Tag Archives: ATK

Successful First Stage Frustum Separation Test

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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. 

View frustrum test (Windows streaming)

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.

Another view of the test (Windows streaming)

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.

First Stage Segments Are on the Move

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The first stage segments are just about ready to go. They have a long trip ahead of them from first stage contractor ATK’s facilities in Promontory, Utah to the launch site at Kennedy Space Center in Florida.

Last week, using specialty transporters, ATK moved the Center Aft Segment to a holding facility where it will be housed in preparation for the cross-country trek via railcar. Some one described these transporters as looking like something out of the Transformers movie and I don’t think that’s too far off. They are impressive looking vehicles.

That big black line you see running diagonally down the side is called a Z-stripe. The Z-stripe is a 24-inch wide stripe painted on the first stage motor segments that wraps from the top of the motor to the bottom.  The main purpose of the Z-stripe is to provide a way for the I-X team to determine the roll attitude and rate from footage recorded by cameras on the ground. That footage serves as a backup to on-board data gathered during the flight.  The Z-stripe will also provide confirmation that the rocket rolled 90° shortly after lift-off from the pad like it is supposed to. Measurement from watching the Z-stripe could be very helpful in the case that the flight goes differently than expected.

We’re expecting to ship the motor segments next month. They are the last few pieces of hardware to ship, so once they make it down to KSC, we’ll be ready to start putting the rocket together.