A bus-size asteroid is racing through space on a trajectory that will bring it close to Earth, and NASA is watching it with the kind of precision that has turned near misses into routine science rather than cause for panic.

The rollout on Saturday, Jan. 17, of the Space Launch System (SLS) rocket is a crucial step signaling that NASA is in the final stretches to get its first crewed lunar mission in five decades off the ground. That mission, known as Artemis 2, will send three Americans and one Canadian on a 10-day trip around the moon.

Challenger exploded 73 seconds after liftoff while carrying seven people, including "Teacher in Space" participant Christa McAuliffe. Nobody survived the launch on Jan. 28, 1986 from NASA's Kennedy Space Center, and the event left a permanent mark upon the agency, its contractors and the nation.

The Space Age lost two of its most recognizable landmarks when NASA brought down towering test structures at Marshall Space Flight Center in Huntsville, Alabama. The controlled implosion erased hardware that helped push rockets to the Moon and into low Earth orbit,

The 40th anniversary of the Challenger disaster cast a shadow over NASA's annual Day of Remembrance event inside the Space Shuttle Atlantis building.

After a Crew-11 member aboard the ISS developed a medical concern on Jan. 7, NASA officials accelerated their return home to Earth by about a month.