"I've thought about Christa and the Challenger crew just about every day since 20-plus years ago," Morgan said in a series of interviews right before class got under way. "I hope that they know that they are here with us in our hearts."
Morgan, 55, who was McAuliffe's backup for the doomed 1986 flight, got her first opportunity to talk with schoolchildren late Tuesday afternoon, almost halfway through her two-week mission.
The youngsters were assembled at the Discovery Center of Idaho in Boise, less than 100 miles from the elementary school where Morgan taught before becoming an astronaut. Morgan's two sons, now teenagers, attended inventors' camp there years ago.
One child wanted to know about exercising in space. In response, Morgan lifted the two large men floating alongside her, one in each hand, and pretended to be straining. Another youngster wanted to see a demonstration of drinking in space. Morgan and her colleagues obliged by squeezing bubbles from a straw in a drink pouch and swallowing the red blobs, which floated everywhere. The four astronauts also used ping-pong balls and a softball for props.
Morgan was asked how being a teacher compared to being an astronaut.
"Astronauts and teachers actually do the same thing," she answered. "We explore, we discover and we share. And the great thing about being a teacher is you get to do that with students, and the great thing about being an astronaut is you get to do it in space, and those are absolutely wonderful jobs."
The 25-minute question-and-answer session was a welcome diversion for NASA, which found itself trying to explain — again — why foam insulation was still falling off shuttle fuel tanks more than four years after the Columbia disaster.
The gouge in shuttle Endeavour's belly is not considered a threat to the crew, but NASA was debating whether to send astronauts out to fix it in order to avoid time-consuming post-flight repairs. Any structural damage to the area resulting from the more than 2,000-degree heat of atmospheric re-entry would take weeks if not longer to repair.
All the testing and analyses are expected to be completed by Wednesday.
"Space flight is a risk management process," former NASA astronaut Tom Henricks told CBS' The Early Show about the challenges facing the Endeavour crew should they make the repairs.
"There is nothing routine," he said.
But Scott Kelly, Endeavour's commander, says crew members are not terribly worried.
"My understanding is that it's really not a safety issue for us on board. There isn't a whole lot of concern on board right now."