Engineering topics

Ehlers, H.

Publications and source records attributed to Ehlers, H..

5 records

NASA NTRS1988

Summary of requirements in NASA work package No. 2

Work package No. 2 (WP2) has a section in the proposal dealing with measurements of the environment. The quantities to be measured as well as the instruments to be used are summerized. The information provided is only a cursory overview of what has been considered at the time of the proposal. Nevertheless the general ideas are given that much work needs to be done to develop specifics. It is important to note that measurements in the field of particles and waves are not part of the proposal. On the other hand, some of the environmental measurements planned and included in the proposal do not fall within the category of contamination. Some concepts of environment monitoring configurations are also given.

Leger, L.↗

NASA NTRS1988

Space station neutral external environment

Molecular contamination levels arising from the external induced neutral environment of the Space Station (Phase 1 configuration) were calculated using the MOLFLUX model. Predicted molecular column densities and deposition rates generally meet the Space Station contamination requirements. In the doubtful cases of deposition due to materials outgassing, proper material selection, generally excluding organic products exposed to the external environment, must be considered to meet contamination requirements. It is important that the Space Station configuration, once defined, is not significantly modified to avoid introducing new unacceptable contamination sources.

Ehlers, H.↗

NASA NTRS1986

Space station contamination considerations

The external induced environment generated by space station activity, or more specifically by gases, particles, and light background is discussed. These contaminant species must be controlled if sensitive systems, such as solar energy collectors or science experiments exposed to the external environment are to function properly. The requirements generally set limits on the level of gas species, matter deposited on surfaces and light background levels over various spectral regions. They also address environment monitoring and contamination controls during manufacturing. Limits on effluent release and system leakages are in turn derived from these requirements.

Leger, L.↗

NASA NTRS1980

STS-1 mission contamination evaluation approach

The space transportation system 1 mission will be the first opportunity to assess the induced environment of the orbiter payload bay region. Two tools were developed to aid in this assessment. The shuttle payload contamination evaluation computer program was developed to provide an analytical tool for prediction of the induced molecular contamination environment of the space shuttle orbiter during its onorbit operations. An induced environment contamination monitor was constructed and tested to measure the space shuttle orbiter contamination environment inside the payload bay during ascent and descent and inside and outside the payload bay during the onorbit phase. Measurements are to be performed during the four orbital flight test series. Measurements planned for the first flight are described and predicted environmental data are discussed. The results indicate that the expected data are within the measurement range of the induced environment contamination monitor instruments evaluated, and therefore it is expected that useful contamination environmental data will be available after the first flight.

Jacobs, S.↗

NASA NTRS1967

A study of a sorption process.

Sorption process for determining sticking probability of molecules on surface of sorbents, diffusion coefficient of molecules through sorbents and adsorption isotherms

DIFFUSION COEFFICIENT↗