The Super Stack 1 assembly is now complete with the mating (stacking) of the forward assembly to the fifth segment simulator. Stack one is made up of eight individual pieces: interstages 1 and 2, the frustum, the forward skirt extension, the forward skirt and the aft, center and forward segments of the fifth segment simulator. It also includes two internal elements, the roll control system and the first stage avionics module.
All five super stack assemblies are now complete in High Bay 4 of the VAB and are ready for stacking on the mobile launcher platform in High Bay 3 later this month.
Just so you know, the reason the rocket is separated into these super stacks has to do with the height and weight of each piece for crane loads during lifting operations.
Super Stack 2: Upper Stage Simulator “Tuna Cans” segment 1
Earlier this month the Ares I-X team conducted a successful frustum separation test. The success of the test showed that the separation charge is fully capable of splitting the joint of the frustum’s aft ring — an important hurdle to clear.
The test simulated the first separation event that will happen about 2 minutes after launch when the propellant in the first stage booster is used up. After the booster burns through all the propellant, the first stage (bottom half of the rocket) splits from the upper stage simulator and crew module/launch abort system simulator (upper part of the rocket). This split happens at a piece of the rocket called the frustum.
The frustum is an upside-down cone-shaped piece that connects the skinnier first stage to the thicker upper stage. The large forward (top) section of the frustum, which connects with the upper stage, is eighteen feet in diameter while the aft (bottom) end is twelve feet in diameter to attach to the booster. During separation, linear shaped charges detonate at the frustum’s aft ring, allowing the first stage to return to Earth where it will be retrieved and refurbished for other Ares missions.
The shock created by the charge was measured by accelerometers and acoustic pressure sensors. Measuring the shock is an important part of the test because if the bang is “too big for the buck,” it could damage some of the avionics or other pieces of hardware. It’s a balancing act between having a bang that is strong enough to separate the metal but not so strong as to damage the working parts of the rocket.
The test took place at ATK’s Promontory facility in Utah. The data from the test will be used to prepare for the Ares I-X flight and will help Ares I engineers make sure the calculations they are currently using are correct.
The Ares I-X team was very excited on Friday when the frustum rolled into the Assembly Refurbishment Facility at Kennedy Space Center, making it the final newly manufactured segment to arrive for this summer’s Ares I-X launch.
The frustum is the segment between the Forward Skirt Extension and the upper stage of the Ares IX launch vehicle. As you can see, it looks a lot like a giant funnel. Its main function is to transition the flight loads from the thicker upper stage to the thinner first stage. It weighs in at approximately 13,000 pounds, and is 10 feet long. It’s composed of two machined, aluminum-forged rings that are attached to a conic section. The large diameter of the cone is 18 feet, while the small diameter is 12 feet. The thickness of the cone is only 1 ¼ inches! Kind of amazing.
Now that the frustum is at Kennedy, technicians will begin the final processing and it will be integrated to the forward skirt and forward skirt extension to make the forward assembly. The completed forward assembly will be moved over to the Vehicle Assembly Building for stacking operations scheduled to begin in April.
With the arrival of the frustum, the team now waits for the final rocket components to arrive — the motors. The rocket motors, manufactured by ATK in Utah and shipped via rail to Kennedy, are scheduled to arrive next month.
Yesterday we successfully tested one of the main separation systems of the Ares I-X rocket at the Alliant Techsystems (ATK) facility in Promontory, Utah. The test demonstrated that the forward skirt extension, which houses the main parachutes will be able to separate from the first stage booster as it falls back to Earth after launch.
During the flight test, the first stage booster will separate for the frustum, which is a cone-shaped piece of the rocket that connects the 12-foot-diameter first stage booster to the 18-foot-diameter upper stage. After the frustum separation, at an altitude of about 15,000 feet, the nose cone of the booster will be jettisoned and the pilot parachute will be deployed. The pilot chute will in turn deploy the drogue parachute, which will re-orient the booster to vertical and will slow it down enough that the main parachutes will be about to open. At about 4,000 feet the forward skirt extension separates from the rest of the first stage and pulls out the three main chutes packed inside. The booster splashes down and is recovered and reused.
During the test at ATK, a linear-shaped charge was used to separate the forward skirt extension and create a clean severance. Engineers also measured the shock created by the charge and will use that data to analyze the system and prepare for the Ares I-X flight test as well as the development of the Ares I rocket.