Portable Computer

dubbed SPOC, for Shuttle Portable

Onboard Computer.

SPOC was an adaptation of the GRID Compass (shown at right), the first true portable laptop computer, produced by GRID Systems Corporation, Fremont, California. Hardware had to be modified and new software developed to meet space requirements, which led to changes in commercial models that benefited the company's competitive position.

Since the shuttle's main computers must handle a multitude of processing functions, NASA wanted a separate computer to provide reliable monitoring of the craft's orbital path and a visual display of its position at any time. Since weight and space are vital considerations in space operations, the computer had to be small and lightweight; nonetheless, it had to have graphic display capability, a large memory storage capacity, high processing speed, and sufficient ruggedness to withstand launch vibration. After evaluating a number of small computers, NASA selected GRID Compass.

The principal modification needed was a fan to cool the computer; GRID computers normally

were cooled by convection, or heat transfer by circulation, but that process does not work in the weightless environment of space. NASA also wanted a larger electroluminescent screen and Velcro strips to keep SPOC from floating. The fan later was incorporated into the larger-screen models of the Compass II line; likewise, Velcro strips have been used on subsequent products, including the new PalmPADTM PC, the first wearable pen computer, shown in use above. Designed for data collection applications, the PalmPAD also features a rugged magnesium case for added protection-an innovation first developed for the Compass line.

Shuttle operations required a sophisticated operating and control system, one of the major

considerations in NASA's selection of the GRID Compass. Nonetheless, NASA and GRID software engineers spent many hours writing, testing, and rewriting source code. This process, the company reports, ultimately benefited GRID and its commercial clients because it helped fine-tune the GRID Operating System and common code documentation.

Over the past decade, GRID Systems' annual sales have grown from less than $1 million to over $250 million. The company's computers are still used by NASA; the GRID Model 1530, a more powerful 386 SL-based laptop that replaced SPOC, helps space shuttle astronauts to keep track of the craft's position in orbit and enables them to control payload experiments, collect data, and instantly transmit research results to investigators on Earth.

During the Apollo program, NASA sought to improve upon the fabrics it had used in fashioning space suits for the Mercury and Gemini astronauts, and began its search for a durable, noncombustible material that was also thin, lightweight, and flexible. At the time, Owens-Corning was developing a glass fiber yarn could be woven into a fabric. The fabric was then coated with Teflon® for added strength, durability, and hydrophobicity-the ability to repel moisture. The material met NASA specifications and was used in space suits throughout the Apollo era.

The technology soon found additional applications. The health care market required flame-resistant draperies and the FiberglasR fabric was adapted for that use. A more recent application is in the construction field, where a heavier version of the fabric is used as a permanent covering for shopping centers nationwide, for sports stadiums such as the new Georgia Dome in Atlanta and the Olympic Stadium in Rome, and for airport terminals in Denver, Colorado and Saudi Arabia.

Architects, engineers, and building owners are turning increasingly to fabric structures because of their aesthetic appeal, relatively low cost, low maintenance

Flat Cable

the use of extremely thin flat wireknown as flat conductor cable (FCC) -instead of the relatively thick and protrusive round cable. Only as thick as a credit card, FCC dramatically reduces the space occupied by the many miles of power lines in aerospace vehicles.

NASA recognized that commercial buildings, which also have miles of wiring, would benefit by adopting FCC technology. In the late 1960s, NASA funded a program in which Marshall Space Flight Center developed prototypes for several FCC applications, including a baseboardmounted system.

Since industry participation was essential to large-scale application of FCC, NASA sponsored formation of a consortium composed of a dozen firms engaged in electrical hardware and associated manufacturing activities. Using Marshall's early work as a departure point, the member companies pooled their resources to develop complete FCC systems which encompass not only the cable but the sheathing, connectors, tools, and

other equipment needed to facilitate FCC use by designers and builders. Subsequently, the use of FCC covered by carpet tiles in commercial buildings gained approval from Underwriters Laboratory and was listed in the National Electrical Code established by the National Fire Protection Association.

The flat cable can be mounted on walls and floors instead of in them; it can be installed beneath a carpet or along a baseboard, its essential sheathing designed to look like decor rather than plumbing. This enables elimination of the traditional ducting, under floors and elsewhere, necessary to accommodate conventional wiring.

And when electrification needs changing, as they frequently do in commercial buildings, the surfacemounted FCC system is readily accessible.

In short, FCC offers simplified building construction, reduced installation time, and ease of alteration, all of which translate into substantial cost savings. Because of these multiple advantages, FCC has gained wide acceptance among builders, interior designers, and building managers.

Bolt Stress Monitor

Research Center, the P2L2 uses sound waves to accurately determine whether a bolt is properly tightened. Precise measurement of stress on a tightened bolt is critical in building and maintaining such structures as pressure vessels, bridges, and power plants, where overtightened or undertightened bolts can fail and cause serious accidents or costly equipment breakdowns.

The most common and least costly method of gauging bolt stress is the torque wrench, which is inherently inaccurate; it does not account for the friction between nut and bolt, which has an influence on stress. At the other end of the spectrum, there are accurate stress measurement systems, but typically they are expensive and bulky.

The battery-powered P2L2 bridges the gap: it is inexpensive, lightweight, portable, and extremely accurate-to within one percent--because it is not subject to friction error. The microprocessor-based instrument transmits a sound wave pulse to the bolt being tightened and receives a return signal indicating changes in resonance due to stress, akin to the tone changes in a violin string as it is

tightened. The monitor measures the changes in resonance and produces a digital reading of stress on the bolt.

NASA has used the invention for bolting applications ranging from space shuttle landing gear wheels to wind tunnel fan blades, and is now transfering the technology to commercial markets.

Last June, the Langley Center held a Bolt Tension Monitor Workshop for industry that generated significant private sector interest in licensing the P2L2 and resulted in Langley's selection of the StressTel Corporation, Scotts Valley, California, as its commercial partner for further development of the system. StressTel, a leading manufacturer of ultrasonic testing equipment, plans to incorporate the NASA technology in its new BoltMike SMIITM, a portable bolting control system offering simple operation, self-calibration, and data upload and download capabilities.

sensitivity,

however, to detect all of the imperfections their users would like to catch and correct.

Diffracto Ltd., Windsor, Ontario, offers an innovative system called D SightTM that reveals tiny flaws previously difficult or impossible to observe. D Sight can be used to inspect both flat and curved surfaces to locate such imperfections as dents, dings, wrinkles, and blisters. It detects and magnifies defects measuring less than one thousandth of an inch.

Industry tests have shown that D Sight can identify 94 percent of the defects when inspecting stamped sheet metal, as compared with only 50 percent for traditional flaw detection methods such as visual inspection.

D Sight is a spinoff from the space shuttle program. Diffracto was licensed to develop commercial applications for the vision guidance system of the shuttle's remote manipulator arm. While

experimenting with the vision system, Diffracto engineers noticed the

D Sight is a quality control inspection workstation capable of detecting surface imperfections measuring less than one thousandth of an inch.

phenomenon of reflected light from the target material. This led to a research and development effort that produced the first commercial D Sight model.

The basic system consists of a solid-state camera equipped with a quartz halogen lamp, a retroreflective screen, and an image processing computer. The camera photographs the part being studied while the screen bounces light off the surface to highlight defects. The resulting image is computer-analyzed and the discovered defects projected onto a video monitor for comparison with a stored master image of an acceptable part. Also included is a hard copy printer that provides documented evidence of product quality and proof of inspection.

For the D Sight technique to work, the target surface must be reflective. Since some surfaces-such as unpainted sheet metal-are not reflective enough, Diffracto created a reflectivity enhancing process that involves wiping an oil- or water-based compound on the surface.

The company has sold units to Chrysler, Ford, General Motors, and other auto suppliers who employ D

Sight to inspect body panels and windshields, and to check "first articles" for die-related defects. Plastics manufacturers use the system to determine what temperatures, pressures, and materials will produce the best quality surfaces. Moreover, several aircraft manufacturers have bought units to inspect aircraft composite skins.

Diffracto has installed more than 60 systems worldwide. In cooperation with the Canadian National Research Council's Institute for Aerospace Research, they have developed a portable unit to perform nondestructive tests on in-service aircraft. The DAIS (D Sight Aircraft Inspection System) enables fast detection of impact damage and other flaws that often go undetected with current visual methods.