NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon

Record Details

Record 3 of 3046
Full Mission Astronaut Radiation Exposure Assessments for Long Duration Lunar Surface Missions
Author and Affiliation:
Adamczyk, Anne M.(Tennessee Univ., Knoxville, TN, United States)
Clowdsley, Martha S.(NASA Langley Research Center, Hampton, VA, United States)
Qualls, Garry D.(NASA Langley Research Center, Hampton, VA, United States)
Blattnig, Steve B.(NASA Langley Research Center, Hampton, VA, United States)
Lee, Kerry T.(NASA Johnson Space Center, Houston, TX, United States)
Fry, Dan J.(NASA Johnson Space Center, Houston, TX, United States)
Stoffle, Nicholas N.(Wyle Integrated Science and Engineering Group, Houston, TX, United States)
Simonsen, Lisa C.(NASA Langley Research Center, Hampton, VA, United States)
Slaba, Tony C.(Old Dominion Univ., Norfolk, VA, United States)
Walker, Steven A.(Old Dominion Univ., Norfolk, VA, United States) Show more authors
Abstract: Risk to astronauts due to ionizing radiation exposure is a primary concern for missions beyond Low Earth Orbit (LEO) and will drive mission architecture requirements, mission timelines, and operational practices. Both galactic cosmic ray (GCR) and solar particle event (SPE) environments pose a risk to astronauts for missions beyond LEO. The GCR environment, which is made up of protons and heavier ions covering a broad energy spectrum, is ever present but varies in intensity with the solar cycle, while SPEs are sporadic events, consisting primarily of protons moving outward through the solar system from the sun. The GCR environment is more penetrating and is more difficult to shield than SPE environments, but lacks the intensity to induce acute effects. Large SPEs are rare, but they could result in a lethal dose, if adequate shielding is not provided. For short missions, radiation risk is dominated by the possibility of a large SPE. Longer missions also require planning for large SPEs; adequate shielding must be provided and operational constraints must allow astronauts to move quickly to shielded locations. The dominant risk for longer missions, however, is GCR exposure, which accumulates over time and can lead to late effects such as cancer. SPE exposure, even low level SPE exposure received in heavily shielded locations, will increase this risk. In addition to GCR and SPE environments, the lunar neutron albedo resulting mainly from the interaction of GCRs with regolith will also contribute to astronaut risk. Full mission exposure assessments were performed for proposed long duration lunar surface mission scenarios. In order to accomplish these assessments, radiation shielding models were developed for a proposed lunar habitat and rover. End-to-End mission exposure assessments were performed by first calculating exposure rates for locations in the habitat, rover, and during extra-vehicular activities (EVA). Subsequently, total mission exposures were evaluated for proposed timelines. A number of computational tools and mathematical models, which have been incorporated into NASA's On-Line Tool for the Assessment of Radiation In Space (OLTARIS), were used for this study. These tools include GCR and SPE environment models, human body models, and the HZETRN space radiation transport code, which is used to calculate the transport of the charged particles and neutrons through shielding materials and human tissue. Mission exposure results, assessed in terms of effective dose, are presented for proposed timelines and recommendations are made for improved astronaut shielding and safer operational practice.
Publication Date: Jan 01, 2010
Document ID:
(Acquired Jul 28, 2010)
Subject Category: SPACE RADIATION
Report/Patent Number: JSC-CN-21080
Document Type: Preprint
Meeting Information: IEEE Aerospace Conference 2011; 5-12 Mar. 2011; Big Sky, MT; United States
Financial Sponsor: NASA Johnson Space Center; Houston, TX, United States
Organization Source: NASA Johnson Space Center; Houston, TX, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
Availability Source: Other Sources
Availability Notes: Abstract Only
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: August 24, 2011
Contact Us