In the 20 years since contact, several expeditions have set out, some in borrowed ships, some in ships built on Earth. The ship "USS Benjamin Franklin", with an all-male crew, set out to visit the core of the Milky Way — actually an unusual quest by the stodgy standards of the typical galactic culture. Another ship has gone as far as the Magellanic Clouds. The pan-European expedition in the ship "Europa", crewed entirely by women, has roamed far outside the local group of cultures. The star-drive technology allows journeys of tens of thousands of parsecs in mere months. In spite of this, most cultures are "stay-at-homes" compared to humans, interacting only with the local group of cultures, known as a "cluster".