Search Results

The Apollo spacecraft has 50 rocket engines arranged in 7 separate and independent systems. During a single mission there are approximately 100,000 rocket engine firings.

This paper describes the current options for performing modal tests of spacecraft structures. Excitation options include sine dwell, sine sweep, fast sine sweep (chirp), random, initial velocity (impulse), initial displacement (twang), and ambient.

The performance of the Paraglider spacecraft recovery system is described in terms of wing aerodynamic characteristics, glide range, maneuver capabilities, and landing trajectories.

Vacuum and radiation conditions in space are discussed, as these appear to cause the major limitations on lubrication for spacecraft equipment. While many lubricants suffer a drastic loss in lifetime as a result of these environments, experimental studies have demonstrated that certain oils and greases can lubricate lightly loaded ball bearings without replenishment for periods of two years and more under the following conditions of operation: speeds of 8000 rpm, temperatures of 160 to 200 F, and vacuum of 10−8 torr.

CJB Developments Limited, (CJBD) assisted by a number of distinguished consultants, undertook a study on behalf of the European Space Agency (ESA) to identify Critical Technologies relating to Spacecraft Habitability. Critical Technologies in this context are those defined as requiring a solution in order that the objectives of the European Manned Space Infrastructure (EMSI) can be met.

This paper highlights the role of electrochemical processes in spacecraft environmental systems development and, by example, describes the fundamentals of these processes.

This paper discusses the development problems of the long life hydraulic pump sets based on electrical brushless D.C. motors with hydraulic static supports. The first test results of the new brushless D.C. motors for long life hydraulic pump sets developed in NPP VNIIEM to use on the space station “Alpha” are presented. The specific feature of the motors is elimination of the traditional bearing units and almost complete exclusion of mechanical wear during motor operation. Electrical pump sets using this type of motor are expected to have 100,000 hours service life.

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.

A method that exploits certain properties of a recirculating gas has been investigated as a means of achieving a sustained accelerative vector force without either the expulsion of mass from or a reaction against an external mass by the accelerated body. A theory of operation is presented that defines the capabilities and limitations of the method, and which has resulted in functioning prototypes. The prototype devices require only a source of electric power and a means of cooling to achieve an internally generated, externally measurable accelerative vector force that is sustained for as long as power is supplied to the device.

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.

Water is an important commodity during spaceflight. The Shuttle-Orbiter produces water on-orbit as a direct result of electricity generation. Hydrogen/oxygen fuel cells provide ample water for drinking, food rehydration and hygiene purposes. During the Shuttle-Mir program, water was transferred between the orbiter and the Mir space station to provide crewmembers with drinking water and water to be used for electrolysis for oxygen production. Due to the incompatibility of Russian and U.S. drinking water biocides (silver versus iodine), methods and hardware were developed to remove iodine and allow for the addition of silver biocide and minerals. At the completion of the Mir program, 5,800 kilograms of water had been transferred from the Orbiter to Mir. A refined version of the hardware used during the Mir program is now under flight development and certification for operations on board the International Space Station (ISS).

When construction of Space Station Freedom reaches the Permanent Manned Capability stage, plans call for the Water Recovery and Management Subsystem to treat distilled urine, spent hygiene water, and humidity condensate in order to reclaim water of potable quality. The reclamation technologies currently baselined to process these wastewaters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that baselined technologies will be able to effectively remove those compounds that present health risks to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in wastewaters representative of those to be encountered on Space Station. This paper reports the efforts by the Water and Food Analytical Laboratory at the Johnson Space Center to enlarge the database of potential contaminants in humidity condensate.

A generalized approach used in the thermal analysis of complex orbiting spacecraft is presented. The approach, consisting of the development of a mathematical model and its refinement, using verification testing, has allowed close predictions of actual spacecraft temperatures during flight. ...The approach, consisting of the development of a mathematical model and its refinement, using verification testing, has allowed close predictions of actual spacecraft temperatures during flight. The application of this approach in the analysis of the Injun V (Explorer 40) spacecraft is presented as an example. ...The application of this approach in the analysis of the Injun V (Explorer 40) spacecraft is presented as an example.

The TIMED spacecraft is a co-manifested launch with the JASON spacecraft (TOPEX follow-on). The TIMED spacecraft is encapsulated in a Dual Payload Attach Fitting (DPAF), with the JASON spacecraft mounting to the top of the DPAF. ...These basic requirements, along with instrument field of view requirements have resulted in a very interesting spacecraft design. The TIMED spacecraft has the subsystems on board necessary to provide the instruments with the power, attitude control and thermal stability they require. ...The spacecraft has a 50 Amp-Hour, 22 cell Nickel-Hydrogen battery split into two halves placed on opposites of the spacecraft. The Ni-H battery is just one component on the TIMED spacecraft which requires careful thermal control.

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.