Thrust Vector Control animation (.exe)

Directions for running the file:

Click the Pre-Launch button to see what the TVC system will be doing during pre-launch countdown at the pad. You will see the TVC circulation pumps circulating the TVC hydraulic fluid to keep it from freezing when the Ares I liquid oxygen tank is being filled. The extremely cold liquid oxygen tank is near the hydraulic lines, just on the other side of the surface on which TVC hardware is mounted.

To see what the TVC system will be doing during Ares I Upper Stage Ascent, click the US Ascent button. This will show hydrogen gas flowing to the turbine pump assemblies, the pump starting to run, the fluid circulating in the hydraulic system and then flowing to the actuators, which results in actuator motion.

Click the Fault Correction button to see one example of how the TVC system responds to a failure. This will show the TVC system operating nominally (each turbine pump assembly and hydraulic system operates a single actuator). Then, you will see the failure of a turbine pump assembly and the shutdown of hydraulic system A. The turbine pump assembly on hydraulic system B will show increased hydrogen flow and increased pump motion and the hydraulic system B will then operate both actuators.

Note: To go from one scenario to another, you must hit Reset in between clicking the scenario buttons.

Note: The Boost Ascent Button does not do anything visually since TVC is not active in Boost Ascent.

Note: The Pause button can be used to freeze the animation at anytime.

When finished, click the Quit button.

To prepare for the Critical Design Review in late 2010, a full TVC subsystem will be assembled and tested.  These tests will demonstrate the ability of the TVC subsystem to steer the upper stage under normal and adverse conditions.  The hardware will be Engineering Model fidelity, which is close to the anticipated flight design.  In order to be able to simulate the loads that the TVC subsystem will experience during flight and allow for assembling the hardware in the correct orientation and layout as flight, the 2-Axis Rig was designed and built.

This test rig was designed by the TVC team at NASA GRC and the test rig components were manufactured at NASA GRC and several local machine shops.  The hardware arrived in February of 2009.  The video below is a time-lapse movie showing the installation of the rig over the course of two weeks.  The entire test rig weighs approximately 80,000 lbs.

Time-lapse of installation of 2-axis rig at NASA GRC TVC Lab

This test rig is the highest fidelity rig of its kind.  The rig can simulate the following flight forces:

• Upper stage engine mass, inertia, center of gravity offset, and thrust offset
  
  
• Viscous friction
  
  
• Coulombic friction (gimbal friction)
  
  
• Upper stage engine duct spring forces
  
  
• Actuator attachment point stiffness at the engine and thrust cone
  
  
• Flexure of the engine & thrust cone
  
  
• Acceleration forces (varies during flight)
  

The Facility is a modular design in order to meet the changing requirements as the Ares I upper stage project matures. The test rig will allow the TVC team to execute a flight profile simulation while experiencing the above forces.  Many of these forces can be varied so the team can also evaluate the sensitivity of the TVC subsystem to variations in these parameters in the event that current requirements change in the future.  Testing is scheduled to begin in late 2009 and carry into mid-2010.