Search Results

Several research programs which have applied thermal scale modeling to a radiation-conduction heat transfer system (unmanned spacecraft) and to a radiation-conduction-convection heat transfer system (manned spacecraft) are reviewed and evaluated. ...The utilization of scaled models in the development of spacecraft thermal control systems is discussed. The criteria necessary to establish thermal similitude are developed as well as techniques for designing scaled thermal models.

The functions performed by pyrotechnic systems and devices in the Apollo spacecraft during a lunar exploration mission and in aborts are presented. The devices and systems are described. ...The modular cartridge concept and the standard electroexplosive device used throughout the spacecraft are innovations and are discussed in detail. Some of the techniques used to attain the high levels of reliability, to assure crew safety, to control quality, and to eliminate human errors are briefly presented.

The design of a spacecraft requires performing of a series of trade-offs, either at component level, sub-system or system level. ...This paper aims to focus the attention of space engineers on the detailed definition and choice of temperature sensors for spacecraft applications. Although the use of previous experiences and lessons-learned should be taken into consideration, the “already flown before” philosophy (If it has flown before in design-X then it has to work in our design-Y!!)

The mission consists of three spacecraft which will accurately monitor the variations in the Earth's magnetic field. This leads to constraints, for the Thermal Control Sub-System, on the selection of thermal finishes and in the selection of heater mats. ...This paper discusses the thermal design of the SWARM spacecraft and how the difficult issues were overcome.

How much integrated system level test should be performed on a spacecraft before it is launched? Although sometimes system test is minimized, experience shows that systems level testing should be thorough and complete. ...Human-rated spacecraft test planning is informal, subjective, and inconsistent, and its extent is often determined by the decision maker's risk tolerance, decision-making style, and long-term or short-term view.

It is therefore imperative to develop a safe, effective method of microbial control. Spacecraft application dictates a more stringent set of requirements for biocide selection than is usually necessary for terrestrial situations. ...Toxicity of the biocide is the driving factor for disinfectant choice in spacecraft. This concern greatly reduces the number and types of chemical agents that can be used as disinfectants. ...Furthermore, the chemical and toxicological properties of these biocides and others are considered in relation to disinfection of spacecraft and allied hardware.

Space Station Freedom (SSF) modules may be unattended for months during the Man-Tended Capability (MTC) phase of the program. The accumulation of airborne contamination from materials offgassing or contingency incidents (e.g., thermodegradation) raise concerns about crew health and safety from the first crew entry throughout the MTC phase. Computer modelling of the MTC phase, and experiences from previous space flight missions confirm that caution must be exercised during nominal first entry operations. This paper will describe first entry procedures used in the industrial setting and examples of the consequences when first-entry procedures were not followed. Experiences during the Skylab program will be presented to highlight the necessity for carefully planned operations. Anecdotal experiences from previous Spacelab missions and the results of first entry samples from the International Microgravity Laboratory (IML-1) will be detailed.

Due to micro-meteorites and space debris, a non-neglectable probability exists of a wall perforation particularly during a long space journey or during the life of a space station. Analysis and tests have been performed at ESTEC and at the Technical University of Delft of various methods to close a hole manually; it has been shown that with certain patches of silicon rubber, polyethylene or flame-retardant similar polymer foams, holes can be easily and adequately sealed without imposing additional risks to the astronaut. Proper sealing maintains for several days, even with hole sizes up to 10 cm2 (this latter size being the largest ones tested, which size corresponds to a probability of less than order 10-2 for a ten years life of the 1993 Station Freedom baseline). The method works also for holes difficult to reach and for holes with large crater-like and sharp edges. Present operational practise calls for emergency evacuation procedures rather than attempts to seal the hole.

The ARTEMIS (Advanced Relay and TEchnology MISsion) satellite represents the first element of the Data Relay and Technology Mission Programme (DRTM) developed for the European Space Agency by Alenia Aerospazio (Italy) as the prime contractor. Although using conventional design features and limited mass, power, telemetry and tele-command budgets, the thermal control of the satellite matches the demands dictated by the peculiarities of the ARTEMIS mission such as the significant overall dissipation, the wide spectrum of payload operational scenarios and the relatively unbalanced distribution of payload equipment dictated by system and payload performance considerations. This paper describes the thermal control design solutions with special regard to consideration on ground testability of the system; the analytical approach to predict on-orbit thermal response; the policy adopted in terms of margins and analytical uncertainties.

Humans are able to acclimatize and later adapt to extreme altitudes, and this will be shown to be beneficial to the human with respect to microgravity and spacecraft environment. Treating the astronaut as a subsystem, which can be enhanced and modified to ultimately benefit the whole spacecraft is an approach that is necessary to forge the next generation of human spaceflight. ...Treating the astronaut as a subsystem, which can be enhanced and modified to ultimately benefit the whole spacecraft is an approach that is necessary to forge the next generation of human spaceflight. A spacecraft environment that is maintained at a pressure of 16 kPa (primarily oxygen) would be both well within the realm of possibility of an astronaut’s physiology and would provide significant benefits for the all the subsystems of a spacecraft from the large intra-stellar spaceship to the EVA suit. ...Treating the astronaut as a subsystem, which can be enhanced and modified to ultimately benefit the whole spacecraft is an approach that is necessary to forge the next generation of human spaceflight. A spacecraft environment that is maintained at a pressure of 16 kPa (primarily oxygen) would be both well within the realm of possibility of an astronaut’s physiology and would provide significant benefits for the all the subsystems of a spacecraft from the large intra-stellar spaceship to the EVA suit.

The ROSETTA mission is a European Space Agency spacecraft which will rendezvous with the comet Wirtanen. The spacecraft will deploy a Surface Science Package (SSP) to land on the comet. ...Thus, the heater power demand at 5.25 AU has to be low, when the spacecraft is in Deep Space Hibernation mode. Prior to the comet rendezvous, the spacecraft is woken up. ...With a fully operational payload, the ROSETTA spacecraft establishes an orbit around comet Wirtanen. The spacecraft follows the comet during its approach to the sun.

However, this technology has been slow to achieve full maturity and operational status for spacecraft use. This paper describes the efforts to advance spacecraft cryogenic refrigerators beyond the technology development demonstration level. ...The requirement for a reliable long-life refrigerator to cool spacecraft payloads to cryogenic temperatures dates to the very beginning of the era of space flight. ...The development of spacecraft cryocooler technology has been funded on a more or less continuous basis for over 30 years.

For efficient, flexible, and high-quality checkout, the capabilities and limitations of checkout equipment must be considered in the spacecraft design. Ideally, spacecraft and GSE should be designed as a working entity, with ground rules established for their concurrent development. ...Some insight into the importance of GSE in meeting space objectives is presented together with an analysis of the degree to which spacecraft design is influenced by GSE.

Research in microgravity (low-gravity) combustion promises innovations and improvements in fire prevention and response for human-crew spacecraft. Findings indicate that material flammability and fire spread in microgravity are significantly affected by atmospheric flow rate, oxygen concentration, and diluent composition. ...Research on smoke-particle changes in microgravity promises future improvements and increased sensitivity of smoke detectors in spacecraft. Research on fire suppression by extinguishing agents and venting can yield new information on effective control of the rare, but serious fire events in spacecraft. ...Research on fire suppression by extinguishing agents and venting can yield new information on effective control of the rare, but serious fire events in spacecraft.

This paper emphasizes the requirements peculiar to spacecraft fluid mechanical systems. Although the design requirements for the fluid power systems used in aircraft, tactical missiles, and launch vehicles have been established successfully, criteria for the design of gaseous and liquid systems in spacecraft demand additional considerations. ...Although the design requirements for the fluid power systems used in aircraft, tactical missiles, and launch vehicles have been established successfully, criteria for the design of gaseous and liquid systems in spacecraft demand additional considerations. Elements of fluid and mechanical systems in manned and unmanned spacecraft are discussed, and additional visibility is provided for those design requirements that differ from earth-oriented vehicles. ...Elements of fluid and mechanical systems in manned and unmanned spacecraft are discussed, and additional visibility is provided for those design requirements that differ from earth-oriented vehicles.

The Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) spacecraft is the first science mission in the Solar Terrestrial Probe program sponsored by the NASA Office of Space Sciences and is being developed by the Johns Hopkins University, Applied Physics Laboratory (APL). ...The TIMED spacecraft is a three axis stabilized, nadir pointing, low earth orbit scientific satellite with one side of the spacecraft always pointing away from the sun. ...The TIMED spacecraft is a three axis stabilized, nadir pointing, low earth orbit scientific satellite with one side of the spacecraft always pointing away from the sun. The instruments' fields of view (FOV), pointing accuracy, jitter requirements, anti-sun pointing of one spacecraft side, and sun angle variations during the year place severe limitations on the design configuration of the solar array.

The new manned space exploration initiative announced by the United States in 1989 will involve the design and development of advanced manned spacecraft to transport crews from Earth orbit to the orbits of the Moon and Mars and back on a regular basis. ...Though the Moon is only a few days distant, a typical round trip to Mars will take about 500 days during which time crews will be confined to a spacecraft environment for two periods of about 235 days each. Under these exceptional circumstances, the crews must be provided with spacecraft habitability standards and accommodation facilities which are as comfortable, efficient and spacious as possible. ...Under these exceptional circumstances, the crews must be provided with spacecraft habitability standards and accommodation facilities which are as comfortable, efficient and spacious as possible.

The Ranger Telerobotic Flight Experiment is a highly complex teleoperated spacecraft, requiring direct human control of 36 major degrees of freedom. The University of Maryland Space Systems Laboratory and the NASA Ames Research Center are cooperating on the development of a virtual reality control station to streamline human interfaces with the Ranger spacecraft. ...The University of Maryland Space Systems Laboratory and the NASA Ames Research Center are cooperating on the development of a virtual reality control station to streamline human interfaces with the Ranger spacecraft. This describes the design and integration of the Ranger Command Chair, a system incorporating fully immersive helmet-mounted stereo displays with head tracking, hand tracking for direct positional control, and supplemental controls and displays to allow a single operator to functionally control the entire vehicle.

For the analysis of outgassing effects of spacecraft surfaces in vacuum conditions, an analyzer program package was developed as extension of the existing plume impingement model analyzer ERIMA (1)*. ...In the geometry section based on the LOHARP-VUFACT routine, the complex spacecraft surfaces are discretized. The view factors from all surface elements to pre-selected surfaces are determined considering special shading techniques In the outgassing analysis section, all surfaces are considered as sources of particle fluxes of a given outgassing rate. ...The spatial mass flow density distribution of various outgassing species is determined at numerous check points in some distance from the spacecraft.

(ADA) is developing a handheld fine water mist fire extinguisher for use on manned spacecraft and in future planetary habitats. This design employs only water and nitrogen as suppression agents to allow local refill and reuse. ...Continued development will result in prototype hardware suitable for use on future manned spacecraft.