"You definitely do not want to be outside now," Husband replied.
In Houston, lead flight director Leroy Cain watched a glowing line track Columbia's reentry across a world map covering one wall in the windowless auditorium of Mission Control. This was his 12th mission.
Abruptly, instrument readings from four temperature sensors aboard Columbia flickered off.
No one in the five rows of systems engineers in front of Cain could tell him why.
To all appearances, the spacecraft was flying normally northeast of Yosemite, heading toward a routine landing in Florida.
Cain double-checked. "Everything look good to you?" he asked the engineer monitoring guidance and control.
"I don't see anything out of the ordinary," came the reply. The Johnson Space Center tape recorders and video cameras preserved every word.
Five minutes later, pressure readings from two of Columbia's tires ceased. The shuttle flew on, approaching Dallas and Fort Worth, slowing to 21 times the speed of sound.
Cain's thoughts raced down a dozen avenues of contingency and response, as he had practiced in so many mission simulations. Each was a dead end.
Ninety seconds passed.
"Columbia, [this is] Houston," radioed Marine Lt. Col. Charles Hobaugh, 42, the astronaut in charge of Mission Control's communications with the shuttle crew. "We see your tire pressure messages, and we did not copy your last call."
Aboard Columbia, shuttle commander Husband keyed the microphone switch. "Roger," he replied. "Uh, buh . "
His transmission ended mid-word.
With all its electronic senses, NASA strained for a telling signal. Frantically, engineers paged deeper into thick manuals of procedures. They sought to restore communication.
"Columbia? Houston. UHF comm check," Hobaugh radioed, trying to raise the crew.
"Columbia? Houston. UHF comm check," he repeated.