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Barnes, R.

Publications and source records attributed to Barnes, R..

12 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Effects of Extreme Obliquity Variations on the Habitability of Exoplanets

We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 108 years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes.

habitability of exoplanets↗
NASA NTRS1995

An inflight refill unit for replenishing research animal drinking water

This paper presents the design process and development approach for a method of maintaining sufficient quantities of water for research animals during a Shuttle mission of long duration. An inflight refill unit (IRU) consisting of two major subsystems, a fluid pumping unit (FPU) and a collapsible water reservoir (CWR), were developed. The FPU provides the system measurement and controls, pump, water lines, and plumbing necessary to collect water coming into the unit from the potable water system and pump it out into the RAHF drinking water tanks. The CWR is a Kevlar (TM) reinforced storage bladder connected to the FPU, which has a capacity of 6 liters in its expanded volume and functions to store the water collected from the potable water system, allowing for transport of the water back to the Spacelab where it is pumped into each of two research animal holding facilities. Additional components of the IRU system include the inlet and outlet fluid hoses, a power cable for providing 29V direct current spacecraft electrical power to the pump within the FPU, a tether system for the unit when in use in Spacelab, and an adapter for mating the unit to the orbiter waste collection system in order to dump excess water after use in Spacelab.

Savage, P. D.↗
NASA NTRS1994

Development of an In-Flight Refill Unit for Replenishing Research Animal Drinking Water

The Spacelab Life Sciences 2 (SLS-2) mission became NASA's longest duration Shuttle mission, lasting fourteen days, when Columbia landed on 1 Nov. 1993. Located within the Spacelab were a total of 48 laboratory rats which were housed in two Research Animal Holding Facilities (RAHF's) developed by the Space Life Sciences Payloads Office (SLSPO) at Ames Research Center. In order to properly maintain the health and well-being of these important research animals, sufficient quantities of food and water had to be available for the duration of the mission. An inflight Refill Unit was developed by the SLSPO to replenish the animals' drinking water inflight using the Shuttle potable water system in the middeck galley as the source of additional water. The Inflight Refill Unit consists of two major subsystems, a Fluid Pumping Unit (FPU) and a Collapsible Water Reservoir (CWR). The FPU provides the system measurement and controls, pump, water lines, and plumbing necessary to collect water coming into the unit from the potable water system and pump it out and into the RAHF drinking water tanks. The CWR is a Kevlar(trademark) reinforced storage bladder, connected to the FPU, which has a capacity of 6 liters in its expanded volume and functions to store the water collected from the potable water system and allows for the transport of the water back to the Spacelab where it is pumped into each of two RAHFs. Additional components of the FPU system include the inlet and outlet fluid hoses, a power cable for providing 28 volt direct current spacecraft electrical power to the pump within the FPU, a tether system for the unit when in use in Spacelab, and an adapter for mating the unit to the orbiter waste collection system in order to dump excess water after use in Spacelab. This paper will present the design process and development approach for the lnflight Refill Unit, define some of the key design issues which had to be addressed, and summarize the inflight operational performance of the unit during the SLS-2 mission.

Savage, P. D.↗
NASA NTRS1989

Trends in ozone profile measurements

From an examination of the agreements and differences between different satellite instruments, it is difficult to believe that existing satellite instruments determine upper stratospheric ozone much better than 4 pct.; by extension, it probably would require at least a 4 pct. change to be reliably detected as a change. The best estimates of the vertical profiles of ozone change in the upper stratosphere between 1979 and 1986 are judged to be those given by the two SAGE satellite instruments. SAGE-2 minus SAGE-1 gives a much lower ozone reduction than that given by the archived Solar Backscatter UV data. The average SAGE profiles of ozone changes between 20 and 50 degs north and between 20 and 50 degs south are given. The SAGE-1 and SAGE-2 comparison gives an ozone reduction of about 4 pct. at 25 km over temperate latitudes. Five ground based Umkehr stations between 36 and 52 degs north, corrected for the effects of volcanic aerosols, report an ozone reduction between 1979 and 1987 at Umkehr layer 8 of 9 + or - 5 pct. The central estimate of upper stratospheric ozone reduction given by SAGE at 40 km is less than the central value estimated by the Umkehr method at layer 8.

Johnston, H.↗
NASA NTRS1988

Space Station atmospheric monitoring systems

A technology assessment study on atmospheric monitoring systems was performed by Battelle Columbus Division for the National Aeronautics and Space Administration's John F. Kennedy Space Center under Contract No. NAS 10-11033. In this assessment, the objective was to identify, analyze, and recommend systems to sample and measure Space Station atmospheric contaminants and identify where additional research and technology advancements were required. To achieve this objective, it was necessary to define atmospheric monitoring requirements and to assess the state of the art and advanced technology and systems for technical and operational compatibility with monitoring goals. Three technical tasks were defined to support these needs: Definition of Monitoring Requirements, Assessment of Sampling and Analytical Technology, and Technology Screening and Recommendations. Based on the analysis, the principal candidates recommended for development at the Space Station's initial operational capability were: (1) long-path Fourier transform infrared for rapid detection of high-risk contamination incidences, and (2) gas chromatography/mass spectrometry utilizing mass selective detection (or ion-trap) technologies for detailed monitoring of extended crew exposure to low level (ppbv) contamination. The development of a gas chromatography/mass spectrometry/matrix isolation-Fourier transform infrared system was recommended as part of the long range program of upgrading Space Station trace-contaminant monitoring needs.

Air Pollution, Indoor/analysis↗