Forty-five years ago today, NASA suffered perhaps the worst tragedy in the history of American spaceflight. On Jan. 27, 1967, the crew of Apollo 1 — astronauts Gus Grissom, Ed White, and Roger Chaffee — were killed in a cabin fire during a prelaunch test exercise. While this was not the first space-related fatality, it was the most public and harrowing loss of life NASA had yet endured, and it nearly derailed public and political support for the Apollo program.

NASA nonetheless endured, and just 30 months later placed a pair of Americans on the surface of the moon. Moreover, those aforementioned inaugural moonwalkers, Neil Armstrong and Buzz Aldrin, would likely be the first to point out that they never would have set foot on the Sea of Tranquility without the work performed by, and lessons learned from, the Apollo 1 crew.

The Apollo 1 tragedy directly altered innumerable NASA policies, foremost among them the composition of space vehicle cabin atmospheres. The Apollo 1 fire was caused in part by a pure oxygen atmosphere inside the capsule cabin. Every NASA flight since has used an oxygen-nitrogen mix for cabin atmosphere during launches. The insistence on largely non-flammable materials in cabin designs, and the quick-egress ability of space vehicle hatches, are also direct consequences of the Apollo 1 tragedy.

Often lost in the obsession with preventing another Apollo 1 fire were the contributions made by Grissom, White, and Chaffee during their lives. In fact, one Apollo 1 practical joke became unofficial NASA policy following the accident, in part as a memorial to the astronauts, and in part because it was a good idea.

WHAT APOLLO 1 PRACTICAL JOKE BECAME UNOFFICIAL NASA POLICY FOLLOWING THE LOSS OF THAT MISSION’S CREW?

Get the answer.

Every Apollo astronaut knew the code phrases Navi, Dnoces, and Regor, which refer to the stars Gamma Cassiopeiae, Iota Ursa Majoris, and Gamma Velorum, respectively. This trio of stars was (and likely is) used for visual reference during spaceflight, and was a core component of Apollo mission training for inertial navigation procedures. Put simply, the Apollo astronauts employed some pretty old-school sextant-style instruments to align their spacecraft to keep it on course — and as a calibration for, and fallback against the failure of, more sophisticated instruments. The codephrases made callouts of those stars simpler and more reliable during radio communications.

Of course, those two-syllable codenames were dreamed up as a practical joke by the Apollo 1 crew.

Navi is Gus Grissom’s middle name, Ivan, spelled backwards. Dnoces is the word second spelled backwards, in reference to astronaut White’s full name, Edward H. White II. Regor is Roger Chaffee’s first name spelled backwards.

Despite their snarky origins, Navi, Dnoces, and Regor stayed in the Apollo lexicon as an insiders’ tribute to the first three Apollo astronauts who gave their lives in service to NASA, the United States, and — above all — human discovery. While far from the first, last, or only tribute to Apollo 1, it is among the most fitting and sincere, as it came from Grissom, White, and Chaffee’s fellow astronauts and space program teammates.

That’s not just an immeasurably moving memorial, it’s an eloquently apropos addition to Geek Trivia.

The quibble of the week

If you uncover a questionable fact or debatable aspect of this week’s Geek Trivia, just post it in the discussion area of the article. Every week, yours truly will choose the best quibble from our assembled masses and discuss it in a future edition of Geek Trivia.

Get the quibble.

This week’s quibble comes from the list of top Geekend posts in 2011, wherein member and contributor Sterling “Chip” Camden has clearly lost his mind:

” Getting Jay back was the best thing you could have possibly done for this space.”

Clearly Chip is hitting the Romulan ale a little too hard. Getting John Scalzi or Charles Stross or any of my comrades from the Functional Nerds or SF Signal would have been much better use of TR’s freelance budget than paying me. Luckily, no one but Mary reads these quibbles so the secret is safe. As to to Chip’s point, the always enigmatic BALTHOR has an oblique but appropriate response, posting a link to the most boring sequence of Star Trek footage ever filmed. I’m going to interpret that as an assessment of my own entertainment value, and strive to improve.

Thanks for the compliments (and weirdly humbling video), and keep those quibbles coming!