ALBERT

Description: Organic Letters DOI: 10.1021/ol5019163

Description: The topics are presented in viewgraph form and include the following: an assessment of cryogenic storage technology; cryogenic boiloff predictions; Space Shuttle/Centaur thermodynamic vent system; zero-g thermodynamic vent system; heat exchanger/mixer pump module; the thick multilayer insulation (MLI) development program; blanket geometry concept evaluations; four-inch thick MLI system on 1/4-scale test tank; combined environments of vibration, acceleration, and temperature testing (CEVAT); Centaur fixed foam insulation; insulation system design; and fixed foam on operational Atlas 2.

Description: The Long Term Cryogenic Storage Facility Systems Study (LTCSFSS) is a Phase A study of a large capacity propellant depot for the space based, cryogenic orbital transfer vehicle. The study is being performed for Marshall Space Flight Center by General Dynamics Space Systems Division and has five principal objectives: (1) Definition of preliminary concept designs for four storage facility concepts; (2) Selection of preferred concepts through the application of trade studies to candidate propellant management system components; (3) Preparation of a conceptual design for an orbital storage facility; (4) Development of supporting research and technology requirements; and (5) Development of a test program to demonstrate facility performance. The initial study has been completed, and continuation activities are just getting under way to provide greater detail in key areas and accommodate changes in study guidelines and assumptions.

Description: Future space missions to geosynchronous, lunar, and planetary orbits will require an orbital depot for stockpiling propellants. This depot will provide long-term storage of cryogens, requiring new technologies for fluid management in microgravity and further development of thermal management technologies for minimization of cryogen boiloff. Preliminary evaluations have been made to define a test program approach for reducing technical risk through verifying performance models and building a base of engineering data for depot design. A number of testing options were defined and evaluated, leading to selection of ground testing combined with an orbital systems test. Ground testing is inadequate because of critical microgravity concerns; extending testing aboard the Space Station was eliminated because the data would not be available soon enough to benefit the propellant depot design. The orbital test would either be a short-term test carried out in the cargo bay of the Space Shuttle Orbiter using a nonhazardous cryogen or a longer term test carried out with hydrogen aboard a free-flying experiment orbited with an expendable launch vehicle.

Description: A comprehensive study has developed the major features of a large capacity orbital propellant depot for the space-based, cryogenic OTV. The study has treated both the Dual-Keel Space Station and co-orbiting platforms as the accommodations base for the propellant storage facilities, and trades have examined both tethered and hard-docked options. Five tank set concepts were developed for storing the propellants, and along with layout options for the station and platform, were evaluated from the standpoints of servicing, propellant delivery, boiloff, micrometeoroid/debris shielding, development requirements, and cost. These trades led to the recommendation that an all-passive storage concept be considered for the platform and an actively refrigerated concept providing for reliquefaction of all boiloff be considered for the Space Station. The tank sets are modular, each storing up to 45,400 kg of LO2/LH2, and employ many advanced features to provide for microgravity fluid management and to limit boiloff. The features include such technologies as zero-gravity mass gauging, total communication capillary liquid acquisition devices, autogenous pressurization, thermodynamic vent systems, thick multilayer insulation, vapor-cooled shields, solar-selective coatings, advanced micrometeoroid/debris protection systems, and long-lived cryogenic refrigeration systems.

Description: The Cryogenic On-Orbit Liquid Depot Storage, Acquisition, and Transfer Satellite (COLD-SAT) will perform subcritical liquid hydrogen handling experiments under low gravity conditions to provide engineering data for future space transportation missions. Comprising the four Class 1 enabling experiments are tank press control, tank chilldown, tank no-vent fill, and liquid acquisition device fill/refill. The nine Class 2 enhancing experiments are tanker thermal performance, pressurization, low-gravity setting and outflow, liquid acquisition device performance, transfer line chilldown, outflow subcooling, low-gravity vented fill, fluid dumping, and advanced instrumentation. Consisting of an experiment module mated to a spacecraft bus, COLD-SAT will be placed in an initial 1300 km circular orbit by an Atlas commercial launch vehicle, and will perform experiments in a semi-autonomous mode for a period of up to six months. The three-axis controlled spacecraft bus provides electric power, control and data management, communications, and attitude control along with propulsive acceleration levels ranging from 10(exp -6) to 10(exp -4) g. It is desired to understand the effects that low acceleration levels might have on the heat and mass transfer processes involved in some of the experiments. The experiment module contains the three liquid hydrogen tanks, valves, pressurization and pumping equipment, and instrumentation. Within the highly insulated tanks are specialized fluid management equipment that might be used in future space transportation systems. At launch all the liquid hydrogen for the experiments is contained in the largest tank, which has helium-purged insulation to prevent cryo-pumping of air on the launch pad. The tank is loaded by the hydrogen tanking system used for the Centaur upper stage of the Atlas. After reaching orbit the two smaller tanks become receivers for fluid transfers, and when tanked, become the vessels for performing many of the experiments.