72 



billion years of its history, and since conditions on Mars were prob- 

 ably similar to those on Earth during this period, there is an excellent 

 chance that life originated on that planet too. We can easily see why 

 and how such life could have died out in the ensuing millenia, leading 

 to the negative results obtained by the Viking investigations 

 (fig. IV-7). But even if there is no life anywhere on Mars today, there 

 seems to be good reasons for returning to Mars to look for evidence 

 of early life forms. 



This will require a careful search in "the right places," as has 

 been required on Earth. A Viking-style lander mission has virtually 

 no chance of success in such an endeavor; a manned mission or a 

 sophisticated system of rovers with capabilities for sample return will 

 be required. It will be an expensive and difficult task, but the 

 rewards would be so great that a considerable effort is justified. To 

 find one more example of the origin of life, to know that this 



. .- •• :*< ••••.-■ _•. 



Figure IV-7.- NASA 's commitment to the exploration of the planets is most 

 dramatically seen in Viking Martian lander. 



