Engineering topics

Fonda, Mark L.

Publications and source records attributed to Fonda, Mark L..

6 records

NASA NTRS2015

Planetary Protection Knowledge Gaps for Human Extraterrestrial Missions Workshop Booklet - 2015

Although NASA's preparations for the Apollo lunar missions had only a limited time to consider issues associated with the protection of the Moon from biological contamination and the quarantine of the astronauts returning to Earth, they learned many valuable lessons (both positive and negative) in the process. As such, those efforts represent the baseline of planetary protection preparations for sending humans to Mars. Neither the post-Apollo experience or the Shuttle and other follow-on missions of either the US or Russian human spaceflight programs could add many additional insights to that baseline. Current mission designers have had the intervening four decades for their consideration, and in that time there has been much learned about human-associated microbes, about Mars, and about humans in space that has helped prepare us for a broad spectrum of considerations regarding potential biological contamination in human Mars missions and how to control it. This paper will review the approaches used in getting this far, and highlight some implications of this history for the future development of planetary protection provisions for human missions to Mars. The role of NASA and ESA's planetary protection offices, and the aegis of COSPAR have been particularly important in the ongoing process.

Fonda, Mark L.↗

NASA NTRS2002

A Simplified Model for an Evolving Protoplanetary Nebula

The dynamical evolution of the protoplanetary nebula is investigated using analytical solutions of the surface density transport equations. Constant and beta viscosity turbulence models are compared with a functional analytical model and the well-known alpha viscosity formulation. The beta viscosity model, heretofore used for steady-state disks, is shown to be a viable tool for separating dynamic and thermodynamic properties of an evolving disk.

Davis, Sanford S.↗

NASA NTRS2000

Survivability of Microbes in Mars Wind Blown Dust Environment

Although the probability of Earth microbes growing (dividing) in the Martian environment is extremely low, the probability of their survival on the Martian surface is unknown. During the course of landed missions to Mars terrestrial microbes may reach the surface of Mars via inadequately sterilized spacecraft landers, rovers, or through accidental impact of orbiters. This investigation studied the potential for Earth microbes to survive in the windblown dust on the surface of Mars. The rationale for the study comes from the fact that Mars regularly has huge dust storms that engulf the planet, shading the surface from solar UV radiation. These storms serve as a mechanism for global transfer of dust particles. If live organisms were to be transported to the surface of Mars they could be picked up with the dust during a dust storm and transported across the planet. Washed, dried spores of Bacillus subtilis strain HA 101 were aseptically mixed with sterile sieved (size range of 1-5microns) Mars soil standard (obtained from NASA Johnson Space Center, Houston, Texas, USA), or Fe-montmorillonite such that the number of microbes equals 5 x 10(exp 6)/g dry wt soil. The microbe soil mixture was placed in a spherical 8 L Mars simulation chamber equipped with a variable speed rotor, gas ports and an Oriel deuterium UV lamp emitting light of wave lengths 180-400 nm. The chamber was sealed, flushed with a simulated Martian atmosphere (96.9% CO2, 3% O2, 0.1% H2O), and the pressure brought to 10 torr. The lamp and rotor were switched on to begin the experiment. Periodically samples were collected from the chamber, and the numbers of microbial survivors g soil was determined using plate counts and the most probable number method (MPN). The data indicate that Bacillus subtilis spores dispersed with Mars analog soil in a Mars atmosphere (wind blown dust) survive exposure to 5.13 KJ m-2 UV radiation, suggesting that Mars wind blown dust has potential to the protect microbes from solar UV radiation.

Mancinelli, Rocco L.↗

NASA NTRS1994

Gas-grain simulation facility: Aerosol and particle research in microgravity

This document reports on the proceedings of the Gas-Grain Simulation Facility (GGSF) Science Workshop which was co-hosted by NASA Ames Research Center and Desert Research Institute, University of Nevada System, and held in Las Vegas, Nevada, on May 4-6, 1992. The intent of the workshop was to bring together the science community of potential GGSF experimenters, Science Working Group and staff members, and the Phase A contractor to review the Phase A design with the science participants and to facilitate communication between the science community and the hardware developers. The purpose of this report is to document the information disseminated at the workshop, to record the participants' review of the Phase A GGSF design concept and the current science and technical requirements for the Facility, and to respond to any questions or concerns that were raised at the Workshop. Recommendations for the future based on numerous discussions with the participants are documented, as well as science presentations and poster sessions that were given at the Workshop and a summary of 21 candidate experiments.

Huntington, Judith L.↗

NASA NTRS1989

Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 1: Executive summary and overview

Fogleman, Guy↗

NASA NTRS1989

Gas-Grain Simulation Facility: Fundamental studies of particle formation and interactions. Volume 2: Abstracts, candidate experiments and feasibility study

An overview of the Gas-Grain Simulation Facility (GGSF) project and its current status is provided. The proceedings of the Gas-Grain Simulation Facility Experiments Workshop are recorded. The goal of the workshop was to define experiments for the GGSF--a small particle microgravity research facility. The workshop addressed the opportunity for performing, in Earth orbit, a wide variety of experiments that involve single small particles (grains) or clouds of particles. Twenty experiments from the fields of exobiology, planetary science, astrophysics, atmospheric science, biology, physics, and chemistry were described at the workshop and are outlined in Volume 2. Each experiment description included specific scientific objectives, an outline of the experimental procedure, and the anticipated GGSF performance requirements. Since these experiments represent the types of studies that will ultimately be proposed for the facility, they will be used to define the general science requirements of the GGSF. Also included in the second volume is a physics feasibility study and abstracts of example Gas-Grain Simulation Facility experiments and related experiments in progress.

Fogleman, Guy↗