The crowds cheered at Cape Canaveral on Jan. 16 as the space shuttle Columbia rocketed into the cloudless sky, but for the children of the astronauts, the celebration was laced with worry.

Ian Clark, the 8-year-old son of mission specialist Laurel Clark, turned to his aunts and uncles and asked, "Why can't any of you go? Then my mom won't have to go."

Nearby, the daughter of Israel's first astronaut, Ilan Ramon, voiced a 5-year-old's fear: "I lost my daddy."

For her mother, Rona Ramon, who had spent the weeks before liftoff avoiding any thoughts of danger, the words seem prophetic now. "Apparently she knew," Ramon said, sobbing.

The accident that plunged the nation into grief also left 12 children without a parent. Ramon's four children, along with pilot William McCool's three sons, commander Rick Husband's two children, payload commander Michael Anderson's two girls and Clark's son, were thrust into a world of private grief shared on the public stage in a way few have ever experienced.

NASA, all too well-prepared for such loss nearly two decades after the Challenger exploded, has provided the families with seclusion since the moment it learned the Columbia was lost. Many of them are expected to attend a memorial service at 1 p.m. today at the Johnson Space Center in Houston, a private event for the relatives, astronauts and NASA officials. President Bush is to attend.

A simultaneous public service will be held at the National Cathedral in Washington.

Thirteen men and women know exactly what is in store for the Columbia children as they cope with the loss of their fathers and mothers under the nation's watch. For the children of the Challenger astronauts, "private grief" was twisted into "public torture," Kathie Scobee Fulgham, daughter of Challenger commander Dick Scobee, wrote in an open letter to the children who lost parents in the Sept. 11 terrorist attacks.

"My father died a hundred times a day on televisions all across the country," she wrote. "And since it happened so publicly, everyone in the country felt like it happened to them, too. And it did. The Challenger explosion was a national tragedy. Everyone saw it, everyone hurt, everyone grieved, everyone wanted to help. But that did not make it any easier for me. They wanted to say good-bye to American heroes. I just wanted to say good-bye to my Daddy."

The Challenger accident and its aftermath left deep scars on the crew's children, said Delbert D. Smith, a Washington attorney who set up a trust fund for them, which he has reactivated for the Columbia children.

"We had reports from psychiatrists and medical personnel later saying, what did we expect in this situation when you not only see your father die but have to see it over six times in the morning and then on the 6 o'clock news and the 11 o'clock news and then for the next two months," Smith said.

NASA will provide counseling to the families, a spokeswoman said yesterday, but its culture is designed to provide astronauts' families with a ready-made support structure, even for routine missions.

As is the custom at the National Aeronautics and Space Administration, the Columbia crew's families were accompanied at liftoff and landing by other astronauts, trusted family friends selected by the crew to provide support and explanation to those left on Earth.

"It's so helpful to have an astronaut there to be able to answer the questions that might arise while watching a launch or a landing," said Tom Jones, a former astronaut in Virginia.

The families will also be able to lean on each other, Jones said. Shuttle crews train together for a year before a mission, and their families tend to become very close, he said.

Evelyn Husband, wife of the Columbia's commander, appeared on NBC's Today show yesterday and said the families are doing "remarkably well."

"We've gotten strength from each other, and it was great to see them yesterday," she said. "We just cried and laughed and hugged each other, and it was very helpful."

After the Challenger exploded, families of the crew remained close, attending each others' children's school graduations, visiting each other and talking on the telephone.

"After the accident, we were each other's best support," Scobee's widow, June Scobee Rodgers, told the Associated Press a year after the accident.

Smith said he and the other volunteer board members of the trust fund will try to do for the Columbia children what they did for those from the Challenger. Although it couldn't help directly with the psychological toll, the fund was able to provide about $1.2 million in education and medical benefits for the Challenger children.

Smith said the trust fund will set up a post office box and take donations through Bank of America. Last time, the trust fund received some corporate support, but most donations came from individuals, often in small amounts.

Given that the nation just got through an outpouring of support for the Sept. 11 victims and may be on the brink of war, Smith said he doesn't know whether the fund will generate as many donations this time.

"If we get lots of support this time, that's wonderful. If we don't, that's the world today," Smith said. "At least we're going to try."

Wire services contributed to this article.