STRUCTURES, DESIGN
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 Full-scale Al-Li development article for a pressurized, welded structure the size of the Shuttle’s external tank indicates a Shuttle launch weight drop of 8,000 lb. Because of the defense and aerospace downturn, the demand for aerospace design engineering is decreasing. Although many companies are downsizing, many are also pursuing unique approaches to developing new markets. Some are focusing on non-aerospace problems while others are shifting from one type of aerospace technology to another. Still others are applying their expertise to creating new commercial markets. Finally, some are successfully advancing their present markets by focusing on their current expertise. Grumman is translating its aerospace experience to a non-aerospace market, leading a team that is designing a new magnetic levitation train for the Dept. of Transportation and the Army Corps of Engineers. The resulting transfer of aerospace technology includes avionics, controls advanced structures, and internal "commercial" aircraft type architecture. The team, which selected an electromagnetic suspension (EMS or attractive) system, applied its expertise in control systems, electronics, and mechanical design to minimize the disadvantages of existing EMS systems. Engineering experience is being translated from one aerospace market (rocket boosters) to another (missile defense) in the LEAP (Lightweight Exoatmospheric Projectile) program. Under an activity funded by the Ballistic Missile Defense Organization (BMDO). Thiokol has translated its solid rocket booster expertise to solid-divert propulsion, providing steering for the LEAP missile interceptor. During a test conducted in April, the 17-1b interceptor flew and hovered using avionics provided by the Boeing Space and Defense Group. It was propelled to a height of 13 ft. where it used built-in sensors to lock on and track a simulated threat missile target. Keeping the target in sight, the vehicle maneuvered sideways 10 ft and stabilized. |
During the flight, the vehicle was controlled by a high-speed
on-board computer that integrated sensor data, target criteria, and propulsion commands. A
second hover test was planned for the solid-divert propulsion in November using avionics
provided by Hughes Missile and Space. NASA-Ames is experimenting with innovative approaches to technology integration through the Human Exploration Demonstration Project. HEDP's goal is to investigate the advanced technology requirements of implementing an integrated working and living environment for a planetary surface habitat. This environment will incorporate life support systems, physical and psychological monitoring of the flight crew, a virtual environment workstation, centralized data acquisition, and habitat system status monitoring. HEDP is scheduled for its first integrated technical demonstration in April 1994. Martin Marietta has developed a family of aluminum-lithium (Al-Li) alloys termed Weldalite, which has enabled design engineers to develop significantly lower weight launch vehicle structures. This new family of alloys overcomes the poor weldability and fracture toughness of current Al-Li alloys. Incorporating the new alloy into the Space Shuttle's external tank would decrease the Shuttle launch weight by 8,000 lb. Aerojet will use expertise it gained in advanced composite rocket motor cases, fuel tanks, and high-performance spacecraft pressure vessels and apply it to natural gas storage. In partnership with Pacific Gas and Electric, the company will design, develop, and certify a low-cost, lightweight, mobile natural gas storage module to supply fuel to companies operating fleets of vehicles. The technology is similar to that used in propulsion systems for the Minuteman, Peacekeeper, and Polaris missiles, and in BMDO initiatives. In another transfer of defense technology to the commercial sector, Lockheed will build the spacecraft buses for Motorola' s Iridium communication satellite. Lockheed will provide the l25 spacecraft buses, systems engineering support, satellite vehicle assembly, integration, and test support. The spacecraft bus includes attitude control propulsion, thermal, electrical power, structures, deployment mechanisms, and solar array wings. Lockheed will use its satellite testing facilities to test the buses.
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