雅思口语准备之火星探路者陨落

　　The Phoenix Mars Lander appears darker, smaller, and with a truncated shadow in 2010, compared with a picture taken from orbit in 2008. An illustration shows how the shadow should appear when the craft and both its solar panels are intact.

　　Diagram courtesy NASA/JPL-Caltech/University of Arizona

　　Richard A. Lovett

　　for National Geographic News

　　Published May 25, 2010

　　The lights have officially gone out for NASAs Phoenix Mars Lander.

　　After several unsuccessful attempts to reestablish communication, a picture of the lander taken from orbit shows at least part of the crafts solar panels has broken off.

　　As seen in the pictures above, Phoenix shines with a bluish tint in a shot taken July 20, 2008, by the HiRISE camera on the Mars Reconnaissance Orbiter. In a picture taken May 7, 2010, the lander is darkened by a covering of reddish material.

　　Phoenix now appears smaller, and its shadow has changed shape.

　　We assumed that one of the most likely things that would cause it to perish over the winter would be ice buildup on the solar arrays, causing them to collapse, said Barry Goldstein, project manager for the Phoenix team at the Jet Propulsion Laboratory in Pasadena, California.

　　The image confirms that this is exactly what happened.

　　No Hope Phoenix Lander Will Rise Again

　　The Phoenix Mars Lander touched down near Marss north pole on May 25, 2008. The stationary craft reported on polar conditions for five months.

　　Although Phoenix was never designed to withstand Martian winter, it was programed with an energy-saving Lazarus mode. Scientists had hoped the craft might be able to maintain enough power to reawaken when sunlight returned in the spring.

　　The lander was last heard from in November 2008, when winter set in and the sun fell too low in the sky to power the crafts electronics.

　　NASA started a listening campaign when spring arrived on Mars in January 2010. Another orbiter, Mars Odyssey, periodically flew over the landers location and tuned in to any potential radio communications.

　　But during all four flybys, Phoenix stayed silent.

　　The new picture is the final nail in the coffin: Most likely, carbon dioxide froze out of the Martian atmosphere during the harsh polar winter. The sheer weight broke the solar panel, depriving Phoenix of its ability to collect enough sunlight to stay alive, Goldstein said.

　　In its time on Mars, the lander made several important finds, including verification that