Search NASA⌕ Search

SEARCH · Search NASA

Results for “End of Year”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

GEOSAT Follow-On (GFO) Altimeter Document Series, Volume 9. GFO and JASON Altimeter Engineering Assessment Report Update: GFO-Acceptance to December 18, 2006, JASON-Acceptance to December 24, 2006. Version 1: June 2007

The initial GFO Altimeter Engineering Assessment Report, March 2001 (NASA/TM-2001-209984/Ver.1/Vol.1) covered the GFO performance from Launch to Acceptance (10 February 1998 to 29 November 2000). The second of the series covered the performance from Acceptance to the end of Cycle 20 (29 November 2000 to 21 November 2001). The third of the series covered the performance from Acceptance to the end of Cycle 42 (29 November 2000 to 30 November 2002). The fourth of the series covered the performance from Acceptance to the end of Cycle 64 (29 November 2000 to 17 December 2003). The fifth of the series covered performance from Acceptance to the end of Cycle 86 (29 November 2000 to 17 December 2004). The sixth of the series covered performance from Acceptance to the end of Cycle 109 (29 November 2000 to 26 December 2005). In this year's GFO report, we have begun the inclusion of analyses of the JASON altimeter. In past years, JASON and TOPEX were compared during our assessment of the TOPEX altimeter; however, with the end of the TOPEX mission, we have developed methods to report on JASON as it relates to GFO. We see no change trend between the three altimeters and conclude all three are stable based on our cross comparison analyses.

Hayne, G. S.↗
NASA NTRS2015

New York City Panel on Climate Change 2015 Report Introduction

The climate of the New York City metropolitan region is changing annual temperatures are hotter, heavy downpours are increasingly frequent, and the sea is rising. These trends, which are also occurring in many parts of the world, are projected to continue and even worsen in the coming decades because of higher concentrations of greenhouse gases in the atmosphere caused by burning of fossil fuels and clearing of forests for agriculture. These changing climate hazards increase the risks for the people, economy, and infrastructure of New York City. As was demonstrated by Hurricane Sandy, coastal and low-lying areas, the elderly and very young, and lower-income neighborhoods are highly vulnerable. In response to these climate challenges, New York City is developing a broad range of climate resiliency policies and programs, as well as the knowledge base to support them. The knowledge base includes up-to-date climate, sea level rise, and coastal flooding projections; a Climate Resiliency Indicators and Monitoring System; and resiliency studies. A special attribute of the New York City response to these challenges is the recognition that both the knowledge base and the programs and policies it supports need to evolve through time as climate risks unfold in the coming decades. In early September 2012, just weeks before Hurricane Sandy hit, the New York City Council passed Local Law 42 that established the New York City Panel on Climate Change (NPCC) as an ongoing body serving the City of New York. The NPCC is required to meet at least twice each calendar year to review recent scientific data on climate change and its potential impacts, and to make recommendations on climate projections for the coming decades to the end of the century. These projections are due within one year of the publication of the Intergovernmental Panel on Climate Change Assessment Reports (http:www.ipcc.ch), or at least every three years. The NPCC also advises the Mayor's Office of Sustainability and the Mayor's Office of Recovery and Resiliency (ORR) on the development of a community- or borough-level communications strategy intended to ensure that the public is informed about the findings of the panel, including the creation of a summary of the climate change projections for dissemination to city residents.

hurricanes↗
NASA NTRS1999

Simulation of the December 1998 Stratospheric Major Warming

Prior to 1991, major warmings (defined by increasing zonal mean temperatures and zonal mean easterly winds from 60degN to the pole at 10 hPa) typically occurred approximately once every two Arctic winters; a major warming in mid-Dec. 1998 was the first since Feb. 1991. The Dec. 1998 warming was also the second earliest on record. The earliest, and the only other major warming on record before the end of Dec. was in early Dec 1987; prior to that, the earliest was in late Dec./early Jan. 1984-85. The 1984-85 and 1987 warmings resulted in the warmest and weakest lower stratospheric polar vortices in the 20 years before 1998-99. Fig. 1 compares temperatures and vortex strength in 1998-99 with those in the previous 20 years, using the US National Center for Environmental Prediction (NCEP) record; 1987-88 and 1984-85 are also highlighted. The Dec. 1998 warming had a more pronounced effect on mid-stratospheric temperatures than the Dec. 1987 warming (Fig. 1a), although smaller than that of warmings later in winter (e.g., 1984-85). 10-hPa temperatures fell well below average again in late Jan. 1999 and remained unusually low until an early final warming began in late Feb. 840 K PV gradients (Fig. 1c) set a record minimum in Jan. 1999, but were near average in Feb before the final warming. The effect of the Dec. 1998 warming on lower stratospheric temperatures was comparable to that of other major warmings; there was a brief period of record-high minimum 46-hPa temperatures in early Jan 1999 (Fig. 1b), and temperatures then fell to near average for a short period in mid-Feb. Lower stratospheric PV gradients were the weakest on record during the 1998-99 winter (Fig. 1d). The evolution of the vortex and minimum temperatures during 1998-99 was remarkably similar to that during 1987-88, the only previous year when a major warming was observed before the end of Dec.

Manney, G. L.↗
NASA NTRS2010

Cassini's Solstice Mission

With the recent approval of NASA's flagship Cassini mission for seven more years of continued operations, dozens more Titan, Enceladus and other icy moon flybys await, as well as many occultations and multiple close passages to Saturn. Seasonal change is the principal scientific theme as Cassini extends its survey of the target-rich system over one full half-season, from just after northern winter solstice at arrival back in 2004, to northern summer solstice at the end of mission in 2017. The new seven-year mission extension requires careful propellant management as well as streamlined operations strategies with smaller spacecraft, sequencing and science teams. Cassini's never-before-envisioned end of mission scenario also includes nearly two dozen high-inclination orbits which pass between the rings and the planet allowing thrilling and unique science opportunities before entry into Saturn's atmosphere.

Seal, David↗
NASA NTRSDate not supplied

Advances in High-rate Delay Tolerant Networking On-board the International Space Station

The High-rate Delay Tolerant Networking (HDTN) project at the NASA John H. Glenn Research Center (GRC) is developing a performance optimized Delay Tolerant Networking (DTN) implementation which is able to provide reliable multigigabit per second automated network communications for near-Earth and deep space missions. To that end, this paper provides an overview of the testing and integration efforts culminating in a high-rate DTN demonstration onboard the International Space Station (ISS). Over several years, the HDTN team has performed a series of end-to-end tests between the Software Development and Integration Laboratory (SDIL) at the Lyndon B. Johnson Space Center (JSC) and Marshall Space Flight Center’s Huntsville Operations Support Center (HOSC). The testing has focused on a realistic emulation of the ISS Ku-band RF link, which operates at a maximum of 500 Mbps downlink with a 600 ms round-trip time. In this environment, the HDTN onboard gateway has been tested for interoperability with ISS payload nodes and the DTN ground gateway, store and forward capability, reliable transport using the Licklider Transmission Protocol (LTP), and successful recovery from unexpected loss of signal. In addition to integration testing, HDTN has developed a series of software engineering practices to ensure the stability and maturity of the implementation. As the result, HDTN has successfully demonstrated high-rate DTN services onboard the ISS. This paper concludes with a summary of preliminary flight testing results from the Integrated LCRD LEO User Modem and Amplifier Terminal networking experiments.

Delay tolerant networking↗
NASA NTRS2009

The Collision of Iridium 33 and Cosmos 2251: The Shape of Things to Come

The collision of Iridium 33 and Cosmos 2251 was the most severe accidental fragmentation on record. More than 1800 debris approx. 10 cm and larger were produced. If solar activity returns to normal, half of the tracked debris will reenter within five years. Less than 60 cataloged debris had reentered by 1 October 2009. Some debris from both satellites will remain in orbit through the end of the century. The collision rate of one every five years will increase without future removal of large derelict spacecraft and launch vehicle orbital stages.

Nicholas, Johnson↗
NASA NTRS2010

Thermographic Methods of Detecting Insulation Voids in Large Cryogenic Tanks

Four very large (900Kgal) cryogenic liquid hydrogen and oxygen storage tanks at Kennedy Space Center's LC-39 launch pads were constructed in 1965 to support the Apollo/Saturn V Program and continue to support the Space Shuttle Program. These double-walled spherical tanks with powdered insulation in the annular region, have received minimal refurbishment or even inspection over the years. As the Shuttle Program comes to an end we now have the time to perform limited refurbishment. Thermography has been used to monitor the state of insulation as one of the four tanks was drained of cryogen and warmed to ambient temperatures. An anomalous region of insulation detected previously with thermography was confirmed by visual inspections during this period. Thermal models and a comparison of images from the cold and warm tanks suggests that the anomalous region can be detected even without cryogen in the tank. The ability to detect and correct probable insulation voids prior to filling with cryogenic fluid can provide significant cost savings by reducing commodity boil-off over many years of use.

Arens, Ellen↗
NASA NTRS1985

Geosynchronous Performance of a Lithium-titanium Disulfide Battery

An ambient temperature rechargeable Lithium-Titanium disulfide (Li-TiS2) five cell battery has completed the first orbital year of accelerated synchronous orbit testing. A novel charge/discharge, state of charge (SOC) control scheme is utilized, together with taper current charge backup to overcome deleterious effects associated with high end of charge and low end of discharge voltages. It is indicated that 10 orbital years of simulated synchronous operation may be achieved. Preliminary findings associated with cell matching and battery performance are identified.

Otzinger, B.↗
NASA NTRS1998

Trace Explosives Signatures from World War II Unexploded Undersea Ordnance

Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion some 50 years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas chromatograph/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance that appeared to be physically intact gave good explosives signatures at the parts per billion level, whereas ordnance that had been cracked open during the explosion gave no signatures at the 10 parts per trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea unexploded ordnance.

Darrach, M. R.↗
NASA NTRS1993

LDEF polymeric materials: 10 months versus 5.8 years of exposure

The chemical characterization of several polymeric materials which received 10 months of exposure and 5.8 years of exposure on a Row 9 Long Duration Exposure Facility (LDEF) experiment (A0134) is reported. Specimens include fluorinated ethylene propylene (FEP) teflon film, polysulfone film, and graphite fiber reinforced epoxy amd polysulfone matrix composites. The responses of these materials to the two LEO exposures are compared. The results of infrared, thermal, x-ray photoelectron, and scanning electron microscope analyses are reported. Solution property measurements of various molecular weight parameters are presented for the thermoplastic polysulfone materials. Molecular level effects attributable to exposure that were present in 10-month exposed specimens were not found in 5.8-year exposed specimens. This result suggests that increased atomic oxygen fluence toward the end of the LDEF mission may have eroded away selected environmentally induced changes in surface chemistry for 5.8-year exposure specimens.

Young, Philip R.↗
NASA NTRS1995

Chemical Sensing of Unexploded Ordnance with the Mobile Underwater Survey System (MUDSS)

The ability to sense explosives residues in the marine environment is a critical tool for identification and classification of underwater unexploded ordnance (UXO). Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion fifty years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater, and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas-chromatography/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance which appeared to be physically intact gave good explosives signatures at the parts-per-billion level, whereas ordnance which had been cracked open during the explosion gave no signatures at the 10 parts-per-trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea UXOs.

Darrach, M. R.↗
NASA NTRS1997

Summer High School Apprenticeship Research Program (SHARP)

The summer of 1997 will not only be noted by NASA for the mission to Mars by the Pathfinder but also for the 179 brilliant apprentices that participated in the SHARP Program. Apprentice participation increased 17% over last year's total of 153 participants. As indicated by the End-of-the-Program Evaluations, 96% of the programs' participants rated the summer experience from very good to excellent. The SHARP Management Team began the year by meeting in Cocoa Beach, Florida for the annual SHARP Planning Conference. Participants strengthened their Education Division Computer Aided Tracking System (EDCATS) skills, toured the world-renowned Kennedy Space Center, and took a journey into space during the Alien Encounter Exercise. The participants returned to their Centers with the same goals and objectives in mind. The 1997 SHARP Program goals were: (1) Utilize NASA's mission, unique facilities and specialized workforce to provide exposure, education, and enrichment experiences to expand participants' career horizons and inspire excellence in formal education and lifelong learning. (2) Develop and implement innovative education reform initiatives which support NASA's Education Strategic Plan and national education goals. (3) Utilize established statistical indicators to measure the effectiveness of SHARP's program goals. (4) Explore new recruiting methods which target the student population for which SHARP was specifically designed. (5) Increase the number of participants in the program. All of the SHARP Coordinators reported that the goals and objectives for the overall program as well as their individual program goals were achieved. Some of the goals and objectives for the Centers were: (1) To increase the students' awareness of science, mathematics, engineering, and computer technology; (2) To provide students with the opportunity to broaden their career objectives; and (3) To expose students to a variety of enrichment activities. Most of the Center goals and objectives were consistent with the overall program goals. Modem Technology Systems, Inc., was able to meet the SHARP Apprentices, Coordinators and Mentors during their site visits to Stennis Space Center, Ames Research Center and Dryden Flight Research Center. All three Centers had very efficient programs and adhered to SHARP's general guidelines and procedures. MTSI was able to meet the apprentices from the other Centers via satellite in July during the SHARP Video-Teleconference(ViTS). The ViTS offered the apprentices and the NASA and SHARP Coordinators the opportunity to introduce themselves. The apprentices from each Center presented topical "Cutting Edge Projects". Some of the accomplishments for the 1997 SHARP Program year included: MTSI hiring apprentices from four of the nine NASA Centers, the full utilization of the EDCATS by apprentices and NASA/SHARP Coordinators, the distribution of the SHARP Apprentice College and Scholarship Directory, a reunion with former apprentices from Langley Research Center and the development of a SHARP Recruitment Poster. MTSI developed another exciting newsletter containing graphics and articles submitted by the apprentices and the SHARP Management Team.

Source record↗
NASA NTRS1989

The temperatures of white dwarfs in accreting binaries

Long-term observations of the dwarf nova WZ Sge with an outburst recurrence time of 33 years are studied. The results indicate that the UV flux reached an equilibrium value at about the end of 1986; this means that the UV flux continued to decrease for 8 years after outburst. If the underlying dwarf has provided a dominant amount of the UV flux since the disk reached quiescence, then the outer layers of the white dwarf cooled by several thousand degrees. The indications are that a 13,500 K + or - 500 K white dwarf contributing most of the UV flux is consistent with the observed parameters of WZ Sge; however, there must be some contribution from the hot disk or a larger emitting area.

Szkody, Paula↗
NASA NTRS1981

ATS-5 12 year in orbit evaluation

The results of the ATS 5 End-of-Life (EOL) tests are presented. Whenever possible, the test data were compared with prelaunch and inflight data. Pertinent memos and other informal documents containing these data are included as appendixes. The EOL tests include communication subsystems tests, power sybsystem tests, and gravity gradient television camera system tests.

Kissel, F. J.↗
NASA NTRS2006

Role of High-End Computing in Meeting NASA's Science and Engineering Challenges

Two years ago, NASA was on the verge of dramatically increasing its HEC capability and capacity. With the 10,240-processor supercomputer, Columbia, now in production for 18 months, HEC has an even greater impact within the Agency and extending to partner institutions. Advanced science and engineering simulations in space exploration, shuttle operations, Earth sciences, and fundamental aeronautics research are occurring on Columbia, demonstrating its ability to accelerate NASA s exploration vision. This talk describes how the integrated production environment fostered at the NASA Advanced Supercomputing (NAS) facility at Ames Research Center is accelerating scientific discovery, achieving parametric analyses of multiple scenarios, and enhancing safety for NASA missions. We focus on Columbia s impact on two key engineering and science disciplines: Aerospace, and Climate. We also discuss future mission challenges and plans for NASA s next-generation HEC environment.

Biswas, Rupak↗
NASA NTRS1973

Eleventh order resonance terms in the geopotential from the orbit of Vanguard 3

The orbit of Vanguard 3 (1959-7A) is strongly resonant with 11th order and odd degree terms in the geopotential. It affords an excellent opportunity to determine a significant linear constraint between these terms. Tracking data on this satellite (in the form of mean Kepler elements) are analyzed over a 3 1/2 year period in the early 1960's, which ends with the orbit having just passed through perfect commensurability. The eccentricity and inclination show the deep resonance variations (up to 0.0002 in e and .02 deg in i) with great clarity. Previous and current geopotential solutions fail to explain these perturbations.

Wagner, C. A.↗
NASA NTRS1985

A comparison of 8.415-, 32.0- and 565646-GHz deep space telemetry links

An economic and performance comparison is made of spacecraft telecommunication links at 8.415, 32.0, and 565646 GHz (0.53-micron wavelength) for the return of 3.43 x 10 to the 11th power bits from a Saturn Orbiter/Titan Probe mission in year 2000. Technical performance and costs for both ends of the links are included. Spacecraft antenna or telescope efficiencies, pointing losses, ground-based or Earth-orbiting relay terminals efficiencies, noise temperatures, recurring and nonrecurring engineering, and maintenance and operations costs are modeled. Weather effects, dc-to-RF or laser power conversion efficiencies, gravity and other environment distortions gain reductions, and the cost of pointing and tracking are analyzed. The effort is focused primarily on the microwave frequency links. There are large uncertainties in the cost results, but conclusions indicate that for a mid-1990's launch, the Ka-band system is as cost effective as X-band. The Ka-band system has a data rate advantage as compared to the X-band system for the same dc power input to the spacecraft. The magnitude of the advantage is a complex function of the weather at the DSN stations and the elevation angle of the ground antenna. A simple numerical comparison of the advantage is difficult and curves are provided. The optical frequency link is more costly based on the launch-to-orbit costs for the orbiting terminal. A more detailed study of the optical system is recommended to quantify astrometric tracking benefits and improve the accuracy of the cost estimate.

Dickinson, R. M.↗
NASA NTRS1986

Far-infrared spectral studies from the G. P. Kuiper Airborne Observatory

The grant to carry out far-infrared spectral studies of astronomical sources from the G. P. Kuiper Airborne Observatory was first funded in October 1978 and officially ended on October 31, 1986. During these eight years, A variety of previously undetected spectral lines was discovered, and these were used to determine the physical and chemical conditions prevailing in regions of active star formation. They served to clarify the nature of the ionized hydrogen regions often adjacent to star-forming clouds, the characteristics of shocks which may signify the onset of star formation, and the nature of coolants that channel away energy thus enabling a cloud to collapse to form new stars.

Harwit, M.↗