Rhatigan, Jennifer L.

NASA NTRS2011

First Crewed Flight: Rationale, Considerations and Challenges from the Constellation Experience

NASA's Constellation Program has made the most progress in a generation towards building an integrated human-rated spacecraft and launch vehicle. During that development, it became clear that NASA's human-rating requirements lacked the specificity necessary to defend a program plan, particularly human-rating test flight plans, from severe budget challenges. This paper addresses the progress Constellation achieved, problems encountered in clarifying and defending a human-rating certification plan, and discusses key considerations for those who find themselves in similar straits with future human-rated spacecraft and vehicles. We assert, and support with space flight data, that NASA's current human-rating requirements do not adequately address "unknown-unknowns", or the unexpected things the hardware can reveal to the designer during test.

Noriega, Carlos↗

NASA NTRS2009

United States Human Access to Space, Exploration of the Moon and Preparation for Mars Exploration

In the past, men like Leonardo da Vinci and Jules Verne imagined the future and envisioned fantastic inventions such as winged flying machines, submarines, and parachutes, and posited human adventures like transoceanic flight and journeys to the Moon. Today, many of their ideas are reality and form the basis for our modern world. While individual visionaries like da Vinci and Verne are remembered for the accuracy of their predictions, today entire nations are involved in the process of envisioning and defining the future development of mankind, both on and beyond the Earth itself. Recently, Russian, European, and Chinese teams have all announced plans for developing their own next generation human space vehicles. The Chinese have announced their intention to conduct human lunar exploration, and have flown three crewed space missions since 2003, including a flight with three crew members to test their extravehicular (spacewalking) capabilities in September 2008. Very soon, the prestige, economic development, scientific discovery, and strategic security advantage historically associated with leadership in space exploration and exploitation may no longer be the undisputed province of the United States. Much like the sponsors of the seafaring explorers of da Vinci's age, we are motivated by the opportunity to obtain new knowledge and new resources for the growth and development of our own civilization. NASA's new Constellation Program, established in 2005, is tasked with maintaining the United States leadership in space, exploring the Moon, creating a sustained human lunar presence, and eventually extending human operations to Mars and beyond. Through 2008, the Constellation Program developed a full set of detailed program requirements and is now completing the preliminary design phase for the new Orion Crew Exploration Vehicle (CEV), the Ares I Crew Launch Vehicle, and the associated infrastructure necessary for humans to explore the Moon. Component testing is well underway, and integrated flight testing will begin in 2009. This white paper summarizes 3 years of Constellation Program progress and accomplishments, and it describes the foundation set for human lunar return in 2020.

Rhatigan, Jennifer L.↗

NASA NTRS2009

NASA's Constellation Program: Milestones Towards the Frontier

This slide presentation reviews the status and progress made in the Constellation Program's work towards the goal of lunar and Martian exploration flights. It includes views of the various components of the program, and reviews the status of the engine tests, and the development of the Ares I-X towards test launch, the Orion Crew Module, the launch abort system, and the ground operations facilities.

Hanley, Jeffrey M.↗

NASA NTRS2005

Exploration-Related Research on ISS: Connecting Science Results to Future Missions

In January, 2004, the U.S. President announced The Vision for Space Exploration, and charged the National Aeronautics and Space Administration (NASA) with using the International Space Station (ISS) for research and technology targeted at supporting U.S. space exploration goals. This paper describes: What we have learned from the first four years of research on ISS relative to the exploration mission; The on-going research being conducted in this regard; and Our current understanding of the major exploration mission risks that the ISS can be used to address. Specifically, we discuss research carried out on the ISS to determine the mechanisms by which human health is affected on long-duration missions, and to develop countermeasures to protect humans from the space environment. These bioastronautics experiments are key enablers of future long duration human exploration missions. We also discuss how targeted technological developments can enable mission design trade studies. We discuss the relationship between the ultimate number of human test subjects available on the ISS to the quality and quantity of scientific insight that can be used to reduce health risks to future explorers. We discuss the results of NASA's efforts over the past year to realign the ISS research programs to support a product-driven portfolio that is directed towards reducing the major risks of exploration missions. The fundamental challenge to science on ISS is completing experiments that answer key questions in time to shape design decisions for future exploration. In this context, exploration relevant research must do more than be conceptually connected to design decisions - it must become a part of the mission design process.

Rhatigan, Jennifer L.↗

NASA NTRS2005

Exploration-Related Research on the International Space Station: Connecting Science Results to the Design of Future Missions

In January, 2004, the US President announced a vision for space exploration, and charged NASA with utilizing the International Space Station (ISS) for research and technology targeted at supporting the US space exploration goals. This paper describes: 1) what we have learned from the first four years of research on ISS relative to the exploration mission, 2) the on-going research being conducted in this regard, 3) our current understanding of the major exploration mission risks that the ISS can be used to address, and 4) current progress in realigning NASA s research portfolio for ISS to support exploration missions. Specifically, we discuss the focus of research on solving the perplexing problems of maintaining human health on long-duration missions, and the development of countermeasures to protect humans from the space environment, enabling long duration exploration missions. The interchange between mission design and research needs is dynamic, where design decisions influence the type of research needed, and results of research influence design decisions. The fundamental challenge to science on ISS is completing experiments that answer key questions in time to shape design decisions for future exploration. In this context, exploration-relevant research must do more than be conceptually connected to design decisions-it must become a part of the mission design process.

Rhatigan, Jennifer L.↗

NASA NTRS2001

Effects of Gas-Phase Radiation and Detailed Kinetics on the Burning and Extinction of a Solid Fuel

This is the first attempt to analyze both radiation and detailed kinetics on the burning and extinction of a solid fuel in a stagnation-point diffusion flame. We present a detailed and comparatively accurate computational model of a solid fuel flame along with a quantitative study of the kinetics mechanism, radiation interactions, and the extinction limits of the flame. A detailed kinetics model for the burning of solid trioxane (a trimer of formaldehyde) is coupled with a narrowband radiation model, with carbon dioxide, carbon monoxide, and water vapor as the gas-phase participating media. The solution of the solid trioxane diffusion flame over the flammable regime is presented in some detail, as this is the first solution of a heterogeneous trioxane flame. We identify high-temperature and low-temperature reaction paths for the heterogeneous trioxane flame. We then compare the adiabatic solution to solutions that include Surface radiation only and gas-phase and surface radiation using a black surface model. The analysis includes discussion of detailed flame chemistry over the flammable regime and, in particular, at the low stretch extinction limit. We emphasize the low stretch regime of the radiatively participating flame, since this is the region representative of microgravity flames. When only surface radiation is included, two extinction limits exist (the blow-off limit, and the low stretch radiative limit), and the burning rate and maximum flame temperatures are lower, as expected. With the inclusion of surface and gas-phase radiation, results show that, while flame temperatures are lower, the burning rate of the trioxane diffusion flame may actually increase at low stretch rate due to radiative feedback from the flame to the surface.

Rhatigan, Jennifer L.↗

NASA NTRS1994

Conceptual design of the Space Station combustion module

The purpose of this paper is to describe the conceptual design of the Combustion Module for the International Space Station Alpha (ISSA). This module is part of the Space Station Fluids/Combustion Facility (SS FCF) under development at the NASA Lewis Research Center. The Fluids/Combustion Facility is one of several science facilities which are being developed to support microgravity science investigations in the US Laboratory Module of the ISSA. The SS FCF will support a multitude of fluids and combustion science investigations over the lifetime of the ISSA and return state-of-the-art science data in a timely and efficient manner to the scientific communities. This will be accomplished through modularization of hardware, with planned, periodic upgrades; modularization of like scientific investigations that make use of common facility functions; and through the use of orbital replacement units (ORU's) for incorporation of new technology and new functionality. The SS FCF is scheduled to become operational on-orbit in 1999. The Combustion Module is presently scheduled for launch to orbit and integration with the Fluids/Combustion Facility in 1999. The objectives of this paper are to describe the history of the Combustion Module concept, the types of combustion science investigations which will be accommodated by the module, the hardware design heritage, the hardware concept, and the hardware breadboarding efforts currently underway.

Morilak, Daniel P.↗

NASA NTRS1994

Conceptual Design of the Space Station Fluids Module

The purpose of this paper is to describe the conceptual design of the Fluids Module for the International Space Station Alpha (ISSA). This module is part of the Space Station Fluids/Combustion Facility (SS FCF) under development at the NASA Lewis Research Center. The Fluids/Combustion Facility is one of several science facilities which are being developed to support microgravity science investigations in the US Laboratory Module of the ISSA. The SS FCF will support a multitude of fluids and combustion science investigations over the lifetime of the ISSA and return state-of-the-art science data in a timely and efficient manner to the scientific communities. This will be accomplished through modularization of hardware, with planned, periodic upgrades; modularization of like scientific investigations that make use of common facility functions; and use of orbital replacement units (ORU's) for incorporation of new technology and new functionality. Portions of the SS FCF are scheduled to become operational on-orbit in 1999. The Fluids Module is presently scheduled for launch to orbit and integration with the Fluids/Combustion Facility in 2001. The objectives of this paper are to describe the history of the Fluids Module concept, the types of fluids science investigations which will be accommodated by the module, the hardware design heritage, the hardware concept, and the hardware breadboarding efforts currently underway.

Rohn, Dennis W.↗

NASA NTRS1992

On protection of Freedom's solar dynamic radiator from the orbital debris environment. I - Preliminary analysis and testing

A great deal of experimentation and analysis was performed to quantify penetration thresholds of components which will experience orbital debris impacts. Penetration was found to depend upon mission specific parameters such as orbital altitude, inclination, and orientation of the component; and upon component specific parameters such as material, density and the geometry particular to its shielding. Experimental results are highly dependent upon shield configuration and cannot be extrapolated with confidence to alternate shield configurations. Also, current experimental capabilities are limited to velocities which only approach the lower limit of predicted orbital debris velocities. Therefore, prediction of the penetrating particle size for a particular component having a complex geometry remains highly uncertain. An approach is described which was developed to assess on-orbit survivability of the solar dynamic radiator due to micrometeoroid and space debris impacts. Preliminary analyses are presented to quantify the solar dynamic radiator survivability, and include the type of particle and particle population expected to defeat the radiator bumpering (i.e., penetrate a fluid flow tube). Results of preliminary hypervelocity impact testing performed on radiator panel samples (in the 6 to 7 km/sec velocity range) are also presented.

Rhatigan, Jennifer L.↗

NASA NTRS1992

On protection of Freedom's solar dynamic radiator from the orbital debris environment. II - Further testing and analyses

Presented here are results of a test program undertaken to further define the response of the solar dynamic radiator to hypervelocity impact (HVI). Tests were conducted on representative radiator panels (under ambient, nonoperating conditions) over a range of velocity. Target parameters are also varied. Data indicate that analytical penetration predictions are conservative (i.e., pessimistic) for the specific configuration of the solar dynamic radiator. Test results are used to define the solar dynamic radiator reliability with respect to HVI more rigorously than previous studies. Test data, reliability, and survivability results are presented.

Rhatigan, Jennifer L.↗

NASA NTRS1991

On protection of Freedom's solar dynamic radiator from the orbital debris environment. Part 2: Further testing and analyses

Presented here are results of a test program undertaken to further define the response of the solar dynamic radiator to hypervelocity impact (HVI). Tests were conducted on representative radiator panels (under ambient, nonoperating conditions) over a range of velocity. Target parameters are also varied. Data indicate that analytical penetration predictions are conservative (i.e., pessimistic) for the specific configuration of the solar dynamic radiator. Test results are used to define the solar dynamic radiator reliability with respect to HVI more rigorously than previous studies. Test data, reliability, and survivability results are presented.

Rhatigan, Jennifer L.↗

NASA NTRS1990

On protection of Freedom's solar dynamic radiator from the orbital debris environment. Part 1: Preliminary analyses and testing

A great deal of experimentation and analysis was performed to quantify penetration thresholds of components which will experience orbital debris impacts. Penetration was found to depend upon mission specific parameters such as orbital altitude, inclination, and orientation of the component; and upon component specific parameters such as material, density and the geometry particular to its shielding. Experimental results are highly dependent upon shield configuration and cannot be extrapolated with confidence to alternate shield configurations. Also, current experimental capabilities are limited to velocities which only approach the lower limit of predicted orbital debris velocities. Therefore, prediction of the penetrating particle size for a particular component having a complex geometry remains highly uncertain. An approach is described which was developed to assess on-orbit survivability of the solar dynamic radiator due to micrometeoroid and space debris impacts. Preliminary analyses are presented to quantify the solar dynamic radiator survivability, and include the type of particle and particle population expected to defeat the radiator bumpering (i.e., penetrate a fluid flow tube). Results of preliminary hypervelocity impact testing performed on radiator panel samples (in the 6 to 7 km/sec velocity range) are also presented. Plans for further analyses and testing are discussed. These efforts are expected to lead to a radiator design which will perform to requirements over the expected lifetime.

Rhatigan, Jennifer L.↗

NASA NTRS1989

Numerical model of solar dynamic radiator for parametric analysis

Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. The SD module rejects waste heat from the power conversion cycle to space through a pumped-loop, multi-panel, deployable radiator. The baseline radiator configuration was defined during the Space Station conceptual design phase and is a function of the state point and heat rejection requirements of the power conversion unit. Requirements determined by the overall station design such as mass, system redundancy, micrometeoroid and space debris impact survivability, launch packaging, costs, and thermal and structural interaction with other station components have also been design drivers for the radiator configuration. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations. A brief description and discussion of the numerical model, it's capabilities and limitations, and results of the parametric studies performed is presented.

Rhatigan, Jennifer L.↗

NASA NTRS1989

Numerical model of solar dynamic radiator for parametric analysis

Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations.

Rhatigan, Jennifer L.↗