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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1990

Space Station Freedom avionics technology

The Space Station Freedom Program (SSFP) encompasses the design, development, test, evaluation, verification, launch, assembly, and operation and utilization of a set of spacecraft in low earth orbit (LEO) and their supporting facilities. The spacecraft set includes: the Space Station Manned Base (SSMB), a European Space Agency (ESA) provided Man-Tended Free Flyer (MTFF) at an inclination of 28.5 degrees and nominal attitude of 410 km, a USA provided Polar Orbiting Platform (POP), and an ESA provided POP in sun-synchronous, near polar orbits at a nominal altitude of 822 km. The SSMB will be assembled using the National Space Transportation System (NSTS). The POPs and the MTFF will be launched by Expendable Launch Vehicles (ELVs): a Titan 4 for the US POP and an Ariane for the ESA POP and MTFF. The US POP will for the most part use derivatives of systems flown on unmanned LEO spacecraft. The SSMB portion of the overall program is presented.

Edwards, A.↗

NASA NTRS1991

Optimum-AIV: A planning and scheduling system for spacecraft AIV

A project undertaken for the European Space Agency (ESA) is presented. The project is developing a knowledge based software system for planning and scheduling of activities for spacecraft assembly, integration, and verification (AIV). The system extends into the monitoring of plan execution and the plan repair phase. The objectives are to develop an operational kernel of a planning, scheduling, and plan repair tool, called OPTIMUM-AIV, and to provide facilities which will allow individual projects to customize the kernel to suit its specific needs. The kernel shall consist of a set of software functionalities for assistance in initial specification of the AIV plan, in verification and generation of valid plans and schedules for the AIV activities, and in interactive monitoring and execution problem recovery for the detailed AIV plans. Embedded in OPTIMUM-AIV are external interfaces which allow integration with alternative scheduling systems and project databases. The current status of the OPTIMUM-AIV project, as of Jan. 1991, is that a further analysis of the AIV domain has taken place through interviews with satellite AIV experts, a software requirement document (SRD) for the full operational tool was approved, and an architectural design document (ADD) for the kernel excluding external interfaces is ready for review.

Arentoft, M. M.↗

NASA NTRS1990

Time and frequency comparisons in Europe by means of ECS 5 geostationary satellite

A time synchronization experiment between some European laboratories using the passive television method applied to the signals broadcasted by Eutelsat I-F5 telecommunication satellite was completed in 1990. The results obtained in the last period, when also range measurements from a Telespazio ground station were performed, are analyzed to evaluate the accuracy level of the time comparisons corrected for the effect of the satellite movement with position data obtained either from the European Space Agency (ESA) or from orbit determination with range data entered into GEODYN program of NASA/GSFC.

Cordara, Franco↗

NASA NTRS1990

Spacelab - Beyond development

Spacelab is a series of multiple configuration payload carriers that fit in the Orbiter cargo bay. The carriers, ranging from pressurized modules to simple support structures that span across the cargo bay, provide a variety of payload support services, such as cooling, power distribution, data management, pointing, and structural attachment. Previously published papers have addressed the joint development of the initial Spacelab system by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). Herein, the emphasis will be on the NASA utilization and evaluation of the system into the operational era of the Space Transportation System (STS), system enhancement, additional carrier configuration, the effects of time on system hardware, and subsequent replacements and improvement. All configurations added were intended to fulfill payload requirements not originally foreseen. Subsystem replacements thus far have resulted from life limits or unreliable performance while assessments and plans are underway to look also for increased performance and new payload requirements, to the transition from Spacelab to the Space Station Freedom.

Johnson, Charles W.↗

NASA NTRS1991

Giotto Extended Mission (GEM)

The primary objectives of the Giotto Extended Mission (GEM), are to determine the composition and physical state of the Grigg Skjellerup Comet's nucleus; to determine the processes that govern the composition and distribution of neutral and ionized species in the cometary atmosphere. Giotto consists of a single European Space Agency (ESA) spacecraft that was launched in 1985 from Center Spatial Guyanis in French Guiana on an Ariane launch vehicle. After a successful launch into geostationary orbit and a heliocentric transfer trajectory, the spacecraft successfully encountered Halley's Comet in 1986. One month after encountering Halley's Comet, Mar. 1986, the spacecraft was placed in hibernation in a heliocentric orbit slightly less than 1 AU. Between Feb. and Jul. 1990 the spacecraft was successfully reactivated, checked out, and placed on a trajectory course to intercept comet Grigg Skjellerup. The spacecraft has been in hibernation since Jul. 1990. Information is presented in tabular form in the following areas: coverage goals, Deep Space Network Support, frequency assignments, telemetry, command, and tracking support responsibility.

Wilkins, D. E. B.↗

NASA NTRS1991

International Solar Terrestrial Physics (ISTP) program

The International Solar Terrestrial Physics (ISTP) Program is a large, multi-national program involving three space agencies and up to eight spacecraft. NASA, together with the Institute of Space and Astronomical Science (ISAS) and the European Space Agency (ESA), has agreed in principle to coordinate their efforts in investigating the Sun and the Earth. Each agency is planning to construct and operate different spacecraft as part of this cooperative venture: Geotail provided by ISAS, the Solar Heliospheric Observatory (SOHO) and Cluster (four spacecraft) contributed by ESA, and Wind and Polar by NASA. A general description of the program is presented.

Sanford, R.↗

NASA NTRS1991

Titan aerosol and gas experiment for the Huygens Probe

The Cassini Mission is a joint undertaking of NASA and the European Space Agency (ESA) to explore the Saturnian System with a Saturn Orbiter and a Titan Probe. The launch vehicle and the Saturn Orbiter are the responsibility of NASA while the Huygens Probe (detachable Titan Probe) is the responsibility of ESA. The spacecraft will be launched in 1996 and the Huygens Probe will arrive at Titan in 2003. The Cassini Mission-Huygens Probe provides a unique opportunity to obtain detailed information about the atmosphere and, possibly, the surface of Titan. Titan possesses a substantial nitrogen atmosphere containing methane and many other organic compounds. Aerosols play an important role in the atmospheric processes on Titan. The Huygens Probe offers an opportunity to determine how organic particles are formed and grow which will clarify their role on Earth. A powerful analytical instrument, capable of addressing the above technology and other science questions, was recently proposed for the Huygens Probe. It is comprised of an aerosol and gas sampler and processor, and a gas chromatograph-ion mobility spectrometer. The instrument will be able to measure complex organics that make up the collected aerosols to the approximate 1 ppm level. Gases will be measured to approximately 10 ppb. Because the Titan atmosphere is expected to be quite complex, a gas chromatograph-ion mobility spectrometer is used to provide unequivocal identification of the components of the analytes. Further details of the science question to be investigated and the proposed instrument are described. The expected results and their implications are also addressed.

Carle, G. C.↗

NASA NTRS1991

A silicone column for GC analysis of polar and nonpolar chemicals

The investigation of the Saturnian System is being proposed jointly by NASA and the European Space Agency (ESA). The mission is scheduled for a launch in 1996. The mission provides an opportunity for close observation and exploration of Saturn's atmosphere, the complex Saturnian System of satellites and rings, Titan (Saturn's planet-sized moon), and Saturn's magnetosphere. The mission gives special attention to Titan which is blanketed by a thick, opaque atmosphere. An atmospheric probe will be deposited into the Titan Atmosphere for in situ measurement during a slow, three hour descent to the surface. The results from this analysis may provide the information which is important to the research of chemical evolution, and the origin of life. An analytical system was developed as a part of the Titan Aerosol Gas Experiment (TAGEX), a proposed experiment for the Cassini Mission. This system will use two highly sensitive detectors, the Metastable Ionization Detector (MID) and the Ion Mobility Spectrometer (IMS). Unfortunately, when commercial columns are utilized with these highly sensitive detectors, volatile components continuously bleed from the column and interfere with the detector. In addition, light columns must be able to separate polar and nonpolar organic chemicals within 10-15 minutes under isothermal conditions for the Titan Mission. Therefore, a highly crosslinked silicone polymeric packed column was developed which is able to efficiently separate amines, alcohols, and hydrocarbons with retention times less that 15 minutes at 100 C isothermal condition.

Shen, T. C.↗

NASA NTRS1990

Advanced multiple access concepts in mobile satellite systems

Some multiple access strategies for Mobile Satellite Systems (MSS) are discussed. These strategies were investigated in the context of three separate studies conducted for the International Maritime Satellite Organization (INMARSAT) and the European Space Agency (ESA). Satellite-Switched Frequency Division Multiple Access (SS-FDMA), Code Division Multiple Access (CDMA), and Frequency-Addressable Beam architectures are addressed, discussing both system and technology aspects and outlining advantages and drawbacks of either solution with associated relevant hardware issues. An attempt is made to compare the considered option from the standpoint of user terminal/space segment complexity, synchronization requirements, spectral efficiency, and interference rejection.

Ananasso, Fulvio↗

NASA NTRS1991

Evaluation of sodium-nickel chloride cells for space applications

The status of the European Space Agency (ESA) program on sodium nickel chloride batteries is outlined. Additionally, the results of initial tests of two prototype space cells are reported. After 2800 cycles typical of a low-earth orbit (LEO) application without failure, the recharge ratio remained at unity, the round trip energy efficiency remained high (87 percent), and the increase in internal cell resistance was modest. Initial tear-down analysis data show no degradation whatsoever of the beta-alumina electrolyte tubes. The low-rate capacity did, however drop by some 40 percent, which needs further investigation, but overall results are encouraging for future use of this couple in geosynchronous (GEO) and LEO spacecraft.

Hendel, B.↗

NASA NTRS1991

Space Network Interoperability Panel (SNIP) study

The Space Network Interoperability Panel (SNIP) study is a tripartite study that involves the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the National Space Development Agency (NASDA) of Japan. SNIP involves an ongoing interoperability study of the Data Relay Satellite (DRS) Systems of the three organizations. The study is broken down into two parts; Phase one deals with S-band (2 GHz) interoperability and Phase two deals with Ka-band (20/30 GHz) interoperability (in addition to S-band). In 1987 the SNIP formed a Working Group to define and study operations concepts and technical subjects to assure compatibility of the international data relay systems. Since that time a number of Panel and Working Group meetings have been held to continue the study. Interoperability is of interest to the three agencies because it offers a number of potential operation and economic benefits. This paper presents the history and status of the SNIP study.

Ryan, Thomas↗

NASA NTRS1992

The comet rendezvous asteroid flyby mission

The Comet Rendezvous Asteroid Flyby (CRAF) mission was approved for a New Start by the United States Congress in 1989. CRAF will be developed in parallel with the Cassini (Saturn orbiter/Titan probe) mission. The two missions have been combined into a joint program because of the substantial cost savings (approximately $500 M, or greater than 25 percent) which can be realized by using a common spacecraft design, several identical science instruments, a single management team, and a joint ground operations and data handling system for the two missions. CRAF and Cassini will be the first users of the new Mariner Mark 2 spacecraft which has been designed to carry out the next generation of planetary missions to the outer planets and to small bodies. CRAF is a joint mission between the United States, Germany, and Italy. Each partner will provide both engineering hardware and science experiments. Cassini is a joint mission between the United States, Germany, Italy, and the European Space Agency (ESA), with ESA providing the Titan atmospheric entry probe, called Huygens.

Weissman, Paul↗

NASA NTRS1992

Deep-space navigation applications of improved ground-based optical astrometry

Improvements in ground-based optical astrometry will eventually be required for navigation of interplanetary spacecraft when these spacecraft communicate at optical wavelengths. Although such spacecraft may be some years off, preliminary versions of the astrometric technology can also be used to obtain navigational improvements for the Galileo and Cassini missions. This article describes a technology-development and observational program to accomplish this, including a cooperative effort with U.S. Naval Observatory Flagstaff Station. For Galileo, Earth-based astrometry of Jupiter's Galilean satellites may improve their ephemeris accuracy by a factor of 3 to 6. This would reduce the requirements for onboard optical navigation pictures, so that more of the data transmission capability (currently limited by high-gain antenna deployment problems) can be used for science data. Also, observations of European Space Agency (ESA) Hipparcos stars with asteroid 243 Ida may provide significantly improved navigation accuracy for a planned August 1993 Galileo spacecraft encounter.

Null, G. W.↗

NASA NTRS1993

The world of NASA microgravity science

It has been said the decades of the 1990's represents a second golden age of science. We are in the midst of one of the most exciting and interesting periods in the history of exploration -- a period which holds the potential for expanding our understanding of scientific phenomena ranging from intricacies of the universe to the subtleties of our own planet. The opportunities to study the effects of microgravity in space seem limitless during the next decade. Using the European Space Agency (ESA) built Spacelab, we will maximize opportunities for development of new microgravity facilities in order to obtain new information and increase our understanding of the effects of gravitational forces on phenomena in biological, chemical and physical systems. NASA intends to move aggressively, but sensibly, to develop additional space research facilities as we built toward the unique Space Station Freedom resources becoming available towards to end of this decade.

Rhome, Robert C.↗

NASA NTRS1992

Introduction to Space Station Freedom

NASA field centers and contractors are organized to develop 'work packages' for Space Station Freedom. Marshall Space Flight Center and Boeing are building the U.S. laboratory and habitation modules, nodes, and environmental control and life support system; Johnson Space Center and McDonnell Douglas are responsible for truss structure, data management, propulsion systems, thermal control, and communications and guidance; Lewis Research Center and Rocketdyne are developing the power system. The Canadian Space Agency (CSA) is contributing a Mobile Servicing Center, Special Dextrous Manipulator, and Mobile Servicing Center Maintenance Depot. The National Space Development Agency of Japan (NASDA) is contributing a Japanese Experiment Module (JEM), which includes a pressurized module, logistics module, and exposed experiment facility. The European Space Agency (ESA) is contributing the Columbus laboratory module. NASA ground facilities, now in various stages of development to support Space Station Freedom, include: Marshall Space Flight Center's Payload Operations Integration Center and Payload Training Complex (Alabama), Johnson Space Center's Space Station Control Center and Space Station Training Facility (Texas), Lewis Research Center's Power System Facility (Ohio), and Kennedy Space Center's Space Station Processing Facility (Florida). Budget appropriations impact the development of the Space Station. In Fiscal Year 1988, Congress appropriated only half of the funds that NASA requested for the space station program ($393 million vs. $767 million). In FY 89, NASA sought $967 million for the program, and Congress appropriated $900 million. NASA's FY 90 request was $2.05 billion compared to an appropriation of $1.75 billion; the FY 91 request was $2.45 billion, and the appropriation was $1.9 billion. After NASA restructured the Space Station Freedom program in response to directions from Congress, the agency's full budget request of $2.029 billion for Space Station Freedom in FY 92 was appropriated. For FY 93, NASA is seeking $2.25 billion for the program; the planned budget for FY 94 is $2.5 billion. Further alterations to the hardware configuration for Freedom would be a serious setback; NASA intends 'to stick with the current baseline' and continue planning for utilization.

Kohrs, Richard↗

NASA NTRS1989

Space biology initiative program definition review. Trade study 6: Space Station Freedom/spacelab modules compatibility

The differences in rack requirements for Spacelab, the Shuttle Orbiter, and the United States (U.S.) laboratory module, European Space Agency (ESA) Columbus module, and the Japanese Experiment Module (JEM) of Space Station Freedom are identified. The feasibility of designing standardized mechanical, structural, electrical, data, video, thermal, and fluid interfaces to allow space flight hardware designed for use in the U.S. laboratory module to be used in other locations is assessed.

Jackson, L. Neal↗

NASA NTRS1993

Trajectory-based heating analysis for the ESA/Rosetta earth return vehicle

A coupled, trajectory based flowfield and material thermal response analysis is presented for the European Space Agency (ESA) proposed Rosetta comet nucleus sample return vehicle. The probe returns to Earth along a hyperbolic trajectory with an entry velocity of 16.5 km/sec and requires an ablative heat shield on the forebody. Combined radiative and convective, ablating flowfield analyses were performed for the significant heating portion of the shallow ballistic entry trajectory. Both quasi-steady ablation and fully transient analyses were performed for a heat shield composed of carbon-phenolic ablative material. Quasi-steady analysis was performed using the two-dimensional, axisymmetric codes RASLE and BLIMPK. Transient computational results were obtained from the one-dimensional ablation/conduction code, CMA. Results are presented for heating, temperature and ablation rate distributions over the probe forebody for various trajectory points. Comparison of transient and quasi-steady results indicates that, for the heating pulse encountered by this probe, the quasi-static approach is conservative from the standpoint of predicted surface recession.

Henline, William D.↗

NASA NTRS1992

Hubble Space Telescope solar cell module thermal cycle test

The Hubble Space Telescope (HST) solar array consists of two identical double roll-out wings designed after the Hughes flexible roll-up solar array (FRUSA) and was developed by the European Space Agency (ESA) to meet specified HST power output requirements at the end of 2 years, with a functional lifetime of 5 years. The requirement that the HST solar array remain functional both mechanically and electrically during its 5-year lifetime meant that the array must withstand 30,000 low Earth orbit (LEO) thermal cycles between approximately +100 and -100 C. In order to evaluate the ability of the array to meet this requirement, an accelerated thermal cycle test in vacuum was conducted at NASA's Marshall Space Flight Center (MSFC), using two 128-cell solar array modules which duplicated the flight HST solar array. Several other tests were performed on the modules. The thermal cycle test was interrupted after 2,577 cycles, and a 'cold-roll' test was performed on one of the modules in order to evaluate the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit. A posttest static shadow test was performed on one of the modules in order to analyze temperature gradients across the module. Finally, current in-flight electrical performance data from the actual HST flight solar array will be tested.

Douglas, Alexander↗