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NASA NTRS2016

NASA's Space Launch System: Development and Progress

NASA is embarked on a new era of space exploration that will lead to new capabilities, new destinations, and new discoveries by both human and robotic explorers. Today, the International Space Station (ISS), supported by NASA's commercial partners, and robotic probes, are yielding knowledge that will help make this exploration possible. NASA is developing both the Orion crew vehicle and the Space Launch System (SLS) that will carry out a series of increasingly challenging missions that will eventually lead to human exploration of Mars. This paper will discuss the development and progress on the SLS. The SLS architecture was designed to be safe, affordable, and sustainable. The current configuration is the result of literally thousands of trade studies involving cost, performance, mission requirements, and other metrics. The initial configuration of SLS, designated Block 1, will launch a minimum of 70 metric tons (t) into low Earth orbit - significantly greater capability than any current launch vehicle. It is designed to evolve to a capability of 130 t through the use of upgraded main engines, advanced boosters, and a new upper stage. With more payload mass and volume capability than any rocket in history, SLS offers mission planners larger payloads, faster trip times, simpler design, shorter design cycles, and greater opportunity for mission success. Since the program was officially created in fall 2011, it has made significant progress toward first launch readiness of the Block 1 vehicle in 2018. Every major element of SLS continued to make significant progress in 2015. The Boosters element fired Qualification Motor 1 (QM-1) in March 2015, to test the 5-segment motor, including new insulation, joint, and propellant grain designs. The Stages element marked the completion of more than 70 major components of test article and flight core stage tanks. The Liquid Engines element conducted seven test firings of an RS-25 engine under SLS conditions. The Spacecraft/Payload Integration and Evolution element marked completion of the upper stage test article. Major work continues in 2016 as the program continues both flight and development RS-25 engine testing, begins welding test article and flight core stage tanks, completes stage adapter manufacturing, and test fires the second booster qualification motor. This paper will discuss the program's key accomplishments to date and the challenging work ahead for what will be the world's most capable launch vehicle.

Honeycutt, John↗

NASA NTRS2016

Evaluation of Skin Friction Drag for Liner Applications in Aircraft

A parameter that is gaining significance in the evaluation of acoustic liner performance is the skin friction drag induced by air flow over the liner surface. Estimates vary widely regarding the amount of drag the liner induces relative to a smooth wall, from less than a 20% increase to nearly 100%, and parameters such as face sheet perforate hole diameter, percent open area, and sheet thickness are expected to figure prominently in the skin friction drag. Even a small increase in liner drag can impose an economic penalty, and current research is focused on developing 'low drag' liner concepts, with the goal being to approach the skin friction drag of a smooth wall. The issue of skin friction drag takes on greater significance as airframe designers investigate the feasibility of putting sound absorbing liners on the non-lifting surfaces of the wings and fuselage, for the purpose of reducing engine noise reflected and scattered toward observers on the ground. Researchers at the NASA Langley Research Center have embarked on investigations of liner skin friction drag with the aims of: developing a systematic drag measurement capability, establishing the drag of current liners, and developing liners that produce reduced drag without compromising acoustic performance. This paper discusses the experimental procedures that have been developed to calculate the drag coefficient based on the change in momentum thickness and the companion research program being carried out to measure the drag directly using a force balance. Liner samples that are evaluated include a solid wall with known roughness and conventional liners with perforated facesheets of varying hole diameter and percent open area.

Gerhold, Carl H.↗

NASA NTRS2014

Skirting Saturn's Rings and Skimming Its Cloud Tops: Planning Cassini's End of Mission

In October 2010, the Cassini spacecraft embarked on the seven-year Solstice Mission. The mission will culminate with a spectacular series of orbits that bring Cassini between Saturn's innermost ring, the D ring, and the cloud tops of the planet. The spacecraft will make its closest passages ever to the planet allowing for unprecedented science to be collected on Saturn and its rings. These final orbits will expose the spacecraft to new environments, which presents a number of challenges to planning the final mission phase. While these challenges will require adaptations to planning processes and operations, they are not insurmountable. This paper describes the challenges identified and the steps taken to mitigate them to enable collection of unique Saturn system science.

Manor-Chapman, Emily↗

NASA NTRS2014

Using AUTORAD for Cassini File Uplinks: Incorporating Automated Commanding into Mission Operations

As the Cassini spacecraft embarked on the Solstice Mission in October 2010, the flight operations team faced a significant challenge in planning and executing the continuing tour of the Saturnian system. Faced with budget cuts that reduced the science and engineering staff by over a third in size, new and streamlined processes had to be developed to allow the Cassini mission to maintain a high level of science data return with a lower amount of available resources while still minimizing the risk. Automation was deemed an important key in enabling mission operations with reduced workforce and the Cassini flight team has made this goal a priority for the Solstice Mission. The operations team learned about a utility called AUTORAD which would give the flight operations team the ability to program selected command files for radiation up to seven days in advance and help minimize the need for off-shift support that could deplete available staffing during the prime shift hours. This paper will describe how AUTORAD is being utilized by the Cassini flight operations team and the processes that were developed or modified to ensure that proper oversight and verification is maintained in the generation and execution of radiated command files.

Goo, Sherwin↗

NASA NTRS2016

Investigation of Secondary Neutron Production in Large Space Vehicles for Deep Space

Future NASA missions will focus on deep space and Mars surface operations with large structures necessary for transportation of crew and cargo. In addition to the challenges of manufacturing these large structures, there are added challenges from the space radiation environment and its impacts on the crew, electronics, and vehicle materials. Primary radiation from the sun (solar particle events) and from outside the solar system (galactic cosmic rays) interact with materials of the vehicle and the elements inside the vehicle. These interactions lead to the primary radiation being absorbed or producing secondary radiation (primarily neutrons). With all vehicles, the high-energy primary radiation is of most concern. However, with larger vehicles, there is more opportunity for secondary radiation production, which can be significant enough to cause concern. In a previous paper, we embarked upon our first steps toward studying neutron production from large vehicles by validating our radiation transport codes for neutron environments against flight data. The following paper will extend the previous work to focus on the deep space environment and the resulting neutron flux from large vehicles in this deep space environment.

Rojdev, Kristina↗

NASA NTRS1971

Skylab: Program Description

In 1973 three Americans will embark on the first of a series of Earth orbiting missions using Skylab, the first United States vehicle created specifically to enable man to live and work in space for extended periods. Sky lab is a program dedicated to the use of space and its unique environment and vantage point to increase our knowledge and understanding of the Earth's importance to man's well-being and man's influence on Earth's ecology. Sky lab will also be a major step in manned space flight. Habitation by the first crew will double our previous man-in-space duration (Gemini VII) and the second visit will redouble that duration. It will, in effect, create a bridge between the development flights of the 60s and the long duration operational space flights of the future. To accomplish its mission, Sky lab will be placed in Earth orbit and will be visited and inhabited by three different crews during an eight-month period. While successfully inhabiting and operating the vehicle for one- and two-month continuous periods, these crews will obtain data in areas pertinent to the man/Earth relationship and to long duration space flight. Data will be acquired by Skylab primarily through the conduct of "experiments." Four categories of investigation are planned. These are summarized in the following paragraphs.

Source record↗

NASA NTRS2016

Predictive Evaluations of Oxygen-Rich Hydrocarbon Combustion Gas-Centered Swirl Coaxial Injectors using a Flamelet-Based 3-D CFD Simulation Approach

NASA Marshall Space Flight Center (MSFC) has embarked upon a joint project with the Air Force to improve the state-of-the-art of space application combustion device design and operational understanding. One goal of the project is to design, build and hot-fire test a 40,000 pound-thrust Oxygen/Rocket Propellant-2 (RP-2) Oxygen-Rich staged engine at MSFC. The overall project goals afford the opportunity to test multiple different injector designs and experimentally evaluate the any effect on the engine performance and combustion dynamics. To maximize the available test resources and benefits, pre-test, combusting flow, Computational Fluid Dynamics (CFD) analysis was performed on the individual injectors to guide the design. The results of the CFD analysis were used to design the injectors for specific, targeted fluid dynamic features and the analysis results also provided some predictive input for acoustic and thermal analysis of the main Thrust Chamber Assembly (TCA). MSFC has developed and demonstrated the ability to utilize a computationally efficient, flamelet-based combustion model to guide the pre-test design of single-element Gas Centered Swirl Coaxial (GCSC) injectors. Previous, Oxygen/RP-2 simulation models utilizing the Loci-STREAM flow solver, were validated using single injector test data from the EC-1 Air Force test facility. The simulation effort herein is an extension of the validated, CFD driven, single-injector design approach applied to single injectors which will be part of a larger engine array. Time-accurate, Three-Dimensional, CFD simulations were performed for five different classes of injector geometries. Simulations were performed to guide the design of the injector to achieve a variety of intended performance goals. For example, two GCSC injectors were designed to achieve stable hydrodynamic behavior of the propellant circuits while providing the largest thermal margin possible within the design envelope. While another injector was designed to purposefully create a hydrodynamic instability in the fuel supply circuit as predicted by the CFD analysis. Future multi-injector analysis and testing will indicate what if any changes occur in the predicted behavior for the single-element injector when the same injector geometry is placed in a multi-element array.

Richardson, Brian R.↗

NASA NTRS2017

Lessons Learned from OSIRIS-Rex Autonomous Navigation Using Natural Feature Tracking

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (Osiris-REx) spacecraft is scheduled to launch in September, 2016 to embark on an asteroid sample return mission. It is expected to rendezvous with the asteroid, Bennu, navigate to the surface, collect a sample (July 20), and return the sample to Earth (September 23). The original mission design called for using one of two Flash Lidar units to provide autonomous navigation to the surface. Following Preliminary design and initial development of the Lidars, reliability issues with the hardware and test program prompted the project to begin development of an alternative navigation technique to be used as a backup to the Lidar. At the critical design review, Natural Feature Tracking (NFT) was added to the mission. NFT is an onboard optical navigation system that compares observed images to a set of asteroid terrain models which are rendered in real-time from a catalog stored in memory on the flight computer. Onboard knowledge of the spacecraft state is then updated by a Kalman filter using the measured residuals between the rendered reference images and the actual observed images. The asteroid terrain models used by NFT are built from a shape model generated from observations collected during earlier phases of the mission and include both terrain shape and albedo information about the asteroid surface. As a result, the success of NFT is highly dependent on selecting a set of topographic features that can be both identified during descent as well as reliably rendered using the shape model data available. During development, the OSIRIS-REx team faced significant challenges in developing a process conducive to robust operation. This was especially true for terrain models to be used as the spacecraft gets close to the asteroid and higher fidelity models are required for reliable image correlation. This paper will present some of the challenges and lessons learned from the development of the NFT system which includes not just the flight hardware and software but the development of the terrain models used to generate the onboard rendered images.

Navigation↗

NASA NTRS2016

Tribological Studies of Dynamic Thermal Seal Materials

Thermal seals are required on high-speed vehicles in many dynamic applications such as variable inlets in propulsion systems and control surfaces. These seals, often referred to as dynamic thermal seals, must not only mitigate inboard heat transfer, but must also exhibit sufficient durability when scrubbed against mating surfaces. For high-temperature high-speed vehicle applications, the mating surfaces are often made from thermal protection system (TPS) materials, which are typically rougher and more abrasive than TPS materials used at lower temperatures. The high-temperature TPS materials used can include non-ablative (e.g., lightweight porous oxides, ceramic matrix composites) andor ablative systems (e.g., phenolic systems). Due to the increased need for durable high-temperature dynamic seals, researchers working with the NASA Glenn Research Center embarked on an effort to (a) characterize the tribological performance of state-of-the-art thermal seal materials against a variety of TPS materials and (b) develop approaches for improved wear resistance. Tests were conducted using a recently upgraded high-temperature tribometer to assess wear resistance for a variety of tribopairs under multiple conditions. This data will begin to frame the challenges of using these materials and eventually permit an improved ability to design and implement these critical TPS components.

thermal protection↗

NASA NTRS2017

Development of Reliable Life Support Systems

The life support systems on the International Space Station (ISS) are the culmination of an extensive effort encompassing development, design, and test to provide the highest possible confidence in their operation on ISS. Many years of development testing are initially performed to identify the optimum technology and the optimum operational approach. The success of this development program depends on the accuracy of the system interfaces. The critical interfaces include the specific operational environment, the composition of the waste stream to be processed and the quality of the product. Once the development program is complete, a detailed system schematic is built based on the specific design requirements, followed by component procurement, assembly, and acceptance testing. A successful acceptance test again depends on accurately simulating the anticipated environment on ISS. The ISS Water Recovery System (WRS) provides an excellent example of where this process worked, as well as lessons learned that can be applied to the success of future missions. More importantly, ISS has provided a test bed to identify these design issues. Mechanical design issues have included an unreliable harmonic drive train in the Urine Processor's fluids pump, and seals in the Water Processor's Catalytic Reactor with insufficient life at the operational temperature. Systems issues have included elevated calcium in crew urine (due to microgravity effect) that resulted in precipitation at the desired water recovery rate, and the presence of an organosilicon compound (dimethylsilanediol) in the condensate that is not well removed by the water treatment process. Modifications to the WRS to address these issues are either complete (and now being evaluated on ISS) or are currently in work to insure the WRS has the required reliability before embarking on a mission to Mars.

Carter, Layne↗

NASA NTRS2017

Coping with Higher Sea Levels and Increased Coastal Flooding in New York City

The 837 km New York City shoreline is lined by significant economic assets and dense population vulnerable to sea level rise and coastal flooding. After Hurricane Sandy in 2012, New York City developed a comprehensive plan to mitigate future climate risks, drawing upon the scientific expertise of the New York City Panel on Climate Change (NPCC), a special advisory group comprised of university and private-sector experts. This paper highlights current NPCC findings regarding sea level rise and coastal flooding, with some of the City's ongoing and planned responses. Twentieth century sea level rise in New York City (2.8 cm/decade) exceeded the global average (1.7 cm/decade), underscoring the enhanced regional risk to coastal hazards. NPCC (2015) projects future sea level rise at the Battery of 28 - 53 cm by the 2050s and 46 - 99 cm by the 2080s, relative to 2000 - 2004 (mid-range, 25th - 75th percentile). High-end SLR estimates (90th percentile) reach 76 cm by the 2050s, and 1.9 m by 2100. Combining these projections with updated FEMA flood return period curves, assuming static flood dynamics and storm behavior, flood heights for the 100-year storm (excluding waves) attain 3.9-4.5 m (mid-range), relative to the NAVD88 tidal datum, and 4.9 m (high end) by the 2080s, up from 3.4 m in the 2000s. Flood heights with a 1% annual chance of occurrence in the 2000s increase to 2.0 - 5.4% (mid-range) and 12.7% per year (high-end), by the 2080s. Guided by NPCC (2013, 2015) findings, New York City has embarked on a suite of initiatives to strengthen coastal defenses, employing various approaches tailored to specific neighborhood needs. NPCC continues its collaboration with the city to investigate vulnerability to extreme climate events, including heat waves, inland floods and coastal storms. Current research entails higher-resolution neighborhood-level coastal flood mapping, changes in storm characteristics, surge height interactions with sea level rise, and stronger engagement with stakeholders and community-based organizations.

Coastal flooding↗

NASA NTRS2017

Development of Reliable Life Support Systems

Carter, Layne↗

NASA NTRS2017

Investigation of Desiccants and CO2 Sorbents for Exploration Systems 2016-2017

NASA has embarked on the mission to enable humans to explore deep space, including the goal of sending humans to Mars. This journey will require significant developments in a wide range of technical areas as resupply and early return are not possible. Additionally, mass, power, and volume must be minimized for all phases to maximize propulsion availability. Among the critical areas identified for development are life support systems, which will require increases in reliability as well as reduce resource usage. Two primary points for reliability are the mechanical stability of sorbent pellets and recovery of CO2 sorbent productivity after off-nominal events. In this paper, we discuss the present efforts towards screening and characterizing commercially-available sorbents for extended operation in desiccant and CO2 removal beds. With minimized dusting as the primary criteria, a commercial 13X zeolite was selected and tested for performance and risk.

Knox, James C.↗

NASA NTRS2017

Development of Carbon Dioxide Removal Systems for NASA's Deep Space Human Exploration Missions 2016-2017

NASA has embarked on an endeavor that will enable humans to explore deep space, with the ultimate goal of sending humans to Mars. This journey will require significant developments in a wide range of technical areas, as resupply is unavailable in the Mars transit phase and early return is not possible. Additionally, mass, power, volume, and other resources must be minimized for all subsystems to reduce propulsion needs. Among the critical areas identified for development are life support systems, which will require increases in reliability and reductions in resources. This paper discusses current and planned developments in the area of carbon dioxide removal to support crewed Mars-class missions.

Knox, James C.↗

NASA NTRS2008

The Apollo Experience Lessons Learned for Constellation Lunar Dust Management

In 2008, NASA was embarking on its Exploration Vision, knowing that many technical challenges would be encountered. For lunar exploration missions, one challenge was to learn to manage lunar dust. References to problems associated with lunar dust during the Apollo Program were found on many of pages of the mission reports and technical debriefs. All engineers designing hardware that would come into contact with lunar dust had to mitigate its effects in the design.

Wagner, Sandra↗

NASA NTRS2006

Foundations of Supply Chain Management for Space Application

Supply Chain Management (SCM) is a key piece of the framework for America's space technology investment as the National Aeronautics and Space Administration (NASA), the aerospace industry, and international partners embark on a bold new vision of human and robotic space exploration beyond Low-Earth-Orbit (LEO). This type of investment is driven by the Agency's need for cost efficient operational support associated with, processing and operating space vehicles and address many of the biggest operational challenge including extremely tight funding profiles, seamless program-to-program transition activities and the reduction of the time gap with human spaceflight capabilities in the post-Shuttle era. An investment of this magnitude is a multiyear task and must include new patterns of thought within the engineering community to respect the importance of SCM and the integration of the material and information flow. Experience within the Department of Defense and commercial sectors which has shown that support cost reductions and or avoidances of upwards to 35% over business as usual are achievable. It is SCM that will ultimately bring the solar system within the economic sphere of our society.

supply chain managemen↗

NASA NTRS2017

Centrifuge in Free Fall: Combustion at Partial Gravity

A centrifuge apparatus is developed to study the effect of variable acceleration levels in a drop tower environment. It consists of a large rotating chamber, within which the experiment is conducted. NASA Glenn Research Center 5.18-second Zero-Gravity Facility drop tests were successfully conducted at rotation rates up to 1 RPS with no measurable effect on the overall Zero-Gravity drop bus. Arbitrary simulated gravity levels from zero to 1-g (at a radius of rotation 30 cm) were produced. A simple combustion experiment was used to exercise the capabilities of the centrifuge. A total of 23 drops burning a simulated candle with heptane and ethanol fuel were performed. The effect of gravity level (rotation rate) and Coriolis force on the flames was observed. Flames became longer, narrower, and brighter as gravity increased. The Coriolis force tended to tilt the flames to one side, as expected, especially as the rotation rate was increased. The Zero-Gravity Centrifuge can be a useful tool for other researchers interested in the effects of arbitrary partial gravity on experiments, especially as NASA embarks on future missions which may be conducted in non-Earth gravity.

microgravity↗

NASA NTRS2017

Exospheric Escape: A Parametrical Study

The study of exospheres can help us understand the long-term loss of volatiles from planetary bodies due to interactions of planets, satellites, and small bodies with the interplanetary medium, solar radiation, and internal forces including diffusion and outgassing. Recent evidence for water and OH on the Moon has spurred interest in processes involving chemistry and sequestration of volatile species at the poles and in voids. In recent years, NASA has sent spacecraft to asteroids including Vesta and Ceres, and ESA sent Rosetta to comet 67P/Churyumov-Gerasimenko and the asteroids Lutetia and Steins. Japan's Hayabusa spacecraft returned a sample from asteroid Itakowa, and OSIRIS-REX will return a sample from a primitive asteroid, Bennu, to Earth. In a surface-bounded exosphere, the gases are derived from the surface and thus reflect the composition of the body's regolith, although not in a one-to-one ratio. Observation of an escaping exosphere, termed a corona, is challenging. We have therefore embarked on a parametrical study of exospheres as a function of mass of the exospheric species, mass of the primary body and source velocity distribution, specifically thermal (Maxwell-Boltzmann) and sputtering. The goal is to provide a quick look to determine under what conditions and for what mass of the primary body the species of interest are expected to be bound or escaping and to quickly estimate the observability of exospheric species. This work does not provide a comprehensive model but rather serves as a starting point for further study. These parameters will be useful for mission planning as well as for students beginning a study of planetary exospheres.

Volatilels↗