The Ares I rocket is central to NASA’s Constellation Program missions to the International Space Station, the moon, Mars, and the solar system. There are two stages to Ares I: In the First Stage, a reusable Solid Rocket Booster lifts the Orion crew vehicle toward low-earth orbit during launch before separating from Ares I. In the Upper Stage, a single J-2X engine propels Orion into orbit. Communication between avionics systems on the two stages, Orion, and Ground Systems is critical to the success of each launch.
In support of NASA, the TriVector Services Team analyzed the timing of more than a dozen Ares I communications buses. By performing discrete-event simulation of Ares I packet-level communications using Simulink®, Stateflow®, and SimEvents®, engineers assessed network latency and verified requirements for the buses before any hardware or software was developed.
“The Ares I buses carry health and status information from avionics sensors to flight computers, Orion, and Ground Systems,” explains Kerry Alexander, senior engineer at TriVector. “With SimEvents, we ran simulations that tracked each packet from its source to its destination and verified that it was delivered within the time frame required by NASA.”