Monday, February 11, 2013

Remembrance: Apollo 1

by Stephanie Osborn

You may remember that I started my career as a payload flight controller for first Shuttle, and then Station. And that I had a friend aboard Columbia during her final flight. For those who have read my all-too-painfully prescient book, Burnout: The mystery of Space Shuttle STS-281, you know I dedicated that book to my friend Kalpana Chawla, her crewmates, and all those who have died in pursuit of space. "Ad astra, per ardua." ("To the stars, through struggle/adversity.")

We've just passed through a period of time of which most people are unaware. You see, all of the major space disasters that America has experienced all occurred within a 2-3 week span on the calendar. And interestingly, they occurred in chronological order on the calendar.

Apollo 1 Fire - January 27

Space Shuttle Challenger disaster - January 28

Space Shuttle Columbia disaster - February 1


So what happened?

The Apollo 1 Fire

Apollo 1, originally designated Apollo/Saturn-204, was to have been the first manned mission of the Apollo program. It was scheduled to launch on February 21, 1967 with the crew component of Gus Grissom, Ed White, and Roger Chaffee. Frayed insulation allowed a spark from a cable to jump to flammable material in the cabin's pure oxygen atmosphere during a countdown checklist test. Velcro was a new product and the crew and especially the ground crew it seems, went crazy in using it inside the cabin to place things within easy reach. Unfortunately it is highly flammable, and in the pure oxygen atmosphere, went up like a blowtorch. The additional design modification of having an inward-opening inner hatch after the near-catastrophe of Gus Grissom's Liberty Bell 7 flight, rendered it impossible to open the hatch for escape. The crew was trapped inside and died in the fire, which created interior pressures so great that the capsule ruptured, sending flames outward and igniting part of the surrounding superstructure.

The timeline: at 6:30:54 (23:30:54 GMT) during a T-10min hold, a voltage transient was recorded. This was likely the initiating spark. At 6:31:04 (ten seconds later), Chaffee exclaimed, "Hey." The voice recorder picked up scuffling sounds, then Commander Grissom reported the fire. At 6:31:12 Chaffee officially reported, "We've got a fire in the cockpit." White responded. Twelve seconds later, Chaffee began urging his colleagues to get out.

Per Wikipedia's entry, "Some witnesses said they saw White on the television monitors, reaching for the inner hatch release handle as flames in the cabin spread from left to right and licked the window." There was also this official report: "Witnesses monitoring the television showing the hatch window reported that flames spread from the left to the right side of the command module and shortly thereafter covered the entire visible area." [Apollo 1: The Fire,]

The last voice transmission was garbled and was variously interpreted by flight control witnesses to be, "They’re fighting a bad fire—let's get out. Open 'er up," "I'm reporting a bad fire. I'm getting out," or possibly, "We've got a bad fire—let's get out. We're burning up."

Transmission ceased suddenly at 6:31:21. Some witnesses "believe there was one sharp cry of pain. Loss of radio signal occurred a few seconds later." [NASA Memorandum, Report on Apollo 204 Review Board Discussions,]

"The oxygen supply to the astronaut suits, which had been holding nearly constant pressure and temperature, started to fluctuate at the time of signal loss. At 6:31:17 or 14 seconds after the fire was first detected, the cabin pressure reached a level of approximately 29 psi and the cabin ruptured." [NASA Memorandum, Report on Apollo 204 Review Board Discussions,]

Once the capsule ruptured, a kind of backdraft ensued and the fire expanded outside the cabin, setting various components of the superstructure afire. "Throughout this period, other pad personnel were fighting secondary fires on level A-8. There was considerable fear that the launch escape tower, mounted above the command module, would be ignited by the fires below and destroy much of the launch complex." [Apollo 1: The Fire,] By the time the interior cabin could be safely reached, there was nothing that could be done to save the crew.

"The official death certificates for all three crew members list the cause of death as asphyxiation due to smoke inhalation due to the fire." [NASA Memorandum, Report on Apollo 204 Review Board Discussions,]


"Three hatches were installed on the command module. The outermost hatch, called the boost protective cover (BPC) hatch, was part of the cover which shielded the command module during launch and was jettisoned prior to orbital operation. The middle hatch was termed the ablative hatch and became the outer hatch when the BPC was jettisoned after launch. The inner hatch closed the pressure vessel wall of the command module and was the first hatch to be opened by the crew in an unaided crew egress.

"On the day of the fire, the outer or BPC hatch was in place but not fully latched because of distortion in the BPC caused by wire bundles temporarily installed for the test. The middle hatch and inner hatch were in place and latched after crew ingress. Although the BPC hatch was not fully latched, it was necessary to insert a specially-designed tool into the hatch in order to provide a hand-hold for lifting it from the command module. By this time the White Room was filling with dense, dark smoke from the command module interior and from secondary fires throughout level A-8. While some personnel were able to locate and don operable gas masks, others were not. Some proceeded without masks while others attempted without success to render masks operable. Even operable masks were unable to cope with the dense smoke present because they were designed for use in toxic rather than dense smoke atmospheres.

"Visibility in the White Room was virtually nonexistent. It was necessary to work essentially by touch since visual observation was limited to a few inches at best. A hatch removal tool was in the White Room. Once the small fire near the BPC hatch had been extinguished and the tool located, the pad leader and an assistant removed the BPC hatch. Although the hatch was not latched, removal was difficult.

"The personnel who removed the BPC hatch could not remain in the White Room because of the smoke. They left the White Room and passed the tool required to open each hatch to other individuals. A total of five individuals took part in opening the three hatches. Each were forced to make several trips to and from the White Room in order to reach breathable air." [Apollo 1: The Fire,]
"When the firefighters arrived, the positions of the crew couches and crew could be perceived through the smoke but only with difficulty. An unsuccessful attempt was made to remove the senior pilot from the command module.
 "Initial observations and subsequent inspection revealed the following facts. The command pilot’s couch (the left couch) was in the “170 degree” position, in which it was essentially horizontal throughout its length. The foot restraints and harness were released and the inlet and outlet oxygen hoses were connected to the suit. The electrical adapter cable was disconnected from the communications cable. The command pilot was lying supine on the aft bulkhead or floor of the command module, with his helmet visor closed and locked and with his head beneath the pilot’s head rest and his feet on his own couch. A fragment of his suit material was found outside the command module pressure vessel five feet from the point of rupture. This indicated that his suit had failed prior to the time of rupture (23:31:19.4 GMT), allowing convection currents to carry the suit fragment through the rupture.
 "The senior pilot’s couch (the center couch) was in the “96 degree” position in which the back portion was horizontal and the lower portion was raised. The buckle releasing the shoulder straps and lap belts was not opened. The straps and belts were burned through. The suit oxygen outlet hose was connected but the inlet hose was disconnected. The helmet visor was closed and locked and all electrical connections were intact. The senior pilot was lying transversely across the command module just below the level of the hatchway.
 "The pilot’s couch (the couch on the right) was in the “264 degree” position in which the back portion was horizontal and the lower portion dropped toward the floor. All restraints were disconnected, all hoses and electrical connections were intact and the helmet visor was closed and locked. The pilot was supine on his couch.
"From the foregoing, it was determined that the command pilot probably left his couch to avoid the initial fire, the senior pilot remained in his couch as planned for emergency egress, attempting to open the hatch until his restraints burned through. The pilot remained in his couch to maintain communications until the hatch could be opened by the senior pilot as planned. With a slightly higher pressure inside the command module than outside, opening the inner hatch was impossible because of the resulting force on the hatch. Thus the inability of the pressure relief system to cope with the pressure increase due to the fire made opening the inner hatch impossible until after cabin rupture. Following rupture, the intense and widespread fire, together with rapidly increasing carbon monoxide concentrations, further prevented egress." [Apollo 1: The Fire,]
Grissom was the command pilot, White the senior pilot, and Chaffee the pilot.

Also, "When the command module had been adequately ventilated, the doctors returned to the White Room with equipment for crew removal. It became apparent that extensive fusion of suit material to melted nylon from the spacecraft would make removal very difficult. For this reason it was decided to discontinue removal efforts in the interest of accident investigation and to photograph the command module with the crew in place before evidence was disarranged.

"Photographs were taken and the removal efforts resumed at approximately 00:30 GMT, 28 January. Removal of the crew took approximately 90 minutes and was completed about seven and one-half hours after the accident." [Apollo 1: The Fire,]

Translated, Grissom's body was found, unstrapped and out of his couch, collapsed on the deck. White was found, per his training, lying sideways on the deck next to the hatch; he had evidently tried valiantly to open it but failed. Chaffee was still strapped in, maintaining comm per his responsibility until White got the hatch open or the fire took him. All three were effectively welded into the interior by the melting of their nylon suits and umbilicals. It took nearly an hour and a half just to cut the bodies free and remove them.


Needless to say, the Apollo program went on hold while a complete redesign was performed on the Apollo capsule. This included a change to a 60/40 oxygen/nitrogen atmosphere for launch, increased safety procedures for construction, a complete change in material construction of the flight suits, and a completely redesigned hatch (already intended to be flown) which opened outward and took 10 seconds or less to open. Ironically, however, the very hatch design which nearly claimed Gus Grissom's life on the Liberty Bell 7 flight was the cause of the newer hatch design which sealed his fate in the Apollo 1 catastrophe.

Sometimes real life is stranger than anything we writers could possibly dream up.

Next week, the Challenger disaster.

-Stephanie Osborn