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The Internal Active Thermal Control System (IATCS) aboard the International Space Station (ISS) contains an aqueous, alkaline fluid (pH 9.5±0.5) that aids in maintaining a habitable environment for the crew. Because microbes have significant potential to cause disease, adverse effects on astronaut health, and microbe-induced corrosion, the presence of both bacteria and viruses within IATCS fluids is of concern. This study sought to detect and identify viral populations in IATCS samples obtained from the Kennedy Space Center as a first step towards characterizing and understanding potential risks associated with them. Samples were concentrated and viral nucleic acids (NA) extracted providing solutions containing 8.87-22.67 μg NA per mL of heat transfer fluid. After further amplification viral DNA and cDNA were then pooled, fluorescently labeled, and hybridized onto a Combimatrix panvira 12K microarray containing probes for ∼1,000 known human viruses.

We have elicited a reliable Raman spectral signature for glucose in rabbit aqueous humor across mammalian physiological ranges in a rabbit model stressed by recent myocardial infarction. The technique employs near infrared Raman laser excitation at 785 nm, multivariate analysis, non-linear artificial neural networks and an offset spectra subtraction strategy. Aqueous humor glucose levels ranged from 37 to 323 mg/dL. Data were obtained in 80 uL samples to anticipate the volume constraints imposed by the human and rabbit anterior chamber of the eye. Total sample collection time was 10 seconds with total power delivered to sample of 30 Mw. Spectra generated from the aqueous humor were compared qualitatively to artificial aqueous samples and an excitation offset technique was devised to counteract broadband background noise partially obscuring the glucose signature.

Launched on NASA's Aura spacecraft on July 15, 2004, JPL's Tropospheric Emission Spectrometer (TES) has been operating successfully for over three years in space. TES is an infrared high resolution, imaging fourier transform spectrometer with spectral coverage of 3.3 to 15.4 μm to measure and profile essentially all infrared-active molecules present in the Earth's lower atmosphere. It measures the three-dimensional distribution of ozone and its precursors in the lower atmosphere on a global scale. The Aura spacecraft was successfully placed in a sun-synchronous near-circular polar orbit with a mean altitude of 705 km and 98.9 minute orbit period. The observatory is designed for a nominal 5 year mission lifetime. The instrument thermal design features include four temperature zones needed for efficient cryogenic staging to provide cooling at 65 K, 180 K, 230 K and 300 K.

A Small Loop Heat Pipe (SLHP) featuring a wick of only 1.27 cm (0.5 inches) in diameter has been designed for use in spacecraft thermal control. It has several features to accommodate a wide range of environmental conditions in both operating and non-operating states. These include flexible transport lines to facilitate hardware integration, a radiator capable of sustaining over 100 freeze-thaw cycles using ammonia as a working fluid and a structural integrity to sustain acceleration loads up to 30 g. The small LHP has a maximum heat transport capacity of 120 Watts with thermal conductance ranging from 17 to 21 W/°C. The design incorporates heaters on the compensation chamber to modulate the heat transport from full-on to full-stop conditions. A set of start up heaters are attached to the evaporator body using a specially designed fin to assist the LHP in starting up when it is connected to a large thermal mass.

This study of samples collected from Mars 01 Orbiter was conducted to gain a better understanding and practical experience in methods to process and preserve samples intended for planetary protection analysis. Samples were evaluated for the viable growth of microbes, the molecular biomarker adenosine triphosphate (ATP), and the presence of lipopolysaccharide, a bacterial cell wall component. Losses were observed in the number of viable microbes after freezing as well as in the detectable lipopolysaccharide. Two independent studies of pooled cleanroom samples demonstrate good ATP recovery and consistent values after freezing at −20 °C.

A technology demonstration propylene Loop Heat Pipe (LHP) has been tested extensively in support of the implementation of this two-phase thermal control technology on NASA’s Earth Observing System (EOS) Tropospheric Emission Spectrometer (TES) instrument. This cryogenic instrument is being developed at the Jet Propulsion Laboratory (JPL) for NASA. This paper reports on the transient characterization testing results showing low frequency temperature oscillations. Steady state performance and model correlation results can be found elsewhere. Results for transient startup and shutdown are also reported elsewhere. In space applications, when LHPs are used for thermal control, the power dissipation components are typically of large mass and may operate over a wide range of power dissipations; there is a concern that the LHP evaporator may see temperature oscillations at low powers and over some temperature range.

The Trace Gas Analyzer (TGA, Figure 1) is a self-contained, battery-powered mass spectrometer that is designed for use by astronauts during extravehicular activities (EVA) on the International Space Station (ISS). The TGA contains a miniature quadrupole mass spectrometer array (QMSA) that determines the partial pressures of ammonia, hydrazines, nitrogen, and oxygen. The QMSA ionizes the ambient gas mixture and analyzes the component species according to their charge-to-mass ratio. The QMSA and its electronics were designed, developed, and tested by the Jet Propulsion Laboratory (1,2). Oceaneering Space Systems supported JPL in QMSA detector development by performing 3D computer for optimal volumetric integration, and by performing stress and thermal analyses to parameterize environmental performance.

In order to meet microbial reduction requirements for all Mars in-situ life detection and sample return missions, entire planetary spacecraft (including planetary entry probes and planetary landing capsules) may have to be exposed to a qualified sterilization process. At JPL, we are developing a low temperature (~45°C) vapor phase hydrogen peroxide sterilization process. This process is currently being used by the medical industry and its effectiveness is well established. In order to effectively and safely apply this technology to sterilize a spacecraft, which is made out of various man-made materials and electronic circuit boards, the following technical issues need to be resolved: 1. Efficacy of sterilization process. 2. Diffusion of H2O2 under sterilization process conditions into hard to reach places. 3. Materials and components compatibility with the sterilization process. 4. Development of methodology to protect (isolate) sensitive components (i.e. electronic ) from H2O2 vapor.

The Mars Exploration Rover (MER) flight system uses mechanical, paraffin-actuated heat switches as part of its secondary battery thermal control system. This paper describes the design, flight qualification, and performance of the heat switch. Although based on previous designs by Starsys Research Corporation1,2, the MER mission requirements have necessitated new design features and an extensive qualification program. The design utilizes the work created by the expansion of a paraffin wax by bringing into contact two aluminum surfaces, thereby forming a heat conduction path. As the paraffin freezes and contracts, compression springs separate the surfaces to remove the conduction path. The flight qualification program involved extensive thermal performance, structural, and life testing.

A paraffin-actuated heat switch has been developed for thermal control of the batteries used on the 2003 Mars Exploration Rovers. The heat switch is used to reject heat from the rover battery to a radiator. This paper describes the development test program designed, in part, to measure the thermal conductance of the heat switch in an 8 Torr CO2 environment over the expected operating temperature range of the battery. The switch has a closed conductance of about 0.6 W/°C and an open conductance of 0.019 W/°C. The test program also included measuring the battery temperature profile over a hot case and a cold case Mars diurnal cycle. The test results confirm that the battery will remain well within the upper and lower allowable flight temperatures in both cases.

Phoenix, NASA's first Mars Scouts mission, will be launched in 2007 and will soft-land inside the Martian Arctic Circle, between north 65° and 72° North latitude, in 2008 to study the water history and to search for habitable zones. Similar to the IDD (Instrument Deployment Device) on the Mars Exploration Rovers (MER), Phoenix has a Robotic Arm (RA) which is equipped with a scoop to dig into the icy soil and to deliver the soil samples to instruments for scientific observations and measurements. As with MER, the actuators and the bearings of the Phoenix RA in a non-operating condition can survive the cold Martian night without any electrical power or any thermal insulation. The RA actuators have a minimum operating allowable flight temperature (AFT) limit of -55°C, so, warm-up heaters are required to bring the temperatures of all the RA actuators above the operating AFT limit prior to early morning operation.

In support of the National Aeronautics and Space Administration(NASA), a laboratory has been established at the Jet Propulsion Laboratory (JPL) to evaluate the characteristics of chemical sensors which are candidates for use in a controlled chemical processing life support system. Such a facility is required for characterizing those sensors under development as well as those commercially available but whose functional properties are typically based upon operating in industrial environments that will not be completely synonomous with space operations. Space environments, such as an orbiting station or lunar base, will generally have different sensor requirements than terrestrial applications with respect to size, multifunctionality, sensitivity, reliability, temperature, ruggedness, mass, consumables, life, and power requirements. Both commercially available and developmental moisture sensors have been evaluated.

The microbial burdens of 69 cabin air samples collected in-flight aboard commercial airliners were assessed via culture-dependent and molecular-based microbial enumeration assays. Cabin air samples from each of four separate flights aboard two different carriers were collected via air-impingement. Microbial enumeration techniques targeting DNA, ATP, and endotoxin were employed to estimate total microbial burden. The total viable microbial population ranged from 0 to 3.6 × 104 cells per 100 liters of air, as assessed by the ATP-assay. When these same samples were plated on minimal medium, anywhere from 2 to 80% of the viable population was cultivable. Five of the 29 samples examined exhibited higher cultivable plate counts than ATP-derived viable counts, perhaps a consequence of the dormant nature (lower concentration of intracellular ATP) of cells inhabiting these air cabin samples.

Dry heat microbial reduction is an approved method to reduce the microbial bioburden on space-flight hardware prior to launch to meet flight project planetary protection requirements. Microbial bioburden reduction also occurs if a spacecraft enters a planetary atmosphere (e.g., Mars) and is heated by frictional forces. However, without further studies, administrative credit for this reduction cannot be applied. The killing of Bacillus subtilis var. niger spores has been examined and lethality data has been collected by placing spores in a vacuum oven or thermal spore exposure vessels (TSEV) in a constant temperature bath. Using this lethality data, a preliminary mathematical model is being developed that can be used to predict spore killing at different temperatures. This paper will present the lethality data that has been collected at this time and the planned future studies.

Previous studies indicated evidence of opportunistic pathogens in samples obtained during missions to the International Space Station (ISS). This study utilized TaqMan quantitative PCR to determine specific gene abundance in potable and non-potable ISS waters. Probe and primer sets specific to the small subunit rRNA genes were designed and used to elucidate overall bacterial rRNA gene numbers. In addition, primer-probe sets specific for Burkholderia cepacia and Stenotrophomonas maltophilia were optimized and genes of these two opportunistic pathogens quantified in the pre- and post-flight drinking water as well as coolant waters. This Q-PCR approach supports findings of previous culture-based studies however; the culture based studies may have underestimated the microbial burden of ISS drinking water.

Certain Eubacteria enter a viable but nonculturable (VBNC) state upon encountering unfavorable environmental conditions. VBNC cells do not divide on conventional media yet remain viable and in some cases retain virulence. Here, we describe the VBNC state of two opportunistic pathogens previously isolated from ISS potable waters, Burkholderia cepacia and Stenotrophomonas maltophilia. Artificially inoculated microcosms were exposed to the biocidal agents copper (CuSO4) and iodine (I2) in an attempt to induce nonculturablility. Viability was assessed via fluorescent microscopy (direct viable count assay coupled with BacLight™ staining) and metabolic activity was monitored by quantifying both intracellular ATP and transcribed rRNA (reverse transcriptase quantitative PCR). Culturablility was lost in both B. cepacia and S. maltophilia within two days of exposure to copper or high concentrations of iodine (6 or 8 ppm).

Various candidates for nonpetroleum electric and hybrid vehicle (EHV) subsystems have been evaluated as part of the Advanced Vehicle (AV) Assessment at the Jet Propulsion Laboratory. The subsystems include battery and power-peaking energy storage, heat engine and fuel cell energy conversion devices, motor/controller subsystems, transmissions, and vehicle subsystem (structure and body) technologies. The primary objective of this effort, was to project the mature capabilities of the various components in the 1990’s for application in the systems evaluations in the next phase of this activity. This paper presents the basic characteristics of the subsystems and compares their capabilities with projected AV subsystem requirements.

This paper describes a novel thermal control system for future Mars landers and rovers designed to keep battery temperatures within the −10 °C to +25 °C temperature range. To keep the battery temperatures above the lower limit, the system uses: 1) a phase change material (PCM) thermal storage module to store and release heat and 2) a loop heat pipe (LHP) to transfer heat from a set of Radioisotope Heater Units (RHUs) to the battery. To keep the battery temperature below the upper limit, a thermal control valve in the LHP opens to redirect the working fluid to an external radiator where excess heat is dumped to the atmosphere. The PCM thermal storage module was designed and fabricated using dodecane paraffin wax (melting point, − 9.6 °C) as the phase change material. A miniature ammonia loop heat pipe with two condensers and an integrated thermal control valve was designed and fabricated for use with the PCM thermal storage unit.

The Jet Propulsion Laboratory Mars Exploration Program Office is currently planning a series of exciting missions to the Red Planet. During each launch opportunity, the missions to Mars will include a Rover mission. During the earlier Rover missions to Mars such as the Mars Pathfinder mission carrying the Sojourner Rover in 1997, the main rover power source was a solar array. The power subsystem of the Sojourner Rover included a solar panel for power during the day, a non-rechargeable lithium battery for power during the night, and a power electronics board for power conditioning and distribution. Starting with the year 2003 the rover missions to Mars will incorporate a rechargeable energy storage device rather than a non-rechargeable power source. Included in the power electronics board, will be a battery controller/charger. The battery controller/charger will be able to monitor and control three parallel 4-cell battery strings.

NASA requires lightweight rechargeable batteries for future missions to Mars and the outer planets that are capable of operating over a wide range of temperatures, with high specific energy and energy densities. Due to the attractive performance characteristics, lithium-ion batteries have been identified as the battery chemistry of choice for a number of future applications, including Mars rovers and landers. The Mars 2001 Lander (Mars Surveyor Program MSP 01) will be among one of the first missions which will utilize lithium-ion technology. This application will require two lithium-ion batteries, each being 28 V (eight cells), 25 Ah and 8 kg. In addition to the requirement of being able to supply at least 200 cycles and 90 days of operation upon the surface of Mars, the battery must be capable of operation (both charge and discharge) at temperatures as low as -20°C.