**1. NAME AND TITLE**

MAVRAC: Model Astronaut and Vehicle Radiation Analysis Code.

**2. CONTRIBUTORS**

Northrop Space Laboratories, Hawthorne, California.

Aerospace Medical Research Laboratory, Wright-Patterson Air Force Base, Ohio.

MAVRAC is held by RSIC as 1960s state of the art technology. It was used extensively by the
originators and distributed by RSIC six times between 1965-1969.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN; IBM 7090.

**4. NATURE OF PROBLEM SOLVED**

The MAVRAC code calculates the dose distribution in a model astronaut inside a space vehicle or the dose distribution in the vehicle.

The spacecraft is assumed to be represented by the combination of several geometrical
surfaces: spherical, conical, and toroidal. Two right elliptical cylinders are utilized to represent the
astronaut. Mathematical models of astronaut and the spacecraft are constructed.

**5. METHOD OF SOLUTION**

The dose rate as a function of wall and tissue thickness is represented by a polynomial expression fit to data obtained by other means. The dose rate is calculated at a specified number of points by computing the slant wall thickness of the vehicle in various directions. The mean dose for a model astronaut is then determined.

For the dose distribution in a space vehicle, material slant thicknesses for each given point is
given as input data. Tissue thicknesses are set equal to zero and the same expressions are used to
calculate dose rate.

**6. RESTRICTIONS OR LIMITATIONS**

Polynomial expressions of up to 8 terms (in powers of tissue thickness) allow up to 10 vehicle wall thicknesses. In addition, the following limitations are to be considered:

Solid angle increments up to 30 x 30 array

Geometric sections of spacecraft < 20

Number of dose points calculated < 200.

**7. TYPICAL RUNNING TIME**

Estimated running time of sample problem is 5 minutes.

**8. COMPUTER HARDWARE REQUIREMENTS**

The IBM 7090 or 7094 computer with a minimum of three tape units may be used to run the
code.

**9. COMPUTER SOFTWARE REQUIREMENTS**

The FORTRAN II Monitor System, any standard version, may be used. The only tapes assigned are those for input, output, and the system.

Logical tape numbers for input and output are defined in the main routine of MAVRAC and
may be changed by the user.

**10. REFERENCE**

G. Duckworth, "Model Astronaut and Vehicle Radiation Analysis Code," NSL-63-159
(September 1963).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced document and one (1.2MB) DOS diskette on which is written in
separate files: the source card deck, input data for a sample problem and output.

**12. DATE OF ABSTRACT**

January 1966; updated July 1981, February 1985.

**KEYWORDS: ** SPACE RADIATION; ENVIRONMENTAL DOSE