Antarctica explored through a robot's eyes

Carnegie Mellon's interactive website, www.bigsignal.net, lets you search for meteorites in Antarctica with a robot named Nomad. Big Signal gives users the experience of exploring a remote location through Nomad's sensors, including a 360 degrees panoramic camera and other devices that let students engage in remote geology. "Big Signal places students in a real scientific setting by giving them access to the same data that a scientist would access," says Peter Coppin, a Carnegie Mellon research fellow responsible for the web site. The site receives information from Nomad daily, making the robot's expedition easily accessible to users. Nomad, a planetary rover prototype, is funded by NASA and was created at Carnegie Mellon's Robotics Institute. The project demonstrates robotics in a science mission under conditions similar to the exploration of Mars and the Moon. Researchers at Carnegie Mellon hope to improve panoramic imagery, advanced radar perception, and multiple sensors used within robots, as a result. E-mail Dimitrios Apostolopoulos, Carnegie Mellon Robotics Institute, at [email protected], or visit www.bigsignal.net.

Photodetector has astronomical resolution

A new charge-coupled device (CCD) developed by Berkeley Lab researcher Steve Holland may help astronomers look deep into the cosmos. The new CCD promises ten times better resolution than detectors now in use. CCDs are semiconductors that convert patterns of light into patterns of electric charge, which can be recorded and computer-processed to form images. A typical particle detector is a slab of silicon 300 micrometers thick. In comparison, to register dim blue light, most astronomical CCDs must be thinned to the width of a human hair. Not only is a thin chip fragile, it sacrifices sensitivity to red and infrared light. Using ultra-pure negatively doped (n-type) silicon, Holland produced a back-illuminated chip that is sensitive to blue light without thinning. "By layering a thin, transparent window onto the back of the n-type silicon substrate-a window that also acts as an electrode-we can apply a bias voltage between the window and the positively doped channel layer under the front circuitry, " says Holland. The voltage fully depletes the substrate's charge density-or clears the silicon of charge carriers. Possible applications include an astronomical CCD with unprecedented efficiency in the infrared spectrum, an X-ray imager, and a new generation of particle detectors. Call Steve Holland at (510) 486-5069, e-mail him at [email protected] , or call Michael Levi at (510) 486-7186 or e-mail him at [email protected].

High-flying UAVs push design envelope

Future high-altitude, long-endurance, unmanned aerial vehicles are in the works by General Atomics Aeronautical Systems Inc. (GA-ASI, San Diego, CA) for Dryden Flight Research Center (Edwards, CA). GA-ASI will develop three new UAVs with a mission endurance of 24 to 48 hours, a range of 40,000 to 65,000 ft, and a payload of at least 660 lbs (300 kg) under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. The first of three testbed aircraft, now in development by GA-ASI, is turboprop-powered and operates at a 40,000- to 50,000-ft altitude for up to 25 hours. Flight testing of a second aircraft, with a Williams FJ44-2A turbofan engine, is scheduled to begin in 2001. This jet version is expected to have a flight endurance of more than 12 hours in the 50,000- to 60,000-ft. altitude range. A third flight-test-Predator B-which is powered by the Honeywell TPE-331-10T turboprop engine, will test advanced subsystems such as over-the-horizon satellite communication-based command and control, a redundant flight control system to improve operational reliability, "see and avoid" capability, and voice relay so air traffic controllers can communicate directly with the ground-based pilot at extreme ranges. These tests will begin in 2002. Call GA-ASI at (858) 455-2810.

Thinking small

Dutch chemists at Eindhoven University of Technology discovered a way to determine the chemical composition of chips or coatings only a few nanometers wide. Their technique promises to help miniaturize microelectronics and semiconductors. The research is based on the radiation emitted by an object when it is irradiated by an electron beam. The measurable phenomenon occurs because the electrons in the beam collide with electrons in the atoms making up the object, so that they enter an excited state. When the electrons return to the free state, with lower energy, x-rays are emitted. The wavelength of this radiation is characteristic of the chemical element, while the intensity of the radiation depends on the overall composition of the material. Electrons produced by a high-resolution electron microscope irradiate a 10 X 10 nanometer area. Using the x-rays emitted from this area, it is possible to determine precisely which chemical elements occur at that location and in what quantity. Research is underway on a new type of electrical contact within chips constructed of a thin layer of cobalt deposited on a semiconductor. The cobalt forms an electrical connection for the semiconductor. When heat is applied, a chemical reaction takes place between the cobalt and the semiconductor, improving the mechanical strength and the electrical conductivity of the contact. Fax Gerben Boon at 011 31 40 244 5619 or e-mail [email protected]

Tiny fibers get strength tested

Carbon nanotubes are ultra-strong fibers 10,000 times smaller than a human hair, yet stronger than steel. They can be electrically conducting, semi-conducting, or insulating. But just how strong are these nanoscale materials? Rodney S. Ruoff, Ph.D., associate professor of physics, and his nanotechnology research group at Washington University (St. Louis, MO) set out to determine how much force a carbon nanotube can withstand before breaking. In his experiment, individual multi-walled carbon nanotubes-rolled sheets of graphite-were picked up, attached to a scale, and tensile loaded (stretched by applying a force) until broken. In some cases, micro-Newtons of force were needed to break individual nanotubes. "We are the first to perform tensile-strength experiments using new micro-measuring instruments developed in our laboratory," says Ruoff. A videotape records the entire tensile loading experiment as it takes place inside of a scanning electron microscope. Ruoff's group is expanding its repertoire of measurements to include determining changes in transport properties as a function of mechanical relaxation. This could lead to new applications, such as in nanoscale sensors. Phone (314) 935-8746 or e-mail bucky5.wustl.edu.

IR sensor built to detect missiles now screens for breast cancer

The war against breast cancer has a new weapon, thanks to an advanced sensor developed at NASA's Jet Propulsion Laboratory (Pasadena, CA). The sensor is the centerpiece of OmniCorder Technologies'(Stony Brook, NY) BioScan Syste. The Quantum Well Infrared Photodetector (QWIP) sensor within the diagnostic tool was invented by JPL principal engineer Dr. Sarath Gunapala. Studies have determined that cancer cells exude nitric oxide. This causes changes in blood flow in tissue surrounding cancer that can be detected by the sensor. BioScan Syste is sensitive to temperature changes of less than 0.027F (0.015C) and has a fast speed of more than 200 frames/sec. When cancer is present, nitric oxide disrupts normal blood flow around it. The digital sensor detects the infrared energy emitted from the body, thus "seeing" the minute differences associated with blood flow changes. It is a non-invasive diagnostic tool, which causes no discomfort to the patient and does not use radiation. OmniCorder president and CEO Mark Fauci calls the sensor "fast, sensitive, stable, uniform, and mass producable." The FDA recently cleared the device, which may also apply to melanoma and vascular disease screening. Ironically, sensor development was first funded by NASA and the Ballistic Missile Defense Organization (BMDO) for missile characterization. JPL's Dr. Gunapala developed the sensor-based imaging camera, which uses a semiconductor chip-based focal plane array to detect the long-wavelength (8-12 micron) infrared region. A camera lens focuses 500,000 individual small detectors that convert the image into an electronic signal, then to a video signal for display on a monitor. "It is a pleasure to see something I invented being used for public benefit," said Gunapala, "especially in the early detection of cancer." For information, fax OmniCorder at (516) 444-8825, e-mail [email protected], or e-mail Dr. Sarath Gunapala at JPL at [email protected].

Cockpit displays: the right stuff or too much information?

A Georgia Institute of Technology researcher hopes her study on an enhanced aircraft cockpit display system will lead to more efficient interaction between air traffic controllers and commercial pilots. The Cockpit Display of Traffic Information (CDTI) system allows pilots to see other aircraft around them and the distances between them. CDTI would allow air traffic controllers to give more sophisticated commands and communicate more directly with the pilots, says Dr. Amy Pritchett, an assistant professor in the Georgia Tech School of Industrial and Systems Engineering. "Instead of just telling the pilot what speed to fly, the controller can tell them what aircraft they are following in to land and how far behind them they must be." This gives the pilot more involvement in air traffic management. But there is a fine line between giving pilots the right information and overwhelming them with too much, so Pritchett and her students conducted studies to help set the standards for enhanced cockpit displays. The system is under test with the Cargo Airlines Association. Fax (404) 894-0199 or e-mail [email protected].