The space shuttle Columbia and its crew of seven astronauts were lost Saturday, minutes before they were scheduled to come home.

The shuttle lost contact with Mission Control at 8 a.m. CST while traveling at an altitude of 203,000 feet and a speed of about Mach 18, or 12,500 miles per hour, above north central Texas.

All seven astronauts — including the first Israeli man and first Indian woman in space, as well as an Ames native — are dead.

Mission commander Col. Rick Husband, pilot Cmdr. William McCool, flight engineer Kalpana Chawla, mission specialist Cmdr. Michael Anderson, medical officer and flight surgeon Cmdr. Laurel Clark, Columbia mission specialist Capt. David Brown and Col. Ilan Ramon were all lost during Columbia’s re-entry.

“These astronauts knew the dangers, and they faced them willingly, knowing they had a high and noble purpose in life,” President Bush said in a live address to the nation. “Because of their courage and daring and idealism, we will miss them all the more.”

The last contact to the shuttle Columbia was made at 7:59 a.m. CST by Mission Control: “Columbia, Houston. We see your tire pressure messages. We did not copy your last.”

There was a delay before the shuttle responded, “Roger … ehrm … “

Radio and data communication were lost at this point, and Columbia did not respond to repeated messages.

Calls of debris from residents of north central Texas to local authorities flooded the phone lines starting at about 8 a.m. CST. The debris stretches from the Dallas-Fort Worth area to more than 200 miles into central Louisiana.

Residents also reported hearing sonic booms.

“The whole house was shaking and I immediately ran outside, and the shuttle was flying extremely low,” said Terry Tawater, of Palestine, Texas. “Almost as soon as I got outside it was gone and there were vapor trails filling the sky — it was unbelievable.”

At about 8:16 a.m. CST, when the shuttle was scheduled to land at Cape Canaveral, Fla., NASA declared that a contingency action plan for Columbia was being implemented.

NASA assigned a former astronaut to each of the crew members’ families for support.

Bush said in his address that this disaster would not stop the mission of NASA. “The cause in which they died will continue. Mankind is led into the darkness beyond our world by the inspiration of discovery and the longing to understand. Our journey into space will go on.”

There may be some implications to the loss of Columbia for NASA.

A British Broadcasting Corp. correspondent said an immediate concern is the fate of the International Space Station. Three crewmen are currently living and working on the station.

Europe, Japan, Canada and Russia have all invested in this project, which relies heavily on the United State’s shuttle fleet. The correspondent said future plans will now be reviewed, and whether the station remains operational will be decided by experts.

Technical Difficulties

Although an exact cause is not known, experts have speculated on possible causes of the catastrophe.

During the Jan. 16 launch, a piece of orange insulating foam on Columbia’s external fuel tank came off during lift off and hit the leading edge of the shuttle’s left wing.

The crew never actually got to look at the area where the foam hit because they did not have a robot arm.

John Tannehill, ISU professor of aerospace engineering, said there were pictures taken from various satellites in space and there appeared to be no damage. Tannehill said there may have been things that the satellites might not have seen.

Leroy Cain, lead flight director in Mission Control, said Friday that engineers had concluded the damage to the wing, if there was any, was considered minor and posed no safety hazard.

“[We] took a very thorough look at the situation with the tile on the left wing and we have no concerns whatsoever,” he said.

An indication of trouble with the left wing began when temperature sensor readings in the wing were not being communicated during re-entry.

NASA officials are looking into the left wing, but are not ignoring other possibilities.

“As we look at that now in hindsight, we can’t discount that there might have been a connection,” Ron Dittemore, the shuttle program manager, said during a news conference on Saturday. “But we have to caution you and ourselves that we can’t rush to judgment on it because there are a lot of things in this business that look like the smoking gun but turn out to be not even close.”

Tire pressure readings for Columbia’s landing gear were lost next during re-entry, then there were indications of “excessive structural heating.”

The last communications to Columbia acknowledged the reading, and then all communication was lost.

A loss of communication is typical during re-entry.

“The shuttle starts to enter and it’s got tiles facing into the wind. An ionized envelope develops around the shuttle and you lose communication,” said William Byrd, director of the NASA space grant consortium. “The radio signal can’t penetrate and the shuttle will come out of it, but that didn’t happen.”

Tannehill said the shuttle should have still been in communication with Mission Control during that time frame of re-entry.

The moment communication was lost was probably the moment that the shuttle started breaking apart, Tannehill said.

Although there have never before been problems with a shuttle during re-entry, it is no less risky than going up even though it is an “engineering wonder,” said Ping Lu, ISU associate professor of aerospace engineering and engineering mechanics.

“It is a engineering wonder because the flight is so flawless, and this is really the first time [trouble has occurred], but you have to keep in perspective that space is full of uncertainty, and the people involved fully understand and fully take the risk,” Lu said.

The shuttle was at a critical point of re-entry, flying at a speed of Mach 18. The shuttle had slowed down, but was still in the middle of re-entry, Tannehill said.

“It appears that somehow the thermal system broke down and lead to structural failure, but that is speculation,” Tannehill said.

During re-entry, the heat surrounding the shuttle is about 3,000 degrees Fahrenheit, Lu said. It is very hostile and everything has to be very precise.

“Re-entry is always a critical moment for any spacecraft because the stress on the vehicle is so high,” Paul K. Harral, vice president and editorial page editor of the Fort Worth Star-Telegram, told the Daily on Saturday. Harral was a UPI space writer during the Apollo series, including the flight of Apollo 13.

“The issue is both the impact with the air which at the speed of re-entry can be substantial, and the resulting heat build-up as the air begins to drag on the spacecraft and slow it down. That friction causes heat, of course, and a critical element is dealing with that heat.”

Harral said NASA will next determine what happened and determine how to reduce the risk in future missions. There is no way to know how long the investigation could take, he said.

Columbia’s Crew

Aboard Columbia were seven astronauts, some of which had connections to the Midwest and some who were making history in their respective countries.

* Col. Rick Husband, 45, was on his second space mission, and his first as the shuttle’s commander. He was also a U.S. Air Force colonel and test pilot. He had a master’s degree from California State University-Fresno in mechanical engineering. Husband was married with two children.

* Pilot William McCool, 41, was a commander for the U.S. Navy and a former test pilot. He was the pilot for Columbia. He had a master of science degree in aeronautical engineering from the U. S. Navy Postgraduate School in 1992 and a master of science degree in computer science from the University of Maryland in 1985. This was his first flight into space.

* Michael Anderson, 43, was the payload commander and a mission specialist for Columbia. Anderson was a lieutenant colonel in the U.S. Air Force and a former instructor and tactical officer. He received a master of science in physics from Creighton University in Omaha, Neb., in 1990. This was his second flight.

* David M. Brown, 46, was a mission specialist for the flight. He was a captain in the U.S. Navy and a naval aviator and flight surgeon. He had a doctorate degree in medicine from Eastern Virginia Medical School in 1982.

* Laurel Clark, 41, was a mission specialist for Columbia. She was a commander in the U.S. Navy and a naval flight surgeon. She was born in Ames, though she called Racine, Wisc., her hometown. She received her doctorate degree in medicine from the University of Wisconsin-Madison in 1987. This was her first flight.

“Today’s space shuttle tragedy took one of Iowa’s native daughters, Laurel Clark, and six other brave heroes. Our thoughts and prayers are with Dr. Clark’s family and all of the families who lost their loved ones on this sad day,” Congressmen Tom Latham said in a statement.

* Kalpana Chawla, 41, was the flight engineer and a mission specialist for the shuttle. She was an aerospace engineer and a FAA certified flight instructor. She had a master of science degree in aerospace engineering from the University of Texas-Arlington in 1984 and a doctorate degree in aerospace engineering from the University of Colorado-Boulder in 1988. Chawla was considered a national hero in India and was the first Indian woman in space.

Chawla had conducted space experiments for the University of Iowa on Columbia in 1997 and spoke to local schools in Iowa in 1998. She helped researchers study the effects of microgravity environment on the stability of flames.

“For the last two days programs in the Indian media about her and after the accident people all over the country were really sad about it,” Deepak Sahoo, Ph.D. student in Electrical engineering and president of the Indian Student Association said.

* Ilan Ramon, 48, was the payload specialist on board Columbia. He was a colonel in the Israeli Air Force and a fighter pilot. Ramon was the first Israeli in space.

“I know my flight is very symbolic for the people of Israel, especially the survivors, the Holocaust survivors, because I was born in Israel, many people will see this as a dream that is come true,” Ramon said before the flight.

“It’s sad that it had to happen,” said Jonathan Gritz, president of Hillel, Iowa State’s Jewish student association.

Worldwide Reactions

Because of the tensions between Israelis and Palestinians, the subject of a terrorist attack was brought up early and were immediately dispelled by Gordon Johndroe, spokesman for the Homeland Security Department in Washington, D.C.

“There is no information at this time that this was a terrorist incident,” he said.

Palestinian Information Minister Yasser Abed Rabbo said the Palestinians are “shocked at the news of the tragedy. We sympathize with the families of the astronauts.”

Ramon’s brother Gadi spoke to Israel’s Channel 10 television on Saturday.

“We are in shock and don’t know what to do,” he said. “This as a dream come true for Ilan.”

— The Washington Post, BBC, The Des Moines Register, Houston Chronicle, The New York Times and NASA contributed to this article.