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May, Todd

Publications and source records attributed to May, Todd.

27 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

Space Launch System (SLS) Safety, Mission Assurance, and Risk Mitigation

SLS Driving Objectives: I. Safe: a) Human-rated to provide safe and reliable systems for human missions. b) Protecting the public, NASA workforce, high-value equipment and property, and the environment from potential harm. II. Affordable: a) Maximum use of common elements and existing assets, infrastructure, and workforce. b) Constrained budget environment. c) Competitive opportunities for affordability on-ramps. III. Sustainable: a) Initial capability: 70 metric tons (t), 2017-2021. 1) Serves as primary transportation for Orion and exploration missions. 2) Provides back-up capability for crew/cargo to ISS. b) Evolved capability: 105 t and 130 t, post-2021. 1) Offers large volume for science missions and payloads. 2) Modular and flexible, right-sized for mission requirements.

May, Todd↗
NASA NTRS2012

NASA's Space Launch System: A Flagship for Exploration Beyond Earth's Orbit

The National Aeronautics and Space Administration s (NASA) Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is making progress toward delivering a new capability for exploration beyond Earth orbit in an austere economic climate. This fact drives the SLS team to find innovative solutions to the challenges of designing, developing, fielding, and operating the largest rocket in history. To arrive at the current SLS plan, government and industry experts carefully analyzed hundreds of architecture options and arrived at the one clear solution to stringent requirements for safety, affordability, and sustainability over the decades that the rocket will be in operation. This paper will explore ways to fit this major development within the funding guidelines by using existing engine assets and hardware now in testing to meet a first launch by 2017. It will explain the SLS Program s long-range plan to keep the budget within bounds, yet evolve the 70 metric ton (t) initial lift capability to 130-t lift capability after the first two flights. To achieve the evolved configuration, advanced technologies must offer appropriate return on investment to be selected through a competitive process. For context, the SLS will be larger than the Saturn V that took 12 men on 6 trips for a total of 11 days on the lunar surface over 4 decades ago. Astronauts train for long-duration voyages on the International Space Station, but have not had transportation to go beyond Earth orbit in modern times, until now. NASA is refining its mission manifest, guided by U.S. Space Policy and the Global Exploration Roadmap. Launching the Orion Multi-Purpose Cargo Vehicle s first autonomous certification flight in 2017, followed by a crewed flight in 2021, the SLS will offer a robust way to transport international crews and the air, water, food, and equipment they need for extended trips to asteroids, Lagrange Points, and Mars. In addition, the SLS will accommodate high-priority science experiments. SLS affordability initiatives include streamlining interfaces, applying risk-based insight into contracted work, centralizing systems engineering and integration, and nurturing a learning culture that continually benchmarks its performance against successful ventures. As this paper will explain, the SLS is making measurable progress toward becoming a global infrastructure asset for robotic and human scouts of all nations by harnessing business and technological innovations to deliver sustainable solutions for space exploration.

May, Todd↗
NASA NTRS2012

NASA's Space Launch System Advanced Booster Engineering Demonstration and Risk Reduction Efforts

The National Aeronautics and Space Administration (NASA) formally initiated the Space Launch System (SLS) development in September 2011, with the approval of the program s acquisition plan, which engages the current workforce and infrastructure to deliver an initial 70 metric ton (t) SLS capability in 2017, while using planned block upgrades to evolve to a full 130 t capability after 2021. A key component of the acquisition plan is a three-phased approach for the first stage boosters. The first phase is to complete the development of the Ares and Space Shuttle heritage 5-segment solid rocket boosters for initial exploration missions in 2017 and 2021. The second phase in the booster acquisition plan is the Advanced Booster Risk Reduction and/or Engineering Demonstration NASA Research Announcement (NRA), which was recently awarded after a full and open competition. The NRA was released to industry on February 9, 2012, and its stated intent was to reduce risks leading to an affordable Advanced Booster and to enable competition. The third and final phase will be a full and open competition for Design, Development, Test, and Evaluation (DDT&E) of the Advanced Boosters. There are no existing boosters that can meet the performance requirements for the 130 t class SLS. The expected thrust class of the Advanced Boosters is potentially double the current 5-segment solid rocket booster capability. These new boosters will enable the flexible path approach to space exploration beyond Earth orbit, opening up vast opportunities including near-Earth asteroids, Lagrange Points, and Mars. This evolved capability offers large volume for science missions and payloads, will be modular and flexible, and will be right-sized for mission requirements. NASA developed the Advanced Booster Engineering Demonstration and/or Risk Reduction NRA to seek industry participation in reducing risks leading to an affordable Advanced Booster that meets the SLS performance requirements. Demonstrations and/or risk reduction efforts were required to be related to a proposed booster concept directly applicable to fielding an Advanced Booster. This paper will discuss, for the first time publicly, the contract awards and how NASA intends to use the data from these efforts to prepare for the planned Advanced Booster DDT&E acquisition as the SLS Program moves forward with competitively procured affordable performance enhancements.

Crumbly, Christopher M.↗
NASA NTRS2008

Dawn: Cooperation, not Control

On September 27, 2007, a Delta II rocket carrying the Dawn spacecraft lifted off from Kennedy Space Center. Part of NASAs Discovery program, the $370 million Dawn mission began its three-billion-mile voyage to the asteroid belt to study the asteroid Vesta and Ceres, a dwarf planet. The spacecraft is scheduled to reach Vesta in 2011. After spending nine months measuring the composition, shape, and topography of that body, it will travel a billion miles to carry out a similar analysis of Ceres in 2015. The Important Lessons: The demands of Dawn and other challenging missions have taught some important lessons for successful program and project management. These are the main ones: a) Program management, particularly of uncoupled and loosely coupled projects, should be more about enabling than controlling. You're working with motivated, high-performing teams and institutions with a track record of quality and success. Emphasize commander's intent over rudder control; let them know where you want to go and when you want to be there, then let them figure out how to get there. b) Open and honest discussion of issues is essential. People fill the void of the unknown with their worst fears. Get folks around the table and have open, honest, and frank dialogue. I've seldom seen this fail to get to the root of issues. c) You have to earn your seat at the table, proving that you are competent, trustworthy, and dedicated to the success of the mission. d) Know when to fold 'em. Your pride can get rolled up in making a milestone or launch date, but you have to make a judgment based on the realities of the situation and not wear down the team trying to meet an increasingly impossible deadline. e) The NASA governance model that gives a voice to the concerns of engineers and safety experts works-trust it and use it.

May, Todd↗
NASA NTRS2003

Gravity Probe B: Testing Einstein with Gyroscopes

Some 40 years in the making, NASA' s historic Gravity Probe B (GP-B) mission is scheduled to launch aboard a Delta II in 2003. GP-B will test two extraordinary predictions from Einstein's General Relativity: geodetic precession and the Lense-Thirring effect (frame-dragging). Employing tiny, ultra-precise gyroscopes, GP-B features a measurement accuracy of 0.5 milli-arc-seconds per year. The extraordinary measurement precision is made possible by a host of breakthrough technologies, including electro-statically suspended, super-conducting quartz gyroscopes; virtual elimination of magnetic flux; a solid quartz star tracking telescope; helium microthrusters for drag-free control of the spacecraft; and a 2400 liter superfluid helium dewar. This paper will provide an overview of the science, key technologies, flight hardware, integration and test, and flight operations of the GP-B space vehicle. It will also examine some of the technical management challenges of a large-scale, technology-driven, Principal Investigator-led mission.

Geveden, Rex D.↗
NASA NTRS2003

Gravity Probe B: Testing Einstein with Gyroscopes

Some 40 years in the making, NASA s historic Gravity Probe B (GP-B) mission is scheduled to launch aboard a Delta I1 in 2003. GP-B will test two extraordinary predictions from Einstein s General Relativity: geodetic precession and the Lense-Thirring effect (frame-dragging). Employing tiny, ultra-precise gyroscopes, GP-B features a measurement accuracy of 0.5 milli-arc-seconds per year. The extraordinary measurement precision is made possible by a host of breakthrough technologies, including electro-statically suspended, super-conducting quartz gyroscopes; virtual elimination of magnetic flux; a solid quartz star- tracking telescope; helium microthrusters for drag-free control of the spacecraft; and a 2400 liter superfluid helium dewar. This paper will provide an overview of the science, key technologies, flight hardware, integration and test, and flight operations of the GP-B space vehicle. It will also examine some of the technical management challenges of a large-scale, technology-driven, Principal Investigator-led mission.

Geveden, Rex D.↗
NASA NTRS1997

Joint US/Russian testing for track propagation

The power thresholds below which track propagation does not occur were determined in Russian spacecraft. The tests were performed in air and vacuum with direct current on different insulation and sample configurations. The examined wire insulations included 100 percent polyimide, modified polyimide-based insulations containing 7 to 8 percent and 100 percent polytetrafluoroethylene. The wires were tested in configurations consisting of seven-wire bundles. The results indicated that the track propagation thresholds were lower in vacuum than in air.

Hirsch, David↗
NASA NTRS1995

International space station wire program

Hardware provider wire systems and current wire insulation issues for the International Space Station (ISS) program are discussed in this viewgraph presentation. Wire insulation issues include silicone wire contamination, Tefzel cold temperature flexibility, and Russian polyimide wire insulation. ISS is a complex program with hardware developed and managed by many countries and hundreds of contractors. Most of the obvious wire insulation issues are known by contractors and have been precluded by proper selection.

May, Todd↗