214 research outputs found
Highly reusable space transportation: Approaches for reducing ETO launch costs to 200 per pound of payload
The Commercial Space Transportation Study (CSTS) suggests that considerable market expansion in earth-to-orbit transportation would take place if current launch prices could be reduced to around 100-100-$200 per pound of payload will require significant coordinated efforts in (1) marketing strategy development, (2) business planning, (3) system operational strategy, (4) vehicle technical design, and (5) vehicle maintenance strategy
Highly Reusable Space Transportation System Concept Evaluation (The Argus Launch Vehicle)
This paper summarizes the results of a conceptual design study that was performed in support of NASA's recent Highly Reusable Space Transportation study. The Argus concept uses a Maglifter magnetic-levitation sled launch assist system to accelerate it to a takeoff ground speed of 800 fps on its way to delivering a payload of 20,000 lb. to low earth orbit. Main propulsion is provided by two supercharged ejector rocket engines. The vehicle is autonomous and is fully reusable. A conceptual design exercise determined the vehicle gross weight to be approximately 597,250 lb. and the dry weight to be 75,500 lb. Aggressive weight and operations cost assumptions were used throughout the design process consistent with a second-generation reusable system that might be deployed in 10-15 years. Drawings, geometry, and weight of the concept are included. Preliminary development, production, and operations costs along with a business scenario assuming a price-elastic payload market are also included. A fleet of three Argus launch vehicles flying a total of 149 flights per year is shown to have a financial internal rate of return of 28%. At 100/lb.-$200/lb., but optimum market price results in only a factor of two to five reduction compared to today's launch systems
Characterizing High-Energy-Density Propellants for Space Propulsion Apllications
57th International Astronautical Congress
October 2006, Valencia, Spain.A technique for determining the thermophysical properties of high-energy-density matter (HEDM) propellants is presented. HEDM compounds are of interest in the liquid rocket engine industry due to their high density and high energy content relative to existing industry standard propellants (liquid hydrogen, kerosene, and hydrazine). In order to model rocket engine performance, cost, and weight in a conceptual design environment, several thermodynamic and physical properties are needed. These properties include enthalpy, entropy, density, viscosity, and thermal conductivity. These properties need to be known over a wide range of temperature and pressure. A technique using a combination of quantum mechanics and molecular dynamics is used to determine these properties for quadricyclane, a HEDM compound of interest. Good agreement is shown with experimentally measured thermophysical properties. A vehicle case study is provided to quantify the system level benefits of using quadricyclane instead of hydrazine for the lunar lander ascent stage of the Exploration Systems Architecture Study. The results show that the use of HEDM propellants can significantly reduce the lunar lander mass and indicate that HEDM propellants are an attractive technology to pursue for future lunar missions
Responsive Access Small Cargo Affordable Launch (RASCAL) Independent Performance Evaluation
13th International Space Planes and Hypersonics Systems and Technologies Conference
May 2005, Capua, ItalyRASCAL is a United States Defense Department initiative that stands for Responsive
Access, Small Cargo, Affordable Launch. The overall launch concept involves three stages.
The first stage will consist of a reusable aircraft similar to a large scale Air Force fighter.
The first stage will also utilize Mass Injection Pre-Compressor Cooling (MIPCC) turbojet
engines that will propel the stage to approximately two hundred thousand feet before
releasing the second and third rocket stages. The first stage will be similar to a large fighter
of the F-22 class, although the turbofans will be that of the more available F100 class. The
MIPCC system will be a plug-in addition to the engines to help high altitude performance.
This stage will act as a first stage in the RASCAL architecture and will contribute
significantly to the overall acceleration of the vehicle. The second and third stages of the
RASCAL concept consist of expendable rockets. Releasing the upper stages outside the
atmosphere will reduce the loads on the stages as well as the risk of staging. Also by relying
on the reusable portion for all atmospheric flight, the expendable stages can be designed
simpler and therefore cheaper.
The purpose of this project is to compare the published RASCAL numbers with those
computed using a design methodology currently used in the Space System Design
Laboratory (SSDL) at The Georgia Institute of Technology. When the initial Space Launch
Corporation design was evaluated using the SSDL methodology it was found to fall short of
the performance as well as the cost goals set by DARPA for the RASCAL program. The
baseline vehicle was found to only carry 52 lbs to the 270 nmi sun synchronous orbit. Several
alternatives were evaluated off of the baseline design. The best of these alternatives can
meet DARPA’s performance goals and reach the cost goals of $5,000 per pound of payload
with eight first stage vehicles flying 46 times per year for a total of 363 flights per year.
Different economic cases were also evaluated to try and meet the cost goals in a less
ambitious number of flights per year. It was found that if the DDT&E was paid for by
another party (NASA, DOD, etc.) the cost goals can be met with just three vehicles flying 42
times per year for a total of 125 flights per year
Technology Estimating: A Process to Determine the Cost and Schedule of Space Technology Research and Development
NASA is investing in new technologies that include 14 primary technology roadmap areas, and aeronautics. Understanding the cost for research and development of these technologies and the time it takes to increase the maturity of the technology is important to the support of the ongoing and future NASA missions. Overall, technology estimating may help provide guidance to technology investment strategies to help improve evaluation of technology affordability, and aid in decision support. The research provides a summary of the framework development of a Technology Estimating process where four technology roadmap areas were selected to be studied. The framework includes definition of terms, discussion for narrowing the focus from 14 NASA Technology Roadmap areas to four, and further refinement to include technologies, TRL range of 2 to 6. Included in this paper is a discussion to address the evaluation of 20 unique technology parameters that were initially identified, evaluated and then subsequently reduced for use in characterizing these technologies. A discussion of data acquisition effort and criteria established for data quality are provided. The findings obtained during the research included gaps identified, and a description of a spreadsheet-based estimating tool initiated as a part of the Technology Estimating process
Results From Australia’s 2016 Report Card on Physical Activity for Children and Youth
Background:
Two years on from the inaugural Active Healthy Kids Australia (AHKA) Physical Activity Report Card, there has been little to no change with the majority of Australian children still insufficiently active. Methods:
The 2016 AHKA Report Card was developed using the best available national- and state-based physical activity data, which were evaluated by the AHKA Research Working Group using predetermined weighting criteria and benchmarks to assign letter grades to the 12 Report Card indicators. Results:
In comparison with 2014, Overall Physical Activity Levels was again assigned a D- with Organized Sport and Physical Activity Participation increasing to a B (was B-) and Active Transport declining to a C- (was C). The settings and sources of influence again performed well (A- to a C+), however Government Strategies and Investments saw a decline (C+ to a D). The traits associated with physical activity were also graded poorly (C- to a D). Conclusions:
Australian youth are insufficiently active and engage in high levels of screen-based sedentary behaviors. While a range of support structures exist, Australia lacks an overarching National Physical Activity Plan that would unify the country and encourage the cultural shift needed to face the inactivity crisis head on
Chimera: A Low Cost Solution to Small Satellite Space Access
In the Proceedings of the 17th Annual AIAA/USU Conference on Small Satellites, UT State University
Logan, UT, August 11 -14, 2003.The Chimera rocket was designed to enter the
small satellite market by offering an affordable and
flexible alternative to the Pegasus launch vehicle. A
number of design concepts were evaluated, and one
was selected to undergo detailed analysis. This
included disciplinary analyses in aerodynamics,
propulsion, trajectory, aeroheating, structures,
weights, operations, and cost. The baseline vehicle,
consisting of a Minuteman 2-2 first stage, a PAM-S
second stage, and a new third stage carries a 100 and
50 kg payload to a 700 km altitude, at inclinations of
60° and 110° respectively. At this point a Monte
Carlo Simulation was performed to determine how
well the system met its price goals. The baseline
vehicle fails to meet the desired launch price of $5
million to a reasonable confidence level. However,
either the implementation of a cost reduction in the
cost of the first stage, or the infusion of appropriate
structural and propellant technologies in the design of
the third stage, help to make the desired launch price
viable
Pointing effects and their consequences for Spitzer IRAC exoplanet observations
Spitzer observations of exoplanets routinely yield accuracies of better than one part in 10,000. However, there remain a number of issues that limit the attainable precision, particularly for long duration observations. These include initial pointing inaccuracies, pointing wobble, initial target drift, long-term pointing drifts, and low and high frequency jitter. Coupled with small scale, intrapixel sensitivity variations, all of these pointing issues have the potential to produce significant, correlated photometric noise. We examine each of these issues in turn, discussing their suspected causes and consequences, and describing possible and planned mitigation techniques
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