A Practical, Affordable Cryogenic Propellant Depot Based on ULA's Flight Experience

Mankind is embarking on the next step in the journey of human exploration. We are returning to the moon and eventually moving to Mars and beyond. The current Exploration architecture seeks a balance between the need for a robust infrastructure on the lunar surface, and the performance limitations of Ares I and V. The ability to refuel or top-off propellant tanks from orbital propellant depots offers NASA the opportunity to cost effectively and reliably satisfy these opposing requirements. The ability to cache large orbital quantities of propellant is also an enabling capability for missions to Mars and beyond. This paper describes an option for a propellant depot that enables orbital refueling supporting Exploration, national security, science and other space endeavors. This proposed concept is launched using a single EELV medium class rocket and thus does not require any orbital assembly. The propellant depot provides cryogenic propellant storage that utilizes flight proven technologies augmented with technologies currently under development. The propellant depot system, propellant management, flight experience, and key technologies are also discussed. Options for refueling the propellant depot along with an overview of Exploration architecture impacts are also presented

Scholarly Needs for Text Analysis Resources: A User Assessment Study for the HathiTrust Research Center

The HathiTrust Research Center (HTRC) is undertaking a study to better understand the needs of current and potential users of the center’s tools and services for computational text analysis. In this paper, we report on the results of the first phase of the study, which consisted of interviews with scholars, administrators, and librarians whose work involves text data mining. Our study reveals that text analysis workflows are specific to the individual research project and are often nonlinear. In spite of, and in some cases because of, the wealth of textual data available, scholars find it most difficult to locate, access, and curate textual data for their research. While the goals of the study directly relate to research and development for the HTRC, our results are useful for other large-scale data providers developing solutions for allowing computational access to their content

Settled Cryogenic Propellant Transfer

Cryogenic propellant transfer can significantly benefit NASA s space exploration initiative. LMSSC parametric studies indicate that "Topping off" the Earth Departure Stage (EDS) in LEO with approx.20 mT of additional propellant using cryogenic propellant transfer increases the lunar delivered payload by 5 mT. Filling the EDS to capacity in LEO with 78 mT of propellants increases the delivered payload by 20 mT. Cryogenic propellant transfer is directly extensible to Mars exploration in that it provides propellant for the Mars Earth Departure stage and in-situ propellant utilization at Mars. To enable the significant performance increase provided by cryogenic propellant transfer, the reliability and robustness of the transfer process must be guaranteed. By utilizing low vehicle acceleration during the cryogenic transfer the operation is significantly simplified and enables the maximum use of existing, reliable, mature upper stage cryogenic-fluid-management (CFM) techniques. Due to settling, large-scale propellant transfer becomes an engineering effort, and not the technology development endeavor required with zero-gravity propellant transfer. The following key CFM technologies are all currently implemented by settling on both the Centaur and Delta IV upper stages: propellant acquisition, hardware chilldown, pressure control, and mass gauging. The key remaining technology, autonomous rendezvous and docking, is already in use by the Russians, and must be perfected for NASA whether the use of propellant transfer is utilized or not

Realistic near-term propellant depots: Implementation of a critical spacefaring capability

Orbital cryogenic propellant depots and the ability to refuel spacecraft in orbit are critical capabilities for the expansion of human life throughout the Solar System. While depots have long been recognized as an important component of large-scale manned spaceflight efforts, questions about their technology readiness have so far prevented their implementation. Technological advancements in settled cryogenic handling, passive thermal control systems, and autonomous rendezvous and docking techniques make near-term implementation of cryogenic propellant depots significantly more realistic. Current work on flight-demonstration tools like ULA\u27s CRYOTE testbed, and Masten Space Systems\u27s XA-1.0 suborbital RLV provide methods for affordably retiring the remaining technical risks for cryogenic depots. Recent depot design concepts, built on high-TRL technologies and existing flight vehicle hardware, can enable easier implementation of first-generation propellant depots without requiring extensive development programs. Some concepts proposed by industry include disposable pre-depots , single-fluid simple depots, self-deployable dual-fluid single-launch depots using existing launchers and near-term launcher upgrades, and multi-launch modular depots. These concepts, particularly the dual-fluid single-launch depot enable robust exploration and commercial transportation throughout the inner Solar System, without the need for HLVs, while providing badly-needed markets to encourage the commercial development of more affordable access to space. Copyright © 2009 by Masten Space Systems, United Launch Alliance, The Boeing Company, and University of Memphis

Mechanical stabilization of uranium fuel elements /

Portions of the material contained in this report have been given in the following reports: ANL-4825, pages 83, 84; ANL-4860, pages 87, 88; ANL-5036, pages 12-14; ANL-5097, pages 18-21; ANL-5153, pages 20, 21; ANL-5257, page 43; ANL-5338, pages 74, 75; ANL-5439, pages 25, 27-29; TID-5185 (Pt.1), pages 200-207.Includes bibliography references.Mode of access: Internet

Comparative Benchmarking of Crewed Lunar and Mars Mission Architectures

© 2020 The MITRE Corporation. All Rights Reserved. Fuel selection is a strong driver of the mass fraction for many proposed lunar and Mars missions, but fuel technology trends have not been comprehensively evaluated for their impact on the system in literature. We evaluate the impact of fuel selection on overall lunar architectures. Our analysis shows that although hydrogen architectures have a higher wet mass cost, they provide more payload capacity to the lunar surface than non-hydrogen architectures given the same number of campaign launches. The Moon has been viewed as a stepping stone for future planetary exploration, so we evaluate both Mars and lunar architectures. We functionally decompose architectural decisions and compare key campaign decisions across 18 notable Mars architectural studies. The 18 landers are classified into four groups depending on which of the four the functional capabilities the lander performs, namely outbound transit, mars descent, mars ascent, and inbound transit. We find that there is no strong relationship between the Martian landers’ wet mass and the length of crewed Martian surface. Furthermore, fuel type selection did not have a clear trend with the aforementioned capabilities. The lack of similarities across Mars architectures suggests the reference studies had a wide range of depths of analysis along with an array of different methods. Furthermore, they were completed at various points in history, some with high political pressure