SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 11 - MAY 30, 2006

93 SPACE RADIATION
Includes cosmic radiation; and inner and outer Earth radiation belts.

For biological effects of radiation on plants and animals see 51 Life Sciences; on human beings see 52 Aerospace Medicine.

For theory see 73 Nuclear Physics.

20060013413 NASA Glenn Research Center, Cleveland, OH, USA

Active Solid State Dosimetry for Lunar EVA

Wrbanek, John D.; Fralick, Gustave C.; Wrbanek, Susan Y.; Chen, Liang-Yu.; January 2006; 14 pp.; In English; Space Resources Roundtable VII: LEAG Conference on Lunar Exploration, 25-28 Oct. 2005, League City, TX, USA; Original contains color illustrations Contract(s)/Grant(s): 22-617-97-99; Copyright; Avail.: CASI: A03, Hardcopy

The primary threat to astronauts from space radiation is high-energy charged particles, such as electrons, protons, alpha and heavier particles, originating from galactic cosmic radiation (GCR), solar particle events (SPEs) and trapped radiation belts in Earth orbit. There is also the added threat of secondary neutrons generated as the space radiation interacts with atmosphere, soil and structural materials.[1] For Lunar exploration missions, the habitats and transfer vehicles are expected to provide shielding from standard background radiation. Unfortunately, the Lunar Extravehicular Activity (EVA) suit is not expected to afford such shielding. Astronauts need to be aware of potentially hazardous conditions in their immediate area on EVA before a health and hardware risk arises. These conditions would include fluctuations of the local radiation field due to changes in the space radiation field and unknown variations in the local surface composition. Should undue exposure occur, knowledge of the dynamic intensity conditions during the exposure will allow more precise diagnostic assessment of the potential health risk to the exposed individual.[2] Derived from text

Astronauts; Charged Particles; Dosimeters; Exposure; Extraterrestrial Radiation; Extravehicular Activity; Galactic Radiation; Radiation Trapping; Radiation Shielding; Radiation Distribution

20060013443 NASA Johnson Space Center, Houston, TX, USA

Radiation measured with TEPC and CR-39 PNTDs in low Earth orbit

Zhou, D.; Semones, E.;Weyland, M.; Johnson, S.; [2006]; 1 pp.; In English; 36th Scientific Assembly of Committee on Space Research (COSPAR), 16-23 Jul. 2006, Beijing, China; No Copyright; Avail.: Other Sources; Abstract Only

The radiation impact to astronauts depends strongly on the particles linear energy transfer (LET) and is dominated by high LET radiation. It is important to investigate the LET spectrum for the radiation field in low Earth orbit (LEO) and the influence of radiation on astronauts. The best active dosimeter used for all LET is the tissue equivalent proportional counter (TEPC); the best passive dosimeter used for high LET is CR-39 plastic nuclear track dosimeter (PNTD). TEPC and CR-39 PNTDs were used to investigate the radiation in LEO. LET spectra and radiation quantities were obtained for STS-112 and STS-114 missions with TEPC and CR-39 PNTDs. This paper introduces the operation principles for the two types of dosimeters, presents radiation results measured and compares the results obtained with different dosimeters. Author

Low Earth Orbits; Linear Energy Transfer (LET); Astronauts; Dosimeters; Radiation Distribution

20060013444 NASA Johnson Space Center, Houston, TX, USA

Simultaneous observation of the radiation environment inside and outside the ISS

Lee, K. T.; Flanders, J.; Semones, E.; Shelfer, T.; Riman, F.; [2006]; 1 pp.; In English; 36th Scientific Assemby of the Committee on Space Research (COSPAR), 16-23 Jul. 2006, Beijing, China; Copyright; Avail.: Other Sources; Abstract Only

The low-Earth orbit (LEO) radiation environment has been directly observed by the IV and EV charged particle directional spectrometers (CPDS) aboard the International Space Station (ISS). The EV instrument is mounted on the S0 truss of the ISS and consists of three separate silicon detector telescopes which are oriented in different directions. The IV instrument is a single silicon detector telescope located inside the US Laboratory module of the ISS. We report on the current state of the data analysis for these instruments, which includes the proton and He stopping particle spectra, relative CNO abundances, LET spectra, and measured dose rate as a function of time. Author

Low Earth Orbits; Charged Particles; Time Dependence; International Space Station; Extraterrestrial Radiation

Source: NASA