The space shuttle Endeavour left the Kennedy Space Center in Cape Canaveral, Fla. at 8:56 a.m. ET Monday morning for what will be its final trip to the International Space Station. The 16-day flight is the second-last for NASA’s shuttles; this July, Atlantis will make NASA’s last shuttle flight before the entire fleet is retired. About 500,000 people gathered to watch the launch from nearby towns and roads, while millions were expected to tune in to a live broadcast online. Endeavour will deliver the Alpha Magnetic Spectrometer (AMS), a particle physics detector that scientists hope will help lead to the understanding of the origin of the universe. The shuttle will also deliver spare parts, including some specifically for Dextre, a Canadian Space Agency robot that rides on the end of the space station’s Canadarm2 robotic arm.