Prediction of Martian Surface Neutron Environment - PowerPoint PPT Presentation

Prediction of martian surface neutron environment l.jpg
Download
1 / 16

Prediction of Martian Surface Neutron Environment M. S. Clowdsley 1 , G. DeAngelis 2 , J. W. Wilson 1 , F. F. Badavi 3 , and R. C. Singleterry 1 1 NASA Langley Research Center, Hampton, VA 2 Old Dominion University, Norfolk, VA 3 Christopher Newport University, Newport News, VA

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Prediction of Martian Surface Neutron Environment

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Prediction of martian surface neutron environment l.jpg

Prediction of Martian Surface Neutron Environment

M. S. Clowdsley1, G. DeAngelis2, J. W. Wilson1, F. F. Badavi3, and R. C. Singleterry1

1 NASA Langley Research Center, Hampton, VA

2Old Dominion University, Norfolk, VA

3Christopher Newport University, Newport News, VA

Solar and Space Physics

and the Vision for Space Exploration Meeting

Wintergreen, Virginia

October 16-20, 2005


Radiation transport codes l.jpg

Radiation Transport Codes

  • Monte Carlo Codes: MCNPX, HETC, FLUKA, TIGRE

    • Accurately model the transport of neutrons, protons, and other light ions (and electrons in the case of TIGRE)

    • GCR ions being added

    • Require large amounts of computer time

  • Deterministic Codes: HZETRN, GRNTRN

    • Accurately model the transport of neutrons, protons, light ions, and GCR

    • Provide rapid transport calculations

HZETRN used in following calculations!!!


Planetary surface material and atmosphere l.jpg

Mars Induced Fields

Planetary Surface Material and Atmosphere

GCR ion

High energy

particles

Diffuse

neutrons

(Simonsen et al.)


Gcr environments l.jpg

GCR Environments

Free Space

Martian Surface

1977 Solar Minimum (solid)

1990 Solar Maximum (dashed)


Mars surface neutrons l.jpg

Mars Surface Neutrons


Mars surface worst case spe environment l.jpg

Mars Surface “Worst Case SPE” Environment

Free Space

Martian Surface

“Worst Case SPE” = 4 X proton component of

Sept. ’89 Event

Exploration Design Basis SPE as yet undefined


Dose equivalent on mars surface due to gcr l.jpg

Dose Equivalent on Mars Surface Due to GCR


Mars surface mapping l.jpg

Mars Surface Mapping

Charged Ions – 1977 Solar Minimum

from Space Ionizing Radiation Environment and Shielding Tools (SIREST) web site

http://sirest.larc.nasa.gov


Mars surface mapping9 l.jpg

Mars Surface Mapping

Neutrons – 1977 Solar Minimum

from Space Ionizing Radiation Environment and Shielding Tools (SIREST) web site

http://sirest.larc.nasa.gov


Mars surface mapping10 l.jpg

Mars Surface Mapping

Low Energy Neutrons – 1977 Solar Minimum

from Space Ionizing Radiation Environment and Shielding Tools (SIREST) web site

http://sirest.larc.nasa.gov


Mars surface environment l.jpg

Mars Surface Environment


Model for mars atmosphere l.jpg

Model for Mars Atmosphere

  • Atmospheric chemical and isotopic composition modeled using results from in-situ Viking 1 & 2 Landers measurements for both major and minor components:

CO2 % 95.32

N2 % 02.70

Ar % 01.60

O2 % 00.13

CO % 00.08


Model for mars surface l.jpg

Model for Mars Surface

  • The surface altitude, or better the atmospheric depth for incoming particles, determined using a model for the Martian topography based on the data provided by the Mars Orbiter Laser Altimeter (MOLA) instrument on board the Mars Global Surveyor (MGS) spacecraft.

  • The Mars surface chemical composition model based on an averaging process over the measurements obtained from orbiting spacecraft, namely the Mars 5 with gamma-ray spectroscopy, and from landers at the various landing sites, namely Viking Lander 1, Viling Lander 2, Phobos 2 and Mars Pathfinder missions.


Model for mars surface14 l.jpg

Model for Mars Surface

SiO2 % 44.2

Fe2O3 % 16.8

Al2O3 % 08.8

CaO % 06.6

MgO % 06.2

SO3 % 05.5

Na2O % 02.5

TiO2 % 01.0

  • The adopted Mars surface chemical composition:


Model for mars surface15 l.jpg

Model for Mars Surface

  • The composition, different with respect to the regolith (e.g. CO2 ice, H2O ice), of seasonal and perennial polar caps has been taken into account by modeling the deposition of the possible volatile inventory over the residual caps, along with its geographical variations all throughout the Martian year, for both the Mars North Pole and South Pole, from results from imaging data of orbiter spacecraft and from groundbased observations

  • No 3D time dependent models for the Martians polar caps was previously available for radiation studies


Conclusions l.jpg

Conclusions

  • The Martian surface environment including albedo neutrons can be calculated using existing transport codes

  • These codes must be validated with detector data!!!!!!


  • Login