Why did you expect to find life on mars?
Answers
Although Mars is smaller than Earth, it is still a very, very big place, so where should scientists aim landers to give them the best chance of finding evidence of life? All life on Earth depends upon water, so spacecraft in orbit and the next few landers will search for more signs of water to help guide later missions to promising locations.
Even if there were no life on Mars, it would be exciting to know whether there used to be life there. So in addition to looking for living bacteria, NASA will be searching for tiny fossils that might indicate life got a start early in Mars' history but, unlike on our home planet, it did not survive and evolve into larger life forms.
Many of the studies of Mars will involve robots, like the ones that have gone there before, but getting more advanced with each flight. Someday a spacecraft may pick up samples from Mars and bring them back to Earth where they can be studied in our best laboratories. Eventually, humans may make the daring journey, but many important problems have to be solved before trying such an expensive, difficult, and exciting voyage.