Fireproofing Apollo

"Fire in the spacecraft!" is a distress call the National Aeronautics and Space Administration hopes never to hear again. In the aftermath of last January's Apollo fire, NASA is spending more than $100 million to that end. By the time Astronauts Wally Schirra, Bonn Eisele and Walter Cunningham lift off a launch pad for the first manned Apollo flight next year, their spacecraft should be virtually fireproof.

Engineers and technicians began working on fireproofing soon after the tragedy. Since then, just about every conceivable combustible has been removed from the moon-bound spacecraft. Flammable components that could not be replaced have been isolated by fire-confining barriers. "It's been an extremely difficult job," says George Low, 41, who was appointed Apollo program manager in April. "But we'll have a spacecraft in which we probably won't be able to even start a fire when we try to this winter."

Critical Changes. Strapped into the conical command module, trapped by hatches impossible to open, Virgil Grissom, Edward White and Roger Chaffee scarcely had a chance. Now Apollo has only one hatch, and it can be opened with a ratchet from inside in about five seconds. The mechanism of the new, 70-lb. hatch, which Low says can be opened "with your little finger," is assisted by a cylinder of compressed nitrogen gas. Better for escape during ground tests, the quick-opening hatch also provides easier exit and re-entry during operations outside the spacecraft in flight. Moreover, it assures astronauts of a simpler solution to docking or passageway problems when they return to the command module in the spacecraft designed to carry them to and from the lunar surface.

While the hatch problem was being solved, NASA and North American Aviation engineers went to work on combustible materials that had cluttered Apollo's spacecraft before the January fire. Aluminum plumbing which melted at 1080DEG F. has been replaced by stainless steel. Brazed joints that withstand temperatures approaching 1,600DEG F. have been substituted for soldered joints that melt at 360DEG F. Coolant pipelines, which service electronic components and can release flammable glycol when ruptured, have been "armor-plated" at joints with high-strength epoxy. Should the joints come open, the epoxy serves as a back-up seal. Along Apollo's 15 miles of electrical wiring, circuit-breaker panels have been fireproofed with twelve coats of Ladicote paint, newly developed by North American. Bundles of wire, previously exposed to dangerous scuffing and wear during assembly, maintenance, tests and flight, are now encased in protective metal panels that double as fire walls. In addition, such flammables as nylon nets and plastic containers have been replaced by nonflammable or fire-resistant materials like Teflon.

New Suit. Like almost everything else aboard during the January holocaust, the Gemini space suits worn by the astronauts burned, as interior temperatures rose to 1,500DEG F. To withstand such heat, the nylon outer covering of the Apollo suit has been replaced by Beta cloth--an advanced form of glass fiber produced by Owens-Corning Fiberglas Corp. Backing up the new fabric are 14 layers of fire-resistant material. Even if they were caught in an on-board inferno, the Apollo astronauts would have several minutes of protection while wearing the new suit. Big gest problem posed by the new fiber is its susceptibility to wear. For protection, the new Apollo suits are patched with tough metallic-fiber cloth at the elbows, shoulders and back.

Critical Factor. The changes have increased the total weight of the spaceship by 3,500 Ibs.--from 94,150 Ibs. to 97,650 Ibs.--including additional fuel needed for maneuvering.

This pushes Apollo to a critical launch-pad weight that is only 350 Ibs. under the Saturn 5's total lifting capacity for lunar missions. As a result, parts of Apollo's parachute system had to be enlarged or redesigned for safe landing at greater weight, and redundant systems on board have been eliminated for a weight reduction of 58 Ibs. Low hopes to peel 400 Ibs. more off Apollo by eliminating the spacecraft's lead ballast. So critical is the weight factor that even metal brackets inside Apollo are being examined for possible perforation to save additional ounces. "So far," Low said last week, "the scheme looks promising."

In effect, the modifications have made Apollo a brand new spacecraft that will have to be tested for structural integrity, vibration characteristics during liftoff, and behavior in a vacuum before it can be requalified for flight. Such testing has pushed the initial launch date for the Apollo series to early summer of next year. But this winter the spacecraft will face its baptism by fire in Houston, when NASA engineers try to set a full-scale Apollo ablaze under varied atmospheric conditions.

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