SEARCH · Engineering Papers

Results for “Astronaut”

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.

SourceResearch connectionFrom yearThrough year

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

At least 613 records · Page 34

All sources NASA NTRS DOE OSTI

NASA NTRSDate not supplied

The Effect of a SEP Event on Astronauts Doing a Spacewalk As Computed By the Nowcast of Aerospace Ionizing Radiation System (NAIRAS)

The Nowcast of Aerospace Ionizing Radiation System (NAIRAS) is a sophisticated physics-based model that has been providing real-time global predictions of cosmic radiation exposure, pertinent to both galactic and solar sources, to air travelers for a decade. The utility of NAIRAS, however, extends beyond the atmospheric ionizing radiation environment. The recently developed NAIRAS 3.0 version demonstrates an expansion of its domain to the space radiation environment. This extension incorporates an additional trapped inner belt proton source, coupled with altitude-dependent and rigidity-dependent geomagnetic shielding for galactic cosmic rays (GCR) and solar energetic particle (SEP) protons. The latest version of NAIRAS operates in two modes: real-time global predictions of the atmospheric radiation environment and a user-specified run-on-request service for global dosimetric calculations or predictions of dosimetric and particle flux quantities along user-uploaded flight path. It is available to the public at the Community Coordinated Modeling Center (CCMC). In this work, we present the computations of the dose in the ISS vicinity during the SEP event of August 8, 2023; which happened a day before a scheduled spacewalk. We demonstrate that astronauts would not have suffered a dose equivalent in excess of 1 mSv if the event happened a day later. As such, NAIRAS 3.0 holds significant potential for human safety and technological advancement in aerospace travel and exploration.

Guillaume Gronoff↗

NASA NTRS2024

Lifetime Surveillance of Astronaut Health Newsletter

Welcome to the April 2024 issue of the Lifetime Surveillance of Astronaut Health (LSAH) Newsletter. In this issue, we celebrate LSAH lead, Dr. Mary Wear’s retirement, inform you of the Apollo Records Synthesis Project (ARSP), and recap information shared at the 2024 Human Research Program (HRP) Investigators’ Workshop (IWS) by our LSAH Epidemiologists and NASA HRP team.

Anna C. Morgenthaler-Cejka↗

NASA NTRSDate not supplied

NASA Astronaut Medical Selection

Invited panel presentation to The National Academies of Sciences, Engineering, and Medicine - A Science Strategy for the Human Exploration of Mars: Panel on Biological and Physical Sciences and Human Factors.

astronaut medical selection↗

NASA NTRS1962

ASTRONAUTICAL FALLOUT

Discussion of benefits to be derived from space exploration

ASTRONAUTICS↗

NASA NTRS1963

NASA TEST FACILITIES AT HOUSTON'S MANNED SPACECRAFT CENTER PROVIDE UNIQUE CAPABILITIES FOR SPACECRAFT DEVELOPMENT AND ASTRONAUT TRAINING

Special test facilities under constuction at houston and their role in man-rated spacecraft programs

MANNED SPACECRAFT↗

NASA NTRS1964

American institute of aeronautics and astronautics, and nasa, manned space flight meeting, 3rd, houston, tex., november 4-6, 1964, technical papers /aiaa publication cp-10/.

Technical papers from AIAA/NASA Third Manned Space Flight Meeting at Houston in November 1964

MANNED SPACE FLIGHT↗

NASA NTRS1966

Experiment S-8/D-13, Visual Acuity and Astronaut Visibility

Preflight, inflight, and postflight tests of visual acvity of Gemini V and VII crew members

VISUAL ACUITY↗

NASA NTRS2003

Effect of short- and long-duration spaceflight on QTc intervals in healthy astronauts

No abstract available

NASA Program Biomedical Research and Countermeasur↗

NASA NTRS2002

A comparison of quality factors and weighting factors for characterizing astronaut radiation exposures

Radiation exposures are typically characterized by two quantities. The first is the absorbed dose, or the energy deposited per unit mass for specific types of radiation passing through specified materials. The same amount of energy deposited in material by two different types of radiation, however, can result in two different levels of risk. Because of this, for the purpose of radiation protection operations, absorbed dose is modified by a second factor intended to normalize the risk associated with a given exposure. We present here an inter-comparison of methods for this modification. First is the radiation quality factor (Q), as defined by ICRP publication 60. This quantity is related functionally to the unrestricted linear energy transfer (LET) of a given radiation, and is multiplied by the absorbed dose to derive the dose equivalent (H). The second method for modifying absorbed dose is the radiation weighting factor, also given in ICRP-60, or as modified in NCRP report 115. To implement the weighting factor, the absorbed dose resulting from incidence of a particular radiation is multiplied by a factor assigned to that type of radiation, giving the equivalent dose. We compare calculations done based on identical fields of radiation representative of that encountered by the MIR space station, applying each of these two methods. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

NASA Center JSC↗

NASA NTRS2001

Effect of spaceflight on cardiovascular responses to upright posture in a 77-year-old astronaut

No abstract available

manned↗

NASA NTRS1994

Space flight and astronaut's immunocompetence

No abstract available

STS-9 Shuttle Project↗

NASA NTRS1999

Predicting cancer rates in astronauts from animal carcinogenesis studies and cellular markers

The radiation space environment includes particles such as protons and multiple species of heavy ions, with much of the exposure to these radiations occurring at extremely low average dose-rates. Limitations in databases needed to predict cancer hazards in human beings from such radiations are significant and currently do not provide confidence that such predictions are acceptably precise or accurate. In this article, we outline the need for animal carcinogenesis data based on a more sophisticated understanding of the dose-response relationship for induction of cancer and correlative cellular endpoints by representative space radiations. We stress the need for a model that can interrelate human and animal carcinogenesis data with cellular mechanisms. Using a broad model for dose-response patterns which we term the "subalpha-alpha-omega (SAO) model", we explore examples in the literature for radiation-induced cancer and for radiation-induced cellular events to illustrate the need for data that define the dose-response patterns more precisely over specific dose ranges, with special attention to low dose, low dose-rate exposure. We present data for multiple endpoints in cells, which vary in their radiosensitivity, that also support the proposed model. We have measured induction of complex chromosome aberrations in multiple cell types by two space radiations, Fe-ions and protons, and compared these to photons delivered at high dose-rate or low dose-rate. Our data demonstrate that at least three factors modulate the relative efficacy of Fe-ions compared to photons: (i) intrinsic radiosensitivity of irradiated cells; (ii) dose-rate; and (iii) another unspecified effect perhaps related to reparability of DNA lesions. These factors can produce respectively up to at least 7-, 6- and 3-fold variability. These data demonstrate the need to understand better the role of intrinsic radiosensitivity and dose-rate effects in mammalian cell response to ionizing radiation. Such understanding is critical in extrapolating databases between cellular response, animal carcinogenesis and human carcinogenesis, and we suggest that the SAO model is a useful tool for such extrapolation.

Non-NASA Center↗

NASA NTRS1998

[Clinical and physiological evaluation of bone changes among astronauts after long-term space flights]

Results of the joint Russian/US studies of the effect of microgravity on bone tissues in 18 cosmonauts on return from 4.5- to 14.5-month long missions are presented. Dual-energy x-ray gamma-absorbtiometry (QDR-1000 W, Hologic, USA) was used to measure bone mineral density (BMD, g/cm2) and mineral content (BMC, g) in the whole body, the scalp including cervical vertebra, arms, ribs, sternal and lumbar regions of the spinal column, pelvis and legs. A clearly defined dependence of topography of changes upon the position of a skeletal segment in the gravity vector was established. The greatest BMD losses have been observed in the skeleton of the lower body, i.e. in pelvic bones (-11.99 +/- 1.22%), lumbar vertebra (-5.63 +/- 0.817%), and in proximal femur, particularly in the femoral neck (-8.17 +/- 1.24%). Bones of the upper skeleton were either unchanged (insignificant) or showed a positive trend. Overall changes in bone mass of the whole skeleton of male cosmonauts during the period of about 6 months on mission made up -1.41 +/- 0.406% and suggest the mean balance of calcium over flight equal to -227 +/- 62.8 mg/day. Reasoning is given to qualify these states of cosmonauts' bone tissues as local osteopenia. On the literature and results of authors' clinical evidence, discussed is availability of the densitometric data for predicting risk of trauma. A biological nature of the changes under observation is hypothesized.

NASA Discipline Musculoskeletal↗

NASA NTRS2017