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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

MEMS reagent and sample handling procedure: Feasibility of viral antibody detection by passive immune agglutination

An attempt was made to develop a test requiring no preadsorption steps for the assessment of antibodies to rubella and mumps viruses using the passive immune agglutination (PIA) method. Both rubella and mumps antigens and antibodies were prepared. Direct PIA tests, using rubella antigen-coated beads, and indirect PIA tests, using rubella antibody-coated beads, were investigated. Attempts, using either method, were unsuccessful. Serum interference along with nonspecific agglutination of beads by the rubella antigen resulted in no specific response under the test conditions investigated. A new, highly sensitive approach, the enzyme immunoassay (EIA) test system, is recommended to overcome the nonspecificity. This system is a logical outgrowth of some of the solid phase work done on MEMS and represents the next generation tests system that can be directly applied to early disease detection and monitoring.

Bailey, G. D.↗
NASA NTRS1963

Vehicle Design for Mars Landing and Return to Mars Orbit

This paper briefly describes three modes for accomplishing the Mars landing mission and compares them on a gross basis to indicate their probable order of merit and to identify design requirements placed on the Mars-excursion module (MEM) by the choice of mode. The paper shows that a flyby-rendezvous mode requiring low weight in earth orbit requires the MEM to enter the Mars atmosphere at velocities ranging from 20,000 to 30,000 ft/sec. The MEM for the flyby-rendezvous mode is not covered in this paper but merits further study. The MEM for the other modes of mission accomplishment begins its active operational sequence in Mars orbit and need not be greatly influenced by the method of delivery to Mars orbit. Parametric studies of the entry problem for two vehicles typifying a ballistic-type and a lifting-body-type were conducted to identify the problems associated with design of a MEM to accommodate the extremes of Mars atmospheric density presently predicted. This brief study indicates that: (a) the presently predicted density extremes of the Mars atmosphere present no serious design problems for a MEM which can operate across the entire band of predicted densities; (b) details of operational requirements and mission objectives will control the choice of configuration rather than entry requirements; and (c) the ballistic-type MEM is lighter and simpler but has less operational flexibility than a high L/D MEM.

Hammock, D. M.↗
NASA NTRS1977

Spectral line similarity in the geomagnetic dipole field variations and length of day fluctuations

Power spectral density analysis using Burg's maximum entropy method (MEM) was applied to the geomagnetic dipole field and its rate of change for the years 1901-1969. Both spectra indicate relative maxima at 0.015 cycle/yr and its harmonics. These maxima correspond approximately to 66-, 33-, 22-, 17-, 13-, 11-, and 9-year spectral lines. The application of the same analysis techniques to the length of day (l.o.d.) fluctuations for the period 1865-1961 reveals similar spectral characteristics. The existence of the common spectral peaks with periods of 66 and 33 years in the l.o.d. fluctuations and the geomagnetic dipole field is clearly established. The existence of the higher harmonics is somewhat uncertain because of the line-splitting problem in the MEM spectral analysis. It is suggested that the spectral line similarity in the l.o.d. fluctuations and the dipole field variations is related to the motion within the earth's fluid core during the past 100 years.

Jin, R.-S.↗
NASA NTRS1975

In-orbit servicing

A concept called the low-cost modular spacecraft, in which the subsystems would be contained in replaceable modules and which would be capable of various applications, is under engineering development. Studies have shown that servicing of such a spacecraft on orbit by the Space Shuttle over an extended lifetime is more economical than three other alternatives: launching replacement satellites on conventional boosters as existing satellites fail, launching replacements by Shuttle, or launching replacement satellites and retrieving malfunctioning satellites by Shuttle. For on-orbit servicing, the Shuttle would use its Remote Manipulator system (RMS) to bring the malfunctioning satellite into its cargo bay. The Flight Support System (FSS) on the Orbiter used for servicing the satellite would include an appendage storage frame, a retention cradle, a positioning platform, a Module Exchange Mechanism (MEM), and a storage magazine. Ground simulations are under way with the Orbiter mockup.

Cepollina, F. J.↗
NASA NTRS1983

Large scale waves in the thermosphere observed by the AE-C satellite

Atmospheric Explorer C (AE-C) data are analyzed to study wavelike perturbations in the thermosphere at an altitude of about 260 km. Four geophysical parameters are analyzed. These are nitrogen and oxygen densities, electron density and ion temperature as measured by three different instruments on board AE-C. The data are processed by normalizing them to their average values and their fluctuations are obtained by passing the normalized data through a high pass filter. These fluctuations exhibit strong periodicities that persist throughout the records, regardless of the filter cutoff frequency. The fluctuations are cross correlated by direct comparison, by comparison of their spectral content as obtained by the MEM and FFT, and by computing cross correlation functions.

Gross, S. H.↗