2006年VOA标准英语-Mars Missions: Breakthrough Landings on the Pla（在线收听）

By Paul Sisco
Washington, DC
02 August 2006
 
watch Viking report
 

An illustration of a Viking landing on the red planet  
  
Thirty years after the first successful landing of a robotic probe on Mars by NASA's Viking spacecraft, the search for life on the red planet still generates enthusiasm for future space exploration.

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Viking 1 was launched August 20, 1975, beginning a 200 million mile journey to Mars.  Two weeks later Viking 2 blasted off with an identical orbiter and lander, and the biggest unmanned program in the history of space exploration was underway.  Eleven months later, on July 20, 1976, the Viking 1 lander touched down on the red planet.

'We're coming down, straight down.  We have a green…we have touch down. We have touch down," was the announcement in the command center to cheers.

A spectacular moment for the Vikings, as the ground crew called themselves, but better still -- receiving the first images from the surface.

Gentry Lee, the Viking project director, said, "A moment in every Vikings' life that he or she will never forget, sitting with that television right in front of you and watching as the first lines came down.  It came down line by line, by line, and there was no way to describe how we felt." 

Bob Boyer   
  
Bob Boyer, the Flight Operations Systems Manager, added, "Since this was a scanning type of means of sending the picture back, you only got it in sections, and you slowly built up this landing pod, and you saw one section, and two sections, three sections, and you started seeing the surface of Mars, and then you knew.  We had done it, you know.  We thought, ‘My gosh, what an achievement!' "

  
Gentry Lee 
  
"How do you possibly describe the first photograph that a human being has every seen from the surface of another planet?" asks Mr. Lee.

Designed to function for 90 days, Viking landers collected data for more than six years, accumulating 4,500 up-close images of the Martian surface.   Vikings' grainy pictures of rocks and rusty soil uncovered nothing organic but did convince scientists the mysterious red planet had more to offer; providing data on seasonal changes, the Martian atmosphere and surface.  

Since the Vikings landed 30 years ago, each new mission and probe has provided more data and detail.  Fifty thousand images later there are indications of water in Mars' history, 97 percent of the red planet has now been mapped, and possible landing sites for manned missions have been identified.