Programmer's manual for the Mission Analysis Evaluation and Space Trajectory Operations program (MAESTRO)

The Mission Analysis Evaluation and Space Trajectory Operations program known as MAESTRO is described. MAESTRO is an all FORTRAN, block style, computer program designed to perform various mission control tasks. This manual is a guide to MAESTRO, providing individuals the capability of modifying the program to suit their needs. Descriptions are presented of each of the subroutines descriptions consist of input/output description, theory, subroutine description, and a flow chart where applicable. The programmer's manual also contains a detailed description of the common blocks, a subroutine cross reference map, and a general description of the program structure

An Astronaut's Risk of Experiencing a Critical Impact from Lunar Ejecta During Lunar EVA

The Moon is under constant bombardment by meteoroids. When the meteoroid is large, the impact craters the surface, launching crater ejecta far from the impact potentially threatening astronauts on the lunar surface. In the early 1960s, the ejecta impact flux was thought no more than the sporadic meteoroid flux but with speeds one to two orders of magnitude smaller. However, the Lunar Module designers realized by 1965 that meteoroid bumpers do not perform well at the smaller ejecta impact speeds. Their estimates of the Lunar Module risk of penetration by ejecta were 25 to 50% of the total risk. This was in spite of the exposure time to ejecta being only a third of that to sporadic meteoroids. The standard committee based the 1969 NASA SP-8013 lunar ejecta environment on Zooks 1967 flux analysis and Gault, Shoemaker and Moores 1963 test data for impacts into solid basalt targets. However, Zook noted in his 1967 analysis, that if the lunar surface was composed of soil, that the ejected soil particles would be smaller than ejected basalt fragments and that the ejection speeds would be smaller. Both effects contribute to reducing the risk of a critical failure due to lunar ejecta. The authors revised Zooks analysis to incorporate soil particle size distributions developed from analysis of Apollo lunar soil samples and ejected mass as a function of ejecta speed developed from coupling parameter analyses of soil impact-test data. The authors estimated EVA risk by assuming failure occurs at a critical impact energy. At these impact speeds, this might be true for suit hard and soft goods. However, these speeds are small enough that there may be significant strength effects that require new test data to modify the hypervelocity critical energy failure criterion. With these caveats, Christiansen, Cour-Palais and Freisen list the critical energy of the ISS EMU hard upper torso as 44 J and the helmet and visor as 71 J at hypervelocity. The authors then assumed that the lunar EVA suit fails at 50 J critical energy. This results in a 1,700,000 years mean time to failure using the results of this analysis and a 3,800 years mean time to failure using NASA SP-8013

Space station integrated wall design and penetration damage control. Task 3: Theoretical analysis of penetration mechanics

The efforts to provide a penetration code called PEN4 version 10 is documented for calculation of projectile and target states for the impact of 2024-T3 aluminum, R sub B 90 1018 steel projectiles and icy meteoroids onto 2024-T3 aluminum plates at impact velocities from 0 to 16 km/s. PEN4 determines whether a plate is perforated by calculating the state of fragmentation of projectile and first plate. Depth of penetration into the second to n sup th plate by fragments resulting from first plate perforation is determined by multiple cratering. The results from applications are given

Radio astronomy Explorer-B in-flight mission control system development effort

A description is given of the development for the Mission Analysis Evaluation and Space Trajectory Operations (MAESTRO) program to be used for the in-flight decision making process during the translunar and lunar orbit adjustment phases of the flight of the Radio Astronomy Explorer-B. THe program serves two functions: performance and evaluation of preflight mission analysis, and in-flight support for the midcourse and lunar insertion command decisions that must be made by the flight director. The topics discussed include: analysis of program and midcourse guidance capabilities; methods for on-line control; printed displays of the MAESTRO program; and in-flight operational logistics and testing

A temperature-sensitive morphological mutant present in Beadle-Tatum and Rockefeller-Lindegren “wild-type” stocks and their derivatives

A temperature-sensitive morphological mutant present in Beadle-Tatum and Rockefeller-Lindegren “wild-type” stocks and their derivative

Hypervelocity Impact of Explosive Transfer Lines

Hypervelocity impact tests of 2.5 grains per foot flexible confined detonating chord (FCDC) shielded by a 1 mm thick 2024-T3 aluminum alloy bumper standing off 51 mm from the FCDC were performed. Testing showed that a 6 mm diameter 2017-T4 aluminum alloy ball impacting the bumper at 6.97 km/s and 45 degrees impact angle initiated the FCDC. However, impact by the same diameter and speed ball at 0 degrees angle of impact did not initiate the FCDC. Furthermore, impact at 45 degrees and the same speed by a slightly smaller diameter ball (5.8 mm diameter) also did not initiate the FCDC

Experimental investigation of crater growth dynamics

This work is a continuation of an ongoing program whose objective is to perform experiments and to develop scaling relationships for large-body impacts onto planetary surfaces. The centrifuge technique is used to provide experimental data for actual target materials of interest. With both power and gas guns mounted on the rotor arm, it is possible to match various dimensionless similarity parameters, which have been shown to govern the behavior of large-scale impacts. The development of the centrifuge technique has been poineered by the present investigators and is documented by numerous publications, the most recent of which are listed below. Understanding the dependence of crater size upon gravity has been shown to be key to the complete determination of the dynamic and kinematic behavior of crater formation as well as ejecta phenomena. Three unique time regimes in the formation of an impact crater have been identified

Endotoxin: A Twofold Effect on Bone Marrow Ultrastructure

Ultrastructural studies of mouse bone marrow reveal that reduction of the marrow-blood barrier precedes the two waves of leukocytosis which follow endotoxin administration. These ultrastructural changes include a decrease in adventitial cover of the marrow sinus wall, an increase in sinus circumference, and a decrease in endothelial cell overlap. The marrow-blood barrier changes which precede the first wave of leukocytosis are transient and are associated with depletion of marrow granulocytes. The changes that precede the second wave of leukocytosis 5 to 6 days later are more sustained and are associated with marked granulocyte hyperplasia. We suggest that endotoxin has two effects on marrow ultrastructure: (1) an early, direct effect on the sinus wall and (2) a later, indirect effect associated with granulocyte proliferation. The late effect may be mediated through endotoxin induced release of colony stimulating factor. Both effects diminish the normal marrow-blood barrier and appear to facilitate cell release from the marrow