Search Results

Growing plants on Mars can reduce the amount of re-supply that a long term human presence will require. A plant growth structure has been designed to test plant performance in a derived Martian atmosphere. The unit will support different lighting and nutrient systems to allow for a large range of plant experiments. The plant growth structure will be tested in a Martian simulator, which is currently under construction at the Kennedy Space Center. The simulator is a commercially available Thermotron environmental testing chamber (1.22m x 1.22m x 1.52m). The Thermotron can accommodate the input of a derived. Martian atmosphere whose composition will be defined by the experimenter. Carbon dioxide, oxygen, nitrogen, and argon will be the major constituents. Testing will be done to determine the temperature, humidity, and pressure ranges that the unit can control.

Our long term objective is to utilize the photocatalytic property of titanium dioxide (TiO2) to convert volatile organic compounds (VOC) in contaminated air to carbon dioxide as a measure of total organic carbon (TOC) for risk assessment in space crafts. Photocatalytically active TiO2 surfaces prepared using Degussa P25 and sol-gel methods were evaluated for this purpose. Photocatalytic oxidation (PCO) of representative air contaminants (e.g. ethanol, toluene, dichloromethane, and acetaldehyde) by Degussa P25 immobilized on aluminum substrate revealed several shortcomings that are not suitable for our intended application. A series of experiments were conducted to optimize parameters during TiO2 sol preparation and thin film deposition.

Alternative lighting sources that offer advantages over traditional lighting regimes are being investigated for space-based plant growth applications. Light emitting diodes (LEDs) and sulfur-microwave lamps are among these candidate systems because of their potential for reduced power consumption and increased radiation use efficiency over conventional lighting systems such as high-pressure sodium (HPS) and cool white fluorescence (CWF). The effects of LEDs and microwave lamps on plant growth must also be characterized before they can be considered for spaceflight applications. Leaf morphology of spinach plants (Spinacia oleracea L. cv. Whitney) grown for 28 days under sulfur-microwave lamps or one of 4 LED arrays with peak output wavelengths of 660, 690, 700 and 725nm, (each supplemented with 470nm blue LEDs) was compared to control plants grown under HPS and CWF. Anatomical features were similar among plants grown under the control, microwave, 660 and 690nm LED lighting systems.

Bioprocessing of human fecal wastes may be an important means for recycling of crop nutrients within a closed Advanced Life Support System. The objectives of this study were to determine the levels of key crop nutrients that can be extracted from human feces that had been autoclave sterilized vs. those that had not. When compared with inedible ALS grown wheat residues, the contribution of feces, which has an ash content 13% to the total potential, recoverable minerals may be small. This paper discusses results from bioreactor runs obtained using continuous stirred tank reactors with an 8 day batch culture of autoclaved or not autoclaved feces. The results suggest that feces should not be autoclaved if mineral recovery is desired. Biodegradation of feces ranged from 27 to 39% in 8 days, with 67 to 79% reduction in soluble total organic carbon (TOC) and concomitant production of carbon dioxide (CO2).