On NASA's #DayofRemembrance, we honor those who lost their lives while furthering the cause of exploration and discovery. We join NASA in remembering the crews of Apollo 1, Space Shuttle Challenger (STS-51L), and Space Shuttle Columbia (STS-107). Apollo 1: Virgil "Gus" Grissom, Edward H. White, Roger B. Chaffee STS-51L: Ellison S. Onizuka, Michael J. Smith, Christa McAuliffe, Francis R. “Dick” Scobee, Gregory B. Jarvis, Judith A. Resnik, Ronald E. McNair STS-107: David M. Brown, Rick D. Husband, Laurel B. Clark, Kalpana Chawla, Michael P. Anderson, William C. McCool, Ilan Ramon