While the National Aeronautics and Space Administration (NASA)'s Hubble Space Telescope has collected a large amount of astrophysical data, has outlived all expectations, and has been described as one of the space agency's most successful missions, the instrument will soon succumb to the extreme environment of space. In addition, with the James Webb Space Telescope costing at least US$9 billion, the agency's astrophysics budget is extremely strained. As a result, NASA's other astrophysics missions have been delayed until funding becomes available.