by Ed Kyle, Updated 10/23/2009
NASA’s Ares I-X will serve as a precursor test of the Agency’s planned Ares I crew launch vehicle. The relatively short suborbital flight will test overall vehicle control, roll control, staging and separation dynamics, launch operations, and vehicle loads. The test will also examine reentry dynamics and first stage recovery for the longer, heavier first stage compared to existing Shuttle solid rocket motors.
Ares I-X will be powered by a live four-segment reusable solid rocket motor reassigned from the Shuttle program. A simulated fifth motor segment, upper stage simulator, and Orion crew module/launch abort system simulator will top the motor. Atlas 5-based avionics, located in the simulated fifth motor segment, will guide and control the vehicle. Hundreds of sensors will feed data to the avionics for telemetering back to the ground.
The rocket will stand 99.7 meters tall and weigh 816.5 tonnes at liftoff. The first stage motor will produce 1,419.8 tonnes maximum thrust and 1,179.4 tonnes average thrust during its two minute burn. Ares I-X will rise straight up from its Kennedy Space Center LC 39B launch platform for six seconds before the vehicle’s pair of 1.13 tonne thrust roll control thrusters, located on opposite sides of the simulated interstage, will begin firing to roll the rocket by 90 degrees. Seven seconds after liftoff, the first stage motor nozzle will gimbal to begin to pitch Ares I-X gradually on a due east course toward the Atlantic Ocean horizon.
First stage burnout will occur 120 seconds after liftoff at an altitude of 39.6 km, about 68.5 km downrange, with the vehicle traveling nearly 1.5 km per second (3,327 mph). Four seconds after first stage motor burnout, the first stage and upper stage simulator will separate just below the flared frustrum section. Eight booster deceleration motors located on the aft skirt of the first stage will fire to “back” the stage away from the upper composite. Meanwhile, four booster tumble motors on the aft skirt will fire to push the stage into a slow flat spin.
The separated stages will rise to an altitude of 45.7 km before beginning to descend. The first stage will be exposed to maximum reentry forces about 252 seconds after liftoff at an altitude of 16.7 km as the booster decelerates to 0.7 km/sec.
About 315 seconds after liftoff, with the stage traveling 0.16 km/sec roughly 4.7 km above the Atlantic, the first stage aeroshell will jettison and the pilot chute, followed by the larger drogue chute, will deploy. 340 seconds after liftoff, 1.4 km above the Atlantic, the Forward Skirt Extension will separate, pulling the main chutes – larger than the Shuttle SRB parachutes – out for deployment. Just before splashdown, about 360 seconds after liftoff and 231.5 km downrange, charges will fire to sever the first stage motor’s nozzle. The booster and fifth segment simulator will splashdown about 369 seconds after liftoff to be recovered by one of NASA’s retrieval ships. The Forward Skirt Extension will float down beneath the drogue chute until splashing down about 430 seconds after liftoff.
Ares I-X differs from the planned Ares I launch vehicle in numerous ways. The most noticeable difference is the outer mold line of the Orion crew module simulator, which matches an early, now discarded design. Ares I/Orion will be topped by a ogive fairing that will completely cover the Orion crew module. Ares I will weigh 90.7 tonnes more than Ares I-X. The five-segment Ares I first stage motor will produce nearly 168 tonnes more peak thrust. As a result, the Ares I first stage will fly faster, higher, and farther than its Ares I-X counterpart.
During 2008 and 2009, LC 39B was modified to support the Ares I-X launch. Three 183 meter tall lightning protection towers were built to surround the pad. The familiar “beanie cap” and crew access arms were removed from the fixed umbilical tower, and an Ares I-X vehicle stabilizer arm was added.
Ares I-X simulator parts began arriving at KSC’s Vehicle Assembly Building during the Fall of 2008.
NASA’s Glenn Center in Cleveland, Ohio built the 204 tonne, 5.5 meter diameter, 30+ meter tall Upper Stage Simulator, which was shipped in 11 segments.
NASA’s Langley Center built the Orion/LAS Simulator.
NASA’s Marshall Center assembled the hypergolic liquid thruster Roll Control System from components harvested from retired MX Peacekeeper ICBMs. The thrusters burn nitrogen tetroxide (N2O4) and monomethyl hydrazine (MMH). Marshall also oversaw development of the Ares I-X avionics system, an effort performed by Jacobs Engineering and Lockheed Martin. Lockheed Martin tested the avionics in a flight simulator lab in Denver, Colorado.
ATK provided the 3.66 meter diameter first stage motor, segment simulator, forward skirt and skirt extension and the tapered Frustum section. The motor looks much like a Shuttle SRB with the addition of a black “Z-stripe” to provide visual roll cues and the red letters “USA” on one side.
Vehicle stacking on Mobile Launcher Platform 1, in High Bay 3, began during early July of 2009. MLP 1 was first used for the Apollo 10 launch from LC 39B in May, 1969. It hosted Apollos 13, 15, 16, and 17, and was used for 51 Space Shuttle launches, including the first (STS-1) in 1981.
The completed rocket, the tallest rocket at KSC since Saturn V, was rolled from the VAB to LC 39B on October 20, 2009 for its planned October 27 launch.