Complex sentence: NASA's Galileo mission to Jupiter provided extensive knowledge about its upper atmosphere, however, further study of Jupiter is crucial not only to the understanding of its origin and nature of the solar system, but also of giant extrasolar planets in general.
Split into simpler sentences: NASA's Galileo mission to Jupiter provided extensive knowledge about its upper atmosphere. However, further study of Jupiter is crucial not only to the understanding of its origin and nature of the solar system, but also of giant extrasolar planets in general.