Space Shuttle Discovery March 9, having spent a cumulative total of almost a full year in space. "Discovery" performed both research and International Space Station (ISS) assembly missions. It also carried the Hubble Space Telescope into orbit. "Discovery" was the first operational shuttle to be retired, followed by "Endeavour" and then "Atlantis". The name "Discovery" was chosen to carry on a tradition based on ships of exploration, primarily , one of the ships commanded by Captain James Cook during his third and final major voyage from 1776 to 1779, and Henry Hudson's , which was used in 1610–1611 to explore Hudson Bay and
Spitzer Space Telescope located in the habitable zone, which means they are capable of supporting liquid water given sufficient parameters. Using the transit method, "Spitzer" helped measure the sizes of the seven planets and estimate the mass and density of the inner six. Further observations will help determine if there is liquid water on any of the planets. Spitzer Space Telescope The Spitzer Space Telescope (SST), formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space telescope launched in 2003 and still operating as of 2018. It is the fourth and final of the NASA Great Observatories program. The planned mission period