Effect of Wean-to-Finish Management on Pig Performance

An experiment consisting of three trials was conducted to determine the effect of wean-to-finish management systems on pig performance. Treatments consisted of: 1) wean-to-finish single stock (WF) at 7.5 ft2/pig from weaning (17 day mean age) to slaughter in a fully slatted finishing facility; 2) double stock (DS) at 3.75 ft2/pig for eight weeks following weaning and then split into two pens at 7.5 ft2/pig each; and 3) nursery (NF) at 3.75 ft2/ pig for eight weeks in a conventional nursery followed by movement to the finisher and stocked at 7.5 ft2/pig to slaughter. All pens had one two-hole wean-finish dry feeder per 15 pigs and one cup-drinker per 15 pigs. While there were health related performance problems in Trials 1 and 2 due to PRRS, there were no trial by treatment interactions. At the end of eight weeks, WF pigs were heavier (P\u3c.01) than DS pigs with NF pigs intermediate in weight (63.1, 59.2, and 60.9 lbs, respectively). The heavier weight was due to a difference (P\u3c.01) in feed intake between the WF and DS treatments. There was no effect of nursery phase treatment on feed efficiency. There was no effect (P\u3e.1) of any management treatment on any grow-finish phase production parameter reported. These data suggest that the performance improvement associated with wean–to-finish production systems occurs during the first eight weeks post-weaning. They also suggest that the response can be expected even when health challenges occur in a production system

Effect of Wean-to-Finish Management on Pig Performance

An experiment consisting of three trials was conducted to determine the effect of wean-to-finish management systems on pig performance. Treatments consisted of: 1) wean-to-finish single stock (WF) at 7.5 ft2/pig from weaning (17 day mean age) to slaughter in a fully slatted finishing facility; 2) double stock (DS) at 3.75 ft2/pig for eight weeks following weaning and then split into two pens at 7.5 ft2/pig each; and 3) nursery (NF) at 3.75 ft2/ pig for eight weeks in a conventional nursery followed by movement to the finisher and stocked at 7.5 ft2/pig to slaughter. All pens had one two-hole wean-finish dry feeder per 15 pigs and one cup-drinker per 15 pigs. While there were health related performance problems in Trials 1 and 2 due to PRRS, there were no trial by treatment interactions. At the end of eight weeks, WF pigs were heavier (P\u3c.01) than DS pigs with NF pigs intermediate in weight (63.1, 59.2, and 60.9 lbs, respectively). The heavier weight was due to a difference (P\u3c.01) in feed intake between the WF and DS treatments. There was no effect of nursery phase treatment on feed efficiency. There was no effect (P\u3e.1) of any management treatment on any grow-finish phase production parameter reported. These data suggest that the performance improvement associated with wean–to-finish production systems occurs during the first eight weeks post-weaning. They also suggest that the response can be expected even when health challenges occur in a production system

Modular Approach to Launch Vehicle Design Based on a Common Core Element

With a heavy lift launch vehicle as the centerpiece of our nation's next exploration architecture's infrastructure, the Advanced Concepts Office at NASA's Marshall Space Flight Center initiated a study to examine the utilization of elements derived from a heavy lift launch vehicle for other potential launch vehicle applications. The premise of this study is to take a vehicle concept, which has been optimized for Lunar Exploration, and utilize the core stage with other existing or near existing stages and boosters to determine lift capabilities for alternative missions. This approach not only yields a vehicle matrix with a wide array of capabilities, but also produces an evolutionary pathway to a vehicle family based on a minimum development and production cost approach to a launch vehicle system architecture, instead of a purely performance driven approach. The upper stages and solid rocket booster selected for this study were chosen to reflect a cross-section of: modified existing assets in the form of a modified Delta IV upper stage and Castor-type boosters; potential near term launch vehicle component designs including an Ares I upper stage and 5-segment boosters; and longer lead vehicle components such as a Shuttle External Tank diameter upper stage. The results of this approach to a modular launch system are given in this paper

Dynamic/Jitter Assessment of Multiple Potential HabEx Structural Designs

One of the driving structural requirements of the Habitable Exo-Planet (HabEx) telescope is to maintain Line Of Sight (LOS) stability between the Primary Mirror (PM) and Secondary Mirror (SM) of 5 mas. Dynamic analyses of two configurations of a proposed (HabEx) 4 meter off-axis telescope structure were performed to predict effects of jitter on primary/secondary mirror alignment. The dynamic disturbance used as the forcing function was the James Webb Space Telescope reaction wheel assembly vibration emission specification level. The objective of these analyses was to predict "order-of-magnitude" performance for various structural configurations which will roll into efforts to define the HabEx structural design's global architecture. Two variations of the basic architectural design were analyzed. Relative motion between the PM and the SM for each design configuration are reported

Reduction of Martian Sample Return Mission Launch Mass with Solar Sail Propulsion

Solar sails have the potential to provide mass and cost savings for spacecraft traveling within the innter solar system. Companies like L'Garde have demonstrated sail manufacturability and various i-space development methods. The purpose of this study was to evaluate a current Mars sample return architecture and to determine how cost and mass would be reduced by incorporating a solar sail propulsion system. The team validated the design proposed by L'Garde, and scaled the design based on a trajectory analysis. Using the solar sail design reduced the required mass, eliminating one of the three launches required in the original architecture

Reduction of Martian Sample Return Mission Launch Mass with Solar Sail Propulsion

Solar sails have the potential to provide mass and cost savings for spacecraft traveling within the inner solar system. Companies like L'Garde have demonstrated sail manufacturability and various in-space deployment methods. The purpose of this study was to evaluate a current Mars sample return architecture and to determine how cost and mass would be reduced by incorporating a solar sail propulsion system. The team validated the design proposed by L'Garde, and scaled the design based on a trajectory analysis. Using the solar sail design reduced the required mass, eliminating one of the three launches required in the original architecture

Propulsion Technology Assessment: Science and Enabling Technologies to Explore the Interstellar Medium

No abstract availabl

Propulsion Technology Assessment: Science and Enabling Technologies to Explore the Interstellar Medium

No abstract availabl

Deep Space Habitat Configurations Based On International Space Station Systems

A Deep Space Habitat (DSH) is the crew habitation module designed for long duration missions. Although humans have lived in space for many years, there has never been a habitat beyond low-Earth-orbit. As part of the Advanced Exploration Systems (AES) Habitation Project, a study was conducted to develop weightless habitat configurations using systems based on International Space Station (ISS) designs. Two mission sizes are described for a 4-crew 60-day mission, and a 4-crew 500-day mission using standard Node, Lab, and Multi-Purpose Logistics Module (MPLM) sized elements, and ISS derived habitation systems. These durations were selected to explore the lower and upper bound for the exploration missions under consideration including a range of excursions within the Earth-Moon vicinity, near earth asteroids, and Mars orbit. Current methods for sizing the mass and volume for habitats are based on mathematical models that assume the construction of a new single volume habitat. In contrast to that approach, this study explored the use of ISS designs based on existing hardware where available and construction of new hardware based on ISS designs where appropriate. Findings included a very robust design that could be reused if the DSH were assembled and based at the ISS and a transportation system were provided for its return after each mission. Mass estimates were found to be higher than mathematical models due primarily to the use of multiple ISS modules instead of one new large module, but the maturity of the designs using flight qualified systems have potential for improved cost, schedule, and risk benefits

Near Earth Object (NEO) Mitigation Options Using Exploration Technologies

This work documents the advancements in MSFC threat modeling and mitigation technology research completed since our last major publication in this field. Most of the work enclosed here are refinements of our work documented in NASA TP-2004-213089. Very long development times from start of funding (10-20 years) can be expected for any mitigation system which suggests that delaying consideration of mitigation technologies could leave the Earth in an unprotected state for a significant period of time. Fortunately there is the potential for strong synergy between architecture requirements for some threat mitigators and crewed deep space exploration. Thus planetary defense has the potential to be integrated into the current U.S. space exploration effort. The number of possible options available for protection against the NEO threat was too numerous for them to all be addressed within the study; instead, a representative selection were modeled and evaluated. A summary of the major lessons learned during this study is presented, as are recommendations for future work