Jul 31 2008
From The Space Library
A team of scientists led by Robert H. Brown of the University of Arizona, Tucson, announced in the journal Nature that NASA’s ESA spacecraft had gathered evidence that Saturn’s moon Titan has at least one lake of liquid hydrocarbons. The discovery made Titan the only known celestial body, besides Earth, to have liquid on its surface. Data from previous fly-bys had shown that Titan has several features that appear to be lakes, but scientists had been unsure whether these bodies contained liquid or solid material. Then, in a December 2007 fly-by, ESA had used its visual and infrared mapping spectrometer (VIMS) to gather data on a lake in the southern polar region named Ontario Lacus. The lake covers an area of 7,800 square miles (20,201.91 square kilometers) and is composed of a liquid ethane solution, along with methane, other hydrocarbons, and nitrogen. At the surface temperature of Titan, which is -300°F (- 184.44°C), these compounds exist both as liquid and as gas. ESA’s data showed that the lake had experienced some evaporation at summer temperatures. Titan has a methane-based hydrological cycle; therefore, the scientists believed that a precipitation of liquid methane fills Ontario Lacus.
Jeanna Bryner, “Giant Lake Confirmed on Saturn’s Moon Titan,” Space.com, 31 July 2008, http://www.space.com/5673-giant-lake-confirmed-saturn-moon-titan.html (accessed 18 May 2011); NASA, “NASA Confirms Liquid Lake in Saturn Moon,” new release 08-193, 30 July 2008, http://www.nasa.gov/home/hqnews/2008/jul/HQ_08_193_Titan_lake.html (accessed 18 May 2011); see also R. H. Brown et al., “The Identification of Liquid Ethane in Titan’s Ontario Lacus,” Nature 454, no. 7204 (31 July 2008): 607-610.
NASA announced that LRO had successfully completed its first round of environmental testing. Engineers had performed the tests, which included a spin test and a vibration test, at NASA’s GSFC. The spin test ascertained the craft’s center of gravity and measured its rotation. The vibration test determined the structural integrity of LRO by simulating the shaking the craft would experience during launch. Before the launch, NASA planned for LRO to undergo acoustics testing, thermal-vacuum testing, and a simulation of separation from the rocket during launch. LRO’s launch window would open on 27 February 2009.
NASA, “NASA Tests Moon Imaging Spacecraft at Goddard,” news release 08-194, 31 July 2008, http://www.nasa.gov/home/hqnews/2008/jul/HQ_08194_LRO_Environment_Tests.html (accessed 18 May 2011).
NASA announced that its Phoenix Mars Lander had verified the presence of water ice in the Martian soil. Phoenix, which landed on Mars on 25 May 2008, had collected a soil sample from a 2-inch-deep (5.08-centimeter-deep) trench. Phoenix Mars Lander had dug the trench in the Martian polar region. The spacecraft had experienced difficulty moving the soil into the Thermal and Evolved-Gas Analyzer (TEGA) for testing, because the freshly dug soil samples had been stickier than scientists had expected. After allowing some of the water to evaporate from a sample measuring 3 cubic centimeters (0.18 cubic inches), scientists had used Phoenix’s whirling rasp to grate the soil into the TEGA. The TEGA had analyzed the vapor that the sample released when heated to the melting point of 32°F (0°C), confirming the presence of water in the soil. The analyzer had also examined the sample while it was heating to 1,800°F (982.22°C). Although the Mars Odyssey spacecraft had first sighted ice on the planet’s surface while orbiting Mars in 2002, Phoenix’s test was the first chemical analysis to prove the existence of water ice on Mars. NASA announced that it planned to add 90 days to Phoenix’s original mission, extending the mission through 30 September 2008.
Kenneth Chang, “Test of Mars Soil Sample Confirms Presence of Ice,” New York Times, 1 August 2008; NASA, “NASA Spacecraft Confirms Martian Water, Mission Extended,” news release 08-195, 31 July 2008, http://www.nasa.gov/home/hqnews/2008/jul/HQ_08_195_Phoenix_water.html (accessed 18 May 2008); David Perlman, “NASA Craft Probes Ice on Mars,” San Francisco Chronicle, 1 August 2008.
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