By Nigel Hey
In late June, a little bit of Sandia flew to the Moon — a working model of the operational heart of the Labs’ miniature synthetic aperture radar (miniSAR).
The miniSAR is an established frequent-flier on reconnaissance drones. But as a special passenger aboard NASA’s Lunar Reconnaissance Orbiter (LRO), a fundamental element of Sandia’s miniSAR technologies has become a component of the spacecraft’s miniature radio frequency imaging radar, called Mini-RF for short.
Its prime mission is to search for subsurface water-ice deposits in the moon’s craters, and collect high-resolution imagery of regions that lie permanently in shadow (see “Water on the moon — what’s the fuss?” below).
Since the LRO entered lunar orbit June 23, mission scientists have been bringing its suite of instruments online one by one.
The Sandia LRO team, which has been working on the lunar project since 2002, has found the opportunity to work with NASA to be highly motivational.
“It is a truly special accomplishment of the Sandia SAR development organizations to apply our technology and capabilities to a high-profile science mission such as NASA’s LRO,” says Dale
Dubbert (5345), the technical lead for Sandia’s piece of the LRO mission.
Steve Becker, manager of Embedded Radar Processing Dept. 5348 and program manager of the Sandia LRO effort, says Dale’s leadership was “essential and indispensable.”
“He was the glue for the entire program,” says Steve.
In addition to the Mini-RF package, the LRO is carrying six other instruments to provide scientists with detailed maps of the lunar surface and enhance understanding of the moon's topography, lighting conditions, mineralogical composition, and natural resources. This information will be used to select safe landing sites, determine locations for future lunar outposts, and help mitigate radiation dangers to astronauts.
Aside from the Mini-RF technology demonstration and its search for subsurface water, six full-scale LRO experiments will probe the Moon’s radiation environment and map its thermal, topographical, and hydrogen distribution characteristics. For example the Lyman Alpha Mapping Project and the Lunar Reconnaissance Orbiter Camera will produce images from far-ultraviolet and visible-light/ultraviolet scans, respectively. The polar regions of the moon are the main focus of the mission because continuous access to sunlight may be possible and water ice may exist in permanently shadowed areas of the poles.
Trapped ice particles?
Of particular interest is Shackleton Crater at the Lunar south pole. At roughly 12 miles wide and more than a mile deep, Shackleton Crater is permanently shadowed. Here the temperature may be as cold as 50 to 70 kelvin (minus 223 to minus 203 Celsius) in areas that some believe may contain trapped ice particles.
During observation opportunities, LRO’s Mini-RF instrument will image both poles in two bands (S-band and X-band) with a spatial resolution down to 15 meters, covering the entire polar regions in a single 28-day window. The Mini-RF also has a supplemental list of goals that may be executed after successful completion of its primary mission. One of these supplemental goals is to conduct a spacecraft-to-spacecraft “bistatic” imaging experiment in which a Mini-RF signal would be transmitted from India’s Chandrayaan-1 (launched in 2008) and received by a sister unit on LRO. Sandia mission planners believe that analysis of the returned backscatter signal potentially could provide the most definitive remote technique for discriminating between ice and rock.
Backup communications capability
If necessary, Mini-RF could provide a backup communication capability for the entire spacecraft. This multimode capability is enabled by a Sandia-designed reconfigurable digital synthesizer and digital receiver module tailored from equivalent technology developed for the miniSAR generation of radars.
All raw data as well as processed data (including higher-order products such as mosaics) will be made available to the scientific community. This will be achieved by archiving the data to the geosciences node of the Planetary Data System (PDS).
Sandia’s participation in LRO resulted from its long-term commitment to miniaturizing synthetic aperture radar technology. The LRO SAR includes a digital waveform synthesizer and digital receiver module, which uses modern field programmable gate array (FPGA) technology from Electronic Systems Center 5300. (Sandia-designed antenna-gimbal assembly and miniaturized RF/microwave electronics, not provided for Mini-RF, are also parts of the miniSARs used in fixed wing aircraft, along with commercial off-the-shelf components.)
The Labs’ partner on the Mini-RF waveform generator/digital receiver is Raytheon, which also provided the systems antenna and analog receiver and exciter. Center 5300 also undertook system performance analysis and aided in the development of operational scenarios; Engineering Sciences Center 1500 supported the project with shock and vibration testing and model verification; Monitoring and Systems Technology Center 5700 with radar system and component level specifications and synergy with other satellite sensor technologies; and, Systems Assessment and Research Center 5900 with signal-processing algorithms.
Why the fuss over water on the moon? Because, if astronauts are ever to return to Earth’s natural satellite, they will need water for an extended stay. LRO is expected to provide fundamental data to enable a human return to the moon, and may in fact be part of a new “race to the moon” involving the US, Japan, China, and India. The Japanese and Chinese launched separate water-seeking lunar spacecraft in the fall of 2007; India’s Chandrayaan took off in October 2008.
In addition to its critical function as a source of water for human visitors, lunar water could be broken down into hydrogen and oxygen for use as rocket fuel and breathable air. Even sufficient concentrations of hydrogen by itself would be valuable because it could be used as fuel or combined with oxygen from the soil to make water. Taking water to the moon for human use might prove prohibitively expensive, so the prospect of finding “cheap” water on-site is more than seductive.
Some critics think the idea of finding frozen water on the moon is no more than wishful thinking. However, previous probes have provided tantalizing hints that there may indeed be water on the moon. Clementine, a small probe launched by NASA and DoD in 1994, picked up radio echoes that may have indicated the presence of ice. Then in 1998 NASA’s Lunar Prospector mission detected hydrogen, a component of ice, in a neutron backscattering experiment. Ironically, since it is so close to the Sun, the planet Mercury has so far produced the strongest radar indications of fully formed extraterrestrial water ice. (In 2002, hydrogen that could indicate water-ice was identified just below Mars’ surface by both a neutron spectrometer and a gamma-ray spectrometer aboard NASA’s Mars Odyssey orbiter. Last year, tests aboard NASA’s Phoenix Mars Lander identified water in a soil sample.) -- Nigel Hey
Stirling Energy Systems (SES) and Tessera Solar unveiled last week four newly designed solar power collection dishes at Sandia’s National Solar Thermal Test Facility (NSTTF).
Called SunCatchers™, the new dishes have a refined design that will be used in commercial-scale deployments of the units beginning in 2010.
“The four new dishes are the next-generation model of the original SunCatcher system. Six first-generation SunCatchers built over the past several years at the NSTTF have been producing up to 150KW [kilowatts] of grid-ready electrical power during the day,” says Chuck Andraka (7337), the lead Sandia project engineer. “Every part of the new system has been upgraded to allow for a high rate of production and cost reduction.”
Chuck and Sandia’s concentrating solar-thermal power (CSP) team have been working closely with SES over the past five years to improve the system design and operation.
The modular CSP SunCatcher uses precision mirrors attached to a parabolic dish to focus the sun’s rays onto a receiver, which transmits the heat to a stirling engine. The engine is a sealed system filled with hydrogen. As the gas heats and cools, its pressure rises and falls. The change in pressure drives the piston inside the engine, producing mechanical power, which in turn drives a generator and makes electricity.
The new SunCatcher is about 5,000 pounds lighter than the original, is round instead of rectangular to allow for more efficient use of steel, has improved optics, and consists of 60 percent fewer engine parts. The revised design also has fewer mirrors — 40 instead of 80. The reflective mirrors are formed into a parabolic shape using stamped sheet metal similar to the hood of a car. The mirrors are made by using automobile manufacturing techniques. The improvements will result in high-volume production, cost reductions, and easier maintenance.
“The new design of the SunCatcher represents more than a decade of innovative engineering and validation testing, making it ready for commercialization,” says Steve Cowman, Stirling Energy Systems CEO. “By utilizing the automotive supply chain to manufacture the SunCatcher, we’re leveraging the talents of an industry that has refined high-volume production through an assembly line process. More than 90 percent of the SunCatcher components will be manufactured in North America.”
In addition to improved manufacturability and easy maintenance, the new SunCatcher minimizes both cost and land use and has numerous environmental advantages, Chuck says.
“They have the lowest water use of any thermal electric generating technology, require minimal grading and trenching, require no excavation for foundations, and will not produce greenhouse gas emissions while converting sunlight into electricity,” he says.
Tessera Solar, the developer and operator of large-scale solar projects using the SunCatcher technology and sister company of SES, is building a 60-unit plant generating 1.5 MW (megawatts) by the end of the year either in Arizona or California. One megawatt powers about 800 homes. The proprietary solar dish technology will then be deployed to develop two of the world’s largest solar generating plants in Southern California with San Diego Gas & Electric in the Imperial Valley and Southern California Edison in the Mojave Desert, in addition to the recently announced project with CPS Energy in West Texas. The projects are expected to produce 1,000 MW by the end of 2012.
Last year one of the original SunCatchers set a new solar-to-grid system conversion efficiency record by achieving a 31.25 percent net efficiency rate, toppling the old 1984 record of 29.4.-- Chris Burroughs
By Neal Singer
Whether it’s the terrorist group al-Qaida, a troubled teenager, a meth-head, or a member of a drug cartel leaving an unexploded bomb at a location near you, no one wants the bomb squad showing up with a robot for which they’re still reading the instruction manual.
To help avoid delays that could risk lives, a “robot rodeo” held last week at Sandia provided 10 scenarios to familiarize bomb squad members from different New Mexico locations with five kinds of robots they may need to operate on short notice.
The point of the spirited competition was to give bomb squads practice operating their own equipment in real-time difficult scenarios, as well as the opportunity to familiarize themselves with robots unavailable on their home turf that they may need to operate when supporting another community.
“Our first responders need to be able to operate on many fields,” says Jake Deuel, manager of Mobile Robotics Dept. 6472. Jake co-led the third annual Western National Robot Rodeo with Chris Ory from Los Alamos National Laboratories.
“If guys from APD [Albuquerque Police Dept.] need to backstop the Santa Fe police force in an emergency, it will be helpful to have experienced some of their tools in advance,” says Ory.
One scenario involved removing explosives placed by a terrorist in an overhead luggage compartment of an airplane and under its seats [see boxed scenario.] This was not as simple as it first appeared. Operators, working at remote distances with site information provided by a video camera on the robot, had to maneuver up and down narrow plane corridors and between even narrower seating. Fiber optic cables that carried not only video from robot to operator but instructions from operator to robot had to remain undamaged and uncut. Murphy’s Law caused seat trays to drop unexpectedly, hindering explosive device removal. Even more insidious were the effects of obstructions beyond the operator’s immediate view.
In other scenarios, the teams used robots to explore a ravine for tripwires of the type used to set off IEDs (improvised explosive devices). They also were involved in a kind of NASCAR rapid-repair effort to replace a robot’s treads, maneuvered through a minefield to recover a hard drive, and dragged a fallen bomb tech out of what seemed to be a crack house before disabling and removing what could have been a bomb. Other scenarios involved securing a communications facility and removing bombs set near two water reservoirs.
The most imaginative scenario: A DC9 transporting captured space aliens, of the kind popularized in the movie Men in Black, has had to land in Albuquerque. Robots must maneuver among the downed aliens and the plastic tubes of their life-support system to retrieve the government team’s memory-erasing light tubes.
The fantastic scenario and those more grounded in potential real-world situations demanded intense concentration. As Jake recounts, “One team reported to its leadership that ‘we think this is going to be a little harder than we first thought.’”
Competing to show the most effective techniques on key steps in each scenario were teams from the Albuquerque Police Department, Santa Fe Police Department, New Mexico State Police, Kirtland Air Force Base, and Los Alamos National Laboratory.
Evidence of the worth of the training was apparent, says Jake, when he was told by the KAFB team leader that their youngest operators were getting the most stick time (driving time) because they were being deployed to Afghanistan in the near term.
“Imagine how valuable the Air Forces thought this training would be for them,” says Jake. At the awards ceremony on Thursday afternoon as part of the after-action debriefing for the competitors, Sgt. Chris Jackson, AF EOD, said, “This was the best training we’ve had.”
Robot limitations brought into sharp relief by the competition will cause Sandia roboticists to suggest projects for DOE and other agency funding, Jake says. Technical improvements are adopted by the robotics companies who sell the robots. Meanwhile, participants in the competition learn about the latest innovations.
“It’s a door that swings several ways,” says Lawrence Vasquez of the Santa Fe bomb team.
Nothing is as easy as it seems
People who read about bomb squads arriving on the scene to remove explosives might be surprised to learn how utterly human is the process by which flesh-and-blood people learn to control the robots that perform the removal process.
In one scenario, a robot enters a three-story cinderblock house clutching a PAN disrupter. Its intent is to shoot a high-pressure stream of water at a possibly dangerous device known to be somewhere in the building. It trundles up a set of unvarnished concrete stairs bordered by an unadorned metal handrail to the second floor — a world of unfinished particle-board walls and narrow, dimly lit hallways. Down one hallway is a suspicious package the size of a hip pouch. But at the top of the stairs, a prone dummy — the dressed simulation of an unconscious bomb tech in his bomb suit — blocks the robot’s path.
Back at the control center, sheltered about 100 feet from the building, the team operating the robot has a choice to make. Do they drive over the fallen worker to get to the device? It’s a 100-pound robot, which makes it 50 pounds on each wheel.
The question is moot because the little robot cannot bestride the man. The operators descend the robot down the ominous stairs and a bigger one — the Remotec Andros F-6A — ascends, forward gripper ready to haul the victim to safety and by doing so, clear the path for the smaller robot.
But take hold of the victim where?
“How can I grab him?” asks the operator at the keyboard, watching the video screen showing a robot’s-eye-view of the fallen worker.
“If it’s ever me,” says another squad member, “you can grab me by my head.” -- Neal Singer