Space environments

This reactor is intended for use on Mars. Unlike many other extraterrestrial environments. Mars has an atmosphere. Specifically the atmosphere is roughly 4-7 millibar of pressure and composed of 95% carbon dioxide, 2.7% nitrogen, 1.5% argon, 0.15% oxygen, and 0.15% water (Keifer, 1992). This presents a host of complications for materials choices in the reactor. The pressure vessel of the reactor will be exposed to this environment while at an elevated temperature. While this temperature is lower than what one would expect for a liquid metal or rankine cycle reactor, it is high enough to 

---

Electronic-Grade MMCs. Metal-matrix composites can be tailored to have optimal thermal and physical properties to meet requirements of electronic packaging systems, eg, cotes, substrates, carriers, and housings. A controUed thermal expansion space tmss, ie, one having a high precision dimensional tolerance in space environment, was developed from a carbon fiber (pitch-based)/Al composite. Continuous boron fiber-reinforced aluminum composites made by diffusion bonding have been used as heat sinks in chip carrier multilayer boards. 

Action of Vacuum on Spacecraft Materials. For service beyond the atmosphere, the vacuum environment allows materials to evaporate or decompose under the action of various forces encountered (1,18,19). These forces include the photons from the sun, charged particles from solar wind, and dust. The action of space environment on materials and spacecraft can be simulated by a source—sink relationship in a vacuum environment. Thus, for example, the lifetime of a solar panel in space operation may be tested (see Photovoltaic cells). 

Compact, low-space environment and low weight per unit volume handled make it second only to the propeller fan. 

Composite materials must survive in the environment to which they are subjected at least as well as the conventional materials they replace. Some of the harmful environments encountered include exposure to humidity, water immersion, salt spray, jet fuel, hydraulic fluid, stack gas (includes sulfur dioxide), fire, lightning, and gunfire as well as the combined effects of the space environment. 

Jursa, A. S. (1985). Handbook of Geophysics and the Space Environment. Springfield VA National Technical... 

The space environment, seen as beginning in the center of the earth, extends to infinity. In the past few decades outer space has been penetrated. These initial successful steps depended on a number of factors, one of which was the use of plastics. As in terrestrial uses, plastics have their place in space. 

Laser cooling can efficiently reduce the velocity of the atoms but cannot circumvent the acceleration due to gravity. On the ground the 1-g gravity level sets clear limitations to the ultimate sensitivities. The HYPER project (Hyper precision cold atom interferometry in space) will follow precisely this line and will benefit from the space environment, which enables very long interaction time (few seconds) and low spurious vibrational level. The sensitivity of the atomic interferometer can achieve few 10 rad.s. Hz to rotation and to acceleration. This very sensitive and accurate apparatus... 

Cable GG, Doherty S. 1999. Acute carbamate and organochlorine toxicity causing convulsions in an agricultural pilot A case report. Aviat Space Environ Med 70(l) 68-72. 

Kamimori, G. H., Johnson, D., Thorne, D. Belenky, G. (2005). Multiple caffeine doses maintain vigilance during early morning operations. Aviat. Space Environ. Med. 76 (11), 1046-50. 

Caldwell, I.A., Caldwell, I.L., Darlington, K.K. Utility of dextroamphetamine for attenuating the impact of sleep deprivation in pilots. Aviat. Space Environ. Med. 74 1125, 2003. 

Until now, Mercury has only been studied more closely by one spacecraft (Mariner 10, 1974), since its nearness to the sun means that spacecraft approaching it are subject to particularly extreme conditions. NASA s MESSENGER (Mercury Surface, Space, Environment, Geochemistry and Ranging) was launched in 2004 and is planned to reach Mercury in March 2011, and then to orbit the planet. The main tasks of the MESSENGER mission are to map the planet, to make measurements of its magnetic field and to collect data relevant to its geological and tectonic history (Solomon, 2007). 

Maier, M.A. and M.R. Landauer. 1990. Onset of behavioral effects in mice exposed to 10 Gy 60Co radiation. Aviation Space Environ. Med. 61 893-898. 

Mattsson, J.L., R.W.Young, C.R.Curran, C.G.Franz, M.J.Cowan, and L.J.Jenkins. 1981. Acute and chronic propylene glycol dinitrate exposure in the monkey. Aviat. Space Environ. Med. 52 340-345. 

Poitrast BJ, Keller WC, Elves RG. 1988. Estimation of chemical hazards in breast milk. Aviat Space Environ Med 59 A87-A92. 

Using UV-visible and IR spectroscopies, thermal analyses and scanning electron microscopes measurements, Young and Slemp studied the performance of several polymeric materials after exposure to an outer-space environment . PEN exhibited good environmental resistance to the oxygen-induced erosion, UV-induced degradation and spacecraft-induced contamination in such an environment [33],... 

Sommese T, Patterson JC. (1995). Acute effects of cigarette smoking withdrawal a review of the literature. Aviat Space Environ Med. 66(2) 164-67. 

Baioh RW, Sharma S, Moskowitz H, Griffith R. (1979). Effect of aicohoi and marijuana on eye movements. Aviat Space Environ Med. 50(1) 18-23. 

PorterHO. 1990. Aviators intoxicated by inhalation of JP-5 fuel vapors. Aviat Space Environ Med 61(7) 654-656. 

Selden A, Ahlborg G, Jr. 1991. Mortality and cancer morbidity after exposure to military aircraft fuel. Aviat Space Environ Med 62(8) 789-794. 

Keller WC Toxicity assessment of hydrazine fuels. Aviat Space Environ Med 59 (11, Suppl) AlOO-6, 1988... 

Voge VM Freon An unsuspected problem. Aviat Space Environ Med 60(10, suppl) B27-B28, 1989... 

Comperatore CA, Lieberman HR, Kirby AW, et al. Melatonin efficacy in aviation missions requiring rapid deployment and night operations. Aviat Space Environ Med 1996 67 520-524. 

For this purpose, nitro compounds have received special attention because of their ability to withstand high temperatures and low pressures encountered in space environments. The research on heat-resistant explosives was reviewed first by Dunstan [26] followed by Urbanski and Vasudeva [27], Lu [28], recently by Agrawal [29, 30] and Sikder [31]. 

Many asteroid spectra tend to be "redder" than the spectra of the corresponding meteorites. Reddened spectra have lower reflectivity, weaker absorptions, and spectral slopes that are flatter in the red end. This phenomenon has been attributed to "space weathering," a catchall term referring to any process that modifies the optical properties of surfaces of airless bodies exposed to the space environment. 

In 2006 Beauchamp reported on the expanding role of mass spectrometry in developing new instruments for laboratory simulations and in situ exploration of the space environment.13 The cometary and interstellar dust analyzer ( ), which was designed for the direct analysis of the space environment and mounted on the spacecraft, is a time-of-flight mass spectrometer for measuring, in situ, the chemical composition and the original mass of the individual dust grains. 

---