Tore Straume

Cosmic Radiation Dose Measurements from the RaD-X Flight Campaign

Abstract The NASA Radiation Dosimetry Experiment (RaD-X) stratospheric balloon flight mission obtained measurements for improving the understanding of cosmic radiation transport in the atmosphere and human exposure to this ionizing radiation field in the aircraft environment. The value of dosimetric measurements from the balloon platform is that they can be used to characterize cosmic ray primaries, the ultimate source of aviation radiation exposure. In addition, radiation detectors were flown to assess their potential application to long-term, continuous monitoring of the aircraft radiation environment. The RaD-X balloon was successfully launched from Fort Sumner, New Mexico (34.5°N, 104.2°W) on 25 September 2015. Over 18 hours of flight data were obtained from each of the four different science instruments at altitudes above 20 km. The RaD-X balloon flight was supplemented by contemporaneous aircraft measurements. Flight-averaged dosimetric quantities are reported at seven altitudes to provide benchmark measurements for improving aviation radiation models. The altitude range of the flight data extends from commercial aircraft altitudes to above the Pfotzer maximum where the dosimetric quantities are influenced by cosmic ray primaries. The RaD-X balloon flight observed an absence of the Pfotzer maximum in the measurements of dose equivalent rate.

NASA Radiation Biomarker WorkshopSeptember 27–28, 2007

Abstract Straume, T., Amundson, S. A., Blakely, W. F., Burns, F. J., Chen, A., Dainiak, N., Franklin, S., Leary, J. A., Loftus, D. J., Morgan, W. F., Pellmar, T. C., Stolc, V., Turteltaub, K. W., Vaughan, A. T., Vijayakumar, S. and Wyrobek, A. J. NASA Radiation Biomarker Workshop. September 27–28, 2007. Radiat. Res. 170, 393–405 (2008). A summary is provided of presentations and discussions at the NASA Radiation Biomarker Workshop held September 27–28, 2007 at NASA Ames Research Center in Mountain View, CA. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including those exposed during long-duration space travel. Topics discussed included the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage after large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. A summary of conclusions is provided at the end of the report.

Biomarker-Detection Technologies for Comprehensive Medical Diagnosis During Deep-Space Missions

Abstract: Human deep-space missions to Mars and beyond will require development of a compact device that can provide comprehensive in-flight medical diagnostic capability to support the health of astronauts. Key features should include the ability to handle multiple sample types (blood, saliva, breath), and the ability to measure virtually any biomarker, including future biomarkers that may emerge. Here we identify compatible technologies and their associated patents that can be integrated to create such a device, to provide essential hematology information (blood cell counts, white cell differential) and to detect proteins and other biomolecules needed to assess spaceflight medical conditions. The ability to analyze breath and saliva specimens is a priority. These specimens are fully non-invasive hence no risk is associated with sampling and can provide rapid health assessment information that could be critical for urgent medical issues that may arise during EVA, prior to removal of the spacesuit. In addition to space applications, the device we envision would have applications for health care on Earth, in the military, in developing countries, and other settings with limited access to conventional medical resources.

Meeting Report--NASA Radiation Biomarker Workshop

A summary is provided of presentations and discussions from the NASA Radiation Biomarker Workshop held September 27-28, 2007, at NASA Ames Research Center in Mountain View, California. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including for long-duration space travel. Topics discussed include the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage following large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass-spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. Summary conclusions are provided at the end of the report.

Cosmic-ray interaction data for designing biological experiments in space

There is growing interest in flying biological experiments beyond low-Earth orbit (LEO) to measure biological responses potentially relevant to those expected during a human mission to Mars. Such experiments could be payloads onboard precursor missions, including unmanned private-public partnerships, as well as small low-cost spacecraft (satellites) designed specifically for biosentinel-type missions. It is the purpose of this paper to provide physical cosmic-ray interaction data and related information useful to biologists who may be planning such experiments. It is not the objective here to actually design such experiments or provide radiobiological response functions, which would be specific for each experiment and biological endpoint. Nuclide-specific flux and dose rates were calculated using OLTARIS and these results were used to determine particle traversal rates and doses in hypothetical biological targets. Comparisons are provided between GCR in interplanetary space and inside the ISS. Calculated probabilistic estimates of dose from solar particle events are also presented. Although the focus here is on biological experiments, the information provided may be useful for designing other payloads as well if the space radiation environment is a factor to be considered.

Space Radiation Effects on Crew During and After Deep Space Missions

PurposeOverview and perspectives are provided of radiation hazards associated with deep space human missions, such as to Mars.Recent FindingsSignificant associations between radiation dose and effects of principal concern from space radiation (cancer, cardiovascular, CNS) have not yet been detected in astronauts. Therefore, estimates of radiation-induced health consequences from extended deep space missions are based on studies available from radiation-exposed human populations on Earth (e.g., A-bomb survivors) supplemented with data from biological experiments (primarily rodents) using space-type radiations obtained at specialized radiation facilities. This approach (the best available at this time) has large uncertainties, which strongly influence the number of days permitted in deep space.SummaryBased on current NASA risk limits, the length of time permitted in space may not be sufficient for a human mission to Mars, even with substantial shielding of the spacecraft. Risk mitigation strategies beyond shielding may therefore be required. Research is continuing to advance in these and related fields.

Assessment of the influence of the RaD-X balloon payload on the onboard radiation detectors: RAD-X CALIBRATION

The NASA Radiation Dosimetry Experiment (RaD-X) stratospheric balloon flight mission, launched on 25 September 2015, provided dosimetric measurements above the Pfotzer maximum. The goal of taking these measurements is to improve aviation radiation models by providing a characterization of cosmic ray primaries, which are the source of radiation exposure at aviation altitudes. The RaD-X science payload consists of four instruments. The main science instrument is a tissue-equivalent proportional counter (TEPC). The other instruments consisted of three solid state silicon dosimeters: Liulin, Teledyne total ionizing dose (TID) and RaySure detectors. The instruments were housed in an aluminum structure protected by a foam cover. The structure partially shielded the detectors from cosmic rays but also created secondary particles, modifying the ambient radiation environment observed by the instruments. Therefore, it is necessary to account for the influence of the payload structure on the measured doses. In this paper, we present the results of modeling the effect of the balloon payload on the radiation detector measurements using a Geant-4 (GEometry ANd Tracking) application. Payload structure correction factors derived for the TEPC, Liulin, and TID instruments are provided as a function of altitude. Overall, the payload corrections are no more than a 7% effect on the radiation environment measurements.