The thought weighed heavy on John Grunsfeld, an astrophysicist and NASA astronaut who had flown on five space shuttle missions, three of which to service Hubble. The press hailed Grunsfeld as a hero, and called him “Dr. Hubble.” He mulled over the hundreds of billions of dollars spent on the ISS and the shuttles, and the comparative sliver of funding required to sustain the golden age of space telescopes. He wondered how NASA’s brawny human exploration program might once again forge a powerful partnership with the agency’s purely scientific side. So, during 2003 and 2004, he served as NASA’s chief scientist and helped develop science applications for Bush’s Constellation program. Big rockets, it turns out, are just as useful for launching extremely large telescopes as they are for hurling astronauts toward the Moon. Such a rocket might make launching JWST and conceivably larger TPF-style observatories easier and cheaper. The planning backfired, however, when Constellation cast its hungry shadow over NASA’s science budget. In early 2010, Grunsfeld left NASA to serve as deputy director of the Space Telescope Science Institute in Baltimore, Maryland—the pulsing nexus of operations for Hubble and, someday, for JWST. He worked closely with the institute’s director, the astronomer Matt Mountain, for nearly two years to lay the groundwork for a future TPF-style telescope. Their preferred in-house design was aptly named ATLAST, the Advanced Technology Large-Aperture Space Telescope, and was intended to deliver images of potentially habitable exoplanets. Dr. Hubble had become Dr. TPF, Dr. ATLAST.