Featuring some of our top Engineering innovations
Collisions of satellites and debris in space have become increasingly problematic. To help satellite operators prevent collisions in space, the Space-Based Telescopes for Actionable Refinement of Ephemeris (STARE) mission, which will consist of a constellation of mini-satellites in low earth orbit, intends to refine orbits of satellites and space debris to less than 100 meters. A team of Lawrence Livermore National Laboratory scientists and engineers are developing mini-satellites that will work as "space cops" to help control traffic in space. In 2014, the team used a series of six images taken over a 60-hour period from a ground-based satellite to prove that it is possible to refine the orbit of another satellite in low earth orbit. Using the ground-based satellite, the Livermore team refined the orbit of the satellite NORAD 27006, based on the first four observations made within the initial 24 hours, and predicted NORAD's trajectory to within less than 50 meters over the following 36 hours. By refining the trajectory of NORAD 27006 with their ground-based payload, the team believes they will be able to do the same thing for other satellites and debris once their payload is orbiting earth. The tools and analysis used to capture the images of NORAD 27006 and refine its orbit are the same ones that will be used during the STARE mission.
Accurately predicting the location of a satellite in low earth orbit at any given time is difficult mainly because of the uncertainty in the quantities needed for the equations of motion. Atmospheric drag, for instance, is a function of the shape and mass of the satellite as well as the density and composition of the unstable atmosphere. These uncertainties and the incompleteness of the equations of motion lead to a quickly growing error in the position and velocity of any satellite being tracked in low earth orbit. To account for these errors, the Space Surveillance Network (SSN) must repeatedly observe the set of nearly 20,000 objects it tracks; however, positional uncertainty of an object is about 1 kilometer. This lack of precision leads to approximately 10,000 false alarms per expected collision. The STARE mission aims to reduce the 1-kilometer uncertainty down to 100 meters or smaller, which will in turn reduce the number of false alarms by roughly two orders of magnitude. The Livermore team was able to reduce the uncertainty to 50 meters, well below the 100-meter goal.Vince Riot; firstname.lastname@example.org
Mark Hart, an engineer in LLNL's Defense Technology Engineering Division (DTED), developed the idea for Intrinsic Use Control (IUC), a concept that is capable of providing improved quantifiable safety and use control within a nuclear weapon. Use control of a weapon is focused on providing unencumbered authorized use while restricting unauthorized use. Safety, use control, and physical security work in concert for the weapon's surety. As a basic concept, use control is best accomplished in the weapon itself rather than depending on administrative controls, fences, and guards. Using established technology, IUC uses passive use control to resist any attacks or unauthorized use of a weapon at either the component or the fully assembled levels. This would be accomplished by designing the components to function in a way that cannot be replicated by any individual. Using the IUC concept, weapon components would be initialized and made secure during assembly by using the weapon's own fluctuating radiation field to generate unique component IDs and use-control numbers, known only to the weapon. Any anomaly in their verification, caused by removal or replacement of any protected component, would cause all protected components to be unusable.
IUC provides a less than 10–18 chance of controlling or operating an individual protected component, and a less than 10–72 chance of controlling or operating the entire protected system. Because of its unique and innovative approach, Hart's IUC concept was awarded the 2015 Surety Transformation Initiative (STI) Award from the National Nuclear Security Administration's (NNSA) Enhanced Surety Program. A prestigious recognition, the STI award aims to stimulate and encourage the development of potentially transformational nuclear weapon surety technologies and explore innovative, preferably monumental shift solutions, to unmet surety needs.Mark Hart; email@example.com
A team of Lawrence Livermore engineers and scientists, in partnership with the U.S. Air Force Research Laboratory, helped design and develop an advanced warhead for the U.S. Air Force Space and Missile Systems Center for high-speed applications. The five-year warhead development effort, which reflected the contributions of dozens of Livermore researchers, culminated in late 2013 in a highly successful sled test in which the warhead was propelled down straight rails by rocket motors and achieved speeds of greater than Mach 3. Conducted at Holloman Air Force Base, the test assessed how this warhead, shrouded and protected by a Livermore-designed carbon-epoxy aeroshell, responded to simulated flight conditions. The test results demonstrated the effectiveness of using advanced computational and manufacturing technologies to efficiently develop complex conventional munitions for the Department of Defense. Livermore researchers used high-performance computer simulations as part of the design process, allowing for a shorter, more efficient, and significantly less expensive testing phase that culminated in the sled test. This approach improves on legacy aerospace industry practices, which often involved expensive and time-consuming tests of prototype designs and candidate materials.
The effort to design and develop the warhead and its protective aeroshell also showcased the Laboratory's long-standing ability to integrate specialists from different disciplines. Experts in high explosives, aerodynamics, thermal mechanics, materials science, systems engineering, and supercomputing simulation quickly formed an interdisciplinary team to meet the Air Force goals. An extensive material testing and characterization program was instituted to evaluate the material and ensure it could meet the structural, aerodynamic, and heat requirements for the sled test. Additionally, the Laboratory's high-performance computing capabilities helped the engineering team optimize the mechanical and thermal properties of the carbon epoxy aeroshell. The fact that all test objectives were met, all systems performed as planned, all diagnostics and targets captured data as designed, and the data were consistent with predictive simulations, made this effort an outstanding success.David Hare; firstname.lastname@example.org
Research conducted this year by a team consisting of members from LLNL Engineering and the Swiss Federal Institute of Technology (ETH) in Zurich has led to advances in two types of nanomaterials. The Livermore-led team has developed an innovative method to create tangled "forests" of double-coated carbon nanotubes that improve the sensing capability of existing detection devices, making it possible for researchers to detect a single molecule of a target substance, such as a chemical or biological toxin. The easily reproducible nanotube structures are a result of research directed at raising the sensitivity of surface-enhanced Raman spectroscopy (SERS) techniques used for nondestructively identifying trace substances. Many researchers have been searching for ways to improve the ability of the SERS technique to amplify weak signals in detector systems. Using the method developed by the team causes hafnium dioxide and gold-coated carbon nanotubes to bunch up, creating nanocrevices at the ends of the nanotubes. The multiple metallic nanocrevices cause extreme amplification of very weak signals, providing intense and reproducible signal enhancements and making this method suitable for many detection applications.
In other research, the team developed a cost-effective and more efficient way to manufacture nanoporous metals over many scales, from nanoscale to macroscale. Nanoporous metals—foam-like materials that have some degree of air vacuum in their structure—have a wide range of applications because of their superior qualities, including a high surface area for better electron transfer and an increased number of available sites for the adsorption of analytes. Beginning with a four-inch silicon wafer, the team applied a sputter coating of metal (gold, silver, or aluminum). Next, a mixture of two polymers was added to the metal substrate to create patterns. The pattern was transformed into a single polymer mask with nanometer-size features. Last, anisotropic ion beam milling (IBM) was used to etch through the mask to make an array of holes, creating the nanoporous metal. Continuous examination of the roughness ensured the finished product had good porosity, which is key to creating the unique properties that make nanoporous materials work. The new technique is inexpensive, can be applied over many length scales, and avoids the "lift-off" process of patterning target materials, which is often unsuccessful at the nanoscale.Tiziana Bond; email@example.com
In 2014, LLNL received two multimillion-dollar awards from the Department of Defense's Defense Advanced Research Projects Agency (DARPA) to develop implantable neural devices. The first effort involves creating a device with the ability to record and stimulate neurons within the brain for treating neuropsychiatric disorders. The technology will help doctors to better understand and treat post-traumatic stress disorder (PTSD), traumatic brain injury (TBI), chronic pain, and other conditions. LLNL researchers are collaborating with several academic and industry entities to develop an implantable neural device with hundreds of electrodes by leveraging their thin-film neural interface technology, which provides a more than tenfold increase over current Deep Brain Stimulation (DBS) devices. The project is part of DARPA's SUBNETS (Systems-Based Neurotechnology for Emerging Therapies) program and supports President Obama's BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative, a new research effort aimed to revolutionize understanding of the human mind and uncover ways to treat, prevent, and cure brain disorders.
In the second effort, LLNL researchers are working to develop an implantable neural device with the ability to record and stimulate neurons within the brain to help restore memory. The goal of LLNL's work—undertaken in collaboration with the University of California, Los Angeles (UCLA) and industry partner Medtronic—is to develop a device that uses real-time recording and closed-loop stimulation of neural tissues to bridge gaps in the injured brain and restore individuals' ability to form new memories and access previously formed ones. LLNL will develop a miniature, wireless, and chronically implantable neural device that will incorporate both single neuron and local field potential recordings into a closed-loop system to implant into TBI patients' brains. The team's goal is to build the new prototype device for clinical testing by 2017. The research is funded by DARPA's Restoring Active Memory (RAM) program, which also supports the BRAIN initiative.Satinderpall Pannu; firstname.lastname@example.org
To address concerns about potential smuggling or misuse of nuclear materials, in particular in an improvised nuclear device, the Departments of Homeland Security and Energy are supporting efforts to develop a new generation of instruments for detecting the neutrons that fissile materials continuously emit. A Lawrence Livermore research team has demonstrated a miniaturized, solid-state detection system that fulfills the need for a far more efficient and compact neutron detector than existing devices. The instrument, called a pillar detector, uses a detection element as thin as a credit card and manufactured primarily from silicon. Currently in advanced development, the device has demonstrated high efficiency without the many disadvantages of competing designs. Other neutron detectors typically contain pressurized tubes filled with helium-3 gas to capture or absorb thermal neutrons. Comprising less than 5 percent the physical volume of a typical helium-3 detector, the pillar detector is ideal for handheld operation or other tasks where small size is critical. In addition, the pillar detector requires less than 5 volts to operate, while typical helium-3 detectors require a 1,000-volt power supply.
Because the pillar detector design is modular, an instrument of virtually any size can be manufactured to meet the needs of different users. For example, a very small detector can be built for handheld applications, or many elements can be "tiled" to cover large areas. In stacking the detectors, one can achieve closer to 100% efficiency. The team already holds several patents for the fabrication technology embodied in the device, and several companies have expressed interest in the instrument. Additional interest from industry is expected as the team demonstrates increasingly larger detector areas while decreasing the size of electronic signal processors.Rebecca Nikolić; email@example.com
Aided by a multidisciplinary approach that integrates precision engineering and manufacturing expertise, materials science research, and high-performance computing, Lawrence Livermore further established itself as a leader in Additive Manufacturing (AM) among Department of Energy laboratories. Following are just two examples:
The Gemini Planet Imager (GPI) is perhaps the most impressive scientific example of Lawrence Livermore's decades-long preeminence in adaptive optics (AO). Deployed on the 8.1-meter-diameter telescope at the Gemini South Observatory at Cerro Pachon, Chile, it is producing the fastest and clearest images of extrasolar planets (exoplanets) ever recorded. GPI features several new approaches that enable astronomers to correct for atmospheric turbulence with precision never before achieved. Using microelectromechanical systems (MEMS) technology, GPI has 10 times the actuator density of a general-purpose AO system. The more actuators, the more accurately the mirror surface can correct for atmospheric turbulence. Given the number of actuators, the system had to be designed to measure all aberrations at the same resolution. The precision in controlling the mirrors is accomplished by a wavefront sensor that breaks incoming light into smaller subregions. The increased number of actuators meant that existing algorithms required far too much computation to adjust the mirrors as quickly as needed. In response, engineer Lisa Poyneer developed a new algorithm that requires 45 times less computation. Consequently, GPI can continually perform all of its calculations within 1 millisecond, and its system of algorithms is self-optimized. A loop monitors and adjusts the control system every 8 seconds, providing the best performance possible as atmospheric conditions change.
In November 2014, the GPI Exoplanet Survey—an international team that includes dozens of leading exoplanet scientists—began an 890-hour-long campaign to discover and characterize giant exoplanets orbiting 600 young stars. Scientists will use GPI over the next three years to discover and characterize dozens or more exoplanets circling stars located up to 230 light-years from Earth.Lisa Poyneer; firstname.lastname@example.org