PhD. Utilized a method called “Dynamic State Vector Propagation” developed by Martin Schwieger, PhD. Assumes a quadratic interpolation of vectors between all known times. Assumes a quadratic interpolation of vectors between all known times. Integration of the acceleration vectors between t n and t n+1 gives us an estimated velocity which is then used to determine position. Integration of the acceleration vectors between t n and t n+1 gives us an estimated velocity which is then used to determine position. Error low enough to allow up to 1.0 x 10 3 time acceleration in LEO which is does not actually have a quadratic interpolation. Error low enough to allow up to 1.0 x 10 3 time acceleration in LEO which is does not actually have a quadratic interpolation. Proof will be available on the ORBITAL website very soon. Proof will be available on the ORBITAL website very soon.

Technical Data Full program is about 3,000 lines of code. Full program is about 3,000 lines of code. Completely coded in C#.NET with no “unsafe” code blocks (i.e. no direct memory management). Completely coded in C#.NET with no “unsafe” code blocks (i.e. no direct memory management). Extensive use of delegates to pass data between forms without needing pointers and unsafe code. Extensive use of delegates to pass data between forms without needing pointers and unsafe code. Client was originally a stand alone render screen that has just recently been added to the new full MDI system. Client was originally a stand alone render screen that has just recently been added to the new full MDI system. Full optimization benchmark completed. Full optimization benchmark completed.

Technical Data (con’t.) Telemetry Data Telemetry Data All telemetry data is stored even if it is not being used in a real-time graph. All telemetry data is stored even if it is not being used in a real-time graph. Allows for later retrieval or mid-simulation display. Allows for later retrieval or mid-simulation display. All data stored in packets ( struct ShipDataPacket ) that allow for very quick extraction of data. All data stored in packets ( struct ShipDataPacket ) that allow for very quick extraction of data. Future Future Allow for statistical analysis of graphs (regression, min, max, mean, standard deviation, etc) Allow for statistical analysis of graphs (regression, min, max, mean, standard deviation, etc) Allow users to add markers to the graphs (horizontal or vertical reference lines). Allow users to add markers to the graphs (horizontal or vertical reference lines).

Optimization Findings After benchmarking the following changes were made: After benchmarking the following changes were made: All foreach loops were changed to for loops which resulted in a Log(N) decrease in runtime. All foreach loops were changed to for loops which resulted in a Log(N) decrease in runtime. All non-inherited classes were changed to sealed improving runtime by allowing all virtual methods to be treated as finally declared. All non-inherited classes were changed to sealed improving runtime by allowing all virtual methods to be treated as finally declared. String modification in frequent methods were concatenation with the StringBuilder class instead of + contamination, decreasing runtime by a factor of 14. String modification in frequent methods were concatenation with the StringBuilder class instead of + contamination, decreasing runtime by a factor of 14. The repaint method was changed from a self-invoke to a System.Threading.Timer invoked event relieving nearly 32% of processor usage. The repaint method was changed from a self-invoke to a System.Threading.Timer invoked event relieving nearly 32% of processor usage.

Contact Aaron Rosenfeld Aaron Rosenfeld