Throughout the week, as mourning continued, Coast Guard and NASA officials undertook the grim task of searching for the wreckage of Challenger. Starting some 30 miles off the cape and then spreading out to cover some 6,000 sq. mi., 13 aircraft and more than a dozen recovery vessels joined the search of the conveniently calm Atlantic waters for any evidence that might give clues as to why the spacecraft had exploded.

The debris raining from the sky had kept the searchers away from the possible impact area for nearly an hour. The sight of a slowly drifting parachute had given viewers a fleeting hope of human survival. News reports first indicated that a frogman had chuted into the ocean in a quick look for any survivors. But officials soon corrected both impressions: the falling parachute was one of the two that normally drop the boosters into the sea for salvaging and reuse of its parts. This one held a booster nose cap, which was retrieved two days later.

Despite the obvious devastation of the explosion, searchers began finding surprisingly large parts of the wreckage, the biggest being a 25-ft.- long section of the spacecraft's fuselage. Parts of the shuttle's wings, cabin and cargo-bay door were tentatively identified. Sonar detected a large metal object 140 ft. below the surface, and deep-diving submersibles went down to inspect it. There was speculation that the object might be Challenger's main cabin, although a more likely possibility was that it was one of Challenger's three main engines, which could have fallen in a cluster. But Coast Guard Spokesman Lieut. Commander James Simpson warned that "it could be a shrimp boat from 20 years ago or a Spanish galleon from 300 years ago." By week's end the mystery had not been solved. Recovery workers also turned their attention to a 13-ft.-diameter orange object sighted some 100 miles east of Savannah. They were hoping that it was the cone of the main fuel tank.

The final farewell for America's seven newest heroes came on Friday at the Johnson Space Center near Houston, where they had lived and trained. Among those who gathered there, under gray skies on a grassy quadrangle amid the squat modern buildings, were some 6,000 employees of NASA and its contractors, 90 Senators and Congressmen, and about 200 relatives of Challenger's crew. Awaiting the start of the memorial service, while an Air Force band played funeral hymns, some of the mourners stood quietly in clusters, dabbing their eyes, while others stared sadly into space. A few held aloft small American flags as tears ran down their faces.

The President and Nancy Reagan met the families in a sparsely furnished classroom. Reagan picked up Mike Smith's daughter Erin, 8, who was holding a brown teddy bear that wore a pink apron. After embracing most of the relatives, one by one, he said, "We'll all go out together in a few minutes. I wish there was something I could say to make it easier, but there just aren't any words." Yet when the music stopped and he stepped onto the outdoor ; rostrum, Reagan once again found the right words, and he delivered them eloquently.

"The sacrifice of your loved ones has stirred the soul of our nation, and, through the pain, our hearts have been opened to a profound truth," said the President. "The future is not free; the story of all human progress is one of a struggle against all odds. We learned again that this America was built on heroism and noble sacrifice. It was built by men and women like our seven star voyagers, who answered a call beyond duty." After paying individual tributes to each member of the crew, the President declared, "Dick, Mike, Judy, El, Ron, Greg and Christa--your families and your country mourn your passing. We bid you goodbye, but we will never forget you."

The dignified 30-minute ceremony ended with a display of an aerial equivalent of the riderless horse procession, which was impressed indelibly on a mourning nation at the funeral of John Kennedy 22 years ago. Four T-38 jets--the trainers in which all astronauts prepare for their dangerous duties --roared overhead. It would have been a perfect V formation except that a fifth plane was missing, and another symbolic void was created when one of the jets veered sharply away from the others. As the band played God Bless America, the President and the First Lady went down the line of family members, shaking their hands, offering final words of solace, and hugging little Erin and the other children as they began to cry.

Reported by Robert Ajemian/Concord, Jerry Hannifin/Cape Canaveral and David S. Jackson/ Houston