Many baby boomers remember the excitement of the space exploration program in the early days. The thought of a man walking on the moon was almost beyond imagination.
This week is a somber week for NASA, a week for remembering three U.S. space disasters. NASA will hold a Day of Remembrance ceremony on Feb. 1 at 10 a.m. EST. The ceremony, held at the Kennedy Space Center's Space Mirror, will be broadcast on NASA TV and by streaming on SPACE.com.
Flags at NASA will be flown at half-staff all day on Feb. 1 in memory of the 17 people who died in the course of three space missions.
On January 27, 1967, Apollo 1 astronauts Gus Grissom, Ed White and Roger Chaffee died when their crew capsule caught fire a month before the planned launch date.
On January 28, 1986, many of us watched in horror as the space shuttle Challenger exploded only 73 seconds after liftoff. Seven died in the disaster, including teacher Sharon "Christa" McAuliffe, who was to be the first teacher in space.
Also killed were Gregory Jarvis, Judy Resnik, Ronald McNair, Michael Smith, Ellison Onizuka, and Commander Dick Scobee.
The final space disaster led to the end of the space shuttle program. On February 1, 2003, the space shuttle Columbia broke apart during re-entry, killing the seven astronauts on board.
Killed in the Columbia were Commander Rick Husband, Kalpana "K.C." Chawla, Laurel Clark, David Brown, William McCool, Michael Anderson and Israeli astronaut Ilan Ramon.
This year's ceremony will be held on the tenth anniversary of the Columbia disaster. There will also be an observance at the astronaut memorials at Arlington National Cemetery.
You can read more about NASA missions, space exploration and aeronautics at the NASA website. You can also view video tributes to the crews of Apollo 1, Challenger and Columbia.