Space Shuttle Day-of-Launch Trajectory Design Operations

A top priority of any launch vehicle is to insert as much mass into the desired orbit as possible. This requirement must be traded against vehicle capability in terms of dynamic control, thermal constraints, and structural margins. The vehicle is certified to specific structural limits which will yield certain performance characteristics of mass to orbit. Some limits cannot be certified generically and must be checked with each mission design. The most sensitive limits require an assessment on the day-of-launch. To further minimize vehicle loads while maximizing vehicle performance, a day-of-launch trajectory can be designed. This design is optimized according to that day s wind and atmospheric conditions, which increase the probability of launch. The day-of-launch trajectory design and verification process is critical to the vehicle s safety. The Day-Of-Launch I-Load Update (DOLILU) is the process by which the National Aeronautics and Space Administration's (NASA) Space Shuttle Program tailors the vehicle steering commands to fit that day s environmental conditions and then rigorously verifies the integrated vehicle trajectory s loads, controls, and performance. This process has been successfully used for almost twenty years and shares many of the same elements with other launch vehicles that execute a day-of-launch trajectory design or day-of-launch trajectory verification. Weather balloon data is gathered at the launch site and transmitted to the Johnson Space Center s Mission Control. The vehicle s first stage trajectory is then adjusted to the measured wind and atmosphere data. The resultant trajectory must satisfy loads and controls constraints. Additionally, these assessments statistically protect for non-observed dispersions. One such dispersion is the change in the wind from the last measured balloon to launch time. This process is started in the hours before launch and is repeated several times as the launch count proceeds. Should the trajectory design not meet all constraint criteria, Shuttle would be No-Go for launch. This Shuttle methodology is very similar to other unmanned launch vehicles. By extension, this method would likely be employed for any future NASA launch vehicle. This paper will review the Shuttle s day-of-launch trajectory optimization and verification operations as an example of a more generic application of day-of-launch design and validation. With Shuttle s retirement, it is fitting to document the current state of this critical process and capture lessons learned to benefit current and future launch vehicle endeavors

Space Shuttle Day-of-Launch Trajectory Design and Verification

A top priority of any launch vehicle is to insert as much mass into the desired orbit as possible. This requirement must be traded against vehicle capability in terms of dynamic control, thermal constraints, and structural margins. The vehicle is certified to a specific structural envelope which will yield certain performance characteristics of mass to orbit. Some envelopes cannot be certified generically and must be checked with each mission design. The most sensitive envelopes require an assessment on the day-of-launch. To further minimize vehicle loads while maximizing vehicle performance, a day-of-launch trajectory can be designed. This design is optimized according to that day s wind and atmospheric conditions, which will increase the probability of launch. The day-of-launch trajectory verification is critical to the vehicle's safety. The Day-Of-Launch I-Load Uplink (DOLILU) is the process by which the Space Shuttle Program redesigns the vehicle steering commands to fit that day's environmental conditions and then rigorously verifies the integrated vehicle trajectory's loads, controls, and performance. The Shuttle methodology is very similar to other United States unmanned launch vehicles. By extension, this method would be similar to the methods employed for any future NASA launch vehicles. This presentation will provide an overview of the Shuttle's day-of-launch trajectory optimization and verification as an example of a more generic application of dayof- launch design and validation

Magnetogasdynamic Flow Acceleration in a Scramjet Nozzle

The effect of magnetogasdynamic (MGD) interactions on flow acceleration and thrust in a scramjet accelerator/nozzle are examined numerically at a free-stream flight condition of Mach 8. The parameters of conductivity pattern and load factor are varied in both inviscid and viscous flow regimes with the intent of increasing axial force exerted on the flow through a scramjet accelerator. The numerical code solves the Navier-Stokes equations with additional source terms for the MGD forces and energy interactions. An accelerating Lorentz force is applied to the flow resulting from a constant magnetic field and an electric field produced by two continuous side wall electrodes. The specific thrust across the accelerator/nozzle is improved in the MGD solutions over the non-MGD solutions when the load factor is increased and an electron beam type ionization pattern is used. The largest increase in specific thrust is observed in viscous and inviscid flow regimes with a load factor of 1.8 producing 226% and 154% thrust increases, respectively. Flows showing increases in specific thrust with higher load factors also show significant increases in temperature due to the energy interaction term

Stowable Energy-Absorbing Rocker-Bogie Suspensions

A report discusses the design of the rocker-bogie suspensions of the Mars Exploration Rover vehicles, which were landed on Mars in January 2004. Going beyond the basic requirements regarding mobility on uneven terrain, the design had to satisfy requirements (1) to enable each suspension to contort so that the rover could be stowed within limited space in a tetrahedral lander prior to deployment and (2) that the suspension be able to absorb appreciable impact loads, with limited deflection, during egress from the lander and traversal of terrain. For stowability, six joints (three on the right, three on the left) were added to the basic rocker-bogie mechanism. One of the joints on each side was a yoke-and-clevis joint at the suspension/differential interface, one was a motorized twist joint in the forward portion of the rocker, and one was a linear joint created by modifying a fixed-length bogie member into a telescoping member. For absorption of impact, the structural members were in the form of box beams made by electron-beam welding of machined, thin-walled, C-channel, titanium components. The box beams were very lightweight and could withstand high bending and torsional loads

Personalising medicine : feasibility and future implications from a payers' perspective

There are considerable differences in how patients respond to treatments due to a number of factors calling for personalised approaches to care, which is happening. However, the early promise of personalised medicine has not always translated into improved care for patients. Payers have concerns that current tests can be costly, requests for funding specific tests have subsequently been reversed as more information becomes available, and there is currently fragmentation in the funding of diagnostic tests. Payers also have concerns that pharmaceutical companies are exploiting the situation by seeking orphan status for their new targeted medicines driving up requested prices. It is also not clear who should fund biomarkers that accompany new expensive medicines. This is changing as the cost of tests come down, and payers develop new models to optimise the managed entry of new medicines as well as evaluate potential prices for new medicines for orphan diseases. There are also developments with ‘big data’ offering new understanding of disease complexity to enhance pipeline productivity and diagnosis as well as ongoing developments with drug resistance testing and research into the role of microbiomes to improve future health. Current challenges and concerns are being addressed. This will continue to improve patient care

Implementing the Mechanistic-Empirical Pavement Design Guide: Implementation Plan

The current 1993 American Association of State Highway and Transportation Officials (AASHTO) Pavement Design Guide is based on the empirical interpretation of the results of the 1960 AASHTO Road Test. With the release of the new Mechanistic-Empirical (M-E) Pavement Design Guide, pavement design has taken a “quantum” leap forward. In order to effectively and efficiently transition to the M-E Pavement Design Guide, state DOTs need a detailed implementation and training strategy. This document is a plan for the M-E Pavement Design Guide to be implemented in Iowa

Mechanistic-Empirical Pavement Design Guide: Technical Report

With the release of the new Mechanistic-Empirical Pavement Design Guide (MEPDG), pavement design has taken a “quantum” leap forward. The current 1993 design guide is solidly based on the empirical interpretation of the results of the 1960 American Association of State Highway and Transportation Officials (AASHTO) Road Test. This report seeks to outline the technical aspects of the new MEPDG. Full detail is essentially impossible and impractical, since the release of the MEPDG was accompanied by eighteen volumes of technical justification and background. Consequently, this report seeks only to provide a potential user with a practical understanding of the workings of the new guide, with only sufficient technical depth to aid in understanding

Nurse Staffing and Deficiencies in the Largest For-Profit Nursing Home Chains and Chains Owned by Private Equity Companies

Objective To compare staffing levels and deficiencies of the 10 largest U.S. for-profit nursing home chains with five other ownership groups and chain staffing and deficiencies before and after purchase by four private equity (PE) companies. Data Sources Facilities for the largest for-profit chains were identified through Internet searches and company reports and matched with federal secondary data for 2003–2008 for each ownership group. Study Design Descriptive statistics and generalized estimation equation panel regression models examined staffing and deficiencies by ownership groups in the 2003–2008 period, controlling for facility characteristics, resident acuity, and market factors with state fixed effects. Principal Findings The top 10 for-profit chains had lower registered nurse and total nurse staffing hours than government facilities, controlling for other factors. The top 10 chains received 36 percent higher deficiencies and 41 percent higher serious deficiencies than government facilities. Other for-profit facilities also had lower staffing and higher deficiencies than government facilities. The chains purchased by PE companies showed little change in staffing levels, but the number of deficiencies and serious deficiencies increased in some postpurchase years compared with the prepurchase period. Conclusions There is a need for greater study of large for-profit chains as well as those chains purchased by PE companies.måsjekke

Effects of Modification of Pain Protocol on Incidence of Post Operative Nausea and Vomiting.

BackgroundA Perioperative Surgical Home (PSH) care model applies a standardized multidisciplinary approach to patient care using evidence-based medicine to modify and improve protocols. Analysis of patient outcome measures, such as postoperative nausea and vomiting (PONV), allows for refinement of existing protocols to improve patient care. We aim to compare the incidence of PONV in patients who underwent primary total joint arthroplasty before and after modification of our PSH pain protocol.MethodsAll total joint replacement PSH (TJR-PSH) patients who underwent primary THA (n=149) or TKA (n=212) in the study period were included. The modified protocol added a single dose of intravenous (IV) ketorolac given in the operating room and oxycodone immediate release orally instead of IV Hydromorphone in the Post Anesthesia Care Unit (PACU). The outcomes were (1) incidence of PONV and (2) average pain score in the PACU. We also examined the effect of primary anesthetic (spinal vs. GA) on these outcomes. The groups were compared using chi-square tests of proportions.ResultsThe incidence of post-operative nausea in the PACU decreased significantly with the modified protocol (27.4% vs. 38.1%, p=0.0442). There was no difference in PONV based on choice of anesthetic or procedure. Average PACU pain scores did not differ significantly between the two protocols.ConclusionSimple modifications to TJR-PSH multimodal pain management protocol, with decrease in IV narcotic use, resulted in a lower incidence of postoperative nausea, without compromising average PACU pain scores. This report demonstrates the need for continuous monitoring of PSH pathways and implementation of revisions as needed