A primary reason is that viruses do not possess a cell membrane or metabolise on their own - characteristics of all living organisms. Examples of common human diseases caused by viruses include the common cold, the flu, chickenpox and cold sores.
In the past spacecraft have taken greatly different amounts of time to make it to Saturn. Pioneer 11 took six and a half years to arrive. Voyager 1 took three years and two months, Voyager 2 took four years, and the Cassini spacecraft took six years and nine months to arrive. The New Horizons spacecraft took a short two years and four months to arrive on the scene.
How long does it take a rocket ship to get to the moon, and how fast will the rocket be going? Answer 1: A rocket ship, on its way to the moon, can get up to almost 25,000 miles per hour in order to escape the Earths atmosphere. However, it does not go that fast the whole way.