This is a composite of three images captured from high speed video showing the test unit in free flight as it approaches and penetrates a concrete target. The images show water vapor (from the light rain that was falling at the time of the test) surrounding the test unit.  The square speckles on the test unit and the concrete target provide a random pattern that is used in digital image correlation algorithms to calculate test unit motion in 3-D using special equipment.

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Sandia LabNews

Sandia conducts B61-11 pull down surveillance test; first in years


This is a composite of three images captured from high speed video showing the test unit in free flight as it approaches and penetrates the concrete target.  The tow rope attached through the nose of the test unit had already been severed from the rocket sled by the time these images were captured.  The images show water vapor (from the light rain that was falling at the time of the test) surrounding the test unit.  The speckle pattern on the test unit and the concrete target provide a random pattern that is used in Digital Image Correlation (DIC) algorithms to calculate test unit motion in 3D using stereo pairs of high-speed video cameras.
This is a composite of three images captured from high speed video showing the test unit in free flight as it approaches and penetrates a concrete target. The images show water vapor (from the light rain that was falling at the time of the test) surrounding the test unit. The square speckles on the test unit and the concrete target provide a random pattern that is used in digital image correlation algorithms to calculate test unit motion in 3-D using special equipment.

A dozen Sandians erupted in applause as they watched on video monitors while a rocket-driven B61 — a nuclear weapon, minus its nuclear components — rammed through a target at a test range in Sandia’s first such impact test in seven years.

“Really nice work,” said Engineering Sciences Center 1500 Director Justine Johannes, who authorized the Nov. 20 test at the aerial cable facility.

“It’s been a while,” said Science and Technology Div. 1000 VP Duane Dimos, who recalled being told the test of the B61 gravity bomb was up next when he took his previous job as Center 1500 director in March 2010. “Thank you all,” he told the team.

Preliminary results look good

The test unit will be disassembled and final data analyzed, but data available the day after the test showed Sandia’s components worked as expected. The test weapon was equipped with instruments to measure component performance and velocity as it slammed into the target. Org. 2110 senior manager Patrick Sena says preliminary data showed the test met

the requirements of the worst-case conditions the B61 is expected to meet with high reliability.

“One of the main purposes of the stockpile is deterrence, and one important way to ensure deterrence is to have a successful surveillance test that shows our systems work,” Patrick says.

The test unit was cooled to an internal and external temperature far below 0 degrees Fahrenheit. It had to be de-iced twice before the test as falling rain froze on the casing.

With weather conditions worsening, test officials decided to go ahead as soon as technicians had everything ready. As a result, the test went off 15 minutes earlier than scheduled on Nov. 20.

Dennis Miller, senior manager of the Validation and Qualification Group (1530) that conducted the pull-down test, sent an email a few minutes after the test, saying preliminary information was all positive. “The test unit was released successfully, and there is a big hole in the concrete target,” he wrote.

Emails of congratulations came in from around Sandia, including from Deputy Labs Director and Executive VP for National Security Programs Jerry McDowell (“Early congratulations to all.”) and Div. 2000 VP for Weapons Engineering and Product Realization Bruce Walker (“Fantastic news. My congratulations to the team.”)

“It’s been a long time coming,” Dennis said shortly before the test. “There’s been a lot of planning and anticipation.”

Data is precious

Sandia’s annual surveillance program for each weapon type consists of flight tests, lab tests, and component and material tests.

Flight tests, the most realistic, subject the test unit to shock, vibration, temperature extremes, rotation, weather, and so on. “Data from flight tests is precious because it is from a single-shot device,” Patrick says.

Sandia had worked toward the test since March 2010, the end of a hiatus on all such testing that was prompted by an October 2008 accident at Sandia’s 10,000-foot sled track. In the last three years, Sandia rebuilt its ability to run the tests, including reconstructing the firing set and safety systems that ignite the rocket motors and explosives-driven cable-cutting systems at the aerial cable facility, acquiring new rocket motors, and putting a strong emphasis on safety and technical performance assurance for the test. In addition, it rebuilt a team. Dennis says nearly all the employees and contractors who set up November’s test had never participated in a pull-down test before.

“This is a very complicated test,” he says. “There were about 60 test participants at the pre-job briefing. This team has been great to work with and together they really did an excellent job.”

Sandia pulls units randomly from the stockpile for such tests, as well as for lab tests on the weapon’s nonnuclear components. Flight tests drop units from aircraft the Tonopah Test Range in Nevada.

The nuclear package, removed prior to the tests, is studied separately by the design laboratory, either Los Alamos or Lawrence Livermore national laboratory. Lab tests study the nonnuclear components under different conditions. Environments are more controlled so researchers can closely measure how components function. Other laboratory tests examine components and materials for signs of aging by repeatedly subjecting them to various conditions.

As test preparations moved forward on Nov. 20, a radio on a table in the room crackled with updates: the rocket motors and explosives were wired; the test team pulled back to a control facility 5,000 feet away to arm the firing system remotely; the final countdown of 5-4-3-2-1. A camera that had been focused on the weapon panned down to the target at T minus 30 seconds to capture the weapon slamming through the concrete.

An unimaginable amount of detail and work goes into getting as much information as possible out of the tests. This one involved a series of calibration tests and qualifying reviews beforehand, dozens of people from Divisions 2000, 4000, and 1000, as well as researchers from Los Alamos who had components on the weapon and personnel helping set up and monitor the test. Some of the test team arrived to begin final preparations at 4 a.m. on test day. Sandia’s Emergency Operations and the Kirtland Air Force Base Fire Department were on hand when the test went off.

Afterward, the radio continued to snap out updates: no fires — a possibility from burning rocket fuel debris; no debris from the weapon around the target; levels of toxic gas from the burning rocket propellant at zero; the cable cutters all fired; in short, everything at the scene indicated the test was normal.

“Boring is good,” commented Justine.

The area was declared safe about 15 minutes after the weapon hit the target, and the test team moved in to begin moving cables and cleaning up the site. Two large cranes moved the target the next day to allow technicians to excavate the B61 in preparation for sending it for disassembly at the Pantex plant in Amarillo, where it was built and where it will be disassembled for analysis.

“So, when can you run another one?” Patrick asked Dennis.