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Davis, Steve

Publications and source records attributed to Davis, Steve.

Ares I-X Flight Test Development Challenges and Success Factors

The NASA Constellation Program's Ares I-X rocket launched successfully on October 28, 2009 collecting valuable data and providing risk reduction for the Ares I project. The Ares I-X mission was formulated and implemented in less than four years commencing with the Exploration Systems Architecture Study in 2005. The test configuration was founded upon assets and processes from other rocket programs including Space Shuttle, Atlas, and Peacekeeper. For example, the test vehicle's propulsion element was a Shuttle Solid Rocket Motor. The Ares I-X rocket comprised a motor assembly, mass and outer mold line simulators of the Ares I Upper Stage, Orion Spacecraft and Launch Abort System, a roll control system, avionics, and other miscellaneous components. The vehicle was 327 feet tall and weighed approximately 1,800,000 pounds. During flight the rocket reached a maximum speed of Mach 4.8 and an altitude of 150,000 feet. The vehicle demonstrated staging at 130,000 feet, tested parachutes for recovery of the motor, and utilized approximately 900 sensors for data collection. Developing a new launch system and preparing for a safe flight presented many challenges. Specific challenges included designing a system to withstand the environments, manufacturing large structures, and re-qualifying heritage hardware. These and other challenges, if not mitigated, may have resulted in test cancellation. Ares I-X succeeded because the mission was founded on carefully derived objectives, led by decisive and flexible management, implemented by an exceptionally talented and dedicated workforce, and supported by a thorough independent review team. Other major success factors include the use of proven heritage hardware, a robust System Integration Laboratory, multi-NASA center and contractor team, concurrent operations, efficient vehicle assembly, effective risk management, and decentralized element development with a centralized control board. Ares I-X was a technically complex test that required creative thinking, risk taking, and a passion to succeed.

Askins, Bruce↗

K-Band Power Enbedded Transmission Line (ETL) MMIC Amplifiers for Satellite Communication Applications

The design, fabrication, and performance of K-band high-efficiency, linear power pHEMT amplifiers implemented in Embedded Transmission Line (ETL) MMIC configuration with unthinned GaAs substrate and topside grounding are reported. A three-stage amplifier achieved a power-added efficiency of 40.5% with 264 mW output at 20.2 GHz. The linear gain is 28.5 dB with 1-dB gain compression output power of 200 mW and 31% power-added efficiency. The carrier-to-third-order intermodulation ratio is approx. 20 dBc at the 1-dB compression point. A RF functional yield of more than 90% has been achieved.

Tserng, Hua-Quen↗

Application of information technology to the National Launch System

The approach to the development of the Unified Information System (UNIS) to provide in a timely manner all the information required to manage, design, manufacture, integrate, test, launch, operate, and support the Advanced Launch System (NLS), as well as the current and planned capabilities are described. STESYM, the Space Transportation Main Engine (STME) development program, is comprised of a collection of data models which can be grouped into two primary models: the Engine Infrastructure Model (ENGIM) and the Engine Integrated Cast Model (ENGICOM). ENGIM is an end-to-end model of the infrastructure needed to perform the fabrication, assembly, and testing of the STEM program and its components. Together, UNIS and STESYM are to provide NLS managers and engineers with the ability to access various types and files of data quickly and use that data to assess the capabilities of the STEM program.

Mauldin, W. T.↗