NASA Remembers Three Space Tragedies

The end of January marks a somber time for NASA with the anniversary of the three major tragedies in the history of U.S. spaceflight.

On Jan. 27, 1967, three of the first group of NASA astronauts - Virgil ?Gus? Grissom, Edward White and Roger Chaffee - died during a routine ground test of the Apollo capsule, later named Apollo 1.

The astronauts suffocated when an electrical spark ignited a fire that engulfed their high-pressurized, pure-oxygen cabin. The Apollo 1 ground test had not been designated as potentially hazardous, the NASA History Web site said.

These were the first U.S. astronaut deaths associated with spaceflight. Sadly, that accident was not the last such tragedy.

The highly anticipated Jan. 28, 1986, launch of Space Shuttle Challenger, which carried the first teacher-astronaut, Christa McAuliffe, was watched live by many around the nation, including school children. But 73 seconds after takeoff, the shuttle erupted in a fireball that killed the entire crew.

In June 1986, the Presidential Commission on the Space Shuttle Challenger Accident, chaired by William P. Rogers, found that the O-ring seals in the right solid-rocket booster failed in the cold temperature, eventually causing the booster to rupture and explode, taking the lives of McAuliffe and astronauts Francis ?Dick? Scobee, Ron McNair, Mike Smith, Ellison Onizuka, Judy Resnik and Greg Jarvis. A complete failure of the O-ring was not expected at frigid temperatures, said Roger Launius, chairman of the Washington-based space history division of the Smithsonian Institute.

Seventeen years later, tragedy struck NASA once again. On Feb. 1, 2003, following a 16-day science mission, the space shuttle Columbia broke apart upon re-entry, killing the entire crew: U.S. astronauts Rick Husband, Willie McCool, Michael Anderson, Kalpana Chawla, David Brown, Laurel Clark and Israeli astronaut Ilan Ramon.

A gouge in the shuttle?s left wing absorbed too much heat as the shuttle re-entered Earth?s atmosphere. NASA officials did not believe that the gouge on the wing - caused by the impact of insulating foam from the shuttle?s external tank during its Jan. 16 liftoff - was severe enough to cause the loss of the shuttle, Launius said.

?The problem with all three of these accidents is they really didn?t know they had a problem,? Launius said in a phone interview.

However, certain individuals did in fact raise awareness about these and other issues. Roger Boisjoly, an engineer for Morton Thiokol which built the space shuttle rocket boosters, warned his superiors and NASA officials that the O-rings might not hold up in cold temperatures. While there had been problems with the O-ring seals during previous shuttle flights, there never was a total breach, Launius said. And without the necessary amount of hard evidence, those objections were not seen as sufficient enough to stop a shuttle launch, he said.

There was not a thorough enough understanding of these risks, he said.

The inability to communicate potential problems in an understandable way between the different groups working on the spacecraft contributed to the accidents that led to the astronauts? deaths, Launius said.

After all three accidents, new protocols immediately were implemented to prevent the problems in the future, including:

• The hatch for the Apollo capsule was reworked to allow faster egress, wiring was redone, flammable materials inside the cabin were replaced with flame-retardant items and the cabin pressure was lessened.

• The O-rings for the shuttle?s solid-rocket boosters were redesigned after the Challenger disaster.

• Foam debris hitting the shuttle was strictly scrutinized after the loss of Columbia, according to the NASA History Web site.

Despite the risks, astronauts continue to risk their lives. ?The spirit of exploration is truly what it is to be human,? astronaut Stephen Robinson said in an August 2005 audio message on flight STS-114, which directly followed the Columbia disaster.

?[W]e hope if anything happens to us, it will not delay the program,? Grissom said just a few weeks before he died, the NASA History Web site said. ?The conquest of space is worth the risk of life.?

• VIDEO: NASA's Apollo 1 Tragedy
• VIDEO: Columbia?s Crew: In Their Own Words
• GALLERY: Columbia?s STS-107 Shuttle Crew