[8] The four-segment solid rocket motor and aft skirt for Ares I-X was drawn directly from the Space Shuttle inventory.

[9] Modifications to the solid rocket booster include: For the Ares I-X flight test, the frustum and forward skirt extension were made of aluminum.

The USS simulated the shape, mass, and center of gravity characteristics of Ares I from the interstage to the top of the service module of the Orion Crew exploration vehicle.

[6]: 7 The USS included a variety of temperature, vibration, thermal, and acoustic sensors to collect the primary data needed to meet the mission objectives.

It also housed the Fault Tolerant Inertial Navigation Unit (FTINU), which controlled the vehicle's flight and primary avionics functions.

Ground operations personnel accessed the FTINU through a crew hatch on the side of the interstage segment, which also housed the roll control system.

Each USS segment included a ladder and ring-shaped platform to allow access to the sensors and cabling for the developmental flight instrumentation.

[13] The RoCS performed two primary functions:[6]: 8 The RoCS modules, placed on opposite sides of the outer skin of the Upper Stage Simulator, used hypergolic monomethyl hydrazine (MMH) and nitrogen tetroxide (NTO) for propellants and each included two nozzles, which fired tangential to the skin and at right angles to the roll axis in order to provide a controlling roll torque.

The propellants were loaded into the modules at Kennedy Space Center's Hypergol Maintenance Facility (HMF) and transported on the ground for installation into the USS in the Vehicle Assembly Building (VAB) prior to rollout to Launch Complex 39B.

The CM/LAS simulator was built with high fidelity to ensure that its hardware components accurately reflect the shape and physical properties of the models used in computer analyses and wind tunnel tests.

Ares I-X also employed 720 thermal, acceleration, acoustic, and vibration sensors as part of its developmental flight instrumentation (DFI) to collect the data necessary for the mission.

The flight test vehicle flew autonomously and was controlled by the FTINU, located on the underside of the lower ballast plates of the upper-stage simulator (USS).

To complete these tasks, wind tunnel testing and computational fluid dynamics (CFD) were used to investigate forces acting on the vehicle in various phases of flight, including lift-off, ascent, stage separation and descent.

Once the basic design was understood SE&I provided structural analyses for the system to assure the rocket would behave properly once it was integrated.

Launching through the day's high cirrus clouds could have caused triboelectrification, potentially interfering with range safety communication and hampering the RSO's ability to issue the self-destruction command.

[19][20] Ultimately, constraints of the 4-hour launch window, coupled with high clouds and other last-minute concerns, caused the mission to be scrubbed for the day at 15:20 UTC on October 27, 2009.

[19][21] Ares I-X launched on October 28, 2009, at 11:30 EDT (15:30 UTC) from Kennedy Space Center LC-39B, successfully completing a brief test flight.

[22] The first stage separated from the upper-stage simulator and parachuted into the Atlantic Ocean roughly 150 miles (240 km) downrange of the launch site.

NASA Watch revealed that the first-stage solid rocket booster of the Ares I could create high vibrations during the first few minutes of ascent.

[28] Due to the Pad Avoidance Maneuver performed by Ares I-X, shortly after liftoff, the Fixed Service Structure at LC-39B received significantly more direct rocket exhaust than occurs during a normal Space Shuttle launch.

[30] According to NASA, partial parachute failures were common in Space Shuttle Solid Rocket Boosters, from which the Ares I-X is derived.

After initial concerns that the motion might have been caused by a collision between the USS and the first stage,[34] further analysis showed that no actual recontact happened and that the tumble had been one of the possible behaviours predicted by pre-flight simulations.